Source file src/cmd/go/internal/load/pkg.go

     1  // Copyright 2011 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  // Package load loads packages.
     6  package load
     7  
     8  import (
     9  	"bytes"
    10  	"context"
    11  	"encoding/json"
    12  	"errors"
    13  	"fmt"
    14  	"go/build"
    15  	"go/scanner"
    16  	"go/token"
    17  	"internal/godebug"
    18  	"internal/platform"
    19  	"io/fs"
    20  	"os"
    21  	pathpkg "path"
    22  	"path/filepath"
    23  	"runtime"
    24  	"runtime/debug"
    25  	"slices"
    26  	"sort"
    27  	"strconv"
    28  	"strings"
    29  	"time"
    30  	"unicode"
    31  	"unicode/utf8"
    32  
    33  	"cmd/internal/objabi"
    34  
    35  	"cmd/go/internal/base"
    36  	"cmd/go/internal/cfg"
    37  	"cmd/go/internal/fips140"
    38  	"cmd/go/internal/fsys"
    39  	"cmd/go/internal/gover"
    40  	"cmd/go/internal/imports"
    41  	"cmd/go/internal/modfetch"
    42  	"cmd/go/internal/modindex"
    43  	"cmd/go/internal/modinfo"
    44  	"cmd/go/internal/modload"
    45  	"cmd/go/internal/search"
    46  	"cmd/go/internal/str"
    47  	"cmd/go/internal/trace"
    48  	"cmd/go/internal/vcs"
    49  	"cmd/internal/par"
    50  	"cmd/internal/pathcache"
    51  	"cmd/internal/pkgpattern"
    52  
    53  	"golang.org/x/mod/modfile"
    54  	"golang.org/x/mod/module"
    55  )
    56  
    57  // A Package describes a single package found in a directory.
    58  type Package struct {
    59  	PackagePublic                 // visible in 'go list'
    60  	Internal      PackageInternal // for use inside go command only
    61  }
    62  
    63  type PackagePublic struct {
    64  	// Note: These fields are part of the go command's public API.
    65  	// See list.go. It is okay to add fields, but not to change or
    66  	// remove existing ones. Keep in sync with ../list/list.go
    67  	Dir           string                `json:",omitempty"` // directory containing package sources
    68  	ImportPath    string                `json:",omitempty"` // import path of package in dir
    69  	ImportComment string                `json:",omitempty"` // path in import comment on package statement
    70  	Name          string                `json:",omitempty"` // package name
    71  	Doc           string                `json:",omitempty"` // package documentation string
    72  	Target        string                `json:",omitempty"` // installed target for this package (may be executable)
    73  	Shlib         string                `json:",omitempty"` // the shared library that contains this package (only set when -linkshared)
    74  	Root          string                `json:",omitempty"` // Go root, Go path dir, or module root dir containing this package
    75  	ConflictDir   string                `json:",omitempty"` // Dir is hidden by this other directory
    76  	ForTest       string                `json:",omitempty"` // package is only for use in named test
    77  	Export        string                `json:",omitempty"` // file containing export data (set by go list -export)
    78  	BuildID       string                `json:",omitempty"` // build ID of the compiled package (set by go list -export)
    79  	Module        *modinfo.ModulePublic `json:",omitempty"` // info about package's module, if any
    80  	Match         []string              `json:",omitempty"` // command-line patterns matching this package
    81  	Goroot        bool                  `json:",omitempty"` // is this package found in the Go root?
    82  	Standard      bool                  `json:",omitempty"` // is this package part of the standard Go library?
    83  	DepOnly       bool                  `json:",omitempty"` // package is only as a dependency, not explicitly listed
    84  	BinaryOnly    bool                  `json:",omitempty"` // package cannot be recompiled
    85  	Incomplete    bool                  `json:",omitempty"` // was there an error loading this package or dependencies?
    86  
    87  	DefaultGODEBUG string `json:",omitempty"` // default GODEBUG setting (only for Name=="main")
    88  
    89  	// Stale and StaleReason remain here *only* for the list command.
    90  	// They are only initialized in preparation for list execution.
    91  	// The regular build determines staleness on the fly during action execution.
    92  	Stale       bool   `json:",omitempty"` // would 'go install' do anything for this package?
    93  	StaleReason string `json:",omitempty"` // why is Stale true?
    94  
    95  	// Source files
    96  	// If you add to this list you MUST add to p.AllFiles (below) too.
    97  	// Otherwise file name security lists will not apply to any new additions.
    98  	GoFiles           []string `json:",omitempty"` // .go source files (excluding CgoFiles, TestGoFiles, XTestGoFiles)
    99  	CgoFiles          []string `json:",omitempty"` // .go source files that import "C"
   100  	CompiledGoFiles   []string `json:",omitempty"` // .go output from running cgo on CgoFiles
   101  	IgnoredGoFiles    []string `json:",omitempty"` // .go source files ignored due to build constraints
   102  	InvalidGoFiles    []string `json:",omitempty"` // .go source files with detected problems (parse error, wrong package name, and so on)
   103  	IgnoredOtherFiles []string `json:",omitempty"` // non-.go source files ignored due to build constraints
   104  	CFiles            []string `json:",omitempty"` // .c source files
   105  	CXXFiles          []string `json:",omitempty"` // .cc, .cpp and .cxx source files
   106  	MFiles            []string `json:",omitempty"` // .m source files
   107  	HFiles            []string `json:",omitempty"` // .h, .hh, .hpp and .hxx source files
   108  	FFiles            []string `json:",omitempty"` // .f, .F, .for and .f90 Fortran source files
   109  	SFiles            []string `json:",omitempty"` // .s source files
   110  	SwigFiles         []string `json:",omitempty"` // .swig files
   111  	SwigCXXFiles      []string `json:",omitempty"` // .swigcxx files
   112  	SysoFiles         []string `json:",omitempty"` // .syso system object files added to package
   113  
   114  	// Embedded files
   115  	EmbedPatterns []string `json:",omitempty"` // //go:embed patterns
   116  	EmbedFiles    []string `json:",omitempty"` // files matched by EmbedPatterns
   117  
   118  	// Cgo directives
   119  	CgoCFLAGS    []string `json:",omitempty"` // cgo: flags for C compiler
   120  	CgoCPPFLAGS  []string `json:",omitempty"` // cgo: flags for C preprocessor
   121  	CgoCXXFLAGS  []string `json:",omitempty"` // cgo: flags for C++ compiler
   122  	CgoFFLAGS    []string `json:",omitempty"` // cgo: flags for Fortran compiler
   123  	CgoLDFLAGS   []string `json:",omitempty"` // cgo: flags for linker
   124  	CgoPkgConfig []string `json:",omitempty"` // cgo: pkg-config names
   125  
   126  	// Dependency information
   127  	Imports   []string          `json:",omitempty"` // import paths used by this package
   128  	ImportMap map[string]string `json:",omitempty"` // map from source import to ImportPath (identity entries omitted)
   129  	Deps      []string          `json:",omitempty"` // all (recursively) imported dependencies
   130  
   131  	// Error information
   132  	// Incomplete is above, packed into the other bools
   133  	Error      *PackageError   `json:",omitempty"` // error loading this package (not dependencies)
   134  	DepsErrors []*PackageError `json:",omitempty"` // errors loading dependencies, collected by go list before output
   135  
   136  	// Test information
   137  	// If you add to this list you MUST add to p.AllFiles (below) too.
   138  	// Otherwise file name security lists will not apply to any new additions.
   139  	TestGoFiles        []string `json:",omitempty"` // _test.go files in package
   140  	TestImports        []string `json:",omitempty"` // imports from TestGoFiles
   141  	TestEmbedPatterns  []string `json:",omitempty"` // //go:embed patterns
   142  	TestEmbedFiles     []string `json:",omitempty"` // files matched by TestEmbedPatterns
   143  	XTestGoFiles       []string `json:",omitempty"` // _test.go files outside package
   144  	XTestImports       []string `json:",omitempty"` // imports from XTestGoFiles
   145  	XTestEmbedPatterns []string `json:",omitempty"` // //go:embed patterns
   146  	XTestEmbedFiles    []string `json:",omitempty"` // files matched by XTestEmbedPatterns
   147  }
   148  
   149  // AllFiles returns the names of all the files considered for the package.
   150  // This is used for sanity and security checks, so we include all files,
   151  // even IgnoredGoFiles, because some subcommands consider them.
   152  // The go/build package filtered others out (like foo_wrongGOARCH.s)
   153  // and that's OK.
   154  func (p *Package) AllFiles() []string {
   155  	files := str.StringList(
   156  		p.GoFiles,
   157  		p.CgoFiles,
   158  		// no p.CompiledGoFiles, because they are from GoFiles or generated by us
   159  		p.IgnoredGoFiles,
   160  		// no p.InvalidGoFiles, because they are from GoFiles
   161  		p.IgnoredOtherFiles,
   162  		p.CFiles,
   163  		p.CXXFiles,
   164  		p.MFiles,
   165  		p.HFiles,
   166  		p.FFiles,
   167  		p.SFiles,
   168  		p.SwigFiles,
   169  		p.SwigCXXFiles,
   170  		p.SysoFiles,
   171  		p.TestGoFiles,
   172  		p.XTestGoFiles,
   173  	)
   174  
   175  	// EmbedFiles may overlap with the other files.
   176  	// Dedup, but delay building the map as long as possible.
   177  	// Only files in the current directory (no slash in name)
   178  	// need to be checked against the files variable above.
   179  	var have map[string]bool
   180  	for _, file := range p.EmbedFiles {
   181  		if !strings.Contains(file, "/") {
   182  			if have == nil {
   183  				have = make(map[string]bool)
   184  				for _, file := range files {
   185  					have[file] = true
   186  				}
   187  			}
   188  			if have[file] {
   189  				continue
   190  			}
   191  		}
   192  		files = append(files, file)
   193  	}
   194  	return files
   195  }
   196  
   197  // Desc returns the package "description", for use in b.showOutput.
   198  func (p *Package) Desc() string {
   199  	if p.ForTest != "" {
   200  		return p.ImportPath + " [" + p.ForTest + ".test]"
   201  	}
   202  	if p.Internal.ForMain != "" {
   203  		return p.ImportPath + " [" + p.Internal.ForMain + "]"
   204  	}
   205  	return p.ImportPath
   206  }
   207  
   208  // IsTestOnly reports whether p is a test-only package.
   209  //
   210  // A “test-only” package is one that:
   211  //   - is a test-only variant of an ordinary package, or
   212  //   - is a synthesized "main" package for a test binary, or
   213  //   - contains only _test.go files.
   214  func (p *Package) IsTestOnly() bool {
   215  	return p.ForTest != "" ||
   216  		p.Internal.TestmainGo != nil ||
   217  		len(p.TestGoFiles)+len(p.XTestGoFiles) > 0 && len(p.GoFiles)+len(p.CgoFiles) == 0
   218  }
   219  
   220  type PackageInternal struct {
   221  	// Unexported fields are not part of the public API.
   222  	Build             *build.Package
   223  	Imports           []*Package          // this package's direct imports
   224  	CompiledImports   []string            // additional Imports necessary when using CompiledGoFiles (all from standard library); 1:1 with the end of PackagePublic.Imports
   225  	RawImports        []string            // this package's original imports as they appear in the text of the program; 1:1 with the end of PackagePublic.Imports
   226  	ForceLibrary      bool                // this package is a library (even if named "main")
   227  	CmdlineFiles      bool                // package built from files listed on command line
   228  	CmdlinePkg        bool                // package listed on command line
   229  	CmdlinePkgLiteral bool                // package listed as literal on command line (not via wildcard)
   230  	Local             bool                // imported via local path (./ or ../)
   231  	LocalPrefix       string              // interpret ./ and ../ imports relative to this prefix
   232  	ExeName           string              // desired name for temporary executable
   233  	FuzzInstrument    bool                // package should be instrumented for fuzzing
   234  	Cover             CoverSetup          // coverage mode and other setup info of -cover is being applied to this package
   235  	OmitDebug         bool                // tell linker not to write debug information
   236  	GobinSubdir       bool                // install target would be subdir of GOBIN
   237  	BuildInfo         *debug.BuildInfo    // add this info to package main
   238  	TestmainGo        *[]byte             // content for _testmain.go
   239  	Embed             map[string][]string // //go:embed comment mapping
   240  	OrigImportPath    string              // original import path before adding '_test' suffix
   241  	PGOProfile        string              // path to PGO profile
   242  	ForMain           string              // the main package if this package is built specifically for it
   243  
   244  	Asmflags   []string // -asmflags for this package
   245  	Gcflags    []string // -gcflags for this package
   246  	Ldflags    []string // -ldflags for this package
   247  	Gccgoflags []string // -gccgoflags for this package
   248  }
   249  
   250  // A NoGoError indicates that no Go files for the package were applicable to the
   251  // build for that package.
   252  //
   253  // That may be because there were no files whatsoever, or because all files were
   254  // excluded, or because all non-excluded files were test sources.
   255  type NoGoError struct {
   256  	Package *Package
   257  }
   258  
   259  func (e *NoGoError) Error() string {
   260  	if len(e.Package.IgnoredGoFiles) > 0 {
   261  		// Go files exist, but they were ignored due to build constraints.
   262  		return "build constraints exclude all Go files in " + e.Package.Dir
   263  	}
   264  	if len(e.Package.TestGoFiles)+len(e.Package.XTestGoFiles) > 0 {
   265  		// Test Go files exist, but we're not interested in them.
   266  		// The double-negative is unfortunate but we want e.Package.Dir
   267  		// to appear at the end of error message.
   268  		return "no non-test Go files in " + e.Package.Dir
   269  	}
   270  	return "no Go files in " + e.Package.Dir
   271  }
   272  
   273  // setLoadPackageDataError presents an error found when loading package data
   274  // as a *PackageError. It has special cases for some common errors to improve
   275  // messages shown to users and reduce redundancy.
   276  //
   277  // setLoadPackageDataError returns true if it's safe to load information about
   278  // imported packages, for example, if there was a parse error loading imports
   279  // in one file, but other files are okay.
   280  func (p *Package) setLoadPackageDataError(err error, path string, stk *ImportStack, importPos []token.Position) {
   281  	matchErr, isMatchErr := err.(*search.MatchError)
   282  	if isMatchErr && matchErr.Match.Pattern() == path {
   283  		if matchErr.Match.IsLiteral() {
   284  			// The error has a pattern has a pattern similar to the import path.
   285  			// It may be slightly different (./foo matching example.com/foo),
   286  			// but close enough to seem redundant.
   287  			// Unwrap the error so we don't show the pattern.
   288  			err = matchErr.Err
   289  		}
   290  	}
   291  
   292  	// Replace (possibly wrapped) *build.NoGoError with *load.NoGoError.
   293  	// The latter is more specific about the cause.
   294  	nogoErr, ok := errors.AsType[*build.NoGoError](err)
   295  	if ok {
   296  		if p.Dir == "" && nogoErr.Dir != "" {
   297  			p.Dir = nogoErr.Dir
   298  		}
   299  		err = &NoGoError{Package: p}
   300  	}
   301  
   302  	// Take only the first error from a scanner.ErrorList. PackageError only
   303  	// has room for one position, so we report the first error with a position
   304  	// instead of all of the errors without a position.
   305  	var pos string
   306  	var isScanErr bool
   307  	if scanErr, ok := err.(scanner.ErrorList); ok && len(scanErr) > 0 {
   308  		isScanErr = true // For stack push/pop below.
   309  
   310  		scanPos := scanErr[0].Pos
   311  		scanPos.Filename = base.ShortPath(scanPos.Filename)
   312  		pos = scanPos.String()
   313  		err = errors.New(scanErr[0].Msg)
   314  	}
   315  
   316  	// Report the error on the importing package if the problem is with the import declaration
   317  	// for example, if the package doesn't exist or if the import path is malformed.
   318  	// On the other hand, don't include a position if the problem is with the imported package,
   319  	// for example there are no Go files (NoGoError), or there's a problem in the imported
   320  	// package's source files themselves (scanner errors).
   321  	//
   322  	// TODO(matloob): Perhaps make each of those the errors in the first group
   323  	// (including modload.ImportMissingError, ImportMissingSumError, and the
   324  	// corresponding "cannot find package %q in any of" GOPATH-mode error
   325  	// produced in build.(*Context).Import; modload.AmbiguousImportError,
   326  	// and modload.PackageNotInModuleError; and the malformed module path errors
   327  	// produced in golang.org/x/mod/module.CheckMod) implement an interface
   328  	// to make it easier to check for them? That would save us from having to
   329  	// move the modload errors into this package to avoid a package import cycle,
   330  	// and from having to export an error type for the errors produced in build.
   331  	if !isMatchErr && (nogoErr != nil || isScanErr) {
   332  		stk.Push(ImportInfo{Pkg: path, Pos: extractFirstImport(importPos)})
   333  		defer stk.Pop()
   334  	}
   335  
   336  	p.Error = &PackageError{
   337  		ImportStack: stk.Copy(),
   338  		Pos:         pos,
   339  		Err:         err,
   340  	}
   341  	p.Incomplete = true
   342  
   343  	top, ok := stk.Top()
   344  	if ok && path != top.Pkg {
   345  		p.Error.setPos(importPos)
   346  	}
   347  }
   348  
   349  // Resolve returns the resolved version of imports,
   350  // which should be p.TestImports or p.XTestImports, NOT p.Imports.
   351  // The imports in p.TestImports and p.XTestImports are not recursively
   352  // loaded during the initial load of p, so they list the imports found in
   353  // the source file, but most processing should be over the vendor-resolved
   354  // import paths. We do this resolution lazily both to avoid file system work
   355  // and because the eventual real load of the test imports (during 'go test')
   356  // can produce better error messages if it starts with the original paths.
   357  // The initial load of p loads all the non-test imports and rewrites
   358  // the vendored paths, so nothing should ever call p.vendored(p.Imports).
   359  func (p *Package) Resolve(s *modload.State, imports []string) []string {
   360  	if len(imports) > 0 && len(p.Imports) > 0 && &imports[0] == &p.Imports[0] {
   361  		panic("internal error: p.Resolve(p.Imports) called")
   362  	}
   363  	seen := make(map[string]bool)
   364  	var all []string
   365  	for _, path := range imports {
   366  		path = ResolveImportPath(s, p, path)
   367  		if !seen[path] {
   368  			seen[path] = true
   369  			all = append(all, path)
   370  		}
   371  	}
   372  	sort.Strings(all)
   373  	return all
   374  }
   375  
   376  // CoverSetup holds parameters related to coverage setup for a given package (covermode, etc).
   377  type CoverSetup struct {
   378  	Mode    string // coverage mode for this package
   379  	Cfg     string // path to config file to pass to "go tool cover"
   380  	GenMeta bool   // ask cover tool to emit a static meta data if set
   381  }
   382  
   383  func (p *Package) copyBuild(opts PackageOpts, pp *build.Package) {
   384  	p.Internal.Build = pp
   385  
   386  	if pp.PkgTargetRoot != "" && cfg.BuildPkgdir != "" {
   387  		old := pp.PkgTargetRoot
   388  		pp.PkgRoot = cfg.BuildPkgdir
   389  		pp.PkgTargetRoot = cfg.BuildPkgdir
   390  		if pp.PkgObj != "" {
   391  			pp.PkgObj = filepath.Join(cfg.BuildPkgdir, strings.TrimPrefix(pp.PkgObj, old))
   392  		}
   393  	}
   394  
   395  	p.Dir = pp.Dir
   396  	p.ImportPath = pp.ImportPath
   397  	p.ImportComment = pp.ImportComment
   398  	p.Name = pp.Name
   399  	p.Doc = pp.Doc
   400  	p.Root = pp.Root
   401  	p.ConflictDir = pp.ConflictDir
   402  	p.BinaryOnly = pp.BinaryOnly
   403  
   404  	// TODO? Target
   405  	p.Goroot = pp.Goroot || fips140.Snapshot() && str.HasFilePathPrefix(p.Dir, fips140.Dir())
   406  	p.Standard = p.Goroot && p.ImportPath != "" && search.IsStandardImportPath(p.ImportPath)
   407  	p.GoFiles = pp.GoFiles
   408  	p.CgoFiles = pp.CgoFiles
   409  	p.IgnoredGoFiles = pp.IgnoredGoFiles
   410  	p.InvalidGoFiles = pp.InvalidGoFiles
   411  	p.IgnoredOtherFiles = pp.IgnoredOtherFiles
   412  	p.CFiles = pp.CFiles
   413  	p.CXXFiles = pp.CXXFiles
   414  	p.MFiles = pp.MFiles
   415  	p.HFiles = pp.HFiles
   416  	p.FFiles = pp.FFiles
   417  	p.SFiles = pp.SFiles
   418  	p.SwigFiles = pp.SwigFiles
   419  	p.SwigCXXFiles = pp.SwigCXXFiles
   420  	p.SysoFiles = pp.SysoFiles
   421  	if cfg.BuildMSan {
   422  		// There's no way for .syso files to be built both with and without
   423  		// support for memory sanitizer. Assume they are built without,
   424  		// and drop them.
   425  		p.SysoFiles = nil
   426  	}
   427  	p.CgoCFLAGS = pp.CgoCFLAGS
   428  	p.CgoCPPFLAGS = pp.CgoCPPFLAGS
   429  	p.CgoCXXFLAGS = pp.CgoCXXFLAGS
   430  	p.CgoFFLAGS = pp.CgoFFLAGS
   431  	p.CgoLDFLAGS = pp.CgoLDFLAGS
   432  	p.CgoPkgConfig = pp.CgoPkgConfig
   433  	// We modify p.Imports in place, so make copy now.
   434  	p.Imports = make([]string, len(pp.Imports))
   435  	copy(p.Imports, pp.Imports)
   436  	p.Internal.RawImports = pp.Imports
   437  	p.TestGoFiles = pp.TestGoFiles
   438  	p.TestImports = pp.TestImports
   439  	p.XTestGoFiles = pp.XTestGoFiles
   440  	p.XTestImports = pp.XTestImports
   441  	if opts.IgnoreImports {
   442  		p.Imports = nil
   443  		p.Internal.RawImports = nil
   444  		p.TestImports = nil
   445  		p.XTestImports = nil
   446  	}
   447  	p.EmbedPatterns = pp.EmbedPatterns
   448  	p.TestEmbedPatterns = pp.TestEmbedPatterns
   449  	p.XTestEmbedPatterns = pp.XTestEmbedPatterns
   450  	p.Internal.OrigImportPath = pp.ImportPath
   451  }
   452  
   453  // A PackageError describes an error loading information about a package.
   454  type PackageError struct {
   455  	ImportStack      ImportStack // shortest path from package named on command line to this one with position
   456  	Pos              string      // position of error
   457  	Err              error       // the error itself
   458  	IsImportCycle    bool        // the error is an import cycle
   459  	alwaysPrintStack bool        // whether to always print the ImportStack
   460  }
   461  
   462  func (p *PackageError) Error() string {
   463  	// TODO(#43696): decide when to print the stack or the position based on
   464  	// the error type and whether the package is in the main module.
   465  	// Document the rationale.
   466  	if p.Pos != "" && (len(p.ImportStack) == 0 || !p.alwaysPrintStack) {
   467  		// Omit import stack. The full path to the file where the error
   468  		// is the most important thing.
   469  		return p.Pos + ": " + p.Err.Error()
   470  	}
   471  
   472  	// If the error is an ImportPathError, and the last path on the stack appears
   473  	// in the error message, omit that path from the stack to avoid repetition.
   474  	// If an ImportPathError wraps another ImportPathError that matches the
   475  	// last path on the stack, we don't omit the path. An error like
   476  	// "package A imports B: error loading C caused by B" would not be clearer
   477  	// if "imports B" were omitted.
   478  	if len(p.ImportStack) == 0 {
   479  		return p.Err.Error()
   480  	}
   481  	var optpos string
   482  	if p.Pos != "" {
   483  		optpos = "\n\t" + p.Pos
   484  	}
   485  	imports := p.ImportStack.Pkgs()
   486  	if p.IsImportCycle {
   487  		imports = p.ImportStack.PkgsWithPos()
   488  	}
   489  	return "package " + strings.Join(imports, "\n\timports ") + optpos + ": " + p.Err.Error()
   490  }
   491  
   492  func (p *PackageError) Unwrap() error { return p.Err }
   493  
   494  // PackageError implements MarshalJSON so that Err is marshaled as a string
   495  // and non-essential fields are omitted.
   496  func (p *PackageError) MarshalJSON() ([]byte, error) {
   497  	perr := struct {
   498  		ImportStack []string // use []string for package names
   499  		Pos         string
   500  		Err         string
   501  	}{p.ImportStack.Pkgs(), p.Pos, p.Err.Error()}
   502  	return json.Marshal(perr)
   503  }
   504  
   505  func (p *PackageError) setPos(posList []token.Position) {
   506  	if len(posList) == 0 {
   507  		return
   508  	}
   509  	pos := posList[0]
   510  	pos.Filename = base.ShortPath(pos.Filename)
   511  	p.Pos = pos.String()
   512  }
   513  
   514  // ImportPathError is a type of error that prevents a package from being loaded
   515  // for a given import path. When such a package is loaded, a *Package is
   516  // returned with Err wrapping an ImportPathError: the error is attached to
   517  // the imported package, not the importing package.
   518  //
   519  // The string returned by ImportPath must appear in the string returned by
   520  // Error. Errors that wrap ImportPathError (such as PackageError) may omit
   521  // the import path.
   522  type ImportPathError interface {
   523  	error
   524  	ImportPath() string
   525  }
   526  
   527  var (
   528  	_ ImportPathError = (*importError)(nil)
   529  	_ ImportPathError = (*mainPackageError)(nil)
   530  	_ ImportPathError = (*modload.ImportMissingError)(nil)
   531  	_ ImportPathError = (*modload.ImportMissingSumError)(nil)
   532  	_ ImportPathError = (*modload.DirectImportFromImplicitDependencyError)(nil)
   533  )
   534  
   535  type importError struct {
   536  	importPath string
   537  	err        error // created with fmt.Errorf
   538  }
   539  
   540  func ImportErrorf(path, format string, args ...any) ImportPathError {
   541  	err := &importError{importPath: path, err: fmt.Errorf(format, args...)}
   542  	if errStr := err.Error(); !strings.Contains(errStr, path) && !strings.Contains(errStr, strconv.Quote(path)) {
   543  		panic(fmt.Sprintf("path %q not in error %q", path, errStr))
   544  	}
   545  	return err
   546  }
   547  
   548  func (e *importError) Error() string {
   549  	return e.err.Error()
   550  }
   551  
   552  func (e *importError) Unwrap() error {
   553  	// Don't return e.err directly, since we're only wrapping an error if %w
   554  	// was passed to ImportErrorf.
   555  	return errors.Unwrap(e.err)
   556  }
   557  
   558  func (e *importError) ImportPath() string {
   559  	return e.importPath
   560  }
   561  
   562  type ImportInfo struct {
   563  	Pkg string
   564  	Pos *token.Position
   565  }
   566  
   567  // An ImportStack is a stack of import paths, possibly with the suffix " (test)" appended.
   568  // The import path of a test package is the import path of the corresponding
   569  // non-test package with the suffix "_test" added.
   570  type ImportStack []ImportInfo
   571  
   572  func NewImportInfo(pkg string, pos *token.Position) ImportInfo {
   573  	return ImportInfo{Pkg: pkg, Pos: pos}
   574  }
   575  
   576  func (s *ImportStack) Push(p ImportInfo) {
   577  	*s = append(*s, p)
   578  }
   579  
   580  func (s *ImportStack) Pop() {
   581  	*s = (*s)[0 : len(*s)-1]
   582  }
   583  
   584  func (s *ImportStack) Copy() ImportStack {
   585  	return slices.Clone(*s)
   586  }
   587  
   588  func (s *ImportStack) Pkgs() []string {
   589  	ss := make([]string, 0, len(*s))
   590  	for _, v := range *s {
   591  		ss = append(ss, v.Pkg)
   592  	}
   593  	return ss
   594  }
   595  
   596  func (s *ImportStack) PkgsWithPos() []string {
   597  	ss := make([]string, 0, len(*s))
   598  	for _, v := range *s {
   599  		if v.Pos != nil {
   600  			ss = append(ss, v.Pkg+" from "+filepath.Base(v.Pos.Filename))
   601  		} else {
   602  			ss = append(ss, v.Pkg)
   603  		}
   604  	}
   605  	return ss
   606  }
   607  
   608  func (s *ImportStack) Top() (ImportInfo, bool) {
   609  	if len(*s) == 0 {
   610  		return ImportInfo{}, false
   611  	}
   612  	return (*s)[len(*s)-1], true
   613  }
   614  
   615  // shorterThan reports whether sp is shorter than t.
   616  // We use this to record the shortest import sequence
   617  // that leads to a particular package.
   618  func (sp *ImportStack) shorterThan(t []string) bool {
   619  	s := *sp
   620  	if len(s) != len(t) {
   621  		return len(s) < len(t)
   622  	}
   623  	// If they are the same length, settle ties using string ordering.
   624  	for i := range s {
   625  		siPkg := s[i].Pkg
   626  		if siPkg != t[i] {
   627  			return siPkg < t[i]
   628  		}
   629  	}
   630  	return false // they are equal
   631  }
   632  
   633  // packageCache is a lookup cache for LoadImport,
   634  // so that if we look up a package multiple times
   635  // we return the same pointer each time.
   636  var packageCache = map[string]*Package{}
   637  
   638  // dirToImportPath returns the pseudo-import path we use for a package
   639  // outside the Go path. It begins with _/ and then contains the full path
   640  // to the directory. If the package lives in c:\home\gopher\my\pkg then
   641  // the pseudo-import path is _/c_/home/gopher/my/pkg.
   642  // Using a pseudo-import path like this makes the ./ imports no longer
   643  // a special case, so that all the code to deal with ordinary imports works
   644  // automatically.
   645  func dirToImportPath(dir string) string {
   646  	return pathpkg.Join("_", strings.Map(makeImportValid, filepath.ToSlash(dir)))
   647  }
   648  
   649  func makeImportValid(r rune) rune {
   650  	// Should match Go spec, compilers, and ../../go/parser/parser.go:/isValidImport.
   651  	const illegalChars = `!"#$%&'()*,:;<=>?[\]^{|}` + "`\uFFFD"
   652  	if !unicode.IsGraphic(r) || unicode.IsSpace(r) || strings.ContainsRune(illegalChars, r) {
   653  		return '_'
   654  	}
   655  	return r
   656  }
   657  
   658  // Mode flags for loadImport and download (in get.go).
   659  const (
   660  	// ResolveImport means that loadImport should do import path expansion.
   661  	// That is, ResolveImport means that the import path came from
   662  	// a source file and has not been expanded yet to account for
   663  	// vendoring or possible module adjustment.
   664  	// Every import path should be loaded initially with ResolveImport,
   665  	// and then the expanded version (for example with the /vendor/ in it)
   666  	// gets recorded as the canonical import path. At that point, future loads
   667  	// of that package must not pass ResolveImport, because
   668  	// disallowVendor will reject direct use of paths containing /vendor/.
   669  	ResolveImport = 1 << iota
   670  
   671  	// ResolveModule is for download (part of "go get") and indicates
   672  	// that the module adjustment should be done, but not vendor adjustment.
   673  	ResolveModule
   674  
   675  	// GetTestDeps is for download (part of "go get") and indicates
   676  	// that test dependencies should be fetched too.
   677  	GetTestDeps
   678  
   679  	// The remainder are internal modes for calls to loadImport.
   680  
   681  	// cmdlinePkg is for a package mentioned on the command line.
   682  	cmdlinePkg
   683  
   684  	// cmdlinePkgLiteral is for a package mentioned on the command line
   685  	// without using any wildcards or meta-patterns.
   686  	cmdlinePkgLiteral
   687  )
   688  
   689  // LoadPackage does Load import, but without a parent package load context
   690  func LoadPackage(loaderstate *modload.State, ctx context.Context, opts PackageOpts, path, srcDir string, stk *ImportStack, importPos []token.Position, mode int) *Package {
   691  	p, err := loadImport(loaderstate, ctx, opts, nil, path, srcDir, nil, stk, importPos, mode)
   692  	if err != nil {
   693  		base.Fatalf("internal error: loadImport of %q with nil parent returned an error", path)
   694  	}
   695  	return p
   696  }
   697  
   698  // loadImport scans the directory named by path, which must be an import path,
   699  // but possibly a local import path (an absolute file system path or one beginning
   700  // with ./ or ../). A local relative path is interpreted relative to srcDir.
   701  // It returns a *Package describing the package found in that directory.
   702  // loadImport does not set tool flags and should only be used by
   703  // this package, as part of a bigger load operation.
   704  // The returned PackageError, if any, describes why parent is not allowed
   705  // to import the named package, with the error referring to importPos.
   706  // The PackageError can only be non-nil when parent is not nil.
   707  func loadImport(loaderstate *modload.State, ctx context.Context, opts PackageOpts, pre *preload, path, srcDir string, parent *Package, stk *ImportStack, importPos []token.Position, mode int) (*Package, *PackageError) {
   708  	ctx, span := trace.StartSpan(ctx, "modload.loadImport "+path)
   709  	defer span.Done()
   710  
   711  	if path == "" {
   712  		panic("LoadImport called with empty package path")
   713  	}
   714  
   715  	var parentPath, parentRoot string
   716  	parentIsStd := false
   717  	if parent != nil {
   718  		parentPath = parent.ImportPath
   719  		parentRoot = parent.Root
   720  		parentIsStd = parent.Standard
   721  	}
   722  	bp, loaded, err := loadPackageData(loaderstate, ctx, path, parentPath, srcDir, parentRoot, parentIsStd, mode)
   723  	if loaded && pre != nil && !opts.IgnoreImports {
   724  		pre.preloadImports(loaderstate, ctx, opts, bp.Imports, bp)
   725  	}
   726  	if bp == nil {
   727  		p := &Package{
   728  			PackagePublic: PackagePublic{
   729  				ImportPath: path,
   730  				Incomplete: true,
   731  			},
   732  		}
   733  		if importErr, ok := err.(ImportPathError); !ok || importErr.ImportPath() != path {
   734  			// Only add path to the error's import stack if it's not already present
   735  			// in the error.
   736  			//
   737  			// TODO(bcmills): setLoadPackageDataError itself has a similar Push / Pop
   738  			// sequence that empirically doesn't trigger for these errors, guarded by
   739  			// a somewhat complex condition. Figure out how to generalize that
   740  			// condition and eliminate the explicit calls here.
   741  			stk.Push(ImportInfo{Pkg: path, Pos: extractFirstImport(importPos)})
   742  			defer stk.Pop()
   743  		}
   744  		p.setLoadPackageDataError(err, path, stk, nil)
   745  		return p, nil
   746  	}
   747  
   748  	setCmdline := func(p *Package) {
   749  		if mode&cmdlinePkg != 0 {
   750  			p.Internal.CmdlinePkg = true
   751  		}
   752  		if mode&cmdlinePkgLiteral != 0 {
   753  			p.Internal.CmdlinePkgLiteral = true
   754  		}
   755  	}
   756  
   757  	importPath := bp.ImportPath
   758  	p := packageCache[importPath]
   759  	if p != nil {
   760  		stk.Push(ImportInfo{Pkg: path, Pos: extractFirstImport(importPos)})
   761  		p = reusePackage(p, stk)
   762  		stk.Pop()
   763  		setCmdline(p)
   764  	} else {
   765  		p = new(Package)
   766  		p.Internal.Local = build.IsLocalImport(path)
   767  		p.ImportPath = importPath
   768  		packageCache[importPath] = p
   769  
   770  		setCmdline(p)
   771  
   772  		// Load package.
   773  		// loadPackageData may return bp != nil even if an error occurs,
   774  		// in order to return partial information.
   775  		p.load(loaderstate, ctx, opts, path, stk, importPos, bp, err)
   776  
   777  		if !cfg.ModulesEnabled && path != cleanImport(path) {
   778  			p.Error = &PackageError{
   779  				ImportStack: stk.Copy(),
   780  				Err:         ImportErrorf(path, "non-canonical import path %q: should be %q", path, pathpkg.Clean(path)),
   781  			}
   782  			p.Incomplete = true
   783  			p.Error.setPos(importPos)
   784  		}
   785  	}
   786  
   787  	// Checked on every import because the rules depend on the code doing the importing.
   788  	if perr := disallowInternal(loaderstate, ctx, srcDir, parent, parentPath, p, stk); perr != nil {
   789  		perr.setPos(importPos)
   790  		return p, perr
   791  	}
   792  	if mode&ResolveImport != 0 {
   793  		if perr := disallowVendor(srcDir, path, parentPath, p, stk); perr != nil {
   794  			perr.setPos(importPos)
   795  			return p, perr
   796  		}
   797  	}
   798  
   799  	if p.Name == "main" && parent != nil && parent.Dir != p.Dir {
   800  		perr := &PackageError{
   801  			ImportStack: stk.Copy(),
   802  			Err:         ImportErrorf(path, "import %q is a program, not an importable package", path),
   803  		}
   804  		perr.setPos(importPos)
   805  		return p, perr
   806  	}
   807  
   808  	if p.Internal.Local && parent != nil && !parent.Internal.Local {
   809  		var err error
   810  		if path == "." {
   811  			err = ImportErrorf(path, "%s: cannot import current directory", path)
   812  		} else {
   813  			err = ImportErrorf(path, "local import %q in non-local package", path)
   814  		}
   815  		perr := &PackageError{
   816  			ImportStack: stk.Copy(),
   817  			Err:         err,
   818  		}
   819  		perr.setPos(importPos)
   820  		return p, perr
   821  	}
   822  
   823  	return p, nil
   824  }
   825  
   826  func extractFirstImport(importPos []token.Position) *token.Position {
   827  	if len(importPos) == 0 {
   828  		return nil
   829  	}
   830  	return &importPos[0]
   831  }
   832  
   833  // loadPackageData loads information needed to construct a *Package. The result
   834  // is cached, and later calls to loadPackageData for the same package will return
   835  // the same data.
   836  //
   837  // loadPackageData returns a non-nil package even if err is non-nil unless
   838  // the package path is malformed (for example, the path contains "mod/" or "@").
   839  //
   840  // loadPackageData returns a boolean, loaded, which is true if this is the
   841  // first time the package was loaded. Callers may preload imports in this case.
   842  func loadPackageData(loaderstate *modload.State, ctx context.Context, path, parentPath, parentDir, parentRoot string, parentIsStd bool, mode int) (bp *build.Package, loaded bool, err error) {
   843  	ctx, span := trace.StartSpan(ctx, "load.loadPackageData "+path)
   844  	defer span.Done()
   845  
   846  	if path == "" {
   847  		panic("loadPackageData called with empty package path")
   848  	}
   849  
   850  	if strings.HasPrefix(path, "mod/") {
   851  		// Paths beginning with "mod/" might accidentally
   852  		// look in the module cache directory tree in $GOPATH/pkg/mod/.
   853  		// This prefix is owned by the Go core for possible use in the
   854  		// standard library (since it does not begin with a domain name),
   855  		// so it's OK to disallow entirely.
   856  		return nil, false, fmt.Errorf("disallowed import path %q", path)
   857  	}
   858  
   859  	if strings.Contains(path, "@") {
   860  		return nil, false, errors.New("can only use path@version syntax with 'go get' and 'go install' in module-aware mode")
   861  	}
   862  
   863  	// Determine canonical package path and directory.
   864  	// For a local import the identifier is the pseudo-import path
   865  	// we create from the full directory to the package.
   866  	// Otherwise it is the usual import path.
   867  	// For vendored imports, it is the expanded form.
   868  	//
   869  	// Note that when modules are enabled, local import paths are normally
   870  	// canonicalized by modload.LoadPackages before now. However, if there's an
   871  	// error resolving a local path, it will be returned untransformed
   872  	// so that 'go list -e' reports something useful.
   873  	importKey := importSpec{
   874  		path:        path,
   875  		parentPath:  parentPath,
   876  		parentDir:   parentDir,
   877  		parentRoot:  parentRoot,
   878  		parentIsStd: parentIsStd,
   879  		mode:        mode,
   880  	}
   881  	r := resolvedImportCache.Do(importKey, func() resolvedImport {
   882  		var r resolvedImport
   883  		if newPath, dir, ok := fips140.ResolveImport(path); ok {
   884  			r.path = newPath
   885  			r.dir = dir
   886  		} else if cfg.ModulesEnabled {
   887  			r.dir, r.path, r.err = modload.Lookup(loaderstate, parentPath, parentIsStd, path)
   888  		} else if build.IsLocalImport(path) {
   889  			r.dir = filepath.Join(parentDir, path)
   890  			r.path = dirToImportPath(r.dir)
   891  		} else if mode&ResolveImport != 0 {
   892  			// We do our own path resolution, because we want to
   893  			// find out the key to use in packageCache without the
   894  			// overhead of repeated calls to buildContext.Import.
   895  			// The code is also needed in a few other places anyway.
   896  			r.path = resolveImportPath(loaderstate, path, parentPath, parentDir, parentRoot, parentIsStd)
   897  		} else if mode&ResolveModule != 0 {
   898  			r.path = moduleImportPath(path, parentPath, parentDir, parentRoot)
   899  		}
   900  		if r.path == "" {
   901  			r.path = path
   902  		}
   903  		return r
   904  	})
   905  	// Invariant: r.path is set to the resolved import path. If the path cannot
   906  	// be resolved, r.path is set to path, the source import path.
   907  	// r.path is never empty.
   908  
   909  	// Load the package from its directory. If we already found the package's
   910  	// directory when resolving its import path, use that.
   911  	p, err := packageDataCache.Do(r.path, func() (*build.Package, error) {
   912  		loaded = true
   913  		var data struct {
   914  			p   *build.Package
   915  			err error
   916  		}
   917  		if r.dir != "" {
   918  			var buildMode build.ImportMode
   919  			buildContext := cfg.BuildContext
   920  			if !cfg.ModulesEnabled {
   921  				buildMode = build.ImportComment
   922  			} else {
   923  				buildContext.GOPATH = "" // Clear GOPATH so packages are imported as pure module packages
   924  			}
   925  			modroot := modload.PackageModRoot(loaderstate, ctx, r.path)
   926  			if modroot == "" && str.HasPathPrefix(r.dir, cfg.GOROOTsrc) {
   927  				modroot = cfg.GOROOTsrc
   928  				gorootSrcCmd := filepath.Join(cfg.GOROOTsrc, "cmd")
   929  				if str.HasPathPrefix(r.dir, gorootSrcCmd) {
   930  					modroot = gorootSrcCmd
   931  				}
   932  			}
   933  			if modroot != "" {
   934  				if rp, err := modindex.GetPackage(modroot, r.dir); err == nil {
   935  					data.p, data.err = rp.Import(cfg.BuildContext, buildMode)
   936  					goto Happy
   937  				} else if !errors.Is(err, modindex.ErrNotIndexed) {
   938  					base.Fatal(err)
   939  				}
   940  			}
   941  			data.p, data.err = buildContext.ImportDir(r.dir, buildMode)
   942  		Happy:
   943  			if cfg.ModulesEnabled {
   944  				// Override data.p.Root, since ImportDir sets it to $GOPATH, if
   945  				// the module is inside $GOPATH/src.
   946  				if info := modload.PackageModuleInfo(loaderstate, ctx, path); info != nil {
   947  					data.p.Root = info.Dir
   948  				}
   949  			}
   950  			if r.err != nil {
   951  				if data.err != nil {
   952  					// ImportDir gave us one error, and the module loader gave us another.
   953  					// We arbitrarily choose to keep the error from ImportDir because
   954  					// that's what our tests already expect, and it seems to provide a bit
   955  					// more detail in most cases.
   956  				} else if errors.Is(r.err, imports.ErrNoGo) {
   957  					// ImportDir said there were files in the package, but the module
   958  					// loader said there weren't. Which one is right?
   959  					// Without this special-case hack, the TestScript/test_vet case fails
   960  					// on the vetfail/p1 package (added in CL 83955).
   961  					// Apparently, imports.ShouldBuild biases toward rejecting files
   962  					// with invalid build constraints, whereas ImportDir biases toward
   963  					// accepting them.
   964  					//
   965  					// TODO(#41410: Figure out how this actually ought to work and fix
   966  					// this mess).
   967  				} else {
   968  					data.err = r.err
   969  				}
   970  			}
   971  		} else if r.err != nil {
   972  			data.p = new(build.Package)
   973  			data.err = r.err
   974  		} else if cfg.ModulesEnabled && path != "unsafe" {
   975  			data.p = new(build.Package)
   976  			data.err = fmt.Errorf("unknown import path %q: internal error: module loader did not resolve import", r.path)
   977  		} else {
   978  			buildMode := build.ImportComment
   979  			if mode&ResolveImport == 0 || r.path != path {
   980  				// Not vendoring, or we already found the vendored path.
   981  				buildMode |= build.IgnoreVendor
   982  			}
   983  			data.p, data.err = cfg.BuildContext.Import(r.path, parentDir, buildMode)
   984  		}
   985  		data.p.ImportPath = r.path
   986  
   987  		// Set data.p.BinDir in cases where go/build.Context.Import
   988  		// may give us a path we don't want.
   989  		if !data.p.Goroot {
   990  			if cfg.GOBIN != "" {
   991  				data.p.BinDir = cfg.GOBIN
   992  			} else if cfg.ModulesEnabled {
   993  				data.p.BinDir = modload.BinDir(loaderstate)
   994  			}
   995  		}
   996  
   997  		if !cfg.ModulesEnabled && data.err == nil &&
   998  			data.p.ImportComment != "" && data.p.ImportComment != path &&
   999  			!strings.Contains(path, "/vendor/") && !strings.HasPrefix(path, "vendor/") {
  1000  			data.err = fmt.Errorf("code in directory %s expects import %q", data.p.Dir, data.p.ImportComment)
  1001  		}
  1002  		return data.p, data.err
  1003  	})
  1004  
  1005  	return p, loaded, err
  1006  }
  1007  
  1008  // importSpec describes an import declaration in source code. It is used as a
  1009  // cache key for resolvedImportCache.
  1010  type importSpec struct {
  1011  	path                              string
  1012  	parentPath, parentDir, parentRoot string
  1013  	parentIsStd                       bool
  1014  	mode                              int
  1015  }
  1016  
  1017  // resolvedImport holds a canonical identifier for a package. It may also contain
  1018  // a path to the package's directory and an error if one occurred. resolvedImport
  1019  // is the value type in resolvedImportCache.
  1020  type resolvedImport struct {
  1021  	path, dir string
  1022  	err       error
  1023  }
  1024  
  1025  // resolvedImportCache maps import strings to canonical package names.
  1026  var resolvedImportCache par.Cache[importSpec, resolvedImport]
  1027  
  1028  // packageDataCache maps canonical package names (string) to package metadata.
  1029  var packageDataCache par.ErrCache[string, *build.Package]
  1030  
  1031  // preloadWorkerCount is the number of concurrent goroutines that can load
  1032  // packages. Experimentally, there are diminishing returns with more than
  1033  // 4 workers. This was measured on the following machines.
  1034  //
  1035  // * MacBookPro with a 4-core Intel Core i7 CPU
  1036  // * Linux workstation with 6-core Intel Xeon CPU
  1037  // * Linux workstation with 24-core Intel Xeon CPU
  1038  //
  1039  // It is very likely (though not confirmed) that this workload is limited
  1040  // by memory bandwidth. We don't have a good way to determine the number of
  1041  // workers that would saturate the bus though, so runtime.GOMAXPROCS
  1042  // seems like a reasonable default.
  1043  var preloadWorkerCount = runtime.GOMAXPROCS(0)
  1044  
  1045  // preload holds state for managing concurrent preloading of package data.
  1046  //
  1047  // A preload should be created with newPreload before loading a large
  1048  // package graph. flush must be called when package loading is complete
  1049  // to ensure preload goroutines are no longer active. This is necessary
  1050  // because of global mutable state that cannot safely be read and written
  1051  // concurrently. In particular, packageDataCache may be cleared by "go get"
  1052  // in GOPATH mode, and modload.loaded (accessed via modload.Lookup) may be
  1053  // modified by modload.LoadPackages.
  1054  type preload struct {
  1055  	cancel chan struct{}
  1056  	sema   chan struct{}
  1057  }
  1058  
  1059  // newPreload creates a new preloader. flush must be called later to avoid
  1060  // accessing global state while it is being modified.
  1061  func newPreload() *preload {
  1062  	pre := &preload{
  1063  		cancel: make(chan struct{}),
  1064  		sema:   make(chan struct{}, preloadWorkerCount),
  1065  	}
  1066  	return pre
  1067  }
  1068  
  1069  // preloadMatches loads data for package paths matched by patterns.
  1070  // When preloadMatches returns, some packages may not be loaded yet, but
  1071  // loadPackageData and loadImport are always safe to call.
  1072  func (pre *preload) preloadMatches(loaderstate *modload.State, ctx context.Context, opts PackageOpts, matches []*search.Match) {
  1073  	for _, m := range matches {
  1074  		for _, pkg := range m.Pkgs {
  1075  			select {
  1076  			case <-pre.cancel:
  1077  				return
  1078  			case pre.sema <- struct{}{}:
  1079  				go func(pkg string) {
  1080  					mode := 0 // don't use vendoring or module import resolution
  1081  					bp, loaded, err := loadPackageData(loaderstate, ctx, pkg, "", base.Cwd(), "", false, mode)
  1082  					<-pre.sema
  1083  					if bp != nil && loaded && err == nil && !opts.IgnoreImports {
  1084  						pre.preloadImports(loaderstate, ctx, opts, bp.Imports, bp)
  1085  					}
  1086  				}(pkg)
  1087  			}
  1088  		}
  1089  	}
  1090  }
  1091  
  1092  // preloadImports queues a list of imports for preloading.
  1093  // When preloadImports returns, some packages may not be loaded yet,
  1094  // but loadPackageData and loadImport are always safe to call.
  1095  func (pre *preload) preloadImports(loaderstate *modload.State, ctx context.Context, opts PackageOpts, imports []string, parent *build.Package) {
  1096  	parentIsStd := parent.Goroot && parent.ImportPath != "" && search.IsStandardImportPath(parent.ImportPath)
  1097  	for _, path := range imports {
  1098  		if path == "C" || path == "unsafe" {
  1099  			continue
  1100  		}
  1101  		select {
  1102  		case <-pre.cancel:
  1103  			return
  1104  		case pre.sema <- struct{}{}:
  1105  			go func(path string) {
  1106  				bp, loaded, err := loadPackageData(loaderstate, ctx, path, parent.ImportPath, parent.Dir, parent.Root, parentIsStd, ResolveImport)
  1107  				<-pre.sema
  1108  				if bp != nil && loaded && err == nil && !opts.IgnoreImports {
  1109  					pre.preloadImports(loaderstate, ctx, opts, bp.Imports, bp)
  1110  				}
  1111  			}(path)
  1112  		}
  1113  	}
  1114  }
  1115  
  1116  // flush stops pending preload operations. flush blocks until preload calls to
  1117  // loadPackageData have completed. The preloader will not make any new calls
  1118  // to loadPackageData.
  1119  func (pre *preload) flush() {
  1120  	// flush is usually deferred.
  1121  	// Don't hang program waiting for workers on panic.
  1122  	if v := recover(); v != nil {
  1123  		panic(v)
  1124  	}
  1125  
  1126  	close(pre.cancel)
  1127  	for i := 0; i < preloadWorkerCount; i++ {
  1128  		pre.sema <- struct{}{}
  1129  	}
  1130  }
  1131  
  1132  func cleanImport(path string) string {
  1133  	orig := path
  1134  	path = pathpkg.Clean(path)
  1135  	if strings.HasPrefix(orig, "./") && path != ".." && !strings.HasPrefix(path, "../") {
  1136  		path = "./" + path
  1137  	}
  1138  	return path
  1139  }
  1140  
  1141  var isDirCache par.Cache[string, bool]
  1142  
  1143  func isDir(path string) bool {
  1144  	return isDirCache.Do(path, func() bool {
  1145  		fi, err := fsys.Stat(path)
  1146  		return err == nil && fi.IsDir()
  1147  	})
  1148  }
  1149  
  1150  // ResolveImportPath returns the true meaning of path when it appears in parent.
  1151  // There are two different resolutions applied.
  1152  // First, there is Go 1.5 vendoring (golang.org/s/go15vendor).
  1153  // If vendor expansion doesn't trigger, then the path is also subject to
  1154  // Go 1.11 module legacy conversion (golang.org/issue/25069).
  1155  func ResolveImportPath(s *modload.State, parent *Package, path string) (found string) {
  1156  	var parentPath, parentDir, parentRoot string
  1157  	parentIsStd := false
  1158  	if parent != nil {
  1159  		parentPath = parent.ImportPath
  1160  		parentDir = parent.Dir
  1161  		parentRoot = parent.Root
  1162  		parentIsStd = parent.Standard
  1163  	}
  1164  	return resolveImportPath(s, path, parentPath, parentDir, parentRoot, parentIsStd)
  1165  }
  1166  
  1167  func resolveImportPath(s *modload.State, path, parentPath, parentDir, parentRoot string, parentIsStd bool) (found string) {
  1168  	if cfg.ModulesEnabled {
  1169  		if _, p, e := modload.Lookup(s, parentPath, parentIsStd, path); e == nil {
  1170  			return p
  1171  		}
  1172  		return path
  1173  	}
  1174  	found = vendoredImportPath(path, parentPath, parentDir, parentRoot)
  1175  	if found != path {
  1176  		return found
  1177  	}
  1178  	return moduleImportPath(path, parentPath, parentDir, parentRoot)
  1179  }
  1180  
  1181  // dirAndRoot returns the source directory and workspace root
  1182  // for the package p, guaranteeing that root is a path prefix of dir.
  1183  func dirAndRoot(path string, dir, root string) (string, string) {
  1184  	origDir, origRoot := dir, root
  1185  	dir = filepath.Clean(dir)
  1186  	root = filepath.Join(root, "src")
  1187  	if !str.HasFilePathPrefix(dir, root) || path != "command-line-arguments" && filepath.Join(root, path) != dir {
  1188  		// Look for symlinks before reporting error.
  1189  		dir = expandPath(dir)
  1190  		root = expandPath(root)
  1191  	}
  1192  
  1193  	if !str.HasFilePathPrefix(dir, root) || len(dir) <= len(root) || dir[len(root)] != filepath.Separator || path != "command-line-arguments" && !build.IsLocalImport(path) && filepath.Join(root, path) != dir {
  1194  		debug.PrintStack()
  1195  		base.Fatalf("unexpected directory layout:\n"+
  1196  			"	import path: %s\n"+
  1197  			"	root: %s\n"+
  1198  			"	dir: %s\n"+
  1199  			"	expand root: %s\n"+
  1200  			"	expand dir: %s\n"+
  1201  			"	separator: %s",
  1202  			path,
  1203  			filepath.Join(origRoot, "src"),
  1204  			filepath.Clean(origDir),
  1205  			origRoot,
  1206  			origDir,
  1207  			string(filepath.Separator))
  1208  	}
  1209  
  1210  	return dir, root
  1211  }
  1212  
  1213  // vendoredImportPath returns the vendor-expansion of path when it appears in parent.
  1214  // If parent is x/y/z, then path might expand to x/y/z/vendor/path, x/y/vendor/path,
  1215  // x/vendor/path, vendor/path, or else stay path if none of those exist.
  1216  // vendoredImportPath returns the expanded path or, if no expansion is found, the original.
  1217  func vendoredImportPath(path, parentPath, parentDir, parentRoot string) (found string) {
  1218  	if parentRoot == "" {
  1219  		return path
  1220  	}
  1221  
  1222  	dir, root := dirAndRoot(parentPath, parentDir, parentRoot)
  1223  
  1224  	vpath := "vendor/" + path
  1225  	for i := len(dir); i >= len(root); i-- {
  1226  		if i < len(dir) && dir[i] != filepath.Separator {
  1227  			continue
  1228  		}
  1229  		// Note: checking for the vendor directory before checking
  1230  		// for the vendor/path directory helps us hit the
  1231  		// isDir cache more often. It also helps us prepare a more useful
  1232  		// list of places we looked, to report when an import is not found.
  1233  		if !isDir(filepath.Join(dir[:i], "vendor")) {
  1234  			continue
  1235  		}
  1236  		targ := filepath.Join(dir[:i], vpath)
  1237  		if isDir(targ) && hasGoFiles(targ) {
  1238  			importPath := parentPath
  1239  			if importPath == "command-line-arguments" {
  1240  				// If parent.ImportPath is 'command-line-arguments'.
  1241  				// set to relative directory to root (also chopped root directory)
  1242  				importPath = dir[len(root)+1:]
  1243  			}
  1244  			// We started with parent's dir c:\gopath\src\foo\bar\baz\quux\xyzzy.
  1245  			// We know the import path for parent's dir.
  1246  			// We chopped off some number of path elements and
  1247  			// added vendor\path to produce c:\gopath\src\foo\bar\baz\vendor\path.
  1248  			// Now we want to know the import path for that directory.
  1249  			// Construct it by chopping the same number of path elements
  1250  			// (actually the same number of bytes) from parent's import path
  1251  			// and then append /vendor/path.
  1252  			chopped := len(dir) - i
  1253  			if chopped == len(importPath)+1 {
  1254  				// We walked up from c:\gopath\src\foo\bar
  1255  				// and found c:\gopath\src\vendor\path.
  1256  				// We chopped \foo\bar (length 8) but the import path is "foo/bar" (length 7).
  1257  				// Use "vendor/path" without any prefix.
  1258  				return vpath
  1259  			}
  1260  			return importPath[:len(importPath)-chopped] + "/" + vpath
  1261  		}
  1262  	}
  1263  	return path
  1264  }
  1265  
  1266  var (
  1267  	modulePrefix   = []byte("\nmodule ")
  1268  	goModPathCache par.Cache[string, string]
  1269  )
  1270  
  1271  // goModPath returns the module path in the go.mod in dir, if any.
  1272  func goModPath(dir string) (path string) {
  1273  	return goModPathCache.Do(dir, func() string {
  1274  		data, err := os.ReadFile(filepath.Join(dir, "go.mod"))
  1275  		if err != nil {
  1276  			return ""
  1277  		}
  1278  		var i int
  1279  		if bytes.HasPrefix(data, modulePrefix[1:]) {
  1280  			i = 0
  1281  		} else {
  1282  			i = bytes.Index(data, modulePrefix)
  1283  			if i < 0 {
  1284  				return ""
  1285  			}
  1286  			i++
  1287  		}
  1288  		line := data[i:]
  1289  
  1290  		// Cut line at \n, drop trailing \r if present.
  1291  		if j := bytes.IndexByte(line, '\n'); j >= 0 {
  1292  			line = line[:j]
  1293  		}
  1294  		if line[len(line)-1] == '\r' {
  1295  			line = line[:len(line)-1]
  1296  		}
  1297  		line = line[len("module "):]
  1298  
  1299  		// If quoted, unquote.
  1300  		path = strings.TrimSpace(string(line))
  1301  		if path != "" && path[0] == '"' {
  1302  			s, err := strconv.Unquote(path)
  1303  			if err != nil {
  1304  				return ""
  1305  			}
  1306  			path = s
  1307  		}
  1308  		return path
  1309  	})
  1310  }
  1311  
  1312  // findVersionElement returns the slice indices of the final version element /vN in path.
  1313  // If there is no such element, it returns -1, -1.
  1314  func findVersionElement(path string) (i, j int) {
  1315  	j = len(path)
  1316  	for i = len(path) - 1; i >= 0; i-- {
  1317  		if path[i] == '/' {
  1318  			if isVersionElement(path[i+1 : j]) {
  1319  				return i, j
  1320  			}
  1321  			j = i
  1322  		}
  1323  	}
  1324  	return -1, -1
  1325  }
  1326  
  1327  // isVersionElement reports whether s is a well-formed path version element:
  1328  // v2, v3, v10, etc, but not v0, v05, v1.
  1329  func isVersionElement(s string) bool {
  1330  	if len(s) < 2 || s[0] != 'v' || s[1] == '0' || s[1] == '1' && len(s) == 2 {
  1331  		return false
  1332  	}
  1333  	for i := 1; i < len(s); i++ {
  1334  		if s[i] < '0' || '9' < s[i] {
  1335  			return false
  1336  		}
  1337  	}
  1338  	return true
  1339  }
  1340  
  1341  // moduleImportPath translates import paths found in go modules
  1342  // back down to paths that can be resolved in ordinary builds.
  1343  //
  1344  // Define “new” code as code with a go.mod file in the same directory
  1345  // or a parent directory. If an import in new code says x/y/v2/z but
  1346  // x/y/v2/z does not exist and x/y/go.mod says “module x/y/v2”,
  1347  // then go build will read the import as x/y/z instead.
  1348  // See golang.org/issue/25069.
  1349  func moduleImportPath(path, parentPath, parentDir, parentRoot string) (found string) {
  1350  	if parentRoot == "" {
  1351  		return path
  1352  	}
  1353  
  1354  	// If there are no vN elements in path, leave it alone.
  1355  	// (The code below would do the same, but only after
  1356  	// some other file system accesses that we can avoid
  1357  	// here by returning early.)
  1358  	if i, _ := findVersionElement(path); i < 0 {
  1359  		return path
  1360  	}
  1361  
  1362  	dir, root := dirAndRoot(parentPath, parentDir, parentRoot)
  1363  
  1364  	// Consider dir and parents, up to and including root.
  1365  	for i := len(dir); i >= len(root); i-- {
  1366  		if i < len(dir) && dir[i] != filepath.Separator {
  1367  			continue
  1368  		}
  1369  		if goModPath(dir[:i]) != "" {
  1370  			goto HaveGoMod
  1371  		}
  1372  	}
  1373  	// This code is not in a tree with a go.mod,
  1374  	// so apply no changes to the path.
  1375  	return path
  1376  
  1377  HaveGoMod:
  1378  	// This import is in a tree with a go.mod.
  1379  	// Allow it to refer to code in GOPATH/src/x/y/z as x/y/v2/z
  1380  	// if GOPATH/src/x/y/go.mod says module "x/y/v2",
  1381  
  1382  	// If x/y/v2/z exists, use it unmodified.
  1383  	if bp, _ := cfg.BuildContext.Import(path, "", build.IgnoreVendor); bp.Dir != "" {
  1384  		return path
  1385  	}
  1386  
  1387  	// Otherwise look for a go.mod supplying a version element.
  1388  	// Some version-like elements may appear in paths but not
  1389  	// be module versions; we skip over those to look for module
  1390  	// versions. For example the module m/v2 might have a
  1391  	// package m/v2/api/v1/foo.
  1392  	limit := len(path)
  1393  	for limit > 0 {
  1394  		i, j := findVersionElement(path[:limit])
  1395  		if i < 0 {
  1396  			return path
  1397  		}
  1398  		if bp, _ := cfg.BuildContext.Import(path[:i], "", build.IgnoreVendor); bp.Dir != "" {
  1399  			if mpath := goModPath(bp.Dir); mpath != "" {
  1400  				// Found a valid go.mod file, so we're stopping the search.
  1401  				// If the path is m/v2/p and we found m/go.mod that says
  1402  				// "module m/v2", then we return "m/p".
  1403  				if mpath == path[:j] {
  1404  					return path[:i] + path[j:]
  1405  				}
  1406  				// Otherwise just return the original path.
  1407  				// We didn't find anything worth rewriting,
  1408  				// and the go.mod indicates that we should
  1409  				// not consider parent directories.
  1410  				return path
  1411  			}
  1412  		}
  1413  		limit = i
  1414  	}
  1415  	return path
  1416  }
  1417  
  1418  // hasGoFiles reports whether dir contains any files with names ending in .go.
  1419  // For a vendor check we must exclude directories that contain no .go files.
  1420  // Otherwise it is not possible to vendor just a/b/c and still import the
  1421  // non-vendored a/b. See golang.org/issue/13832.
  1422  func hasGoFiles(dir string) bool {
  1423  	files, _ := os.ReadDir(dir)
  1424  	for _, f := range files {
  1425  		if !f.IsDir() && strings.HasSuffix(f.Name(), ".go") {
  1426  			return true
  1427  		}
  1428  	}
  1429  	return false
  1430  }
  1431  
  1432  // reusePackage reuses package p to satisfy the import at the top
  1433  // of the import stack stk. If this use causes an import loop,
  1434  // reusePackage updates p's error information to record the loop.
  1435  func reusePackage(p *Package, stk *ImportStack) *Package {
  1436  	// We use p.Internal.Imports==nil to detect a package that
  1437  	// is in the midst of its own loadPackage call
  1438  	// (all the recursion below happens before p.Internal.Imports gets set).
  1439  	if p.Internal.Imports == nil {
  1440  		if p.Error == nil {
  1441  			p.Error = &PackageError{
  1442  				ImportStack:   stk.Copy(),
  1443  				Err:           errors.New("import cycle not allowed"),
  1444  				IsImportCycle: true,
  1445  			}
  1446  		} else if !p.Error.IsImportCycle {
  1447  			// If the error is already set, but it does not indicate that
  1448  			// we are in an import cycle, set IsImportCycle so that we don't
  1449  			// end up stuck in a loop down the road.
  1450  			p.Error.IsImportCycle = true
  1451  		}
  1452  		p.Incomplete = true
  1453  	}
  1454  	// Don't rewrite the import stack in the error if we have an import cycle.
  1455  	// If we do, we'll lose the path that describes the cycle.
  1456  	if p.Error != nil && p.Error.ImportStack != nil &&
  1457  		!p.Error.IsImportCycle && stk.shorterThan(p.Error.ImportStack.Pkgs()) {
  1458  		p.Error.ImportStack = stk.Copy()
  1459  	}
  1460  	return p
  1461  }
  1462  
  1463  // disallowInternal checks that srcDir (containing package importerPath, if non-empty)
  1464  // is allowed to import p.
  1465  // If the import is allowed, disallowInternal returns the original package p.
  1466  // If not, it returns a new package containing just an appropriate error.
  1467  func disallowInternal(loaderstate *modload.State, ctx context.Context, srcDir string, importer *Package, importerPath string, p *Package, stk *ImportStack) *PackageError {
  1468  	// golang.org/s/go14internal:
  1469  	// An import of a path containing the element “internal”
  1470  	// is disallowed if the importing code is outside the tree
  1471  	// rooted at the parent of the “internal” directory.
  1472  
  1473  	// There was an error loading the package; stop here.
  1474  	if p.Error != nil {
  1475  		return nil
  1476  	}
  1477  
  1478  	// The generated 'testmain' package is allowed to access testing/internal/...,
  1479  	// as if it were generated into the testing directory tree
  1480  	// (it's actually in a temporary directory outside any Go tree).
  1481  	// This cleans up a former kludge in passing functionality to the testing package.
  1482  	if str.HasPathPrefix(p.ImportPath, "testing/internal") && importerPath == "testmain" {
  1483  		return nil
  1484  	}
  1485  
  1486  	// We can't check standard packages with gccgo.
  1487  	if cfg.BuildContext.Compiler == "gccgo" && p.Standard {
  1488  		return nil
  1489  	}
  1490  
  1491  	// The sort package depends on internal/reflectlite, but during bootstrap
  1492  	// the path rewriting causes the normal internal checks to fail.
  1493  	// Instead, just ignore the internal rules during bootstrap.
  1494  	if p.Standard && strings.HasPrefix(importerPath, "bootstrap/") {
  1495  		return nil
  1496  	}
  1497  
  1498  	// importerPath is empty: we started
  1499  	// with a name given on the command line, not an
  1500  	// import. Anything listed on the command line is fine.
  1501  	if importerPath == "" {
  1502  		return nil
  1503  	}
  1504  
  1505  	// Check for "internal" element: three cases depending on begin of string and/or end of string.
  1506  	i, ok := findInternal(p.ImportPath)
  1507  	if !ok {
  1508  		return nil
  1509  	}
  1510  
  1511  	// Internal is present.
  1512  	// Map import path back to directory corresponding to parent of internal.
  1513  	if i > 0 {
  1514  		i-- // rewind over slash in ".../internal"
  1515  	}
  1516  
  1517  	// FIPS-140 snapshots are special, because they comes from a non-GOROOT
  1518  	// directory, so the usual directory rules don't work apply, or rather they
  1519  	// apply differently depending on whether we are using a snapshot or the
  1520  	// in-tree copy of the code. We apply a consistent rule here:
  1521  	// crypto/internal/fips140 can only see crypto/internal, never top-of-tree internal.
  1522  	// Similarly, crypto/... can see crypto/internal/fips140 even though the usual rules
  1523  	// would not allow it in snapshot mode.
  1524  	if str.HasPathPrefix(importerPath, "crypto") && str.HasPathPrefix(p.ImportPath, "crypto/internal/fips140") {
  1525  		return nil // crypto can use crypto/internal/fips140
  1526  	}
  1527  	if str.HasPathPrefix(importerPath, "crypto/internal/fips140") {
  1528  		if str.HasPathPrefix(p.ImportPath, "crypto/internal") {
  1529  			return nil // crypto/internal/fips140 can use crypto/internal
  1530  		}
  1531  		goto Error
  1532  	}
  1533  
  1534  	if p.Module == nil {
  1535  		parent := p.Dir[:i+len(p.Dir)-len(p.ImportPath)]
  1536  
  1537  		if str.HasFilePathPrefix(filepath.Clean(srcDir), filepath.Clean(parent)) {
  1538  			return nil
  1539  		}
  1540  
  1541  		// Look for symlinks before reporting error.
  1542  		srcDir = expandPath(srcDir)
  1543  		parent = expandPath(parent)
  1544  		if str.HasFilePathPrefix(filepath.Clean(srcDir), filepath.Clean(parent)) {
  1545  			return nil
  1546  		}
  1547  	} else {
  1548  		// p is in a module, so make it available based on the importer's import path instead
  1549  		// of the file path (https://golang.org/issue/23970).
  1550  		if importer.Internal.CmdlineFiles {
  1551  			// The importer is a list of command-line files.
  1552  			// Pretend that the import path is the import path of the
  1553  			// directory containing them.
  1554  			// If the directory is outside the main modules, this will resolve to ".",
  1555  			// which is not a prefix of any valid module.
  1556  			importerPath, _ = loaderstate.MainModules.DirImportPath(loaderstate, ctx, importer.Dir)
  1557  		}
  1558  		parentOfInternal := p.ImportPath[:i]
  1559  		if str.HasPathPrefix(importerPath, parentOfInternal) {
  1560  			return nil
  1561  		}
  1562  	}
  1563  
  1564  Error:
  1565  	// Internal is present, and srcDir is outside parent's tree. Not allowed.
  1566  	perr := &PackageError{
  1567  		alwaysPrintStack: true,
  1568  		ImportStack:      stk.Copy(),
  1569  		Err:              ImportErrorf(p.ImportPath, "use of internal package %s not allowed", p.ImportPath),
  1570  	}
  1571  	return perr
  1572  }
  1573  
  1574  // findInternal looks for the final "internal" path element in the given import path.
  1575  // If there isn't one, findInternal returns ok=false.
  1576  // Otherwise, findInternal returns ok=true and the index of the "internal".
  1577  func findInternal(path string) (index int, ok bool) {
  1578  	// Three cases, depending on internal at start/end of string or not.
  1579  	// The order matters: we must return the index of the final element,
  1580  	// because the final one produces the most restrictive requirement
  1581  	// on the importer.
  1582  	switch {
  1583  	case strings.HasSuffix(path, "/internal"):
  1584  		return len(path) - len("internal"), true
  1585  	case strings.Contains(path, "/internal/"):
  1586  		return strings.LastIndex(path, "/internal/") + 1, true
  1587  	case path == "internal", strings.HasPrefix(path, "internal/"):
  1588  		return 0, true
  1589  	}
  1590  	return 0, false
  1591  }
  1592  
  1593  // disallowVendor checks that srcDir is allowed to import p as path.
  1594  // If the import is allowed, disallowVendor returns the original package p.
  1595  // If not, it returns a PackageError.
  1596  func disallowVendor(srcDir string, path string, importerPath string, p *Package, stk *ImportStack) *PackageError {
  1597  	// If the importerPath is empty, we started
  1598  	// with a name given on the command line, not an
  1599  	// import. Anything listed on the command line is fine.
  1600  	if importerPath == "" {
  1601  		return nil
  1602  	}
  1603  
  1604  	if perr := disallowVendorVisibility(srcDir, p, importerPath, stk); perr != nil {
  1605  		return perr
  1606  	}
  1607  
  1608  	// Paths like x/vendor/y must be imported as y, never as x/vendor/y.
  1609  	if i, ok := FindVendor(path); ok {
  1610  		perr := &PackageError{
  1611  			ImportStack: stk.Copy(),
  1612  			Err:         ImportErrorf(path, "%s must be imported as %s", path, path[i+len("vendor/"):]),
  1613  		}
  1614  		return perr
  1615  	}
  1616  
  1617  	return nil
  1618  }
  1619  
  1620  // disallowVendorVisibility checks that srcDir is allowed to import p.
  1621  // The rules are the same as for /internal/ except that a path ending in /vendor
  1622  // is not subject to the rules, only subdirectories of vendor.
  1623  // This allows people to have packages and commands named vendor,
  1624  // for maximal compatibility with existing source trees.
  1625  func disallowVendorVisibility(srcDir string, p *Package, importerPath string, stk *ImportStack) *PackageError {
  1626  	// The stack does not include p.ImportPath.
  1627  	// If there's nothing on the stack, we started
  1628  	// with a name given on the command line, not an
  1629  	// import. Anything listed on the command line is fine.
  1630  	if importerPath == "" {
  1631  		return nil
  1632  	}
  1633  
  1634  	// Check for "vendor" element.
  1635  	i, ok := FindVendor(p.ImportPath)
  1636  	if !ok {
  1637  		return nil
  1638  	}
  1639  
  1640  	// Vendor is present.
  1641  	// Map import path back to directory corresponding to parent of vendor.
  1642  	if i > 0 {
  1643  		i-- // rewind over slash in ".../vendor"
  1644  	}
  1645  	truncateTo := i + len(p.Dir) - len(p.ImportPath)
  1646  	if truncateTo < 0 || len(p.Dir) < truncateTo {
  1647  		return nil
  1648  	}
  1649  	parent := p.Dir[:truncateTo]
  1650  	if str.HasFilePathPrefix(filepath.Clean(srcDir), filepath.Clean(parent)) {
  1651  		return nil
  1652  	}
  1653  
  1654  	// Look for symlinks before reporting error.
  1655  	srcDir = expandPath(srcDir)
  1656  	parent = expandPath(parent)
  1657  	if str.HasFilePathPrefix(filepath.Clean(srcDir), filepath.Clean(parent)) {
  1658  		return nil
  1659  	}
  1660  
  1661  	// Vendor is present, and srcDir is outside parent's tree. Not allowed.
  1662  
  1663  	perr := &PackageError{
  1664  		ImportStack: stk.Copy(),
  1665  		Err:         errors.New("use of vendored package not allowed"),
  1666  	}
  1667  	return perr
  1668  }
  1669  
  1670  // FindVendor looks for the last non-terminating "vendor" path element in the given import path.
  1671  // If there isn't one, FindVendor returns ok=false.
  1672  // Otherwise, FindVendor returns ok=true and the index of the "vendor".
  1673  //
  1674  // Note that terminating "vendor" elements don't count: "x/vendor" is its own package,
  1675  // not the vendored copy of an import "" (the empty import path).
  1676  // This will allow people to have packages or commands named vendor.
  1677  // This may help reduce breakage, or it may just be confusing. We'll see.
  1678  func FindVendor(path string) (index int, ok bool) {
  1679  	// Two cases, depending on internal at start of string or not.
  1680  	// The order matters: we must return the index of the final element,
  1681  	// because the final one is where the effective import path starts.
  1682  	switch {
  1683  	case strings.Contains(path, "/vendor/"):
  1684  		return strings.LastIndex(path, "/vendor/") + 1, true
  1685  	case strings.HasPrefix(path, "vendor/"):
  1686  		return 0, true
  1687  	}
  1688  	return 0, false
  1689  }
  1690  
  1691  type TargetDir int
  1692  
  1693  const (
  1694  	ToTool    TargetDir = iota // to GOROOT/pkg/tool (default for cmd/*)
  1695  	ToBin                      // to bin dir inside package root (default for non-cmd/*)
  1696  	StalePath                  // an old import path; fail to build
  1697  )
  1698  
  1699  // InstallTargetDir reports the target directory for installing the command p.
  1700  func InstallTargetDir(p *Package) TargetDir {
  1701  	if strings.HasPrefix(p.ImportPath, "code.google.com/p/go.tools/cmd/") {
  1702  		return StalePath
  1703  	}
  1704  	if p.Goroot && strings.HasPrefix(p.ImportPath, "cmd/") && p.Name == "main" {
  1705  		switch p.ImportPath {
  1706  		case "cmd/go", "cmd/gofmt":
  1707  			return ToBin
  1708  		}
  1709  		return ToTool
  1710  	}
  1711  	return ToBin
  1712  }
  1713  
  1714  var cgoExclude = map[string]bool{
  1715  	"runtime/cgo": true,
  1716  }
  1717  
  1718  var cgoSyscallExclude = map[string]bool{
  1719  	"runtime/cgo":  true,
  1720  	"runtime/race": true,
  1721  	"runtime/msan": true,
  1722  	"runtime/asan": true,
  1723  }
  1724  
  1725  var foldPath = make(map[string]string)
  1726  
  1727  // exeFromImportPath returns an executable name
  1728  // for a package using the import path.
  1729  //
  1730  // The executable name is the last element of the import path.
  1731  // In module-aware mode, an additional rule is used on import paths
  1732  // consisting of two or more path elements. If the last element is
  1733  // a vN path element specifying the major version, then the
  1734  // second last element of the import path is used instead.
  1735  func (p *Package) exeFromImportPath() string {
  1736  	_, elem := pathpkg.Split(p.ImportPath)
  1737  	if cfg.ModulesEnabled {
  1738  		// If this is example.com/mycmd/v2, it's more useful to
  1739  		// install it as mycmd than as v2. See golang.org/issue/24667.
  1740  		if elem != p.ImportPath && isVersionElement(elem) {
  1741  			_, elem = pathpkg.Split(pathpkg.Dir(p.ImportPath))
  1742  		}
  1743  	}
  1744  	return elem
  1745  }
  1746  
  1747  // exeFromFiles returns an executable name for a package
  1748  // using the first element in GoFiles or CgoFiles collections without the prefix.
  1749  //
  1750  // Returns empty string in case of empty collection.
  1751  func (p *Package) exeFromFiles() string {
  1752  	var src string
  1753  	if len(p.GoFiles) > 0 {
  1754  		src = p.GoFiles[0]
  1755  	} else if len(p.CgoFiles) > 0 {
  1756  		src = p.CgoFiles[0]
  1757  	} else {
  1758  		return ""
  1759  	}
  1760  	_, elem := filepath.Split(src)
  1761  	return elem[:len(elem)-len(".go")]
  1762  }
  1763  
  1764  // DefaultExecName returns the default executable name for a package
  1765  func (p *Package) DefaultExecName() string {
  1766  	if p.Internal.CmdlineFiles {
  1767  		return p.exeFromFiles()
  1768  	}
  1769  	return p.exeFromImportPath()
  1770  }
  1771  
  1772  // load populates p using information from bp, err, which should
  1773  // be the result of calling build.Context.Import.
  1774  // stk contains the import stack, not including path itself.
  1775  func (p *Package) load(loaderstate *modload.State, ctx context.Context, opts PackageOpts, path string, stk *ImportStack, importPos []token.Position, bp *build.Package, err error) {
  1776  	p.copyBuild(opts, bp)
  1777  
  1778  	// The localPrefix is the path we interpret ./ imports relative to,
  1779  	// if we support them at all (not in module mode!).
  1780  	// Synthesized main packages sometimes override this.
  1781  	if p.Internal.Local && !cfg.ModulesEnabled {
  1782  		p.Internal.LocalPrefix = dirToImportPath(p.Dir)
  1783  	}
  1784  
  1785  	// setError sets p.Error if it hasn't already been set. We may proceed
  1786  	// after encountering some errors so that 'go list -e' has more complete
  1787  	// output. If there's more than one error, we should report the first.
  1788  	setError := func(err error) {
  1789  		if p.Error == nil {
  1790  			p.Error = &PackageError{
  1791  				ImportStack: stk.Copy(),
  1792  				Err:         err,
  1793  			}
  1794  			p.Incomplete = true
  1795  
  1796  			// Add the importer's position information if the import position exists, and
  1797  			// the current package being examined is the importer.
  1798  			// If we have not yet accepted package p onto the import stack,
  1799  			// then the cause of the error is not within p itself: the error
  1800  			// must be either in an explicit command-line argument,
  1801  			// or on the importer side (indicated by a non-empty importPos).
  1802  			top, ok := stk.Top()
  1803  			if ok && path != top.Pkg && len(importPos) > 0 {
  1804  				p.Error.setPos(importPos)
  1805  			}
  1806  		}
  1807  	}
  1808  
  1809  	if err != nil {
  1810  		p.Incomplete = true
  1811  		p.setLoadPackageDataError(err, path, stk, importPos)
  1812  	}
  1813  
  1814  	useBindir := p.Name == "main"
  1815  	if !p.Standard {
  1816  		switch cfg.BuildBuildmode {
  1817  		case "c-archive", "c-shared", "plugin":
  1818  			useBindir = false
  1819  		}
  1820  	}
  1821  
  1822  	if useBindir {
  1823  		// Report an error when the old code.google.com/p/go.tools paths are used.
  1824  		if InstallTargetDir(p) == StalePath {
  1825  			// TODO(matloob): remove this branch, and StalePath itself. code.google.com/p/go is so
  1826  			// old, even this code checking for it is stale now!
  1827  			newPath := strings.Replace(p.ImportPath, "code.google.com/p/go.", "golang.org/x/", 1)
  1828  			e := ImportErrorf(p.ImportPath, "the %v command has moved; use %v instead.", p.ImportPath, newPath)
  1829  			setError(e)
  1830  			return
  1831  		}
  1832  		elem := p.DefaultExecName() + cfg.ExeSuffix
  1833  		full := filepath.Join(cfg.BuildContext.GOOS+"_"+cfg.BuildContext.GOARCH, elem)
  1834  		if cfg.BuildContext.GOOS != runtime.GOOS || cfg.BuildContext.GOARCH != runtime.GOARCH {
  1835  			// Install cross-compiled binaries to subdirectories of bin.
  1836  			elem = full
  1837  		}
  1838  		if p.Internal.Build.BinDir == "" && cfg.ModulesEnabled {
  1839  			p.Internal.Build.BinDir = modload.BinDir(loaderstate)
  1840  		}
  1841  		if p.Internal.Build.BinDir != "" {
  1842  			// Install to GOBIN or bin of GOPATH entry.
  1843  			p.Target = filepath.Join(p.Internal.Build.BinDir, elem)
  1844  			if !p.Goroot && strings.Contains(elem, string(filepath.Separator)) && cfg.GOBIN != "" {
  1845  				// Do not create $GOBIN/goos_goarch/elem.
  1846  				p.Target = ""
  1847  				p.Internal.GobinSubdir = true
  1848  			}
  1849  		}
  1850  		if InstallTargetDir(p) == ToTool {
  1851  			// This is for 'go tool'.
  1852  			// Override all the usual logic and force it into the tool directory.
  1853  			if cfg.BuildToolchainName == "gccgo" {
  1854  				p.Target = filepath.Join(build.ToolDir, elem)
  1855  			} else {
  1856  				p.Target = filepath.Join(cfg.GOROOTpkg, "tool", full)
  1857  			}
  1858  		}
  1859  	} else if p.Internal.Local {
  1860  		// Local import turned into absolute path.
  1861  		// No permanent install target.
  1862  		p.Target = ""
  1863  	} else if p.Standard && cfg.BuildContext.Compiler == "gccgo" {
  1864  		// gccgo has a preinstalled standard library that cmd/go cannot rebuild.
  1865  		p.Target = ""
  1866  	} else {
  1867  		p.Target = p.Internal.Build.PkgObj
  1868  		if cfg.BuildBuildmode == "shared" && p.Internal.Build.PkgTargetRoot != "" {
  1869  			// TODO(matloob): This shouldn't be necessary, but the cmd/cgo/internal/testshared
  1870  			// test fails without Target set for this condition. Figure out why and
  1871  			// fix it.
  1872  			p.Target = filepath.Join(p.Internal.Build.PkgTargetRoot, p.ImportPath+".a")
  1873  		}
  1874  		if cfg.BuildLinkshared && p.Internal.Build.PkgTargetRoot != "" {
  1875  			// TODO(bcmills): The reliance on PkgTargetRoot implies that -linkshared does
  1876  			// not work for any package that lacks a PkgTargetRoot — such as a non-main
  1877  			// package in module mode. We should probably fix that.
  1878  			targetPrefix := filepath.Join(p.Internal.Build.PkgTargetRoot, p.ImportPath)
  1879  			p.Target = targetPrefix + ".a"
  1880  			shlibnamefile := targetPrefix + ".shlibname"
  1881  			shlib, err := os.ReadFile(shlibnamefile)
  1882  			if err != nil && !os.IsNotExist(err) {
  1883  				base.Fatalf("reading shlibname: %v", err)
  1884  			}
  1885  			if err == nil {
  1886  				libname := strings.TrimSpace(string(shlib))
  1887  				if cfg.BuildContext.Compiler == "gccgo" {
  1888  					p.Shlib = filepath.Join(p.Internal.Build.PkgTargetRoot, "shlibs", libname)
  1889  				} else {
  1890  					p.Shlib = filepath.Join(p.Internal.Build.PkgTargetRoot, libname)
  1891  				}
  1892  			}
  1893  		}
  1894  	}
  1895  
  1896  	// Build augmented import list to add implicit dependencies.
  1897  	// Be careful not to add imports twice, just to avoid confusion.
  1898  	importPaths := p.Imports
  1899  	addImport := func(path string, forCompiler bool) {
  1900  		for _, p := range importPaths {
  1901  			if path == p {
  1902  				return
  1903  			}
  1904  		}
  1905  		importPaths = append(importPaths, path)
  1906  		if forCompiler {
  1907  			p.Internal.CompiledImports = append(p.Internal.CompiledImports, path)
  1908  		}
  1909  	}
  1910  
  1911  	if !opts.IgnoreImports {
  1912  		// Cgo translation adds imports of "unsafe", "runtime/cgo" and "syscall",
  1913  		// except for certain packages, to avoid circular dependencies.
  1914  		if p.UsesCgo() {
  1915  			addImport("unsafe", true)
  1916  		}
  1917  		if p.UsesCgo() && (!p.Standard || !cgoExclude[p.ImportPath]) && cfg.BuildContext.Compiler != "gccgo" {
  1918  			addImport("runtime/cgo", true)
  1919  		}
  1920  		if p.UsesCgo() && (!p.Standard || !cgoSyscallExclude[p.ImportPath]) {
  1921  			addImport("syscall", true)
  1922  		}
  1923  
  1924  		// SWIG adds imports of some standard packages.
  1925  		if p.UsesSwig() {
  1926  			addImport("unsafe", true)
  1927  			if cfg.BuildContext.Compiler != "gccgo" {
  1928  				addImport("runtime/cgo", true)
  1929  			}
  1930  			addImport("syscall", true)
  1931  			addImport("sync", true)
  1932  
  1933  			// TODO: The .swig and .swigcxx files can use
  1934  			// %go_import directives to import other packages.
  1935  		}
  1936  
  1937  		// The linker loads implicit dependencies.
  1938  		if p.Name == "main" && !p.Internal.ForceLibrary {
  1939  			ldDeps, err := LinkerDeps(loaderstate, p)
  1940  			if err != nil {
  1941  				setError(err)
  1942  				return
  1943  			}
  1944  			for _, dep := range ldDeps {
  1945  				addImport(dep, false)
  1946  			}
  1947  		}
  1948  	}
  1949  
  1950  	// Check for case-insensitive collisions of import paths.
  1951  	// If modifying, consider changing checkPathCollisions() in
  1952  	// src/cmd/go/internal/modcmd/vendor.go
  1953  	fold := str.ToFold(p.ImportPath)
  1954  	if other := foldPath[fold]; other == "" {
  1955  		foldPath[fold] = p.ImportPath
  1956  	} else if other != p.ImportPath {
  1957  		setError(ImportErrorf(p.ImportPath, "case-insensitive import collision: %q and %q", p.ImportPath, other))
  1958  		return
  1959  	}
  1960  
  1961  	if !SafeArg(p.ImportPath) {
  1962  		setError(ImportErrorf(p.ImportPath, "invalid import path %q", p.ImportPath))
  1963  		return
  1964  	}
  1965  
  1966  	// Errors after this point are caused by this package, not the importing
  1967  	// package. Pushing the path here prevents us from reporting the error
  1968  	// with the position of the import declaration.
  1969  	stk.Push(ImportInfo{Pkg: path, Pos: extractFirstImport(importPos)})
  1970  	defer stk.Pop()
  1971  
  1972  	pkgPath := p.ImportPath
  1973  	if p.Internal.CmdlineFiles {
  1974  		pkgPath = "command-line-arguments"
  1975  	}
  1976  	if cfg.ModulesEnabled {
  1977  		p.Module = modload.PackageModuleInfo(loaderstate, ctx, pkgPath)
  1978  	}
  1979  	p.DefaultGODEBUG = defaultGODEBUG(loaderstate, p, nil, nil, nil)
  1980  
  1981  	if !opts.SuppressEmbedFiles {
  1982  		p.EmbedFiles, p.Internal.Embed, err = resolveEmbed(p.Dir, p.EmbedPatterns)
  1983  		if err != nil {
  1984  			p.Incomplete = true
  1985  			setError(err)
  1986  			embedErr := err.(*EmbedError)
  1987  			p.Error.setPos(p.Internal.Build.EmbedPatternPos[embedErr.Pattern])
  1988  		}
  1989  	}
  1990  
  1991  	// Check for case-insensitive collision of input files.
  1992  	// To avoid problems on case-insensitive files, we reject any package
  1993  	// where two different input files have equal names under a case-insensitive
  1994  	// comparison.
  1995  	inputs := p.AllFiles()
  1996  	f1, f2 := str.FoldDup(inputs)
  1997  	if f1 != "" {
  1998  		setError(fmt.Errorf("case-insensitive file name collision: %q and %q", f1, f2))
  1999  		return
  2000  	}
  2001  
  2002  	// If first letter of input file is ASCII, it must be alphanumeric.
  2003  	// This avoids files turning into flags when invoking commands,
  2004  	// and other problems we haven't thought of yet.
  2005  	// Also, _cgo_ files must be generated by us, not supplied.
  2006  	// They are allowed to have //go:cgo_ldflag directives.
  2007  	// The directory scan ignores files beginning with _,
  2008  	// so we shouldn't see any _cgo_ files anyway, but just be safe.
  2009  	for _, file := range inputs {
  2010  		if !SafeArg(file) || strings.HasPrefix(file, "_cgo_") {
  2011  			setError(fmt.Errorf("invalid input file name %q", file))
  2012  			return
  2013  		}
  2014  	}
  2015  	if name := pathpkg.Base(p.ImportPath); !SafeArg(name) {
  2016  		setError(fmt.Errorf("invalid input directory name %q", name))
  2017  		return
  2018  	}
  2019  	if strings.ContainsAny(p.Dir, "\r\n") {
  2020  		setError(fmt.Errorf("invalid package directory %q", p.Dir))
  2021  		return
  2022  	}
  2023  
  2024  	// Build list of imported packages and full dependency list.
  2025  	imports := make([]*Package, 0, len(p.Imports))
  2026  	for i, path := range importPaths {
  2027  		if path == "C" {
  2028  			continue
  2029  		}
  2030  		p1, err := loadImport(loaderstate, ctx, opts, nil, path, p.Dir, p, stk, p.Internal.Build.ImportPos[path], ResolveImport)
  2031  		if err != nil && p.Error == nil {
  2032  			p.Error = err
  2033  			p.Incomplete = true
  2034  		}
  2035  
  2036  		path = p1.ImportPath
  2037  		importPaths[i] = path
  2038  		if i < len(p.Imports) {
  2039  			p.Imports[i] = path
  2040  		}
  2041  
  2042  		imports = append(imports, p1)
  2043  		if p1.Incomplete {
  2044  			p.Incomplete = true
  2045  		}
  2046  	}
  2047  	p.Internal.Imports = imports
  2048  	if p.Error == nil && p.Name == "main" && !p.Internal.ForceLibrary && !p.Incomplete && !opts.SuppressBuildInfo {
  2049  		// TODO(bcmills): loading VCS metadata can be fairly slow.
  2050  		// Consider starting this as a background goroutine and retrieving the result
  2051  		// asynchronously when we're actually ready to build the package, or when we
  2052  		// actually need to evaluate whether the package's metadata is stale.
  2053  		p.setBuildInfo(ctx, loaderstate.Fetcher(), opts.AutoVCS)
  2054  	}
  2055  
  2056  	// If cgo is not enabled, ignore cgo supporting sources
  2057  	// just as we ignore go files containing import "C".
  2058  	if !cfg.BuildContext.CgoEnabled {
  2059  		p.CFiles = nil
  2060  		p.CXXFiles = nil
  2061  		p.MFiles = nil
  2062  		p.SwigFiles = nil
  2063  		p.SwigCXXFiles = nil
  2064  		// Note that SFiles are okay (they go to the Go assembler)
  2065  		// and HFiles are okay (they might be used by the SFiles).
  2066  		// Also Sysofiles are okay (they might not contain object
  2067  		// code; see issue #16050).
  2068  	}
  2069  
  2070  	// The gc toolchain only permits C source files with cgo or SWIG.
  2071  	if len(p.CFiles) > 0 && !p.UsesCgo() && !p.UsesSwig() && cfg.BuildContext.Compiler == "gc" {
  2072  		setError(fmt.Errorf("C source files not allowed when not using cgo or SWIG: %s", strings.Join(p.CFiles, " ")))
  2073  		return
  2074  	}
  2075  
  2076  	// C++, Objective-C, and Fortran source files are permitted only with cgo or SWIG,
  2077  	// regardless of toolchain.
  2078  	if len(p.CXXFiles) > 0 && !p.UsesCgo() && !p.UsesSwig() {
  2079  		setError(fmt.Errorf("C++ source files not allowed when not using cgo or SWIG: %s", strings.Join(p.CXXFiles, " ")))
  2080  		return
  2081  	}
  2082  	if len(p.MFiles) > 0 && !p.UsesCgo() && !p.UsesSwig() {
  2083  		setError(fmt.Errorf("Objective-C source files not allowed when not using cgo or SWIG: %s", strings.Join(p.MFiles, " ")))
  2084  		return
  2085  	}
  2086  	if len(p.FFiles) > 0 && !p.UsesCgo() && !p.UsesSwig() {
  2087  		setError(fmt.Errorf("Fortran source files not allowed when not using cgo or SWIG: %s", strings.Join(p.FFiles, " ")))
  2088  		return
  2089  	}
  2090  }
  2091  
  2092  // An EmbedError indicates a problem with a go:embed directive.
  2093  type EmbedError struct {
  2094  	Pattern string
  2095  	Err     error
  2096  }
  2097  
  2098  func (e *EmbedError) Error() string {
  2099  	return fmt.Sprintf("pattern %s: %v", e.Pattern, e.Err)
  2100  }
  2101  
  2102  func (e *EmbedError) Unwrap() error {
  2103  	return e.Err
  2104  }
  2105  
  2106  // ResolveEmbed resolves //go:embed patterns and returns only the file list.
  2107  // For use by go mod vendor to find embedded files it should copy into the
  2108  // vendor directory.
  2109  // TODO(#42504): Once go mod vendor uses load.PackagesAndErrors, just
  2110  // call (*Package).ResolveEmbed
  2111  func ResolveEmbed(dir string, patterns []string) ([]string, error) {
  2112  	files, _, err := resolveEmbed(dir, patterns)
  2113  	return files, err
  2114  }
  2115  
  2116  var embedfollowsymlinks = godebug.New("embedfollowsymlinks")
  2117  
  2118  // resolveEmbed resolves //go:embed patterns to precise file lists.
  2119  // It sets files to the list of unique files matched (for go list),
  2120  // and it sets pmap to the more precise mapping from
  2121  // patterns to files.
  2122  func resolveEmbed(pkgdir string, patterns []string) (files []string, pmap map[string][]string, err error) {
  2123  	var pattern string
  2124  	defer func() {
  2125  		if err != nil {
  2126  			err = &EmbedError{
  2127  				Pattern: pattern,
  2128  				Err:     err,
  2129  			}
  2130  		}
  2131  	}()
  2132  
  2133  	// TODO(rsc): All these messages need position information for better error reports.
  2134  	pmap = make(map[string][]string)
  2135  	have := make(map[string]int)
  2136  	dirOK := make(map[string]bool)
  2137  	pid := 0 // pattern ID, to allow reuse of have map
  2138  	for _, pattern = range patterns {
  2139  		pid++
  2140  
  2141  		glob, all := strings.CutPrefix(pattern, "all:")
  2142  		// Check pattern is valid for //go:embed.
  2143  		if _, err := pathpkg.Match(glob, ""); err != nil || !validEmbedPattern(glob) {
  2144  			return nil, nil, fmt.Errorf("invalid pattern syntax")
  2145  		}
  2146  
  2147  		// Glob to find matches.
  2148  		match, err := fsys.Glob(str.QuoteGlob(str.WithFilePathSeparator(pkgdir)) + filepath.FromSlash(glob))
  2149  		if err != nil {
  2150  			return nil, nil, err
  2151  		}
  2152  
  2153  		// Filter list of matches down to the ones that will still exist when
  2154  		// the directory is packaged up as a module. (If p.Dir is in the module cache,
  2155  		// only those files exist already, but if p.Dir is in the current module,
  2156  		// then there may be other things lying around, like symbolic links or .git directories.)
  2157  		var list []string
  2158  		for _, file := range match {
  2159  			// relative path to p.Dir which begins without prefix slash
  2160  			rel := filepath.ToSlash(str.TrimFilePathPrefix(file, pkgdir))
  2161  
  2162  			what := "file"
  2163  			info, err := fsys.Lstat(file)
  2164  			if err != nil {
  2165  				return nil, nil, err
  2166  			}
  2167  			if info.IsDir() {
  2168  				what = "directory"
  2169  			}
  2170  
  2171  			// Check that directories along path do not begin a new module
  2172  			// (do not contain a go.mod).
  2173  			for dir := file; len(dir) > len(pkgdir)+1 && !dirOK[dir]; dir = filepath.Dir(dir) {
  2174  				if _, err := fsys.Stat(filepath.Join(dir, "go.mod")); err == nil {
  2175  					return nil, nil, fmt.Errorf("cannot embed %s %s: in different module", what, rel)
  2176  				}
  2177  				if dir != file {
  2178  					if info, err := fsys.Lstat(dir); err == nil && !info.IsDir() {
  2179  						return nil, nil, fmt.Errorf("cannot embed %s %s: in non-directory %s", what, rel, dir[len(pkgdir)+1:])
  2180  					}
  2181  				}
  2182  				dirOK[dir] = true
  2183  				if elem := filepath.Base(dir); isBadEmbedName(elem) {
  2184  					if dir == file {
  2185  						return nil, nil, fmt.Errorf("cannot embed %s %s: invalid name %s", what, rel, elem)
  2186  					} else {
  2187  						return nil, nil, fmt.Errorf("cannot embed %s %s: in invalid directory %s", what, rel, elem)
  2188  					}
  2189  				}
  2190  			}
  2191  
  2192  			switch {
  2193  			default:
  2194  				return nil, nil, fmt.Errorf("cannot embed irregular file %s", rel)
  2195  
  2196  			case info.Mode().IsRegular():
  2197  				if have[rel] != pid {
  2198  					have[rel] = pid
  2199  					list = append(list, rel)
  2200  				}
  2201  
  2202  			// If the embedfollowsymlinks GODEBUG is set to 1, allow the leaf file to be a
  2203  			// symlink (#59924). We don't allow directories to be symlinks and have already
  2204  			// checked that none of the parent directories of the file are symlinks in the
  2205  			// loop above. The file pointed to by the symlink must be a regular file.
  2206  			case embedfollowsymlinks.Value() == "1" && info.Mode()&fs.ModeType == fs.ModeSymlink:
  2207  				info, err := fsys.Stat(file)
  2208  				if err != nil {
  2209  					return nil, nil, err
  2210  				}
  2211  				if !info.Mode().IsRegular() {
  2212  					return nil, nil, fmt.Errorf("cannot embed irregular file %s", rel)
  2213  				}
  2214  				if have[rel] != pid {
  2215  					embedfollowsymlinks.IncNonDefault()
  2216  					have[rel] = pid
  2217  					list = append(list, rel)
  2218  				}
  2219  
  2220  			case info.IsDir():
  2221  				// Gather all files in the named directory, stopping at module boundaries
  2222  				// and ignoring files that wouldn't be packaged into a module.
  2223  				count := 0
  2224  				err := fsys.WalkDir(file, func(path string, d fs.DirEntry, err error) error {
  2225  					if err != nil {
  2226  						return err
  2227  					}
  2228  					rel := filepath.ToSlash(str.TrimFilePathPrefix(path, pkgdir))
  2229  					name := d.Name()
  2230  					if path != file && (isBadEmbedName(name) || ((name[0] == '.' || name[0] == '_') && !all)) {
  2231  						// Avoid hidden files that user may not know about.
  2232  						// See golang.org/issue/42328.
  2233  						if d.IsDir() {
  2234  							return fs.SkipDir
  2235  						}
  2236  						// Ignore hidden files.
  2237  						if name[0] == '.' || name[0] == '_' {
  2238  							return nil
  2239  						}
  2240  						// Error on bad embed names.
  2241  						// See golang.org/issue/54003.
  2242  						if isBadEmbedName(name) {
  2243  							return fmt.Errorf("cannot embed file %s: invalid name %s", rel, name)
  2244  						}
  2245  						return nil
  2246  					}
  2247  					if d.IsDir() {
  2248  						if _, err := fsys.Stat(filepath.Join(path, "go.mod")); err == nil {
  2249  							return filepath.SkipDir
  2250  						}
  2251  						return nil
  2252  					}
  2253  					if !d.Type().IsRegular() {
  2254  						return nil
  2255  					}
  2256  					count++
  2257  					if have[rel] != pid {
  2258  						have[rel] = pid
  2259  						list = append(list, rel)
  2260  					}
  2261  					return nil
  2262  				})
  2263  				if err != nil {
  2264  					return nil, nil, err
  2265  				}
  2266  				if count == 0 {
  2267  					return nil, nil, fmt.Errorf("cannot embed directory %s: contains no embeddable files", rel)
  2268  				}
  2269  			}
  2270  		}
  2271  
  2272  		if len(list) == 0 {
  2273  			return nil, nil, fmt.Errorf("no matching files found")
  2274  		}
  2275  		sort.Strings(list)
  2276  		pmap[pattern] = list
  2277  	}
  2278  
  2279  	for file := range have {
  2280  		files = append(files, file)
  2281  	}
  2282  	sort.Strings(files)
  2283  	return files, pmap, nil
  2284  }
  2285  
  2286  func validEmbedPattern(pattern string) bool {
  2287  	return pattern != "." && fs.ValidPath(pattern)
  2288  }
  2289  
  2290  // isBadEmbedName reports whether name is the base name of a file that
  2291  // can't or won't be included in modules and therefore shouldn't be treated
  2292  // as existing for embedding.
  2293  func isBadEmbedName(name string) bool {
  2294  	if err := module.CheckFilePath(name); err != nil {
  2295  		return true
  2296  	}
  2297  	switch name {
  2298  	// Empty string should be impossible but make it bad.
  2299  	case "":
  2300  		return true
  2301  	// Version control directories won't be present in module.
  2302  	case ".bzr", ".hg", ".git", ".svn":
  2303  		return true
  2304  	}
  2305  	return false
  2306  }
  2307  
  2308  // vcsStatusCache maps repository directories (string)
  2309  // to their VCS information.
  2310  var vcsStatusCache par.ErrCache[string, vcs.Status]
  2311  
  2312  func appendBuildSetting(info *debug.BuildInfo, key, value string) {
  2313  	value = strings.ReplaceAll(value, "\n", " ") // make value safe
  2314  	info.Settings = append(info.Settings, debug.BuildSetting{Key: key, Value: value})
  2315  }
  2316  
  2317  // setBuildInfo gathers build information and sets it into
  2318  // p.Internal.BuildInfo, which will later be formatted as a string and embedded
  2319  // in the binary. setBuildInfo should only be called on a main package with no
  2320  // errors.
  2321  //
  2322  // This information can be retrieved using debug.ReadBuildInfo.
  2323  //
  2324  // Note that the GoVersion field is not set here to avoid encoding it twice.
  2325  // It is stored separately in the binary, mostly for historical reasons.
  2326  func (p *Package) setBuildInfo(ctx context.Context, f *modfetch.Fetcher, autoVCS bool) {
  2327  	setPkgErrorf := func(format string, args ...any) {
  2328  		if p.Error == nil {
  2329  			p.Error = &PackageError{Err: fmt.Errorf(format, args...)}
  2330  			p.Incomplete = true
  2331  		}
  2332  	}
  2333  
  2334  	var debugModFromModinfo func(*modinfo.ModulePublic) *debug.Module
  2335  	debugModFromModinfo = func(mi *modinfo.ModulePublic) *debug.Module {
  2336  		version := mi.Version
  2337  		if version == "" {
  2338  			version = "(devel)"
  2339  		}
  2340  		dm := &debug.Module{
  2341  			Path:    mi.Path,
  2342  			Version: version,
  2343  		}
  2344  		if mi.Replace != nil {
  2345  			dm.Replace = debugModFromModinfo(mi.Replace)
  2346  		} else if mi.Version != "" && cfg.BuildMod != "vendor" {
  2347  			dm.Sum = modfetch.Sum(ctx, module.Version{Path: mi.Path, Version: mi.Version})
  2348  		}
  2349  		return dm
  2350  	}
  2351  
  2352  	var main debug.Module
  2353  	if p.Module != nil {
  2354  		main = *debugModFromModinfo(p.Module)
  2355  	}
  2356  
  2357  	visited := make(map[*Package]bool)
  2358  	mdeps := make(map[module.Version]*debug.Module)
  2359  	var q []*Package
  2360  	q = append(q, p.Internal.Imports...)
  2361  	for len(q) > 0 {
  2362  		p1 := q[0]
  2363  		q = q[1:]
  2364  		if visited[p1] {
  2365  			continue
  2366  		}
  2367  		visited[p1] = true
  2368  		if p1.Module != nil {
  2369  			m := module.Version{Path: p1.Module.Path, Version: p1.Module.Version}
  2370  			if p1.Module.Path != main.Path && mdeps[m] == nil {
  2371  				mdeps[m] = debugModFromModinfo(p1.Module)
  2372  			}
  2373  		}
  2374  		q = append(q, p1.Internal.Imports...)
  2375  	}
  2376  	sortedMods := make([]module.Version, 0, len(mdeps))
  2377  	for mod := range mdeps {
  2378  		sortedMods = append(sortedMods, mod)
  2379  	}
  2380  	gover.ModSort(sortedMods)
  2381  	deps := make([]*debug.Module, len(sortedMods))
  2382  	for i, mod := range sortedMods {
  2383  		deps[i] = mdeps[mod]
  2384  	}
  2385  
  2386  	pkgPath := p.ImportPath
  2387  	if p.Internal.CmdlineFiles {
  2388  		pkgPath = "command-line-arguments"
  2389  	}
  2390  	info := &debug.BuildInfo{
  2391  		Path: pkgPath,
  2392  		Main: main,
  2393  		Deps: deps,
  2394  	}
  2395  	appendSetting := func(key, value string) {
  2396  		appendBuildSetting(info, key, value)
  2397  	}
  2398  
  2399  	// Add command-line flags relevant to the build.
  2400  	// This is informational, not an exhaustive list.
  2401  	// Please keep the list sorted.
  2402  	if cfg.BuildASan {
  2403  		appendSetting("-asan", "true")
  2404  	}
  2405  	if BuildAsmflags.present {
  2406  		appendSetting("-asmflags", BuildAsmflags.String())
  2407  	}
  2408  	buildmode := cfg.BuildBuildmode
  2409  	if buildmode == "default" {
  2410  		if p.Name == "main" {
  2411  			buildmode = "exe"
  2412  		} else {
  2413  			buildmode = "archive"
  2414  		}
  2415  	}
  2416  	appendSetting("-buildmode", buildmode)
  2417  	appendSetting("-compiler", cfg.BuildContext.Compiler)
  2418  	if gccgoflags := BuildGccgoflags.String(); gccgoflags != "" && cfg.BuildContext.Compiler == "gccgo" {
  2419  		appendSetting("-gccgoflags", gccgoflags)
  2420  	}
  2421  	if gcflags := BuildGcflags.String(); gcflags != "" && cfg.BuildContext.Compiler == "gc" {
  2422  		appendSetting("-gcflags", gcflags)
  2423  	}
  2424  	if ldflags := BuildLdflags.String(); ldflags != "" {
  2425  		// https://go.dev/issue/52372: only include ldflags if -trimpath is not set,
  2426  		// since it can include system paths through various linker flags (notably
  2427  		// -extar, -extld, and -extldflags).
  2428  		//
  2429  		// TODO: since we control cmd/link, in theory we can parse ldflags to
  2430  		// determine whether they may refer to system paths. If we do that, we can
  2431  		// redact only those paths from the recorded -ldflags setting and still
  2432  		// record the system-independent parts of the flags.
  2433  		if !cfg.BuildTrimpath {
  2434  			appendSetting("-ldflags", ldflags)
  2435  		}
  2436  	}
  2437  	if cfg.BuildCover {
  2438  		appendSetting("-cover", "true")
  2439  	}
  2440  	if cfg.BuildMSan {
  2441  		appendSetting("-msan", "true")
  2442  	}
  2443  	// N.B. -pgo added later by setPGOProfilePath.
  2444  	if cfg.BuildRace {
  2445  		appendSetting("-race", "true")
  2446  	}
  2447  	if tags := cfg.BuildContext.BuildTags; len(tags) > 0 {
  2448  		appendSetting("-tags", strings.Join(tags, ","))
  2449  	}
  2450  	if cfg.BuildTrimpath {
  2451  		appendSetting("-trimpath", "true")
  2452  	}
  2453  	if p.DefaultGODEBUG != "" {
  2454  		appendSetting("DefaultGODEBUG", p.DefaultGODEBUG)
  2455  	}
  2456  	cgo := "0"
  2457  	if cfg.BuildContext.CgoEnabled {
  2458  		cgo = "1"
  2459  	}
  2460  	appendSetting("CGO_ENABLED", cgo)
  2461  	// https://go.dev/issue/52372: only include CGO flags if -trimpath is not set.
  2462  	// (If -trimpath is set, it is possible that these flags include system paths.)
  2463  	// If cgo is involved, reproducibility is already pretty well ruined anyway,
  2464  	// given that we aren't stamping header or library versions.
  2465  	//
  2466  	// TODO(bcmills): perhaps we could at least parse the flags and stamp the
  2467  	// subset of flags that are known not to be paths?
  2468  	if cfg.BuildContext.CgoEnabled && !cfg.BuildTrimpath {
  2469  		for _, name := range []string{"CGO_CFLAGS", "CGO_CPPFLAGS", "CGO_CXXFLAGS", "CGO_LDFLAGS"} {
  2470  			appendSetting(name, cfg.Getenv(name))
  2471  		}
  2472  	}
  2473  	appendSetting("GOARCH", cfg.BuildContext.GOARCH)
  2474  	if cfg.RawGOEXPERIMENT != "" {
  2475  		appendSetting("GOEXPERIMENT", cfg.RawGOEXPERIMENT)
  2476  	}
  2477  	if fips140.Enabled() {
  2478  		appendSetting("GOFIPS140", fips140.Version())
  2479  	}
  2480  	appendSetting("GOOS", cfg.BuildContext.GOOS)
  2481  	if key, val, _ := cfg.GetArchEnv(); key != "" && val != "" {
  2482  		appendSetting(key, val)
  2483  	}
  2484  
  2485  	// Add VCS status if all conditions are true:
  2486  	//
  2487  	// - -buildvcs is enabled.
  2488  	// - p is a non-test contained within a main module (there may be multiple
  2489  	//   main modules in a workspace, but local replacements don't count).
  2490  	// - Both the current directory and p's module's root directory are contained
  2491  	//   in the same local repository.
  2492  	// - We know the VCS commands needed to get the status.
  2493  	setVCSError := func(err error) {
  2494  		setPkgErrorf("error obtaining VCS status: %v\n\tUse -buildvcs=false to disable VCS stamping.", err)
  2495  	}
  2496  
  2497  	var repoDir string
  2498  	var vcsCmd *vcs.Cmd
  2499  	var err error
  2500  
  2501  	wantVCS := false
  2502  	switch cfg.BuildBuildvcs {
  2503  	case "true":
  2504  		wantVCS = true // Include VCS metadata even for tests if requested explicitly; see https://go.dev/issue/52648.
  2505  	case "auto":
  2506  		wantVCS = autoVCS && !p.IsTestOnly()
  2507  	case "false":
  2508  	default:
  2509  		panic(fmt.Sprintf("unexpected value for cfg.BuildBuildvcs: %q", cfg.BuildBuildvcs))
  2510  	}
  2511  
  2512  	if wantVCS && p.Module != nil && p.Module.Version == "" && !p.Standard {
  2513  		if p.Module.Path == "bootstrap" && cfg.GOROOT == os.Getenv("GOROOT_BOOTSTRAP") {
  2514  			// During bootstrapping, the bootstrap toolchain is built in module
  2515  			// "bootstrap" (instead of "std"), with GOROOT set to GOROOT_BOOTSTRAP
  2516  			// (so the bootstrap toolchain packages don't even appear to be in GOROOT).
  2517  			goto omitVCS
  2518  		}
  2519  		repoDir, vcsCmd, err = vcs.FromDir(base.Cwd(), "")
  2520  		if err != nil && !errors.Is(err, os.ErrNotExist) {
  2521  			setVCSError(err)
  2522  			return
  2523  		}
  2524  		if !str.HasFilePathPrefix(p.Module.Dir, repoDir) &&
  2525  			!str.HasFilePathPrefix(repoDir, p.Module.Dir) {
  2526  			// The module containing the main package does not overlap with the
  2527  			// repository containing the working directory. Don't include VCS info.
  2528  			// If the repo contains the module or vice versa, but they are not
  2529  			// the same directory, it's likely an error (see below).
  2530  			goto omitVCS
  2531  		}
  2532  		if cfg.BuildBuildvcs == "auto" && vcsCmd != nil && vcsCmd.Cmd != "" {
  2533  			if _, err := pathcache.LookPath(vcsCmd.Cmd); err != nil {
  2534  				// We fould a repository, but the required VCS tool is not present.
  2535  				// "-buildvcs=auto" means that we should silently drop the VCS metadata.
  2536  				goto omitVCS
  2537  			}
  2538  		}
  2539  	}
  2540  	if repoDir != "" && vcsCmd.Status != nil {
  2541  		// Check that the current directory, package, and module are in the same
  2542  		// repository. vcs.FromDir disallows nested VCS and multiple VCS in the
  2543  		// same repository, unless the GODEBUG allowmultiplevcs is set. The
  2544  		// current directory may be outside p.Module.Dir when a workspace is
  2545  		// used.
  2546  		pkgRepoDir, _, err := vcs.FromDir(p.Dir, "")
  2547  		if err != nil {
  2548  			setVCSError(err)
  2549  			return
  2550  		}
  2551  		if pkgRepoDir != repoDir {
  2552  			if cfg.BuildBuildvcs != "auto" {
  2553  				setVCSError(fmt.Errorf("main package is in repository %q but current directory is in repository %q", pkgRepoDir, repoDir))
  2554  				return
  2555  			}
  2556  			goto omitVCS
  2557  		}
  2558  		modRepoDir, _, err := vcs.FromDir(p.Module.Dir, "")
  2559  		if err != nil {
  2560  			setVCSError(err)
  2561  			return
  2562  		}
  2563  		if modRepoDir != repoDir {
  2564  			if cfg.BuildBuildvcs != "auto" {
  2565  				setVCSError(fmt.Errorf("main module is in repository %q but current directory is in repository %q", modRepoDir, repoDir))
  2566  				return
  2567  			}
  2568  			goto omitVCS
  2569  		}
  2570  
  2571  		st, err := vcsStatusCache.Do(repoDir, func() (vcs.Status, error) {
  2572  			return vcsCmd.Status(vcsCmd, repoDir)
  2573  		})
  2574  		if err != nil {
  2575  			setVCSError(err)
  2576  			return
  2577  		}
  2578  
  2579  		appendSetting("vcs", vcsCmd.Cmd)
  2580  		if st.Revision != "" {
  2581  			appendSetting("vcs.revision", st.Revision)
  2582  		}
  2583  		if !st.CommitTime.IsZero() {
  2584  			stamp := st.CommitTime.UTC().Format(time.RFC3339Nano)
  2585  			appendSetting("vcs.time", stamp)
  2586  		}
  2587  		appendSetting("vcs.modified", strconv.FormatBool(st.Uncommitted))
  2588  		// Determine the correct version of this module at the current revision and update the build metadata accordingly.
  2589  		rootModPath := goModPath(repoDir)
  2590  		// If no root module is found, skip embedding VCS data since we cannot determine the module path of the root.
  2591  		if rootModPath == "" {
  2592  			goto omitVCS
  2593  		}
  2594  		codeRoot, _, ok := module.SplitPathVersion(rootModPath)
  2595  		if !ok {
  2596  			goto omitVCS
  2597  		}
  2598  		repo := f.LookupLocal(ctx, codeRoot, p.Module.Path, repoDir)
  2599  		revInfo, err := repo.Stat(ctx, st.Revision)
  2600  		if err != nil {
  2601  			goto omitVCS
  2602  		}
  2603  		vers := revInfo.Version
  2604  		if vers != "" {
  2605  			if st.Uncommitted {
  2606  				// SemVer build metadata is dot-separated https://semver.org/#spec-item-10
  2607  				if strings.HasSuffix(vers, "+incompatible") {
  2608  					vers += ".dirty"
  2609  				} else {
  2610  					vers += "+dirty"
  2611  				}
  2612  			}
  2613  			info.Main.Version = vers
  2614  		}
  2615  	}
  2616  omitVCS:
  2617  
  2618  	p.Internal.BuildInfo = info
  2619  }
  2620  
  2621  // SafeArg reports whether arg is a "safe" command-line argument,
  2622  // meaning that when it appears in a command-line, it probably
  2623  // doesn't have some special meaning other than its own name.
  2624  // Obviously args beginning with - are not safe (they look like flags).
  2625  // Less obviously, args beginning with @ are not safe (they look like
  2626  // GNU binutils flagfile specifiers, sometimes called "response files").
  2627  // To be conservative, we reject almost any arg beginning with non-alphanumeric ASCII.
  2628  // We accept leading . _ and / as likely in file system paths.
  2629  // There is a copy of this function in cmd/compile/internal/gc/noder.go.
  2630  func SafeArg(name string) bool {
  2631  	if name == "" {
  2632  		return false
  2633  	}
  2634  	c := name[0]
  2635  	return '0' <= c && c <= '9' || 'A' <= c && c <= 'Z' || 'a' <= c && c <= 'z' || c == '.' || c == '_' || c == '/' || c >= utf8.RuneSelf
  2636  }
  2637  
  2638  // LinkerDeps returns the list of linker-induced dependencies for main package p.
  2639  func LinkerDeps(s *modload.State, p *Package) ([]string, error) {
  2640  	// Everything links runtime.
  2641  	deps := []string{"runtime"}
  2642  
  2643  	// External linking mode forces an import of runtime/cgo.
  2644  	if what := externalLinkingReason(s, p); what != "" && cfg.BuildContext.Compiler != "gccgo" {
  2645  		if !cfg.BuildContext.CgoEnabled {
  2646  			return nil, fmt.Errorf("%s requires external (cgo) linking, but cgo is not enabled", what)
  2647  		}
  2648  		deps = append(deps, "runtime/cgo")
  2649  	}
  2650  	// On ARM with GOARM=5, it forces an import of math, for soft floating point.
  2651  	if cfg.Goarch == "arm" {
  2652  		deps = append(deps, "math")
  2653  	}
  2654  	// Using the race detector forces an import of runtime/race.
  2655  	if cfg.BuildRace {
  2656  		deps = append(deps, "runtime/race")
  2657  	}
  2658  	// Using memory sanitizer forces an import of runtime/msan.
  2659  	if cfg.BuildMSan {
  2660  		deps = append(deps, "runtime/msan")
  2661  	}
  2662  	// Using address sanitizer forces an import of runtime/asan.
  2663  	if cfg.BuildASan {
  2664  		deps = append(deps, "runtime/asan")
  2665  	}
  2666  	// Building for coverage forces an import of runtime/coverage.
  2667  	if cfg.BuildCover {
  2668  		deps = append(deps, "runtime/coverage")
  2669  	}
  2670  
  2671  	return deps, nil
  2672  }
  2673  
  2674  // externalLinkingReason reports the reason external linking is required
  2675  // even for programs that do not use cgo, or the empty string if external
  2676  // linking is not required.
  2677  func externalLinkingReason(s *modload.State, p *Package) (what string) {
  2678  	// Some targets must use external linking even inside GOROOT.
  2679  	if platform.MustLinkExternal(cfg.Goos, cfg.Goarch, false) {
  2680  		return cfg.Goos + "/" + cfg.Goarch
  2681  	}
  2682  
  2683  	// Some build modes always require external linking.
  2684  	switch cfg.BuildBuildmode {
  2685  	case "c-shared":
  2686  		if cfg.BuildContext.GOARCH == "wasm" {
  2687  			break
  2688  		}
  2689  		fallthrough
  2690  	case "plugin":
  2691  		return "-buildmode=" + cfg.BuildBuildmode
  2692  	}
  2693  
  2694  	// Using -linkshared always requires external linking.
  2695  	if cfg.BuildLinkshared {
  2696  		return "-linkshared"
  2697  	}
  2698  
  2699  	// Decide whether we are building a PIE,
  2700  	// bearing in mind that some systems default to PIE.
  2701  	isPIE := false
  2702  	if cfg.BuildBuildmode == "pie" {
  2703  		isPIE = true
  2704  	} else if cfg.BuildBuildmode == "default" && platform.DefaultPIE(cfg.BuildContext.GOOS, cfg.BuildContext.GOARCH, cfg.BuildRace) {
  2705  		isPIE = true
  2706  	}
  2707  	// If we are building a PIE, and we are on a system
  2708  	// that does not support PIE with internal linking mode,
  2709  	// then we must use external linking.
  2710  	if isPIE && !platform.InternalLinkPIESupported(cfg.BuildContext.GOOS, cfg.BuildContext.GOARCH) {
  2711  		if cfg.BuildBuildmode == "pie" {
  2712  			return "-buildmode=pie"
  2713  		}
  2714  		return "default PIE binary"
  2715  	}
  2716  
  2717  	// Using -ldflags=-linkmode=external forces external linking.
  2718  	// If there are multiple -linkmode options, the last one wins.
  2719  	if p != nil {
  2720  		ldflags := BuildLdflags.For(s, p)
  2721  		for i := len(ldflags) - 1; i >= 0; i-- {
  2722  			a := ldflags[i]
  2723  			if a == "-linkmode=external" ||
  2724  				a == "-linkmode" && i+1 < len(ldflags) && ldflags[i+1] == "external" {
  2725  				return a
  2726  			} else if a == "-linkmode=internal" ||
  2727  				a == "-linkmode" && i+1 < len(ldflags) && ldflags[i+1] == "internal" {
  2728  				return ""
  2729  			}
  2730  		}
  2731  	}
  2732  
  2733  	return ""
  2734  }
  2735  
  2736  // mkAbs rewrites list, which must be paths relative to p.Dir,
  2737  // into a sorted list of absolute paths. It edits list in place but for
  2738  // convenience also returns list back to its caller.
  2739  func (p *Package) mkAbs(list []string) []string {
  2740  	for i, f := range list {
  2741  		list[i] = filepath.Join(p.Dir, f)
  2742  	}
  2743  	sort.Strings(list)
  2744  	return list
  2745  }
  2746  
  2747  // InternalGoFiles returns the list of Go files being built for the package,
  2748  // using absolute paths.
  2749  func (p *Package) InternalGoFiles() []string {
  2750  	return p.mkAbs(str.StringList(p.GoFiles, p.CgoFiles, p.TestGoFiles))
  2751  }
  2752  
  2753  // InternalXGoFiles returns the list of Go files being built for the XTest package,
  2754  // using absolute paths.
  2755  func (p *Package) InternalXGoFiles() []string {
  2756  	return p.mkAbs(p.XTestGoFiles)
  2757  }
  2758  
  2759  // InternalAllGoFiles returns the list of all Go files possibly relevant for the package,
  2760  // using absolute paths. "Possibly relevant" means that files are not excluded
  2761  // due to build tags, but files with names beginning with . or _ are still excluded.
  2762  func (p *Package) InternalAllGoFiles() []string {
  2763  	return p.mkAbs(str.StringList(p.IgnoredGoFiles, p.GoFiles, p.CgoFiles, p.TestGoFiles, p.XTestGoFiles))
  2764  }
  2765  
  2766  // UsesSwig reports whether the package needs to run SWIG.
  2767  func (p *Package) UsesSwig() bool {
  2768  	return len(p.SwigFiles) > 0 || len(p.SwigCXXFiles) > 0
  2769  }
  2770  
  2771  // UsesCgo reports whether the package needs to run cgo
  2772  func (p *Package) UsesCgo() bool {
  2773  	return len(p.CgoFiles) > 0
  2774  }
  2775  
  2776  // PackageList returns the list of packages in the dag rooted at roots
  2777  // as visited in a depth-first post-order traversal.
  2778  func PackageList(roots []*Package) []*Package {
  2779  	seen := map[*Package]bool{}
  2780  	all := []*Package{}
  2781  	var walk func(*Package)
  2782  	walk = func(p *Package) {
  2783  		if seen[p] {
  2784  			return
  2785  		}
  2786  		seen[p] = true
  2787  		for _, p1 := range p.Internal.Imports {
  2788  			walk(p1)
  2789  		}
  2790  		all = append(all, p)
  2791  	}
  2792  	for _, root := range roots {
  2793  		walk(root)
  2794  	}
  2795  	return all
  2796  }
  2797  
  2798  // TestPackageList returns the list of packages in the dag rooted at roots
  2799  // as visited in a depth-first post-order traversal, including the test
  2800  // imports of the roots. This ignores errors in test packages.
  2801  func TestPackageList(loaderstate *modload.State, ctx context.Context, opts PackageOpts, roots []*Package) []*Package {
  2802  	seen := map[*Package]bool{}
  2803  	all := []*Package{}
  2804  	var walk func(*Package)
  2805  	walk = func(p *Package) {
  2806  		if seen[p] {
  2807  			return
  2808  		}
  2809  		seen[p] = true
  2810  		for _, p1 := range p.Internal.Imports {
  2811  			walk(p1)
  2812  		}
  2813  		all = append(all, p)
  2814  	}
  2815  	walkTest := func(root *Package, path string) {
  2816  		var stk ImportStack
  2817  		p1, err := loadImport(loaderstate, ctx, opts, nil, path, root.Dir, root, &stk, root.Internal.Build.TestImportPos[path], ResolveImport)
  2818  		if err != nil && root.Error == nil {
  2819  			// Assign error importing the package to the importer.
  2820  			root.Error = err
  2821  			root.Incomplete = true
  2822  		}
  2823  		if p1.Error == nil {
  2824  			walk(p1)
  2825  		}
  2826  	}
  2827  	for _, root := range roots {
  2828  		walk(root)
  2829  		for _, path := range root.TestImports {
  2830  			walkTest(root, path)
  2831  		}
  2832  		for _, path := range root.XTestImports {
  2833  			walkTest(root, path)
  2834  		}
  2835  	}
  2836  	return all
  2837  }
  2838  
  2839  // LoadImportWithFlags loads the package with the given import path and
  2840  // sets tool flags on that package. This function is useful loading implicit
  2841  // dependencies (like sync/atomic for coverage).
  2842  // TODO(jayconrod): delete this function and set flags automatically
  2843  // in LoadImport instead.
  2844  func LoadImportWithFlags(loaderstate *modload.State, path, srcDir string, parent *Package, stk *ImportStack, importPos []token.Position, mode int) (*Package, *PackageError) {
  2845  	p, err := loadImport(loaderstate, context.TODO(), PackageOpts{}, nil, path, srcDir, parent, stk, importPos, mode)
  2846  	setToolFlags(loaderstate, p)
  2847  	return p, err
  2848  }
  2849  
  2850  // LoadPackageWithFlags is the same as LoadImportWithFlags but without a parent.
  2851  // It's then guaranteed to not return an error
  2852  func LoadPackageWithFlags(loaderstate *modload.State, path, srcDir string, stk *ImportStack, importPos []token.Position, mode int) *Package {
  2853  	p := LoadPackage(loaderstate, context.TODO(), PackageOpts{}, path, srcDir, stk, importPos, mode)
  2854  	setToolFlags(loaderstate, p)
  2855  	return p
  2856  }
  2857  
  2858  // PackageOpts control the behavior of PackagesAndErrors and other package
  2859  // loading functions.
  2860  type PackageOpts struct {
  2861  	// IgnoreImports controls whether we ignore explicit and implicit imports
  2862  	// when loading packages.  Implicit imports are added when supporting Cgo
  2863  	// or SWIG and when linking main packages.
  2864  	IgnoreImports bool
  2865  
  2866  	// ModResolveTests indicates whether calls to the module loader should also
  2867  	// resolve test dependencies of the requested packages.
  2868  	//
  2869  	// If ModResolveTests is true, then the module loader needs to resolve test
  2870  	// dependencies at the same time as packages; otherwise, the test dependencies
  2871  	// of those packages could be missing, and resolving those missing dependencies
  2872  	// could change the selected versions of modules that provide other packages.
  2873  	ModResolveTests bool
  2874  
  2875  	// MainOnly is true if the caller only wants to load main packages.
  2876  	// For a literal argument matching a non-main package, a stub may be returned
  2877  	// with an error. For a non-literal argument (with "..."), non-main packages
  2878  	// are not be matched, and their dependencies may not be loaded. A warning
  2879  	// may be printed for non-literal arguments that match no main packages.
  2880  	MainOnly bool
  2881  
  2882  	// AutoVCS controls whether we also load version-control metadata for main packages
  2883  	// when -buildvcs=auto (the default).
  2884  	AutoVCS bool
  2885  
  2886  	// SuppressBuildInfo is true if the caller does not need p.Stale, p.StaleReason, or p.Internal.BuildInfo
  2887  	// to be populated on the package.
  2888  	SuppressBuildInfo bool
  2889  
  2890  	// SuppressEmbedFiles is true if the caller does not need any embed files to be populated on the
  2891  	// package.
  2892  	SuppressEmbedFiles bool
  2893  }
  2894  
  2895  // PackagesAndErrors returns the packages named by the command line arguments
  2896  // 'patterns'. If a named package cannot be loaded, PackagesAndErrors returns
  2897  // a *Package with the Error field describing the failure. If errors are found
  2898  // loading imported packages, the DepsErrors field is set. The Incomplete field
  2899  // may be set as well.
  2900  //
  2901  // To obtain a flat list of packages, use PackageList.
  2902  // To report errors loading packages, use ReportPackageErrors.
  2903  func PackagesAndErrors(loaderstate *modload.State, ctx context.Context, opts PackageOpts, patterns []string) []*Package {
  2904  	ctx, span := trace.StartSpan(ctx, "load.PackagesAndErrors")
  2905  	defer span.Done()
  2906  
  2907  	for _, p := range patterns {
  2908  		// Listing is only supported with all patterns referring to either:
  2909  		// - Files that are part of the same directory.
  2910  		// - Explicit package paths or patterns.
  2911  		if strings.HasSuffix(p, ".go") {
  2912  			// We need to test whether the path is an actual Go file and not a
  2913  			// package path or pattern ending in '.go' (see golang.org/issue/34653).
  2914  			if fi, err := fsys.Stat(p); err == nil && !fi.IsDir() {
  2915  				pkgs := []*Package{GoFilesPackage(loaderstate, ctx, opts, patterns)}
  2916  				setPGOProfilePath(pkgs)
  2917  				return pkgs
  2918  			}
  2919  		}
  2920  	}
  2921  
  2922  	var matches []*search.Match
  2923  	if modload.Init(loaderstate); cfg.ModulesEnabled {
  2924  		modOpts := modload.PackageOpts{
  2925  			ResolveMissingImports: true,
  2926  			LoadTests:             opts.ModResolveTests,
  2927  			SilencePackageErrors:  true,
  2928  		}
  2929  		matches, _ = modload.LoadPackages(loaderstate, ctx, modOpts, patterns...)
  2930  	} else {
  2931  		matches = search.ImportPaths(patterns)
  2932  	}
  2933  
  2934  	var (
  2935  		pkgs    []*Package
  2936  		stk     ImportStack
  2937  		seenPkg = make(map[*Package]bool)
  2938  	)
  2939  
  2940  	pre := newPreload()
  2941  	defer pre.flush()
  2942  	pre.preloadMatches(loaderstate, ctx, opts, matches)
  2943  
  2944  	for _, m := range matches {
  2945  		for _, pkg := range m.Pkgs {
  2946  			if pkg == "" {
  2947  				panic(fmt.Sprintf("ImportPaths returned empty package for pattern %s", m.Pattern()))
  2948  			}
  2949  			mode := cmdlinePkg
  2950  			if m.IsLiteral() {
  2951  				// Note: do not set = m.IsLiteral unconditionally
  2952  				// because maybe we'll see p matching both
  2953  				// a literal and also a non-literal pattern.
  2954  				mode |= cmdlinePkgLiteral
  2955  			}
  2956  			p, perr := loadImport(loaderstate, ctx, opts, pre, pkg, base.Cwd(), nil, &stk, nil, mode)
  2957  			if perr != nil {
  2958  				base.Fatalf("internal error: loadImport of %q with nil parent returned an error", pkg)
  2959  			}
  2960  			p.Match = append(p.Match, m.Pattern())
  2961  			if seenPkg[p] {
  2962  				continue
  2963  			}
  2964  			seenPkg[p] = true
  2965  			pkgs = append(pkgs, p)
  2966  		}
  2967  
  2968  		if len(m.Errs) > 0 {
  2969  			// In addition to any packages that were actually resolved from the
  2970  			// pattern, there was some error in resolving the pattern itself.
  2971  			// Report it as a synthetic package.
  2972  			p := new(Package)
  2973  			p.ImportPath = m.Pattern()
  2974  			// Pass an empty ImportStack and nil importPos: the error arose from a pattern, not an import.
  2975  			var stk ImportStack
  2976  			var importPos []token.Position
  2977  			p.setLoadPackageDataError(m.Errs[0], m.Pattern(), &stk, importPos)
  2978  			p.Incomplete = true
  2979  			p.Match = append(p.Match, m.Pattern())
  2980  			p.Internal.CmdlinePkg = true
  2981  			if m.IsLiteral() {
  2982  				p.Internal.CmdlinePkgLiteral = true
  2983  			}
  2984  			pkgs = append(pkgs, p)
  2985  		}
  2986  	}
  2987  
  2988  	if opts.MainOnly {
  2989  		pkgs = mainPackagesOnly(pkgs, matches)
  2990  	}
  2991  
  2992  	// Now that CmdlinePkg is set correctly,
  2993  	// compute the effective flags for all loaded packages
  2994  	// (not just the ones matching the patterns but also
  2995  	// their dependencies).
  2996  	setToolFlags(loaderstate, pkgs...)
  2997  
  2998  	setPGOProfilePath(pkgs)
  2999  
  3000  	return pkgs
  3001  }
  3002  
  3003  // setPGOProfilePath sets the PGO profile path for pkgs.
  3004  // In -pgo=auto mode, it finds the default PGO profile.
  3005  func setPGOProfilePath(pkgs []*Package) {
  3006  	updateBuildInfo := func(p *Package, file string) {
  3007  		// Don't create BuildInfo for packages that didn't already have it.
  3008  		if p.Internal.BuildInfo == nil {
  3009  			return
  3010  		}
  3011  
  3012  		if cfg.BuildTrimpath {
  3013  			appendBuildSetting(p.Internal.BuildInfo, "-pgo", filepath.Base(file))
  3014  		} else {
  3015  			appendBuildSetting(p.Internal.BuildInfo, "-pgo", file)
  3016  		}
  3017  		// Adding -pgo breaks the sort order in BuildInfo.Settings. Restore it.
  3018  		slices.SortFunc(p.Internal.BuildInfo.Settings, func(x, y debug.BuildSetting) int {
  3019  			return strings.Compare(x.Key, y.Key)
  3020  		})
  3021  	}
  3022  
  3023  	switch cfg.BuildPGO {
  3024  	case "off":
  3025  		return
  3026  
  3027  	case "auto":
  3028  		// Locate PGO profiles from the main packages, and
  3029  		// attach the profile to the main package and its
  3030  		// dependencies.
  3031  		// If we're building multiple main packages, they may
  3032  		// have different profiles. We may need to split (unshare)
  3033  		// the dependency graph so they can attach different
  3034  		// profiles.
  3035  		for _, p := range pkgs {
  3036  			if p.Name != "main" {
  3037  				continue
  3038  			}
  3039  			pmain := p
  3040  			file := filepath.Join(pmain.Dir, "default.pgo")
  3041  			if _, err := os.Stat(file); err != nil {
  3042  				continue // no profile
  3043  			}
  3044  
  3045  			// Packages already visited. The value should replace
  3046  			// the key, as it may be a forked copy of the original
  3047  			// Package.
  3048  			visited := make(map[*Package]*Package)
  3049  			var split func(p *Package) *Package
  3050  			split = func(p *Package) *Package {
  3051  				if p1 := visited[p]; p1 != nil {
  3052  					return p1
  3053  				}
  3054  
  3055  				if len(pkgs) > 1 && p != pmain {
  3056  					// Make a copy, then attach profile.
  3057  					// No need to copy if there is only one root package (we can
  3058  					// attach profile directly in-place).
  3059  					// Also no need to copy the main package.
  3060  					if p.Internal.PGOProfile != "" {
  3061  						panic("setPGOProfilePath: already have profile")
  3062  					}
  3063  					p1 := new(Package)
  3064  					*p1 = *p
  3065  					// Unalias the Imports and Internal.Imports slices,
  3066  					// which we're going to modify. We don't copy other slices as
  3067  					// we don't change them.
  3068  					p1.Imports = slices.Clone(p.Imports)
  3069  					p1.Internal.Imports = slices.Clone(p.Internal.Imports)
  3070  					p1.Internal.ForMain = pmain.ImportPath
  3071  					visited[p] = p1
  3072  					p = p1
  3073  				} else {
  3074  					visited[p] = p
  3075  				}
  3076  				p.Internal.PGOProfile = file
  3077  				updateBuildInfo(p, file)
  3078  				// Recurse to dependencies.
  3079  				for i, pp := range p.Internal.Imports {
  3080  					p.Internal.Imports[i] = split(pp)
  3081  				}
  3082  				return p
  3083  			}
  3084  
  3085  			// Replace the package and imports with the PGO version.
  3086  			split(pmain)
  3087  		}
  3088  
  3089  	default:
  3090  		// Profile specified from the command line.
  3091  		// Make it absolute path, as the compiler runs on various directories.
  3092  		file, err := filepath.Abs(cfg.BuildPGO)
  3093  		if err != nil {
  3094  			base.Fatalf("fail to get absolute path of PGO file %s: %v", cfg.BuildPGO, err)
  3095  		}
  3096  
  3097  		for _, p := range PackageList(pkgs) {
  3098  			p.Internal.PGOProfile = file
  3099  			updateBuildInfo(p, file)
  3100  		}
  3101  	}
  3102  }
  3103  
  3104  // CheckPackageErrors prints errors encountered loading pkgs and their
  3105  // dependencies, then exits with a non-zero status if any errors were found.
  3106  func CheckPackageErrors(pkgs []*Package) {
  3107  	PackageErrors(pkgs, func(p *Package) {
  3108  		DefaultPrinter().Errorf(p, "%v", p.Error)
  3109  	})
  3110  	base.ExitIfErrors()
  3111  }
  3112  
  3113  // PackageErrors calls report for errors encountered loading pkgs and their dependencies.
  3114  func PackageErrors(pkgs []*Package, report func(*Package)) {
  3115  	var anyIncomplete, anyErrors bool
  3116  	for _, pkg := range pkgs {
  3117  		if pkg.Incomplete {
  3118  			anyIncomplete = true
  3119  		}
  3120  	}
  3121  	if anyIncomplete {
  3122  		all := PackageList(pkgs)
  3123  		for _, p := range all {
  3124  			if p.Error != nil {
  3125  				report(p)
  3126  				anyErrors = true
  3127  			}
  3128  		}
  3129  	}
  3130  	if anyErrors {
  3131  		return
  3132  	}
  3133  
  3134  	// Check for duplicate loads of the same package.
  3135  	// That should be impossible, but if it does happen then
  3136  	// we end up trying to build the same package twice,
  3137  	// usually in parallel overwriting the same files,
  3138  	// which doesn't work very well.
  3139  	seen := map[string]bool{}
  3140  	reported := map[string]bool{}
  3141  	for _, pkg := range PackageList(pkgs) {
  3142  		// -pgo=auto with multiple main packages can cause a package being
  3143  		// built multiple times (with different profiles).
  3144  		// We check that package import path + profile path is unique.
  3145  		key := pkg.ImportPath
  3146  		if pkg.Internal.PGOProfile != "" {
  3147  			key += " pgo:" + pkg.Internal.PGOProfile
  3148  		}
  3149  		if seen[key] && !reported[key] {
  3150  			reported[key] = true
  3151  			base.Errorf("internal error: duplicate loads of %s", pkg.ImportPath)
  3152  		}
  3153  		seen[key] = true
  3154  	}
  3155  	if len(reported) > 0 {
  3156  		base.ExitIfErrors()
  3157  	}
  3158  }
  3159  
  3160  // mainPackagesOnly filters out non-main packages matched only by arguments
  3161  // containing "..." and returns the remaining main packages.
  3162  //
  3163  // Packages with missing, invalid, or ambiguous names may be treated as
  3164  // possibly-main packages.
  3165  //
  3166  // mainPackagesOnly sets a non-main package's Error field and returns it if it
  3167  // is named by a literal argument.
  3168  //
  3169  // mainPackagesOnly prints warnings for non-literal arguments that only match
  3170  // non-main packages.
  3171  func mainPackagesOnly(pkgs []*Package, matches []*search.Match) []*Package {
  3172  	treatAsMain := map[string]bool{}
  3173  	for _, m := range matches {
  3174  		if m.IsLiteral() {
  3175  			for _, path := range m.Pkgs {
  3176  				treatAsMain[path] = true
  3177  			}
  3178  		}
  3179  	}
  3180  
  3181  	var mains []*Package
  3182  	for _, pkg := range pkgs {
  3183  		if pkg.Name == "main" || (pkg.Name == "" && pkg.Error != nil) {
  3184  			treatAsMain[pkg.ImportPath] = true
  3185  			mains = append(mains, pkg)
  3186  			continue
  3187  		}
  3188  
  3189  		if len(pkg.InvalidGoFiles) > 0 { // TODO(#45999): && pkg.Name == "", but currently go/build sets pkg.Name arbitrarily if it is ambiguous.
  3190  			// The package has (or may have) conflicting names, and we can't easily
  3191  			// tell whether one of them is "main". So assume that it could be, and
  3192  			// report an error for the package.
  3193  			treatAsMain[pkg.ImportPath] = true
  3194  		}
  3195  		if treatAsMain[pkg.ImportPath] {
  3196  			if pkg.Error == nil {
  3197  				pkg.Error = &PackageError{Err: &mainPackageError{importPath: pkg.ImportPath}}
  3198  				pkg.Incomplete = true
  3199  			}
  3200  			mains = append(mains, pkg)
  3201  		}
  3202  	}
  3203  
  3204  	for _, m := range matches {
  3205  		if m.IsLiteral() || len(m.Pkgs) == 0 {
  3206  			continue
  3207  		}
  3208  		foundMain := false
  3209  		for _, path := range m.Pkgs {
  3210  			if treatAsMain[path] {
  3211  				foundMain = true
  3212  				break
  3213  			}
  3214  		}
  3215  		if !foundMain {
  3216  			fmt.Fprintf(os.Stderr, "go: warning: %q matched only non-main packages\n", m.Pattern())
  3217  		}
  3218  	}
  3219  
  3220  	return mains
  3221  }
  3222  
  3223  type mainPackageError struct {
  3224  	importPath string
  3225  }
  3226  
  3227  func (e *mainPackageError) Error() string {
  3228  	return fmt.Sprintf("package %s is not a main package", e.importPath)
  3229  }
  3230  
  3231  func (e *mainPackageError) ImportPath() string {
  3232  	return e.importPath
  3233  }
  3234  
  3235  func setToolFlags(loaderstate *modload.State, pkgs ...*Package) {
  3236  	for _, p := range PackageList(pkgs) {
  3237  		p.Internal.Asmflags = BuildAsmflags.For(loaderstate, p)
  3238  		p.Internal.Gcflags = BuildGcflags.For(loaderstate, p)
  3239  		p.Internal.Ldflags = BuildLdflags.For(loaderstate, p)
  3240  		p.Internal.Gccgoflags = BuildGccgoflags.For(loaderstate, p)
  3241  	}
  3242  }
  3243  
  3244  // GoFilesPackage creates a package for building a collection of Go files
  3245  // (typically named on the command line). The target is named p.a for
  3246  // package p or named after the first Go file for package main.
  3247  func GoFilesPackage(loaderstate *modload.State, ctx context.Context, opts PackageOpts, gofiles []string) *Package {
  3248  	modload.Init(loaderstate)
  3249  
  3250  	for _, f := range gofiles {
  3251  		if !strings.HasSuffix(f, ".go") {
  3252  			pkg := new(Package)
  3253  			pkg.Internal.Local = true
  3254  			pkg.Internal.CmdlineFiles = true
  3255  			pkg.Name = f
  3256  			pkg.Error = &PackageError{
  3257  				Err: fmt.Errorf("named files must be .go files: %s", pkg.Name),
  3258  			}
  3259  			pkg.Incomplete = true
  3260  			return pkg
  3261  		}
  3262  	}
  3263  
  3264  	var stk ImportStack
  3265  	ctxt := cfg.BuildContext
  3266  	ctxt.UseAllFiles = true
  3267  
  3268  	// Synthesize fake "directory" that only shows the named files,
  3269  	// to make it look like this is a standard package or
  3270  	// command directory. So that local imports resolve
  3271  	// consistently, the files must all be in the same directory.
  3272  	var dirent []fs.FileInfo
  3273  	var dir string
  3274  	for _, file := range gofiles {
  3275  		fi, err := fsys.Stat(file)
  3276  		if err != nil {
  3277  			base.Fatalf("%s", err)
  3278  		}
  3279  		if fi.IsDir() {
  3280  			base.Fatalf("%s is a directory, should be a Go file", file)
  3281  		}
  3282  		dir1 := filepath.Dir(file)
  3283  		if dir == "" {
  3284  			dir = dir1
  3285  		} else if dir != dir1 {
  3286  			base.Fatalf("named files must all be in one directory; have %s and %s", dir, dir1)
  3287  		}
  3288  		dirent = append(dirent, fi)
  3289  	}
  3290  	ctxt.ReadDir = func(string) ([]fs.FileInfo, error) { return dirent, nil }
  3291  
  3292  	if cfg.ModulesEnabled {
  3293  		modload.ImportFromFiles(loaderstate, ctx, gofiles)
  3294  	}
  3295  
  3296  	var err error
  3297  	if dir == "" {
  3298  		dir = base.Cwd()
  3299  	}
  3300  	dir, err = filepath.Abs(dir)
  3301  	if err != nil {
  3302  		base.Fatalf("%s", err)
  3303  	}
  3304  
  3305  	bp, err := ctxt.ImportDir(dir, 0)
  3306  	pkg := new(Package)
  3307  	pkg.Internal.Local = true
  3308  	pkg.Internal.CmdlineFiles = true
  3309  	pkg.load(loaderstate, ctx, opts, "command-line-arguments", &stk, nil, bp, err)
  3310  	if !cfg.ModulesEnabled {
  3311  		pkg.Internal.LocalPrefix = dirToImportPath(dir)
  3312  	}
  3313  	pkg.ImportPath = "command-line-arguments"
  3314  	pkg.Target = ""
  3315  	pkg.Match = gofiles
  3316  
  3317  	if pkg.Name == "main" {
  3318  		exe := pkg.DefaultExecName() + cfg.ExeSuffix
  3319  
  3320  		if cfg.GOBIN != "" {
  3321  			pkg.Target = filepath.Join(cfg.GOBIN, exe)
  3322  		} else if cfg.ModulesEnabled {
  3323  			pkg.Target = filepath.Join(modload.BinDir(loaderstate), exe)
  3324  		}
  3325  	}
  3326  
  3327  	if opts.MainOnly && pkg.Name != "main" && pkg.Error == nil {
  3328  		pkg.Error = &PackageError{Err: &mainPackageError{importPath: pkg.ImportPath}}
  3329  		pkg.Incomplete = true
  3330  	}
  3331  	setToolFlags(loaderstate, pkg)
  3332  
  3333  	return pkg
  3334  }
  3335  
  3336  // PackagesAndErrorsOutsideModule is like PackagesAndErrors but runs in
  3337  // module-aware mode and ignores the go.mod file in the current directory or any
  3338  // parent directory, if there is one. This is used in the implementation of 'go
  3339  // install pkg@version' and other commands that support similar forms.
  3340  //
  3341  // modload.ForceUseModules must be true, and modload.RootMode must be NoRoot
  3342  // before calling this function.
  3343  //
  3344  // PackagesAndErrorsOutsideModule imposes several constraints to avoid
  3345  // ambiguity. All arguments must have the same version suffix (not just a suffix
  3346  // that resolves to the same version). They must refer to packages in the same
  3347  // module, which must not be std or cmd. That module is not considered the main
  3348  // module, but its go.mod file (if it has one) must not contain directives that
  3349  // would cause it to be interpreted differently if it were the main module
  3350  // (replace, exclude).
  3351  func PackagesAndErrorsOutsideModule(loaderstate *modload.State, ctx context.Context, opts PackageOpts, args []string) ([]*Package, error) {
  3352  	if !loaderstate.ForceUseModules {
  3353  		panic("modload.ForceUseModules must be true")
  3354  	}
  3355  	if loaderstate.RootMode != modload.NoRoot {
  3356  		panic("modload.RootMode must be NoRoot")
  3357  	}
  3358  
  3359  	// Check that the arguments satisfy syntactic constraints.
  3360  	var version string
  3361  	var firstPath string
  3362  	for _, arg := range args {
  3363  		if i := strings.Index(arg, "@"); i >= 0 {
  3364  			firstPath, version = arg[:i], arg[i+1:]
  3365  			if version == "" {
  3366  				return nil, fmt.Errorf("%s: version must not be empty", arg)
  3367  			}
  3368  			break
  3369  		}
  3370  	}
  3371  	patterns := make([]string, len(args))
  3372  	for i, arg := range args {
  3373  		p, found := strings.CutSuffix(arg, "@"+version)
  3374  		if !found {
  3375  			return nil, fmt.Errorf("%s: all arguments must refer to packages in the same module at the same version (@%s)", arg, version)
  3376  		}
  3377  		switch {
  3378  		case build.IsLocalImport(p):
  3379  			return nil, fmt.Errorf("%s: argument must be a package path, not a relative path", arg)
  3380  		case filepath.IsAbs(p):
  3381  			return nil, fmt.Errorf("%s: argument must be a package path, not an absolute path", arg)
  3382  		case search.IsMetaPackage(p):
  3383  			return nil, fmt.Errorf("%s: argument must be a package path, not a meta-package", arg)
  3384  		case pathpkg.Clean(p) != p:
  3385  			return nil, fmt.Errorf("%s: argument must be a clean package path", arg)
  3386  		case !strings.Contains(p, "...") && search.IsStandardImportPath(p) && modindex.IsStandardPackage(cfg.GOROOT, cfg.BuildContext.Compiler, p):
  3387  			return nil, fmt.Errorf("%s: argument must not be a package in the standard library", arg)
  3388  		default:
  3389  			patterns[i] = p
  3390  		}
  3391  	}
  3392  	patterns = search.CleanPatterns(patterns)
  3393  
  3394  	// Query the module providing the first argument, load its go.mod file, and
  3395  	// check that it doesn't contain directives that would cause it to be
  3396  	// interpreted differently if it were the main module.
  3397  	//
  3398  	// If multiple modules match the first argument, accept the longest match
  3399  	// (first result). It's possible this module won't provide packages named by
  3400  	// later arguments, and other modules would. Let's not try to be too
  3401  	// magical though.
  3402  	allowed := loaderstate.CheckAllowed
  3403  	if modload.IsRevisionQuery(firstPath, version) {
  3404  		// Don't check for retractions if a specific revision is requested.
  3405  		allowed = nil
  3406  	}
  3407  	noneSelected := func(path string) (version string) { return "none" }
  3408  	qrs, err := modload.QueryPackages(loaderstate, ctx, patterns[0], version, noneSelected, allowed)
  3409  	if err != nil {
  3410  		return nil, fmt.Errorf("%s: %w", args[0], err)
  3411  	}
  3412  	rootMod := qrs[0].Mod
  3413  	deprecation, err := modload.CheckDeprecation(loaderstate, ctx, rootMod)
  3414  	if err != nil {
  3415  		return nil, fmt.Errorf("%s: %w", args[0], err)
  3416  	}
  3417  	if deprecation != "" {
  3418  		fmt.Fprintf(os.Stderr, "go: module %s is deprecated: %s\n", rootMod.Path, modload.ShortMessage(deprecation, ""))
  3419  	}
  3420  	data, err := loaderstate.Fetcher().GoMod(ctx, rootMod.Path, rootMod.Version)
  3421  	if err != nil {
  3422  		return nil, fmt.Errorf("%s: %w", args[0], err)
  3423  	}
  3424  	f, err := modfile.Parse("go.mod", data, nil)
  3425  	if err != nil {
  3426  		return nil, fmt.Errorf("%s (in %s): %w", args[0], rootMod, err)
  3427  	}
  3428  	directiveFmt := "%s (in %s):\n" +
  3429  		"\tThe go.mod file for the module providing named packages contains one or\n" +
  3430  		"\tmore %s directives. It must not contain directives that would cause\n" +
  3431  		"\tit to be interpreted differently than if it were the main module."
  3432  	if len(f.Replace) > 0 {
  3433  		return nil, fmt.Errorf(directiveFmt, args[0], rootMod, "replace")
  3434  	}
  3435  	if len(f.Exclude) > 0 {
  3436  		return nil, fmt.Errorf(directiveFmt, args[0], rootMod, "exclude")
  3437  	}
  3438  
  3439  	// Since we are in NoRoot mode, the build list initially contains only
  3440  	// the dummy command-line-arguments module. Add a requirement on the
  3441  	// module that provides the packages named on the command line.
  3442  	if _, err := modload.EditBuildList(loaderstate, ctx, nil, []module.Version{rootMod}); err != nil {
  3443  		return nil, fmt.Errorf("%s: %w", args[0], err)
  3444  	}
  3445  
  3446  	// Load packages for all arguments.
  3447  	pkgs := PackagesAndErrors(loaderstate, ctx, opts, patterns)
  3448  
  3449  	// Check that named packages are all provided by the same module.
  3450  	for _, pkg := range pkgs {
  3451  		var pkgErr error
  3452  		if pkg.Module == nil {
  3453  			// Packages in std, cmd, and their vendored dependencies
  3454  			// don't have this field set.
  3455  			pkgErr = fmt.Errorf("package %s not provided by module %s", pkg.ImportPath, rootMod)
  3456  		} else if pkg.Module.Path != rootMod.Path || pkg.Module.Version != rootMod.Version {
  3457  			pkgErr = fmt.Errorf("package %s provided by module %s@%s\n\tAll packages must be provided by the same module (%s).", pkg.ImportPath, pkg.Module.Path, pkg.Module.Version, rootMod)
  3458  		}
  3459  		if pkgErr != nil && pkg.Error == nil {
  3460  			pkg.Error = &PackageError{Err: pkgErr}
  3461  			pkg.Incomplete = true
  3462  		}
  3463  	}
  3464  
  3465  	matchers := make([]func(string) bool, len(patterns))
  3466  	for i, p := range patterns {
  3467  		if strings.Contains(p, "...") {
  3468  			matchers[i] = pkgpattern.MatchPattern(p)
  3469  		}
  3470  	}
  3471  	return pkgs, nil
  3472  }
  3473  
  3474  // EnsureImport ensures that package p imports the named package.
  3475  func EnsureImport(s *modload.State, p *Package, pkg string) {
  3476  	for _, d := range p.Internal.Imports {
  3477  		if d.Name == pkg {
  3478  			return
  3479  		}
  3480  	}
  3481  
  3482  	p1, err := LoadImportWithFlags(s, pkg, p.Dir, p, &ImportStack{}, nil, 0)
  3483  	if err != nil {
  3484  		base.Fatalf("load %s: %v", pkg, err)
  3485  	}
  3486  	if p1.Error != nil {
  3487  		base.Fatalf("load %s: %v", pkg, p1.Error)
  3488  	}
  3489  
  3490  	p.Internal.Imports = append(p.Internal.Imports, p1)
  3491  }
  3492  
  3493  // PrepareForCoverageBuild is a helper invoked for "go install
  3494  // -cover", "go run -cover", and "go build -cover" (but not used by
  3495  // "go test -cover"). It walks through the packages being built (and
  3496  // dependencies) and marks them for coverage instrumentation when
  3497  // appropriate, and possibly adding additional deps where needed.
  3498  func PrepareForCoverageBuild(s *modload.State, pkgs []*Package) {
  3499  	var match []func(*modload.State, *Package) bool
  3500  
  3501  	matchMainModAndCommandLine := func(_ *modload.State, p *Package) bool {
  3502  		// note that p.Standard implies p.Module == nil below.
  3503  		return p.Internal.CmdlineFiles || p.Internal.CmdlinePkg || (p.Module != nil && p.Module.Main)
  3504  	}
  3505  
  3506  	if len(cfg.BuildCoverPkg) != 0 {
  3507  		// If -coverpkg has been specified, then we instrument only
  3508  		// the specific packages selected by the user-specified pattern(s).
  3509  		match = make([]func(*modload.State, *Package) bool, len(cfg.BuildCoverPkg))
  3510  		for i := range cfg.BuildCoverPkg {
  3511  			match[i] = MatchPackage(cfg.BuildCoverPkg[i], base.Cwd())
  3512  		}
  3513  	} else {
  3514  		// Without -coverpkg, instrument only packages in the main module
  3515  		// (if any), as well as packages/files specifically named on the
  3516  		// command line.
  3517  		match = []func(*modload.State, *Package) bool{matchMainModAndCommandLine}
  3518  	}
  3519  
  3520  	// Visit the packages being built or installed, along with all of
  3521  	// their dependencies, and mark them to be instrumented, taking
  3522  	// into account the matchers we've set up in the sequence above.
  3523  	SelectCoverPackages(s, PackageList(pkgs), match, "build")
  3524  }
  3525  
  3526  func SelectCoverPackages(s *modload.State, roots []*Package, match []func(*modload.State, *Package) bool, op string) []*Package {
  3527  	var warntag string
  3528  	var includeMain bool
  3529  	switch op {
  3530  	case "build":
  3531  		warntag = "built"
  3532  		includeMain = true
  3533  	case "test":
  3534  		warntag = "tested"
  3535  	default:
  3536  		panic("internal error, bad mode passed to SelectCoverPackages")
  3537  	}
  3538  
  3539  	covered := []*Package{}
  3540  	matched := make([]bool, len(match))
  3541  	for _, p := range roots {
  3542  		haveMatch := false
  3543  		for i := range match {
  3544  			if match[i](s, p) {
  3545  				matched[i] = true
  3546  				haveMatch = true
  3547  			}
  3548  		}
  3549  		if !haveMatch {
  3550  			continue
  3551  		}
  3552  
  3553  		// There is nothing to cover in package unsafe; it comes from
  3554  		// the compiler.
  3555  		if p.ImportPath == "unsafe" {
  3556  			continue
  3557  		}
  3558  
  3559  		// A package which only has test files can't be imported as a
  3560  		// dependency, and at the moment we don't try to instrument it
  3561  		// for coverage. There isn't any technical reason why
  3562  		// *_test.go files couldn't be instrumented, but it probably
  3563  		// doesn't make much sense to lump together coverage metrics
  3564  		// (ex: percent stmts covered) of *_test.go files with
  3565  		// non-test Go code.
  3566  		if len(p.GoFiles)+len(p.CgoFiles) == 0 {
  3567  			continue
  3568  		}
  3569  
  3570  		// Silently ignore attempts to run coverage on sync/atomic
  3571  		// and/or internal/runtime/atomic when using atomic coverage
  3572  		// mode. Atomic coverage mode uses sync/atomic, so we can't
  3573  		// also do coverage on it.
  3574  		if cfg.BuildCoverMode == "atomic" && p.Standard &&
  3575  			(p.ImportPath == "sync/atomic" || p.ImportPath == "internal/runtime/atomic") {
  3576  			continue
  3577  		}
  3578  
  3579  		// If using the race detector, silently ignore attempts to run
  3580  		// coverage on the runtime packages. It will cause the race
  3581  		// detector to be invoked before it has been initialized. Note
  3582  		// the use of "regonly" instead of just ignoring the package
  3583  		// completely-- we do this due to the requirements of the
  3584  		// package ID numbering scheme. See the comment in
  3585  		// $GOROOT/src/internal/coverage/pkid.go dealing with
  3586  		// hard-coding of runtime package IDs.
  3587  		cmode := cfg.BuildCoverMode
  3588  		if cfg.BuildRace && p.Standard && objabi.LookupPkgSpecial(p.ImportPath).Runtime {
  3589  			cmode = "regonly"
  3590  		}
  3591  
  3592  		// If -coverpkg is in effect and for some reason we don't want
  3593  		// coverage data for the main package, make sure that we at
  3594  		// least process it for registration hooks.
  3595  		if includeMain && p.Name == "main" && !haveMatch {
  3596  			haveMatch = true
  3597  			cmode = "regonly"
  3598  		}
  3599  
  3600  		// Mark package for instrumentation.
  3601  		p.Internal.Cover.Mode = cmode
  3602  		covered = append(covered, p)
  3603  
  3604  		// Force import of sync/atomic into package if atomic mode.
  3605  		if cfg.BuildCoverMode == "atomic" {
  3606  			EnsureImport(s, p, "sync/atomic")
  3607  		}
  3608  	}
  3609  
  3610  	// Warn about -coverpkg arguments that are not actually used.
  3611  	for i := range cfg.BuildCoverPkg {
  3612  		if !matched[i] {
  3613  			fmt.Fprintf(os.Stderr, "warning: no packages being %s depend on matches for pattern %s\n", warntag, cfg.BuildCoverPkg[i])
  3614  		}
  3615  	}
  3616  
  3617  	return covered
  3618  }
  3619  

View as plain text