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Source file src/go/build/deps_test.go

     1  // Copyright 2022 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  // This file exercises the import parser but also checks that
     6  // some low-level packages do not have new dependencies added.
     7  
     8  package build
     9  
    10  import (
    11  	"bytes"
    12  	"fmt"
    13  	"go/token"
    14  	"internal/dag"
    15  	"internal/testenv"
    16  	"io/fs"
    17  	"os"
    18  	"path/filepath"
    19  	"slices"
    20  	"strings"
    21  	"testing"
    22  )
    23  
    24  // depsRules defines the expected dependencies between packages in
    25  // the Go source tree. It is a statement of policy.
    26  //
    27  // DO NOT CHANGE THIS DATA TO FIX BUILDS.
    28  // Existing packages should not have their constraints relaxed
    29  // without prior discussion.
    30  // Negative assertions should almost never be removed.
    31  //
    32  // "a < b" means package b can import package a.
    33  //
    34  // See `go doc internal/dag` for the full syntax.
    35  //
    36  // All-caps names are pseudo-names for specific points
    37  // in the dependency lattice.
    38  var depsRules = `
    39  	# No dependencies allowed for any of these packages.
    40  	NONE
    41  	< unsafe
    42  	< cmp,
    43  	  container/list,
    44  	  container/ring,
    45  	  internal/byteorder,
    46  	  internal/cfg,
    47  	  internal/coverage,
    48  	  internal/coverage/rtcov,
    49  	  internal/coverage/uleb128,
    50  	  internal/coverage/calloc,
    51  	  internal/cpu,
    52  	  internal/goarch,
    53  	  internal/godebugs,
    54  	  internal/goexperiment,
    55  	  internal/goos,
    56  	  internal/goversion,
    57  	  internal/nettrace,
    58  	  internal/platform,
    59  	  internal/profilerecord,
    60  	  internal/runtime/pprof/label,
    61  	  internal/simd/variants,
    62  	  internal/syslist,
    63  	  internal/trace/tracev2,
    64  	  internal/trace/traceviewer/format,
    65  	  log/internal,
    66  	  math/bits,
    67  	  structs,
    68  	  unicode,
    69  	  unicode/utf8,
    70  	  unicode/utf16;
    71  
    72  	internal/goarch < internal/abi;
    73  	internal/byteorder, internal/cpu, internal/goarch < internal/chacha8rand;
    74  	internal/goarch, math/bits < internal/strconv;
    75  
    76  	internal/strconv < simd/internal/simdfmt;
    77  	internal/cpu, simd/internal/simdfmt < simd/archsimd;
    78  
    79  	# RUNTIME is the core runtime group of packages, all of them very light-weight.
    80  	internal/abi,
    81  	internal/chacha8rand,
    82  	internal/coverage/rtcov,
    83  	internal/cpu,
    84  	internal/goarch,
    85  	internal/godebugs,
    86  	internal/goexperiment,
    87  	internal/goos,
    88  	internal/profilerecord,
    89  	internal/runtime/pprof/label,
    90  	internal/strconv,
    91  	internal/trace/tracev2,
    92  	math/bits,
    93  	structs,
    94  	simd/archsimd
    95  	< internal/bytealg
    96  	< internal/stringslite
    97  	< internal/unsafeheader
    98  	< internal/race
    99  	< internal/msan
   100  	< internal/asan
   101  	< internal/runtime/sys
   102  	< internal/runtime/syscall/linux
   103  	< internal/runtime/syscall/windows
   104  	< internal/runtime/atomic
   105  	< internal/runtime/exithook
   106  	< internal/runtime/gc
   107  	< internal/runtime/math
   108  	< internal/runtime/maps
   109  	< internal/runtime/cgroup
   110  	< internal/runtime/gc/scan
   111  	< runtime
   112  	< runtime/secret
   113  	< sync/atomic
   114  	< internal/sync
   115  	< weak
   116  	< internal/synctest
   117  	< sync
   118  	< internal/bisect
   119  	< internal/godebug
   120  	< internal/reflectlite
   121  	< errors
   122  	< internal/oserror;
   123  
   124  	cmp, runtime, math/bits
   125  	< iter
   126  	< maps, slices;
   127  
   128  	internal/oserror, maps, slices
   129  	< RUNTIME;
   130  
   131  	RUNTIME
   132  	< sort
   133  	< container/heap
   134  	< unique;
   135  
   136  	RUNTIME
   137  	< io;
   138  
   139  	RUNTIME
   140  	< arena;
   141  
   142  	syscall !< io;
   143  	reflect !< sort;
   144  
   145  	RUNTIME, unicode/utf8
   146  	< path;
   147  
   148  	unicode !< path;
   149  
   150  	# SYSCALL is RUNTIME plus the packages necessary for basic system calls.
   151  	RUNTIME, unicode/utf8, unicode/utf16, internal/synctest
   152  	< internal/syscall/windows/sysdll, syscall/js
   153  	< syscall
   154  	< internal/syscall/unix, internal/syscall/windows, internal/syscall/windows/registry
   155  	< internal/syscall/execenv
   156  	< SYSCALL;
   157  
   158  	# TIME is SYSCALL plus the core packages about time, including context.
   159  	SYSCALL
   160  	< time/tzdata
   161  	< time
   162  	< context
   163  	< TIME;
   164  
   165  	TIME, io, path, slices
   166  	< io/fs;
   167  
   168  	# MATH is RUNTIME plus the basic math packages.
   169  	RUNTIME
   170  	< math
   171  	< MATH;
   172  
   173  	unicode !< math;
   174  
   175  	MATH
   176  	< math/cmplx;
   177  
   178  	MATH
   179  	< math/rand, math/rand/v2;
   180  
   181  	MATH
   182  	< runtime/metrics;
   183  
   184  	MATH, unicode/utf8
   185  	< strconv;
   186  
   187  	unicode !< strconv;
   188  
   189  	# STR is basic string and buffer manipulation.
   190  	RUNTIME, io, unicode/utf8, unicode/utf16, unicode
   191  	< bytes, strings
   192  	< bufio;
   193  
   194  	bufio, path, strconv
   195  	< STR;
   196  
   197  	# OS is basic OS access, including helpers (path/filepath, os/exec, etc).
   198  	# OS includes string routines, but those must be layered above package os.
   199  	# OS does not include reflection.
   200  	io/fs
   201  	< internal/testlog
   202  	< internal/poll
   203  	< internal/filepathlite
   204  	< os
   205  	< os/signal;
   206  
   207  	io/fs
   208  	< embed;
   209  
   210  	unicode, fmt !< net, os, os/signal;
   211  
   212  	os/signal, internal/filepathlite, STR
   213  	< path/filepath
   214  	< io/ioutil;
   215  
   216  	path/filepath, internal/godebug < os/exec;
   217  
   218  	io/ioutil, os/exec, os/signal
   219  	< OS;
   220  
   221  	reflect !< OS;
   222  
   223  	OS
   224  	< golang.org/x/sys/cpu;
   225  
   226  	# FMT is OS (which includes string routines) plus reflect and fmt.
   227  	# It does not include package log, which should be avoided in core packages.
   228  	arena, strconv, unicode
   229  	< reflect;
   230  
   231  	os, reflect
   232  	< internal/fmtsort
   233  	< fmt;
   234  
   235  	OS, fmt
   236  	< FMT;
   237  
   238  	log !< FMT;
   239  
   240  	# Misc packages needing only FMT.
   241  	FMT
   242  	< html,
   243  	  internal/dag,
   244  	  internal/goroot,
   245  	  internal/types/errors,
   246  	  mime/quotedprintable,
   247  	  net/internal/socktest,
   248  	  runtime/trace,
   249  	  text/scanner,
   250  	  text/tabwriter;
   251  
   252  	io, reflect
   253  	< internal/saferio;
   254  
   255  	# encodings
   256  	# core ones do not use fmt.
   257  	io, strconv, slices
   258  	< encoding, encoding/base32, encoding/base64;
   259  
   260  	encoding, reflect
   261  	< encoding/binary;
   262  
   263  	FMT, encoding < flag;
   264  
   265  	FMT, MATH
   266  	< simd/internal/spec
   267  	< simd/internal/simdref;
   268  
   269  	FMT, simd/archsimd < simd/internal/bridge;
   270  
   271  	simd/internal/bridge, internal/simd/variants < simd;
   272  
   273  	fmt !< encoding/base32, encoding/base64;
   274  
   275  	FMT, encoding, encoding/base32, encoding/base64, encoding/binary,
   276  	internal/saferio
   277  	< encoding/ascii85, encoding/csv, encoding/gob, encoding/hex,
   278  	  encoding/pem, encoding/xml, mime;
   279  
   280  	STR, errors
   281  	< encoding/json/internal
   282  	< encoding/json/internal/jsonflags
   283  	< encoding/json/internal/jsonopts
   284  	< encoding/json/internal/jsonwire
   285  	< encoding/json/jsontext;
   286  
   287  	FMT,
   288  	encoding/hex,
   289  	encoding/base32,
   290  	encoding/base64,
   291  	encoding/binary,
   292  	encoding/json/jsontext,
   293  	encoding/json/internal,
   294  	encoding/json/internal/jsonflags,
   295  	encoding/json/internal/jsonopts,
   296  	encoding/json/internal/jsonwire
   297  	< encoding/json/v2
   298  	< encoding/json;
   299  
   300  	# hashes
   301  	io
   302  	< hash
   303  	< hash/adler32, hash/crc32, hash/crc64, hash/fnv, hash/maphash;
   304  
   305  	# math/big
   306  	FMT, math/rand
   307  	< math/big;
   308  
   309  	# compression
   310  	FMT, encoding/binary, hash/adler32, hash/crc32, sort
   311  	< compress/bzip2, compress/flate, compress/lzw, internal/zstd
   312  	< archive/zip, compress/gzip, compress/zlib;
   313  
   314  	# templates
   315  	FMT
   316  	< text/template/parse;
   317  
   318  	internal/bytealg, math/bits, slices, strconv, unique
   319  	< net/netip;
   320  
   321  	FMT, net/netip
   322  	< net/url;
   323  
   324  	net/url, text/template/parse
   325  	< text/template
   326  	< internal/lazytemplate;
   327  
   328  	# regexp
   329  	FMT, sort
   330  	< regexp/syntax
   331  	< regexp
   332  	< internal/lazyregexp;
   333  
   334  	encoding/json, html, text/template, regexp
   335  	< html/template;
   336  
   337  	# suffix array
   338  	encoding/binary, regexp
   339  	< index/suffixarray;
   340  
   341  	# executable parsing
   342  	FMT, encoding/binary, compress/zlib, internal/saferio, internal/zstd, sort
   343  	< runtime/debug
   344  	< debug/dwarf
   345  	< debug/elf, debug/gosym, debug/macho, debug/pe, debug/plan9obj, internal/xcoff
   346  	< debug/buildinfo
   347  	< DEBUG;
   348  
   349  	# go parser and friends.
   350  	FMT, sort
   351  	< internal/gover
   352  	< go/version
   353  	< go/token
   354  	< go/scanner
   355  	< go/ast
   356  	< go/internal/typeparams;
   357  
   358  	FMT
   359  	< go/build/constraint;
   360  
   361  	FMT, sort
   362  	< go/doc/comment;
   363  
   364  	go/internal/typeparams, go/build/constraint
   365  	< go/parser;
   366  
   367  	go/doc/comment, go/parser, text/tabwriter
   368  	< go/printer
   369  	< go/format;
   370  
   371  	math/big, go/token
   372  	< go/constant;
   373  
   374  	FMT, internal/goexperiment
   375  	< internal/buildcfg;
   376  
   377  	# The vast majority of standard library packages should not be resorting to regexp.
   378  	# go/types is a good chokepoint. It shouldn't use regexp, nor should anything
   379  	# that is low-enough level to be used by go/types.
   380  	regexp !< go/types;
   381  
   382  	go/doc/comment, go/parser, internal/lazyregexp, text/template
   383  	< go/doc;
   384  
   385  	go/build/constraint, go/doc, go/parser, internal/buildcfg, internal/goroot, internal/goversion, internal/platform, internal/syslist
   386  	< go/build;
   387  
   388  	# images
   389  	FMT, compress/lzw, compress/zlib
   390  	< image/color
   391  	< image, image/color/palette
   392  	< image/internal/imageutil
   393  	< image/draw
   394  	< image/gif, image/jpeg, image/png;
   395  
   396  	# cgo, delayed as long as possible.
   397  	# If you add a dependency on CGO, you must add the package
   398  	# to cgoPackages in cmd/dist/test.go as well.
   399  	RUNTIME
   400  	< C
   401  	< runtime/cgo
   402  	< CGO
   403  	< runtime/msan, runtime/asan;
   404  
   405  	# runtime/race
   406  	NONE < runtime/race/internal/amd64v1;
   407  	NONE < runtime/race/internal/amd64v3;
   408  	CGO, runtime/race/internal/amd64v1, runtime/race/internal/amd64v3 < runtime/race;
   409  
   410  	# Bulk of the standard library must not use cgo.
   411  	# The prohibition stops at net and os/user.
   412  	C !< fmt, go/types, CRYPTO-MATH, log/slog;
   413  
   414  	CGO, OS
   415  	< plugin;
   416  
   417  	CGO, FMT
   418  	< os/user
   419  	< archive/tar;
   420  
   421  	sync
   422  	< internal/singleflight;
   423  
   424  	os
   425  	< golang.org/x/net/dns/dnsmessage,
   426  	  golang.org/x/net/lif;
   427  
   428  	os, net/netip
   429  	< internal/routebsd;
   430  
   431  	# net is unavoidable when doing any networking,
   432  	# so large dependencies must be kept out.
   433  	# This is a long-looking list but most of these
   434  	# are small with few dependencies.
   435  	CGO,
   436  	golang.org/x/net/dns/dnsmessage,
   437  	golang.org/x/net/lif,
   438  	internal/godebug,
   439  	internal/goversion,
   440  	internal/nettrace,
   441  	internal/poll,
   442  	internal/routebsd,
   443  	internal/singleflight,
   444  	net/netip,
   445  	os,
   446  	sort
   447  	< net;
   448  
   449  	fmt, unicode !< net;
   450  	math/rand !< net; # net uses runtime instead
   451  
   452  	# NET is net plus net-helper packages.
   453  	FMT, net
   454  	< net/textproto;
   455  
   456  	mime, net/textproto, net/url
   457  	< NET;
   458  
   459  	# logging - most packages should not import; http and up is allowed
   460  	FMT, log/internal
   461  	< log;
   462  
   463  	log, log/slog !< crypto/tls, database/sql, go/importer, testing;
   464  
   465  	FMT, log, net
   466  	< log/syslog;
   467  
   468  	RUNTIME
   469  	< log/slog/internal, log/slog/internal/buffer;
   470  
   471  	FMT,
   472  	encoding, encoding/json,
   473  	log, log/internal,
   474  	log/slog/internal, log/slog/internal/buffer,
   475  	slices
   476  	< log/slog
   477  	< log/slog/internal/slogtest, log/slog/internal/benchmarks;
   478  
   479  	NET, log
   480  	< net/mail;
   481  
   482  	# FIPS is the FIPS 140 module.
   483  	# It must not depend on external crypto packages.
   484  	# Package hash is ok as it's only the interface.
   485  	# See also fips140deps.AllowedInternalPackages.
   486  
   487  	io, math/rand/v2 < crypto/internal/randutil;
   488  
   489  	NONE < crypto/internal/constanttime;
   490  
   491  	STR < crypto/internal/impl;
   492  
   493  	OS < crypto/internal/sysrand
   494  	< crypto/internal/entropy;
   495  
   496  	internal/byteorder < crypto/internal/fips140deps/byteorder;
   497  	internal/cpu, internal/goarch < crypto/internal/fips140deps/cpu;
   498  	internal/godebug < crypto/internal/fips140deps/godebug;
   499  	time, internal/syscall/windows < crypto/internal/fips140deps/time;
   500  
   501  	crypto/internal/fips140deps/time, errors, math/bits, sync/atomic, unsafe
   502  	< crypto/internal/entropy/v1.0.0;
   503  
   504  	STR, hash,
   505  	crypto/internal/impl,
   506  	crypto/internal/entropy,
   507  	crypto/internal/randutil,
   508  	crypto/internal/constanttime,
   509  	crypto/internal/entropy/v1.0.0,
   510  	crypto/internal/fips140deps/byteorder,
   511  	crypto/internal/fips140deps/cpu,
   512  	crypto/internal/fips140deps/godebug
   513  	< crypto/internal/fips140
   514  	< crypto/internal/fips140/alias
   515  	< crypto/internal/fips140/subtle
   516  	< crypto/internal/fips140/sha256
   517  	< crypto/internal/fips140/sha512
   518  	< crypto/internal/fips140/sha3
   519  	< crypto/internal/fips140/hmac
   520  	< crypto/internal/fips140/check
   521  	< crypto/internal/fips140/pbkdf2
   522  	< crypto/internal/fips140/aes
   523  	< crypto/internal/fips140/drbg
   524  	< crypto/internal/fips140/aes/gcm
   525  	< crypto/internal/fips140/hkdf
   526  	< crypto/internal/fips140/mlkem
   527  	< crypto/internal/fips140/mldsa
   528  	< crypto/internal/fips140/ssh
   529  	< crypto/internal/fips140/tls12
   530  	< crypto/internal/fips140/tls13
   531  	< crypto/internal/fips140/bigmod
   532  	< crypto/internal/fips140/nistec/fiat
   533  	< crypto/internal/fips140/nistec
   534  	< crypto/internal/fips140/ecdh
   535  	< crypto/internal/fips140/ecdsa
   536  	< crypto/internal/fips140/edwards25519/field
   537  	< crypto/internal/fips140/edwards25519
   538  	< crypto/internal/fips140/ed25519
   539  	< crypto/internal/fips140/rsa
   540  	< crypto/fips140 < FIPS;
   541  
   542  	crypto !< FIPS;
   543  
   544  	# CRYPTO is core crypto algorithms - no cgo, fmt, net.
   545  	# Mostly wrappers around the FIPS module.
   546  
   547  	NONE < crypto/internal/boring/sig, crypto/internal/boring/syso;
   548  	sync/atomic < crypto/internal/boring/bcache;
   549  
   550  	FIPS, internal/godebug, embed,
   551  	crypto/internal/boring/sig,
   552  	crypto/internal/boring/syso,
   553  	crypto/internal/boring/bcache
   554  	< crypto/internal/fips140only
   555  	< crypto
   556  	< crypto/subtle
   557  	< crypto/sha3
   558  	< crypto/internal/fips140hash
   559  	< crypto/cipher
   560  	< crypto/internal/boring
   561  	< crypto/boring
   562  	< crypto/internal/rand
   563  	< crypto/aes,
   564  	  crypto/des,
   565  	  crypto/rc4,
   566  	  crypto/md5,
   567  	  crypto/sha1,
   568  	  crypto/sha256,
   569  	  crypto/sha512,
   570  	  crypto/hmac,
   571  	  crypto/hkdf,
   572  	  crypto/pbkdf2,
   573  	  crypto/ecdh,
   574  	  crypto/mlkem,
   575  	  crypto/mldsa
   576  	< CRYPTO;
   577  
   578  	CRYPTO
   579  	< golang.org/x/crypto/hkdf;
   580  
   581  	CGO, fmt, net !< CRYPTO;
   582  
   583  	# CRYPTO-MATH is crypto that exposes math/big APIs - no cgo, net; fmt now ok.
   584  
   585  	CRYPTO, FMT, math/big, internal/saferio
   586  	< crypto/internal/boring/bbig
   587  	< crypto/internal/fips140cache
   588  	< crypto/rand
   589  	< crypto/ed25519 # depends on crypto/rand.Reader
   590  	< encoding/asn1
   591  	< golang.org/x/crypto/cryptobyte/asn1
   592  	< golang.org/x/crypto/cryptobyte
   593  	< crypto/dsa, crypto/elliptic, crypto/rsa
   594  	< crypto/ecdsa
   595  	< CRYPTO-MATH;
   596  
   597  	CGO, net !< CRYPTO-MATH;
   598  
   599  	# uuids
   600  	crypto/rand, errors, encoding/binary, encoding/hex
   601  	< uuid;
   602  
   603  	# databases
   604  	FMT, uuid
   605  	< database/sql/internal
   606  	< database/sql/driver;
   607  
   608  	database/sql/driver, math/rand/v2 < database/sql;
   609  
   610  	# TLS, Prince of Dependencies.
   611  
   612  	crypto/fips140, sync/atomic < crypto/tls/internal/fips140tls;
   613  
   614  	crypto/internal/boring/sig, crypto/tls/internal/fips140tls < crypto/tls/fipsonly;
   615  
   616  	CRYPTO, golang.org/x/sys/cpu, encoding/binary, reflect
   617  	< golang.org/x/crypto/internal/alias
   618  	< golang.org/x/crypto/internal/subtle
   619  	< golang.org/x/crypto/chacha20
   620  	< golang.org/x/crypto/internal/poly1305
   621  	< golang.org/x/crypto/chacha20poly1305;
   622  
   623  	CRYPTO-MATH, golang.org/x/crypto/chacha20poly1305
   624  	< crypto/hpke;
   625  
   626  	CRYPTO-MATH, NET, container/list, encoding/hex, encoding/pem, crypto/hpke,
   627  	golang.org/x/crypto/chacha20poly1305, crypto/tls/internal/fips140tls
   628  	< crypto/x509/internal/macos
   629  	< crypto/x509/pkix
   630  	< crypto/x509
   631  	< crypto/tls;
   632  
   633  	# crypto-aware packages
   634  
   635  	FMT, hash/maphash
   636  	< container/hash;
   637  
   638  	hash/maphash, container/heap, go/constant, go/parser, internal/buildcfg, internal/goversion, internal/types/errors
   639  	< go/types;
   640  
   641  	# x/tools
   642  	# These are the only allowed dependencies of gcexportdata. Any change here
   643  	# must be mirrored in x/tools/go/gcexportdata/deps_test.go.
   644  	FMT, STR, crypto/md5, encoding/binary, encoding/json, go/build, go/token, go/types
   645  	< golang.org/x/tools/go/types/objectpath,
   646  	  golang.org/x/tools/internal/pkgbits
   647  	< golang.org/x/tools/internal/gcimporter
   648  	< golang.org/x/tools/go/gcexportdata;
   649  
   650  	# go/importer
   651  	DEBUG, crypto/sha256, go/build, go/types, text/scanner
   652  	< internal/exportdata, internal/pkgbits;
   653  
   654  	golang.org/x/tools/go/gcexportdata, internal/exportdata, internal/pkgbits
   655  	< go/internal/gcimporter;
   656  
   657  	internal/exportdata, internal/pkgbits
   658  	< go/internal/gccgoimporter, go/internal/srcimporter;
   659  
   660  	go/internal/gccgoimporter, go/internal/gcimporter, go/internal/srcimporter
   661  	< go/importer;
   662  
   663  	NET, crypto/rand, mime/quotedprintable
   664  	< mime/multipart;
   665  
   666  	crypto/tls
   667  	< net/smtp;
   668  
   669  	# HTTP, King of Dependencies.
   670  
   671  	context
   672  	< internal/gate;
   673  
   674  	FMT, encoding/binary
   675  	< golang.org/x/net/http2/hpack
   676  	< net/http/internal, net/http/internal/ascii, net/http/internal/testcert;
   677  
   678  	FMT, NET, container/list, encoding/binary, log
   679  	< golang.org/x/text/transform
   680  	< golang.org/x/text/unicode/norm
   681  	< golang.org/x/text/unicode/bidi
   682  	< golang.org/x/text/secure/bidirule
   683  	< golang.org/x/net/idna
   684  	< golang.org/x/net/http/httpguts, golang.org/x/net/http/httpproxy;
   685  
   686  	NET, crypto/tls
   687  	< net/http/httptrace;
   688  
   689  	compress/gzip,
   690  	golang.org/x/net/http/httpguts,
   691  	golang.org/x/net/http/httpproxy,
   692  	golang.org/x/net/http2/hpack,
   693  	net/http/internal,
   694  	net/http/internal/ascii,
   695  	net/http/internal/testcert,
   696  	net/http/httptrace,
   697  	mime/multipart,
   698  	log
   699  	< net/http/internal/httpcommon, net/http/internal/httpsfv
   700  	< net/http/internal/http2
   701  	< net/http;
   702  
   703  	net/http, golang.org/x/crypto/hkdf, log/slog
   704  	< golang.org/x/net/internal/quic/quicwire
   705  	< golang.org/x/net/quic
   706  	< net/http/internal/http3;
   707  
   708  	# HTTP-aware packages
   709  
   710  	encoding/json, net/http
   711  	< expvar;
   712  
   713  	net/http, net/http/internal/ascii
   714  	< net/http/cookiejar, net/http/httputil;
   715  
   716  	net/http, regexp
   717  	< net/http/cgi
   718  	< net/http/fcgi;
   719  
   720  	# Profiling
   721  	internal/runtime/pprof/label, runtime, context < internal/runtime/pprof;
   722  	FMT, compress/gzip, encoding/binary, sort, text/tabwriter, internal/runtime/pprof, internal/runtime/pprof/label
   723  	< runtime/pprof;
   724  
   725  	OS, compress/gzip, internal/lazyregexp
   726  	< internal/profile;
   727  
   728  	html, internal/profile, net/http, runtime/pprof, runtime/trace
   729  	< net/http/pprof;
   730  
   731  	# RPC
   732  	encoding/gob, encoding/json, go/token, html/template, net/http
   733  	< net/rpc
   734  	< net/rpc/jsonrpc;
   735  
   736  	# System Information
   737  	bufio, bytes, internal/cpu, io, os, strings, sync
   738  	< internal/sysinfo;
   739  
   740  	# Test-only
   741  	log
   742  	< testing/iotest
   743  	< testing/fstest;
   744  
   745  	FMT, flag, math/rand
   746  	< testing/quick;
   747  
   748  	FMT, DEBUG, flag, runtime/trace, internal/sysinfo, math/rand
   749  	< testing;
   750  
   751  	testing, math
   752  	< simd/archsimd/internal/test_helpers, simd/internal/test_helpers;
   753  
   754  	log/slog, testing
   755  	< testing/slogtest;
   756  
   757  	testing, crypto/rand
   758  	< testing/cryptotest;
   759  
   760  	NET, internal/gate
   761  	< internal/nettest;
   762  
   763  	net/http, flag, internal/nettest, testing
   764  	< net/http/httptest;
   765  
   766  	FMT, crypto/sha256, encoding/binary, encoding/json,
   767  	go/ast, go/parser, go/token,
   768  	internal/godebug, math/rand, encoding/hex
   769  	< internal/fuzz;
   770  
   771  	OS, flag, testing, internal/cfg, internal/platform, internal/goroot
   772  	< internal/testenv;
   773  
   774  	OS, encoding/base64
   775  	< internal/obscuretestdata;
   776  
   777  	CGO, OS, fmt
   778  	< internal/testpty;
   779  
   780  	NET, testing, math/rand
   781  	< golang.org/x/net/nettest;
   782  
   783  	syscall
   784  	< os/exec/internal/fdtest;
   785  
   786  	FMT, sort
   787  	< internal/diff;
   788  
   789  	FMT
   790  	< internal/txtar;
   791  
   792  	internal/synctest, testing
   793  	< testing/synctest;
   794  
   795  	testing
   796  	< internal/testhash;
   797  
   798  	CRYPTO-MATH
   799  	< crypto/mlkem/mlkemtest;
   800  
   801  	CRYPTO-MATH, testing, internal/testenv, internal/testhash, encoding/json, regexp
   802  	< crypto/internal/cryptotest;
   803  
   804  	crypto/internal/cryptotest, encoding/hex
   805  	< crypto/internal/cryptotest/wycheproof;
   806  
   807  	FMT, encoding/json, time, regexp
   808  	< crypto/internal/cryptotest/x509limbo;
   809  
   810  	CGO, FMT
   811  	< crypto/internal/sysrand/internal/seccomp;
   812  
   813  	FIPS
   814  	< crypto/internal/fips140/check/checktest;
   815  
   816  	# v2 execution trace parser.
   817  	FMT, io, internal/trace/tracev2
   818  	< internal/trace/version;
   819  
   820  	FMT, encoding/binary, internal/trace/version
   821  	< internal/trace/raw;
   822  
   823  	FMT, internal/trace/version, io, sort, encoding/binary
   824  	< internal/trace/internal/tracev1;
   825  
   826  	FMT, encoding/binary, internal/trace/version, internal/trace/internal/tracev1, container/heap, math/rand, regexp
   827  	< internal/trace;
   828  
   829  	# cmd/trace dependencies.
   830  	FMT,
   831  	embed,
   832  	encoding/json,
   833  	html/template,
   834  	internal/profile,
   835  	internal/trace,
   836  	internal/trace/traceviewer/format,
   837  	net/http
   838  	< internal/trace/traceviewer;
   839  
   840  	# Coverage.
   841  	FMT, hash/fnv, encoding/binary, regexp, sort, text/tabwriter,
   842  	internal/coverage, internal/coverage/uleb128
   843  	< internal/coverage/cmerge,
   844  	  internal/coverage/pods,
   845  	  internal/coverage/slicereader,
   846  	  internal/coverage/slicewriter;
   847  
   848  	internal/coverage/slicereader, internal/coverage/slicewriter
   849  	< internal/coverage/stringtab
   850  	< internal/coverage/decodecounter, internal/coverage/decodemeta,
   851  	  internal/coverage/encodecounter, internal/coverage/encodemeta;
   852  
   853  	internal/coverage/cmerge
   854  	< internal/coverage/cformat;
   855  
   856  	internal/coverage, crypto/sha256, FMT
   857  	< cmd/internal/cov/covcmd;
   858  
   859  	encoding/json,
   860  	runtime/debug,
   861  	internal/coverage/calloc,
   862  	internal/coverage/cformat,
   863  	internal/coverage/decodecounter, internal/coverage/decodemeta,
   864  	internal/coverage/encodecounter, internal/coverage/encodemeta,
   865  	internal/coverage/pods
   866  	< internal/coverage/cfile
   867  	< runtime/coverage;
   868  
   869  	internal/coverage/cfile, internal/fuzz, internal/testlog, runtime/pprof, regexp
   870  	< testing/internal/testdeps;
   871  
   872  	# Test-only packages can have anything they want
   873  
   874  	FMT, compress/gzip, embed, encoding/binary
   875  	< encoding/json/internal/jsontest;
   876  
   877  	CGO, internal/syscall/unix
   878  	< net/internal/cgotest;
   879  
   880  	FMT, testing
   881  	< internal/cgrouptest;
   882  
   883  	regexp, internal/testenv, internal/trace, internal/trace/raw, internal/txtar, testing
   884  	< internal/trace/testtrace;
   885  
   886  	C, CGO
   887  	< internal/runtime/cgobench;
   888  
   889  	# Generate-only packages can have anything they want.
   890  
   891  	container/heap,
   892  	encoding/binary,
   893  	fmt,
   894  	hash/maphash,
   895  	io,
   896  	log,
   897  	math/bits,
   898  	os,
   899  	reflect,
   900  	strings,
   901  	sync
   902  	< internal/runtime/gc/internal/gen;
   903  
   904  	regexp, internal/txtar, internal/trace, internal/trace/raw
   905  	< internal/trace/internal/testgen;
   906  
   907  	FMT
   908  	< math/big/internal/asmgen;
   909  `
   910  
   911  // listStdPkgs returns the same list of packages as "go list std".
   912  func listStdPkgs(goroot string) ([]string, error) {
   913  	// Based on cmd/go's matchPackages function.
   914  	var pkgs []string
   915  
   916  	src := filepath.Join(goroot, "src") + string(filepath.Separator)
   917  	walkFn := func(path string, d fs.DirEntry, err error) error {
   918  		if err != nil || !d.IsDir() || path == src {
   919  			return nil
   920  		}
   921  
   922  		base := filepath.Base(path)
   923  		if strings.HasPrefix(base, ".") || strings.HasPrefix(base, "_") || base == "testdata" {
   924  			return filepath.SkipDir
   925  		}
   926  
   927  		name := filepath.ToSlash(path[len(src):])
   928  		if name == "builtin" || name == "cmd" {
   929  			return filepath.SkipDir
   930  		}
   931  
   932  		pkgs = append(pkgs, strings.TrimPrefix(name, "vendor/"))
   933  		return nil
   934  	}
   935  	if err := filepath.WalkDir(src, walkFn); err != nil {
   936  		return nil, err
   937  	}
   938  	return pkgs, nil
   939  }
   940  
   941  func TestDependencies(t *testing.T) {
   942  	testenv.MustHaveSource(t)
   943  
   944  	ctxt := Default
   945  	all, err := listStdPkgs(ctxt.GOROOT)
   946  	if err != nil {
   947  		t.Fatal(err)
   948  	}
   949  	slices.Sort(all)
   950  
   951  	sawImport := map[string]map[string]bool{} // from package => to package => true
   952  	policy := depsPolicy(t)
   953  
   954  	for _, pkg := range all {
   955  		imports, err := findImports(pkg)
   956  		if err != nil {
   957  			t.Error(err)
   958  			continue
   959  		}
   960  		if sawImport[pkg] == nil {
   961  			sawImport[pkg] = map[string]bool{}
   962  		}
   963  		var bad []string
   964  		for _, imp := range imports {
   965  			sawImport[pkg][imp] = true
   966  			if !policy.HasEdge(pkg, imp) {
   967  				bad = append(bad, imp)
   968  			}
   969  		}
   970  		if bad != nil {
   971  			t.Errorf("unexpected dependency: %s imports %v", pkg, bad)
   972  		}
   973  	}
   974  }
   975  
   976  var buildIgnore = []byte("\n//go:build ignore")
   977  
   978  func findImports(pkg string) ([]string, error) {
   979  	vpkg := pkg
   980  	if strings.HasPrefix(pkg, "golang.org") {
   981  		vpkg = "vendor/" + pkg
   982  	}
   983  	dir := filepath.Join(Default.GOROOT, "src", vpkg)
   984  	files, err := os.ReadDir(dir)
   985  	if err != nil {
   986  		return nil, err
   987  	}
   988  	var imports []string
   989  	var haveImport = map[string]bool{}
   990  	if pkg == "crypto/internal/boring" {
   991  		haveImport["C"] = true // kludge: prevent C from appearing in crypto/internal/boring imports
   992  	}
   993  	fset := token.NewFileSet()
   994  	for _, file := range files {
   995  		name := file.Name()
   996  		if name == "slice_go14.go" || name == "slice_go18.go" {
   997  			// These files are for compiler bootstrap with older versions of Go and not built in the standard build.
   998  			continue
   999  		}
  1000  		if !strings.HasSuffix(name, ".go") || strings.HasSuffix(name, "_test.go") {
  1001  			continue
  1002  		}
  1003  		info := fileInfo{
  1004  			name: filepath.Join(dir, name),
  1005  			fset: fset,
  1006  		}
  1007  		f, err := os.Open(info.name)
  1008  		if err != nil {
  1009  			return nil, err
  1010  		}
  1011  		err = readGoInfo(f, &info)
  1012  		f.Close()
  1013  		if err != nil {
  1014  			return nil, fmt.Errorf("reading %v: %v", name, err)
  1015  		}
  1016  		if info.parsed.Name.Name == "main" {
  1017  			continue
  1018  		}
  1019  		if bytes.Contains(info.header, buildIgnore) {
  1020  			continue
  1021  		}
  1022  		for _, imp := range info.imports {
  1023  			path := imp.path
  1024  			if !haveImport[path] {
  1025  				haveImport[path] = true
  1026  				imports = append(imports, path)
  1027  			}
  1028  		}
  1029  	}
  1030  	slices.Sort(imports)
  1031  	return imports, nil
  1032  }
  1033  
  1034  // depsPolicy returns a map m such that m[p][d] == true when p can import d.
  1035  func depsPolicy(t *testing.T) *dag.Graph {
  1036  	g, err := dag.Parse(depsRules)
  1037  	if err != nil {
  1038  		t.Fatal(err)
  1039  	}
  1040  	return g
  1041  }
  1042  
  1043  // TestStdlibLowercase tests that all standard library package names are
  1044  // lowercase. See Issue 40065.
  1045  func TestStdlibLowercase(t *testing.T) {
  1046  	testenv.MustHaveSource(t)
  1047  
  1048  	ctxt := Default
  1049  	all, err := listStdPkgs(ctxt.GOROOT)
  1050  	if err != nil {
  1051  		t.Fatal(err)
  1052  	}
  1053  
  1054  	for _, pkgname := range all {
  1055  		if strings.ToLower(pkgname) != pkgname {
  1056  			t.Errorf("package %q should not use upper-case path", pkgname)
  1057  		}
  1058  	}
  1059  }
  1060  
  1061  // TestFindImports tests that findImports works.  See #43249.
  1062  func TestFindImports(t *testing.T) {
  1063  	imports, err := findImports("go/build")
  1064  	if err != nil {
  1065  		t.Fatal(err)
  1066  	}
  1067  	t.Logf("go/build imports %q", imports)
  1068  	want := []string{"bytes", "os", "path/filepath", "strings"}
  1069  wantLoop:
  1070  	for _, w := range want {
  1071  		for _, imp := range imports {
  1072  			if imp == w {
  1073  				continue wantLoop
  1074  			}
  1075  		}
  1076  		t.Errorf("expected to find %q in import list", w)
  1077  	}
  1078  }
  1079  

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