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/itoa,
    58  	  internal/nettrace,
    59  	  internal/platform,
    60  	  internal/profilerecord,
    61  	  internal/runtime/pprof/label,
    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/cpu, internal/strconv < simd/archsimd;
    77  
    78  	# RUNTIME is the core runtime group of packages, all of them very light-weight.
    79  	internal/abi,
    80  	internal/chacha8rand,
    81  	internal/coverage/rtcov,
    82  	internal/cpu,
    83  	internal/goarch,
    84  	internal/godebugs,
    85  	internal/goexperiment,
    86  	internal/goos,
    87  	internal/itoa,
    88  	internal/profilerecord,
    89  	internal/runtime/pprof/label,
    90  	internal/strconv,
    91  	internal/trace/tracev2,
    92  	math/bits,
    93  	structs
    94  	< internal/bytealg
    95  	< internal/stringslite
    96  	< internal/unsafeheader
    97  	< internal/race
    98  	< internal/msan
    99  	< internal/asan
   100  	< internal/runtime/sys
   101  	< internal/runtime/syscall/linux
   102  	< internal/runtime/syscall/windows
   103  	< internal/runtime/atomic
   104  	< internal/runtime/exithook
   105  	< internal/runtime/gc
   106  	< internal/runtime/math
   107  	< internal/runtime/maps
   108  	< internal/runtime/cgroup
   109  	< internal/runtime/gc/scan
   110  	< runtime
   111  	< runtime/secret
   112  	< sync/atomic
   113  	< internal/sync
   114  	< weak
   115  	< internal/synctest
   116  	< sync
   117  	< internal/bisect
   118  	< internal/godebug
   119  	< internal/reflectlite
   120  	< errors
   121  	< internal/oserror;
   122  
   123  	cmp, runtime, math/bits
   124  	< iter
   125  	< maps, slices;
   126  
   127  	internal/oserror, maps, slices
   128  	< RUNTIME;
   129  
   130  	RUNTIME
   131  	< sort
   132  	< container/heap
   133  	< unique;
   134  
   135  	RUNTIME
   136  	< io;
   137  
   138  	RUNTIME
   139  	< arena;
   140  
   141  	syscall !< io;
   142  	reflect !< sort;
   143  
   144  	RUNTIME, unicode/utf8
   145  	< path;
   146  
   147  	unicode !< path;
   148  
   149  	# SYSCALL is RUNTIME plus the packages necessary for basic system calls.
   150  	RUNTIME, unicode/utf8, unicode/utf16, internal/synctest
   151  	< internal/syscall/windows/sysdll, syscall/js
   152  	< syscall
   153  	< internal/syscall/unix, internal/syscall/windows, internal/syscall/windows/registry
   154  	< internal/syscall/execenv
   155  	< SYSCALL;
   156  
   157  	# TIME is SYSCALL plus the core packages about time, including context.
   158  	SYSCALL
   159  	< time/tzdata
   160  	< time
   161  	< context
   162  	< TIME;
   163  
   164  	TIME, io, path, slices
   165  	< io/fs;
   166  
   167  	# MATH is RUNTIME plus the basic math packages.
   168  	RUNTIME
   169  	< math
   170  	< MATH;
   171  
   172  	unicode !< math;
   173  
   174  	MATH
   175  	< math/cmplx;
   176  
   177  	MATH
   178  	< math/rand, math/rand/v2;
   179  
   180  	MATH
   181  	< runtime/metrics;
   182  
   183  	MATH, unicode/utf8
   184  	< strconv;
   185  
   186  	unicode !< strconv;
   187  
   188  	# STR is basic string and buffer manipulation.
   189  	RUNTIME, io, unicode/utf8, unicode/utf16, unicode
   190  	< bytes, strings
   191  	< bufio;
   192  
   193  	bufio, path, strconv
   194  	< STR;
   195  
   196  	# OS is basic OS access, including helpers (path/filepath, os/exec, etc).
   197  	# OS includes string routines, but those must be layered above package os.
   198  	# OS does not include reflection.
   199  	io/fs
   200  	< internal/testlog
   201  	< internal/poll
   202  	< internal/filepathlite
   203  	< os
   204  	< os/signal;
   205  
   206  	io/fs
   207  	< embed;
   208  
   209  	unicode, fmt !< net, os, os/signal;
   210  
   211  	os/signal, internal/filepathlite, STR
   212  	< path/filepath
   213  	< io/ioutil;
   214  
   215  	path/filepath, internal/godebug < os/exec;
   216  
   217  	io/ioutil, os/exec, os/signal
   218  	< OS;
   219  
   220  	reflect !< OS;
   221  
   222  	OS
   223  	< golang.org/x/sys/cpu;
   224  
   225  	# FMT is OS (which includes string routines) plus reflect and fmt.
   226  	# It does not include package log, which should be avoided in core packages.
   227  	arena, strconv, unicode
   228  	< reflect;
   229  
   230  	os, reflect
   231  	< internal/fmtsort
   232  	< fmt;
   233  
   234  	OS, fmt
   235  	< FMT;
   236  
   237  	log !< FMT;
   238  
   239  	# Misc packages needing only FMT.
   240  	FMT
   241  	< html,
   242  	  internal/dag,
   243  	  internal/goroot,
   244  	  internal/types/errors,
   245  	  mime/quotedprintable,
   246  	  net/internal/socktest,
   247  	  runtime/trace,
   248  	  text/scanner,
   249  	  text/tabwriter;
   250  
   251  	io, reflect
   252  	< internal/saferio;
   253  
   254  	# encodings
   255  	# core ones do not use fmt.
   256  	io, strconv, slices
   257  	< encoding, encoding/base32, encoding/base64;
   258  
   259  	encoding, reflect
   260  	< encoding/binary;
   261  
   262  	FMT, encoding < flag;
   263  
   264  	fmt !< encoding/base32, encoding/base64;
   265  
   266  	FMT, encoding, encoding/base32, encoding/base64, encoding/binary,
   267  	internal/saferio
   268  	< encoding/ascii85, encoding/csv, encoding/gob, encoding/hex,
   269  	  encoding/pem, encoding/xml, mime;
   270  
   271  	STR, errors
   272  	< encoding/json/internal
   273  	< encoding/json/internal/jsonflags
   274  	< encoding/json/internal/jsonopts
   275  	< encoding/json/internal/jsonwire
   276  	< encoding/json/jsontext;
   277  
   278  	FMT,
   279  	encoding/hex,
   280  	encoding/base32,
   281  	encoding/base64,
   282  	encoding/binary,
   283  	encoding/json/jsontext,
   284  	encoding/json/internal,
   285  	encoding/json/internal/jsonflags,
   286  	encoding/json/internal/jsonopts,
   287  	encoding/json/internal/jsonwire
   288  	< encoding/json/v2
   289  	< encoding/json;
   290  
   291  	# hashes
   292  	io
   293  	< hash
   294  	< hash/adler32, hash/crc32, hash/crc64, hash/fnv;
   295  
   296  	# math/big
   297  	FMT, math/rand
   298  	< math/big;
   299  
   300  	# compression
   301  	FMT, encoding/binary, hash/adler32, hash/crc32, sort
   302  	< compress/bzip2, compress/flate, compress/lzw, internal/zstd
   303  	< archive/zip, compress/gzip, compress/zlib;
   304  
   305  	# templates
   306  	FMT
   307  	< text/template/parse;
   308  
   309  	internal/bytealg, math/bits, slices, strconv, unique
   310  	< net/netip;
   311  
   312  	FMT, net/netip
   313  	< net/url;
   314  
   315  	net/url, text/template/parse
   316  	< text/template
   317  	< internal/lazytemplate;
   318  
   319  	# regexp
   320  	FMT, sort
   321  	< regexp/syntax
   322  	< regexp
   323  	< internal/lazyregexp;
   324  
   325  	encoding/json, html, text/template, regexp
   326  	< html/template;
   327  
   328  	# suffix array
   329  	encoding/binary, regexp
   330  	< index/suffixarray;
   331  
   332  	# executable parsing
   333  	FMT, encoding/binary, compress/zlib, internal/saferio, internal/zstd, sort
   334  	< runtime/debug
   335  	< debug/dwarf
   336  	< debug/elf, debug/gosym, debug/macho, debug/pe, debug/plan9obj, internal/xcoff
   337  	< debug/buildinfo
   338  	< DEBUG;
   339  
   340  	# go parser and friends.
   341  	FMT, sort
   342  	< internal/gover
   343  	< go/version
   344  	< go/token
   345  	< go/scanner
   346  	< go/ast
   347  	< go/internal/typeparams;
   348  
   349  	FMT
   350  	< go/build/constraint;
   351  
   352  	FMT, sort
   353  	< go/doc/comment;
   354  
   355  	go/internal/typeparams, go/build/constraint
   356  	< go/parser;
   357  
   358  	go/doc/comment, go/parser, text/tabwriter
   359  	< go/printer
   360  	< go/format;
   361  
   362  	math/big, go/token
   363  	< go/constant;
   364  
   365  	FMT, internal/goexperiment
   366  	< internal/buildcfg;
   367  
   368  	container/heap, go/constant, go/parser, internal/buildcfg, internal/goversion, internal/types/errors
   369  	< go/types;
   370  
   371  	# The vast majority of standard library packages should not be resorting to regexp.
   372  	# go/types is a good chokepoint. It shouldn't use regexp, nor should anything
   373  	# that is low-enough level to be used by go/types.
   374  	regexp !< go/types;
   375  
   376  	go/doc/comment, go/parser, internal/lazyregexp, text/template
   377  	< go/doc;
   378  
   379  	go/build/constraint, go/doc, go/parser, internal/buildcfg, internal/goroot, internal/goversion, internal/platform, internal/syslist
   380  	< go/build;
   381  
   382  	# databases
   383  	FMT
   384  	< database/sql/internal
   385  	< database/sql/driver;
   386  
   387  	database/sql/driver, math/rand/v2 < database/sql;
   388  
   389  	# images
   390  	FMT, compress/lzw, compress/zlib
   391  	< image/color
   392  	< image, image/color/palette
   393  	< image/internal/imageutil
   394  	< image/draw
   395  	< image/gif, image/jpeg, image/png;
   396  
   397  	# cgo, delayed as long as possible.
   398  	# If you add a dependency on CGO, you must add the package
   399  	# to cgoPackages in cmd/dist/test.go as well.
   400  	RUNTIME
   401  	< C
   402  	< runtime/cgo
   403  	< CGO
   404  	< runtime/msan, runtime/asan;
   405  
   406  	# runtime/race
   407  	NONE < runtime/race/internal/amd64v1;
   408  	NONE < runtime/race/internal/amd64v3;
   409  	CGO, runtime/race/internal/amd64v1, runtime/race/internal/amd64v3 < runtime/race;
   410  
   411  	# Bulk of the standard library must not use cgo.
   412  	# The prohibition stops at net and os/user.
   413  	C !< fmt, go/types, CRYPTO-MATH, log/slog;
   414  
   415  	CGO, OS
   416  	< plugin;
   417  
   418  	CGO, FMT
   419  	< os/user
   420  	< archive/tar;
   421  
   422  	sync
   423  	< internal/singleflight;
   424  
   425  	os
   426  	< golang.org/x/net/dns/dnsmessage,
   427  	  golang.org/x/net/lif;
   428  
   429  	os, net/netip
   430  	< internal/routebsd;
   431  
   432  	# net is unavoidable when doing any networking,
   433  	# so large dependencies must be kept out.
   434  	# This is a long-looking list but most of these
   435  	# are small with few dependencies.
   436  	CGO,
   437  	golang.org/x/net/dns/dnsmessage,
   438  	golang.org/x/net/lif,
   439  	internal/godebug,
   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;
   576  
   577  	CGO, fmt, net !< CRYPTO;
   578  
   579  	# CRYPTO-MATH is crypto that exposes math/big APIs - no cgo, net; fmt now ok.
   580  
   581  	CRYPTO, FMT, math/big, internal/saferio
   582  	< crypto/internal/boring/bbig
   583  	< crypto/internal/fips140cache
   584  	< crypto/rand
   585  	< crypto/ed25519 # depends on crypto/rand.Reader
   586  	< encoding/asn1
   587  	< golang.org/x/crypto/cryptobyte/asn1
   588  	< golang.org/x/crypto/cryptobyte
   589  	< crypto/dsa, crypto/elliptic, crypto/rsa
   590  	< crypto/ecdsa
   591  	< CRYPTO-MATH;
   592  
   593  	CGO, net !< CRYPTO-MATH;
   594  
   595  	# TLS, Prince of Dependencies.
   596  
   597  	crypto/fips140, sync/atomic < crypto/tls/internal/fips140tls;
   598  
   599  	crypto/internal/boring/sig, crypto/tls/internal/fips140tls < crypto/tls/fipsonly;
   600  
   601  	CRYPTO, golang.org/x/sys/cpu, encoding/binary, reflect
   602  	< golang.org/x/crypto/internal/alias
   603  	< golang.org/x/crypto/internal/subtle
   604  	< golang.org/x/crypto/chacha20
   605  	< golang.org/x/crypto/internal/poly1305
   606  	< golang.org/x/crypto/chacha20poly1305;
   607  
   608  	CRYPTO-MATH, golang.org/x/crypto/chacha20poly1305
   609  	< crypto/hpke;
   610  
   611  	CRYPTO-MATH, NET, container/list, encoding/hex, encoding/pem, crypto/hpke,
   612  	golang.org/x/crypto/chacha20poly1305, crypto/tls/internal/fips140tls
   613  	< crypto/x509/internal/macos
   614  	< crypto/x509/pkix
   615  	< crypto/x509
   616  	< crypto/tls;
   617  
   618  	# crypto-aware packages
   619  
   620  	DEBUG, go/build, go/types, text/scanner, crypto/sha256
   621  	< internal/pkgbits, internal/exportdata
   622  	< go/internal/gcimporter, go/internal/gccgoimporter, go/internal/srcimporter
   623  	< go/importer;
   624  
   625  	NET, crypto/rand, mime/quotedprintable
   626  	< mime/multipart;
   627  
   628  	crypto/tls
   629  	< net/smtp;
   630  
   631  	crypto/rand
   632  	< hash/maphash; # for purego implementation
   633  
   634  	# HTTP, King of Dependencies.
   635  
   636  	FMT
   637  	< golang.org/x/net/http2/hpack
   638  	< net/http/internal, net/http/internal/ascii, net/http/internal/testcert;
   639  
   640  	FMT, NET, container/list, encoding/binary, log
   641  	< golang.org/x/text/transform
   642  	< golang.org/x/text/unicode/norm
   643  	< golang.org/x/text/unicode/bidi
   644  	< golang.org/x/text/secure/bidirule
   645  	< golang.org/x/net/idna
   646  	< golang.org/x/net/http/httpguts, golang.org/x/net/http/httpproxy;
   647  
   648  	NET, crypto/tls
   649  	< net/http/httptrace;
   650  
   651  	compress/gzip,
   652  	golang.org/x/net/http/httpguts,
   653  	golang.org/x/net/http/httpproxy,
   654  	golang.org/x/net/http2/hpack,
   655  	net/http/internal,
   656  	net/http/internal/ascii,
   657  	net/http/internal/testcert,
   658  	net/http/httptrace,
   659  	mime/multipart,
   660  	log
   661  	< net/http/internal/httpcommon, net/http/internal/httpsfv
   662  	< net/http;
   663  
   664  	# HTTP-aware packages
   665  
   666  	encoding/json, net/http
   667  	< expvar;
   668  
   669  	net/http, net/http/internal/ascii
   670  	< net/http/cookiejar, net/http/httputil;
   671  
   672  	net/http, flag
   673  	< net/http/httptest;
   674  
   675  	net/http, regexp
   676  	< net/http/cgi
   677  	< net/http/fcgi;
   678  
   679  	# Profiling
   680  	internal/runtime/pprof/label, runtime, context < internal/runtime/pprof;
   681  	FMT, compress/gzip, encoding/binary, sort, text/tabwriter, internal/runtime/pprof, internal/runtime/pprof/label
   682  	< runtime/pprof;
   683  
   684  	OS, compress/gzip, internal/lazyregexp
   685  	< internal/profile;
   686  
   687  	html, internal/profile, net/http, runtime/pprof, runtime/trace
   688  	< net/http/pprof;
   689  
   690  	# RPC
   691  	encoding/gob, encoding/json, go/token, html/template, net/http
   692  	< net/rpc
   693  	< net/rpc/jsonrpc;
   694  
   695  	# System Information
   696  	bufio, bytes, internal/cpu, io, os, strings, sync
   697  	< internal/sysinfo;
   698  
   699  	# Test-only
   700  	log
   701  	< testing/iotest
   702  	< testing/fstest;
   703  
   704  	FMT, flag, math/rand
   705  	< testing/quick;
   706  
   707  	FMT, DEBUG, flag, runtime/trace, internal/sysinfo, math/rand
   708  	< testing;
   709  
   710  	testing, math
   711  	< simd/archsimd/internal/test_helpers;
   712  
   713  	log/slog, testing
   714  	< testing/slogtest;
   715  
   716  	testing, crypto/rand
   717  	< testing/cryptotest;
   718  
   719  	FMT, crypto/sha256, encoding/binary, encoding/json,
   720  	go/ast, go/parser, go/token,
   721  	internal/godebug, math/rand, encoding/hex
   722  	< internal/fuzz;
   723  
   724  	OS, flag, testing, internal/cfg, internal/platform, internal/goroot
   725  	< internal/testenv;
   726  
   727  	OS, encoding/base64
   728  	< internal/obscuretestdata;
   729  
   730  	CGO, OS, fmt
   731  	< internal/testpty;
   732  
   733  	NET, testing, math/rand
   734  	< golang.org/x/net/nettest;
   735  
   736  	syscall
   737  	< os/exec/internal/fdtest;
   738  
   739  	FMT, sort
   740  	< internal/diff;
   741  
   742  	FMT
   743  	< internal/txtar;
   744  
   745  	internal/synctest, testing
   746  	< testing/synctest;
   747  
   748  	testing
   749  	< internal/testhash;
   750  
   751  	CRYPTO-MATH
   752  	< crypto/mlkem/mlkemtest;
   753  
   754  	CRYPTO-MATH, testing, internal/testenv, internal/testhash, encoding/json
   755  	< crypto/internal/cryptotest;
   756  
   757  	CGO, FMT
   758  	< crypto/internal/sysrand/internal/seccomp;
   759  
   760  	FIPS
   761  	< crypto/internal/fips140/check/checktest;
   762  
   763  	# v2 execution trace parser.
   764  	FMT, io, internal/trace/tracev2
   765  	< internal/trace/version;
   766  
   767  	FMT, encoding/binary, internal/trace/version
   768  	< internal/trace/raw;
   769  
   770  	FMT, internal/trace/version, io, sort, encoding/binary
   771  	< internal/trace/internal/tracev1;
   772  
   773  	FMT, encoding/binary, internal/trace/version, internal/trace/internal/tracev1, container/heap, math/rand, regexp
   774  	< internal/trace;
   775  
   776  	# cmd/trace dependencies.
   777  	FMT,
   778  	embed,
   779  	encoding/json,
   780  	html/template,
   781  	internal/profile,
   782  	internal/trace,
   783  	internal/trace/traceviewer/format,
   784  	net/http
   785  	< internal/trace/traceviewer;
   786  
   787  	# Coverage.
   788  	FMT, hash/fnv, encoding/binary, regexp, sort, text/tabwriter,
   789  	internal/coverage, internal/coverage/uleb128
   790  	< internal/coverage/cmerge,
   791  	  internal/coverage/pods,
   792  	  internal/coverage/slicereader,
   793  	  internal/coverage/slicewriter;
   794  
   795  	internal/coverage/slicereader, internal/coverage/slicewriter
   796  	< internal/coverage/stringtab
   797  	< internal/coverage/decodecounter, internal/coverage/decodemeta,
   798  	  internal/coverage/encodecounter, internal/coverage/encodemeta;
   799  
   800  	internal/coverage/cmerge
   801  	< internal/coverage/cformat;
   802  
   803  	internal/coverage, crypto/sha256, FMT
   804  	< cmd/internal/cov/covcmd;
   805  
   806  	encoding/json,
   807  	runtime/debug,
   808  	internal/coverage/calloc,
   809  	internal/coverage/cformat,
   810  	internal/coverage/decodecounter, internal/coverage/decodemeta,
   811  	internal/coverage/encodecounter, internal/coverage/encodemeta,
   812  	internal/coverage/pods
   813  	< internal/coverage/cfile
   814  	< runtime/coverage;
   815  
   816  	internal/coverage/cfile, internal/fuzz, internal/testlog, runtime/pprof, regexp
   817  	< testing/internal/testdeps;
   818  
   819  	# Test-only packages can have anything they want
   820  
   821  	FMT, compress/gzip, embed, encoding/binary
   822  	< encoding/json/internal/jsontest;
   823  
   824  	CGO, internal/syscall/unix
   825  	< net/internal/cgotest;
   826  
   827  	FMT, testing
   828  	< internal/cgrouptest;
   829  
   830  	regexp, internal/testenv, internal/trace, internal/trace/raw, internal/txtar, testing
   831  	< internal/trace/testtrace;
   832  
   833  	C, CGO
   834  	< internal/runtime/cgobench;
   835  
   836  	# Generate-only packages can have anything they want.
   837  
   838  	container/heap,
   839  	encoding/binary,
   840  	fmt,
   841  	hash/maphash,
   842  	io,
   843  	log,
   844  	math/bits,
   845  	os,
   846  	reflect,
   847  	strings,
   848  	sync
   849  	< internal/runtime/gc/internal/gen;
   850  
   851  	regexp, internal/txtar, internal/trace, internal/trace/raw
   852  	< internal/trace/internal/testgen;
   853  
   854  	FMT
   855  	< math/big/internal/asmgen;
   856  `
   857  
   858  // listStdPkgs returns the same list of packages as "go list std".
   859  func listStdPkgs(goroot string) ([]string, error) {
   860  	// Based on cmd/go's matchPackages function.
   861  	var pkgs []string
   862  
   863  	src := filepath.Join(goroot, "src") + string(filepath.Separator)
   864  	walkFn := func(path string, d fs.DirEntry, err error) error {
   865  		if err != nil || !d.IsDir() || path == src {
   866  			return nil
   867  		}
   868  
   869  		base := filepath.Base(path)
   870  		if strings.HasPrefix(base, ".") || strings.HasPrefix(base, "_") || base == "testdata" {
   871  			return filepath.SkipDir
   872  		}
   873  
   874  		name := filepath.ToSlash(path[len(src):])
   875  		if name == "builtin" || name == "cmd" {
   876  			return filepath.SkipDir
   877  		}
   878  
   879  		pkgs = append(pkgs, strings.TrimPrefix(name, "vendor/"))
   880  		return nil
   881  	}
   882  	if err := filepath.WalkDir(src, walkFn); err != nil {
   883  		return nil, err
   884  	}
   885  	return pkgs, nil
   886  }
   887  
   888  func TestDependencies(t *testing.T) {
   889  	testenv.MustHaveSource(t)
   890  
   891  	ctxt := Default
   892  	all, err := listStdPkgs(ctxt.GOROOT)
   893  	if err != nil {
   894  		t.Fatal(err)
   895  	}
   896  	slices.Sort(all)
   897  
   898  	sawImport := map[string]map[string]bool{} // from package => to package => true
   899  	policy := depsPolicy(t)
   900  
   901  	for _, pkg := range all {
   902  		imports, err := findImports(pkg)
   903  		if err != nil {
   904  			t.Error(err)
   905  			continue
   906  		}
   907  		if sawImport[pkg] == nil {
   908  			sawImport[pkg] = map[string]bool{}
   909  		}
   910  		var bad []string
   911  		for _, imp := range imports {
   912  			sawImport[pkg][imp] = true
   913  			if !policy.HasEdge(pkg, imp) {
   914  				bad = append(bad, imp)
   915  			}
   916  		}
   917  		if bad != nil {
   918  			t.Errorf("unexpected dependency: %s imports %v", pkg, bad)
   919  		}
   920  	}
   921  }
   922  
   923  var buildIgnore = []byte("\n//go:build ignore")
   924  
   925  func findImports(pkg string) ([]string, error) {
   926  	vpkg := pkg
   927  	if strings.HasPrefix(pkg, "golang.org") {
   928  		vpkg = "vendor/" + pkg
   929  	}
   930  	dir := filepath.Join(Default.GOROOT, "src", vpkg)
   931  	files, err := os.ReadDir(dir)
   932  	if err != nil {
   933  		return nil, err
   934  	}
   935  	var imports []string
   936  	var haveImport = map[string]bool{}
   937  	if pkg == "crypto/internal/boring" {
   938  		haveImport["C"] = true // kludge: prevent C from appearing in crypto/internal/boring imports
   939  	}
   940  	fset := token.NewFileSet()
   941  	for _, file := range files {
   942  		name := file.Name()
   943  		if name == "slice_go14.go" || name == "slice_go18.go" {
   944  			// These files are for compiler bootstrap with older versions of Go and not built in the standard build.
   945  			continue
   946  		}
   947  		if !strings.HasSuffix(name, ".go") || strings.HasSuffix(name, "_test.go") {
   948  			continue
   949  		}
   950  		info := fileInfo{
   951  			name: filepath.Join(dir, name),
   952  			fset: fset,
   953  		}
   954  		f, err := os.Open(info.name)
   955  		if err != nil {
   956  			return nil, err
   957  		}
   958  		err = readGoInfo(f, &info)
   959  		f.Close()
   960  		if err != nil {
   961  			return nil, fmt.Errorf("reading %v: %v", name, err)
   962  		}
   963  		if info.parsed.Name.Name == "main" {
   964  			continue
   965  		}
   966  		if bytes.Contains(info.header, buildIgnore) {
   967  			continue
   968  		}
   969  		for _, imp := range info.imports {
   970  			path := imp.path
   971  			if !haveImport[path] {
   972  				haveImport[path] = true
   973  				imports = append(imports, path)
   974  			}
   975  		}
   976  	}
   977  	slices.Sort(imports)
   978  	return imports, nil
   979  }
   980  
   981  // depsPolicy returns a map m such that m[p][d] == true when p can import d.
   982  func depsPolicy(t *testing.T) *dag.Graph {
   983  	g, err := dag.Parse(depsRules)
   984  	if err != nil {
   985  		t.Fatal(err)
   986  	}
   987  	return g
   988  }
   989  
   990  // TestStdlibLowercase tests that all standard library package names are
   991  // lowercase. See Issue 40065.
   992  func TestStdlibLowercase(t *testing.T) {
   993  	testenv.MustHaveSource(t)
   994  
   995  	ctxt := Default
   996  	all, err := listStdPkgs(ctxt.GOROOT)
   997  	if err != nil {
   998  		t.Fatal(err)
   999  	}
  1000  
  1001  	for _, pkgname := range all {
  1002  		if strings.ToLower(pkgname) != pkgname {
  1003  			t.Errorf("package %q should not use upper-case path", pkgname)
  1004  		}
  1005  	}
  1006  }
  1007  
  1008  // TestFindImports tests that findImports works.  See #43249.
  1009  func TestFindImports(t *testing.T) {
  1010  	imports, err := findImports("go/build")
  1011  	if err != nil {
  1012  		t.Fatal(err)
  1013  	}
  1014  	t.Logf("go/build imports %q", imports)
  1015  	want := []string{"bytes", "os", "path/filepath", "strings"}
  1016  wantLoop:
  1017  	for _, w := range want {
  1018  		for _, imp := range imports {
  1019  			if imp == w {
  1020  				continue wantLoop
  1021  			}
  1022  		}
  1023  		t.Errorf("expected to find %q in import list", w)
  1024  	}
  1025  }
  1026  

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