modfile.go

     1  // Copyright 2020 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 modload
     6  
     7  import (
     8  	"context"
     9  	"errors"
    10  	"fmt"
    11  	"os"
    12  	"path/filepath"
    13  	"strings"
    14  	"sync"
    15  	"unicode"
    16  
    17  	"cmd/go/internal/base"
    18  	"cmd/go/internal/cfg"
    19  	"cmd/go/internal/fsys"
    20  	"cmd/go/internal/gover"
    21  	"cmd/go/internal/lockedfile"
    22  	"cmd/go/internal/modfetch"
    23  	"cmd/go/internal/trace"
    24  	"cmd/internal/par"
    25  
    26  	"golang.org/x/mod/modfile"
    27  	"golang.org/x/mod/module"
    28  )
    29  
    30  // ReadModFile reads and parses the mod file at gomod. ReadModFile properly applies the
    31  // overlay, locks the file while reading, and applies fix, if applicable.
    32  func ReadModFile(gomod string, fix modfile.VersionFixer) (data []byte, f *modfile.File, err error) {
    33  	if fsys.Replaced(gomod) {
    34  		// Don't lock go.mod if it's part of the overlay.
    35  		// On Plan 9, locking requires chmod, and we don't want to modify any file
    36  		// in the overlay. See #44700.
    37  		data, err = os.ReadFile(fsys.Actual(gomod))
    38  	} else {
    39  		data, err = lockedfile.Read(gomod)
    40  	}
    41  	if err != nil {
    42  		return nil, nil, err
    43  	}
    44  
    45  	f, err = modfile.Parse(gomod, data, fix)
    46  	if err != nil {
    47  		f, laxErr := modfile.ParseLax(gomod, data, fix)
    48  		if laxErr == nil {
    49  			if f.Go != nil && gover.Compare(f.Go.Version, gover.Local()) > 0 {
    50  				toolchain := ""
    51  				if f.Toolchain != nil {
    52  					toolchain = f.Toolchain.Name
    53  				}
    54  				return nil, nil, &gover.TooNewError{What: base.ShortPath(gomod), GoVersion: f.Go.Version, Toolchain: toolchain}
    55  			}
    56  		}
    57  
    58  		// Errors returned by modfile.Parse begin with file:line.
    59  		return nil, nil, fmt.Errorf("errors parsing %s:\n%w", base.ShortPath(gomod), shortPathErrorList(err))
    60  	}
    61  	if f.Go != nil && gover.Compare(f.Go.Version, gover.Local()) > 0 {
    62  		toolchain := ""
    63  		if f.Toolchain != nil {
    64  			toolchain = f.Toolchain.Name
    65  		}
    66  		return nil, nil, &gover.TooNewError{What: base.ShortPath(gomod), GoVersion: f.Go.Version, Toolchain: toolchain}
    67  	}
    68  	if f.Module == nil {
    69  		// No module declaration. Must add module path.
    70  		return nil, nil, fmt.Errorf("error reading %s: missing module declaration. To specify the module path:\n\tgo mod edit -module=example.com/mod", base.ShortPath(gomod))
    71  	}
    72  
    73  	return data, f, err
    74  }
    75  
    76  func shortPathErrorList(err error) error {
    77  	var el modfile.ErrorList
    78  	if errors.As(err, &el) {
    79  		for i := range el {
    80  			el[i].Filename = base.ShortPath(el[i].Filename)
    81  		}
    82  	}
    83  	return err
    84  }
    85  
    86  // A modFileIndex is an index of data corresponding to a modFile
    87  // at a specific point in time.
    88  type modFileIndex struct {
    89  	data         []byte
    90  	dataNeedsFix bool // true if fixVersion applied a change while parsing data
    91  	module       module.Version
    92  	goVersion    string // Go version (no "v" or "go" prefix)
    93  	toolchain    string
    94  	require      map[module.Version]requireMeta
    95  	replace      map[module.Version]module.Version
    96  	exclude      map[module.Version]bool
    97  }
    98  
    99  type requireMeta struct {
   100  	indirect bool
   101  }
   102  
   103  // A modPruning indicates whether transitive dependencies of Go 1.17 dependencies
   104  // are pruned out of the module subgraph rooted at a given module.
   105  // (See https://golang.org/ref/mod#graph-pruning.)
   106  type modPruning uint8
   107  
   108  const (
   109  	pruned    modPruning = iota // transitive dependencies of modules at go 1.17 and higher are pruned out
   110  	unpruned                    // no transitive dependencies are pruned out
   111  	workspace                   // pruned to the union of modules in the workspace
   112  )
   113  
   114  func (p modPruning) String() string {
   115  	switch p {
   116  	case pruned:
   117  		return "pruned"
   118  	case unpruned:
   119  		return "unpruned"
   120  	case workspace:
   121  		return "workspace"
   122  	default:
   123  		return fmt.Sprintf("%T(%d)", p, p)
   124  	}
   125  }
   126  
   127  func pruningForGoVersion(goVersion string) modPruning {
   128  	if gover.Compare(goVersion, gover.ExplicitIndirectVersion) < 0 {
   129  		// The go.mod file does not duplicate relevant information about transitive
   130  		// dependencies, so they cannot be pruned out.
   131  		return unpruned
   132  	}
   133  	return pruned
   134  }
   135  
   136  // CheckAllowed returns an error equivalent to ErrDisallowed if m is excluded by
   137  // the main module's go.mod or retracted by its author. Most version queries use
   138  // this to filter out versions that should not be used.
   139  func CheckAllowed(ctx context.Context, m module.Version) error {
   140  	if err := CheckExclusions(ctx, m); err != nil {
   141  		return err
   142  	}
   143  	if err := CheckRetractions(ctx, m); err != nil {
   144  		return err
   145  	}
   146  	return nil
   147  }
   148  
   149  // ErrDisallowed is returned by version predicates passed to Query and similar
   150  // functions to indicate that a version should not be considered.
   151  var ErrDisallowed = errors.New("disallowed module version")
   152  
   153  // CheckExclusions returns an error equivalent to ErrDisallowed if module m is
   154  // excluded by the main module's go.mod file.
   155  func CheckExclusions(ctx context.Context, m module.Version) error {
   156  	for _, mainModule := range MainModules.Versions() {
   157  		if index := MainModules.Index(mainModule); index != nil && index.exclude[m] {
   158  			return module.VersionError(m, errExcluded)
   159  		}
   160  	}
   161  	return nil
   162  }
   163  
   164  var errExcluded = &excludedError{}
   165  
   166  type excludedError struct{}
   167  
   168  func (e *excludedError) Error() string     { return "excluded by go.mod" }
   169  func (e *excludedError) Is(err error) bool { return err == ErrDisallowed }
   170  
   171  // CheckRetractions returns an error if module m has been retracted by
   172  // its author.
   173  func CheckRetractions(ctx context.Context, m module.Version) (err error) {
   174  	defer func() {
   175  		if retractErr := (*ModuleRetractedError)(nil); err == nil || errors.As(err, &retractErr) {
   176  			return
   177  		}
   178  		// Attribute the error to the version being checked, not the version from
   179  		// which the retractions were to be loaded.
   180  		if mErr := (*module.ModuleError)(nil); errors.As(err, &mErr) {
   181  			err = mErr.Err
   182  		}
   183  		err = &retractionLoadingError{m: m, err: err}
   184  	}()
   185  
   186  	if m.Version == "" {
   187  		// Main module, standard library, or file replacement module.
   188  		// Cannot be retracted.
   189  		return nil
   190  	}
   191  	if repl := Replacement(module.Version{Path: m.Path}); repl.Path != "" {
   192  		// All versions of the module were replaced.
   193  		// Don't load retractions, since we'd just load the replacement.
   194  		return nil
   195  	}
   196  
   197  	// Find the latest available version of the module, and load its go.mod. If
   198  	// the latest version is replaced, we'll load the replacement.
   199  	//
   200  	// If there's an error loading the go.mod, we'll return it here. These errors
   201  	// should generally be ignored by callers since they happen frequently when
   202  	// we're offline. These errors are not equivalent to ErrDisallowed, so they
   203  	// may be distinguished from retraction errors.
   204  	//
   205  	// We load the raw file here: the go.mod file may have a different module
   206  	// path that we expect if the module or its repository was renamed.
   207  	// We still want to apply retractions to other aliases of the module.
   208  	rm, err := queryLatestVersionIgnoringRetractions(ctx, m.Path)
   209  	if err != nil {
   210  		return err
   211  	}
   212  	summary, err := rawGoModSummary(rm)
   213  	if err != nil && !errors.Is(err, gover.ErrTooNew) {
   214  		return err
   215  	}
   216  
   217  	var rationale []string
   218  	isRetracted := false
   219  	for _, r := range summary.retract {
   220  		if gover.ModCompare(m.Path, r.Low, m.Version) <= 0 && gover.ModCompare(m.Path, m.Version, r.High) <= 0 {
   221  			isRetracted = true
   222  			if r.Rationale != "" {
   223  				rationale = append(rationale, r.Rationale)
   224  			}
   225  		}
   226  	}
   227  	if isRetracted {
   228  		return module.VersionError(m, &ModuleRetractedError{Rationale: rationale})
   229  	}
   230  	return nil
   231  }
   232  
   233  type ModuleRetractedError struct {
   234  	Rationale []string
   235  }
   236  
   237  func (e *ModuleRetractedError) Error() string {
   238  	msg := "retracted by module author"
   239  	if len(e.Rationale) > 0 {
   240  		// This is meant to be a short error printed on a terminal, so just
   241  		// print the first rationale.
   242  		msg += ": " + ShortMessage(e.Rationale[0], "retracted by module author")
   243  	}
   244  	return msg
   245  }
   246  
   247  func (e *ModuleRetractedError) Is(err error) bool {
   248  	return err == ErrDisallowed
   249  }
   250  
   251  type retractionLoadingError struct {
   252  	m   module.Version
   253  	err error
   254  }
   255  
   256  func (e *retractionLoadingError) Error() string {
   257  	return fmt.Sprintf("loading module retractions for %v: %v", e.m, e.err)
   258  }
   259  
   260  func (e *retractionLoadingError) Unwrap() error {
   261  	return e.err
   262  }
   263  
   264  // ShortMessage returns a string from go.mod (for example, a retraction
   265  // rationale or deprecation message) that is safe to print in a terminal.
   266  //
   267  // If the given string is empty, ShortMessage returns the given default. If the
   268  // given string is too long or contains non-printable characters, ShortMessage
   269  // returns a hard-coded string.
   270  func ShortMessage(message, emptyDefault string) string {
   271  	const maxLen = 500
   272  	if i := strings.Index(message, "\n"); i >= 0 {
   273  		message = message[:i]
   274  	}
   275  	message = strings.TrimSpace(message)
   276  	if message == "" {
   277  		return emptyDefault
   278  	}
   279  	if len(message) > maxLen {
   280  		return "(message omitted: too long)"
   281  	}
   282  	for _, r := range message {
   283  		if !unicode.IsGraphic(r) && !unicode.IsSpace(r) {
   284  			return "(message omitted: contains non-printable characters)"
   285  		}
   286  	}
   287  	// NOTE: the go.mod parser rejects invalid UTF-8, so we don't check that here.
   288  	return message
   289  }
   290  
   291  // CheckDeprecation returns a deprecation message from the go.mod file of the
   292  // latest version of the given module. Deprecation messages are comments
   293  // before or on the same line as the module directives that start with
   294  // "Deprecated:" and run until the end of the paragraph.
   295  //
   296  // CheckDeprecation returns an error if the message can't be loaded.
   297  // CheckDeprecation returns "", nil if there is no deprecation message.
   298  func CheckDeprecation(ctx context.Context, m module.Version) (deprecation string, err error) {
   299  	defer func() {
   300  		if err != nil {
   301  			err = fmt.Errorf("loading deprecation for %s: %w", m.Path, err)
   302  		}
   303  	}()
   304  
   305  	if m.Version == "" {
   306  		// Main module, standard library, or file replacement module.
   307  		// Don't look up deprecation.
   308  		return "", nil
   309  	}
   310  	if repl := Replacement(module.Version{Path: m.Path}); repl.Path != "" {
   311  		// All versions of the module were replaced.
   312  		// We'll look up deprecation separately for the replacement.
   313  		return "", nil
   314  	}
   315  
   316  	latest, err := queryLatestVersionIgnoringRetractions(ctx, m.Path)
   317  	if err != nil {
   318  		return "", err
   319  	}
   320  	summary, err := rawGoModSummary(latest)
   321  	if err != nil && !errors.Is(err, gover.ErrTooNew) {
   322  		return "", err
   323  	}
   324  	return summary.deprecated, nil
   325  }
   326  
   327  func replacement(mod module.Version, replace map[module.Version]module.Version) (fromVersion string, to module.Version, ok bool) {
   328  	if r, ok := replace[mod]; ok {
   329  		return mod.Version, r, true
   330  	}
   331  	if r, ok := replace[module.Version{Path: mod.Path}]; ok {
   332  		return "", r, true
   333  	}
   334  	return "", module.Version{}, false
   335  }
   336  
   337  // Replacement returns the replacement for mod, if any. If the path in the
   338  // module.Version is relative it's relative to the single main module outside
   339  // workspace mode, or the workspace's directory in workspace mode.
   340  func Replacement(mod module.Version) module.Version {
   341  	r, foundModRoot, _ := replacementFrom(mod)
   342  	return canonicalizeReplacePath(r, foundModRoot)
   343  }
   344  
   345  // replacementFrom returns the replacement for mod, if any, the modroot of the replacement if it appeared in a go.mod,
   346  // and the source of the replacement. The replacement is relative to the go.work or go.mod file it appears in.
   347  func replacementFrom(mod module.Version) (r module.Version, modroot string, fromFile string) {
   348  	foundFrom, found, foundModRoot := "", module.Version{}, ""
   349  	if MainModules == nil {
   350  		return module.Version{}, "", ""
   351  	} else if MainModules.Contains(mod.Path) && mod.Version == "" {
   352  		// Don't replace the workspace version of the main module.
   353  		return module.Version{}, "", ""
   354  	}
   355  	if _, r, ok := replacement(mod, MainModules.WorkFileReplaceMap()); ok {
   356  		return r, "", workFilePath
   357  	}
   358  	for _, v := range MainModules.Versions() {
   359  		if index := MainModules.Index(v); index != nil {
   360  			if from, r, ok := replacement(mod, index.replace); ok {
   361  				modRoot := MainModules.ModRoot(v)
   362  				if foundModRoot != "" && foundFrom != from && found != r {
   363  					base.Errorf("conflicting replacements found for %v in workspace modules defined by %v and %v",
   364  						mod, modFilePath(foundModRoot), modFilePath(modRoot))
   365  					return found, foundModRoot, modFilePath(foundModRoot)
   366  				}
   367  				found, foundModRoot = r, modRoot
   368  			}
   369  		}
   370  	}
   371  	return found, foundModRoot, modFilePath(foundModRoot)
   372  }
   373  
   374  func replaceRelativeTo() string {
   375  	if workFilePath := WorkFilePath(); workFilePath != "" {
   376  		return filepath.Dir(workFilePath)
   377  	}
   378  	return MainModules.ModRoot(MainModules.mustGetSingleMainModule())
   379  }
   380  
   381  // canonicalizeReplacePath ensures that relative, on-disk, replaced module paths
   382  // are relative to the workspace directory (in workspace mode) or to the module's
   383  // directory (in module mode, as they already are).
   384  func canonicalizeReplacePath(r module.Version, modRoot string) module.Version {
   385  	if filepath.IsAbs(r.Path) || r.Version != "" || modRoot == "" {
   386  		return r
   387  	}
   388  	workFilePath := WorkFilePath()
   389  	if workFilePath == "" {
   390  		return r
   391  	}
   392  	abs := filepath.Join(modRoot, r.Path)
   393  	if rel, err := filepath.Rel(filepath.Dir(workFilePath), abs); err == nil {
   394  		return module.Version{Path: ToDirectoryPath(rel), Version: r.Version}
   395  	}
   396  	// We couldn't make the version's path relative to the workspace's path,
   397  	// so just return the absolute path. It's the best we can do.
   398  	return module.Version{Path: ToDirectoryPath(abs), Version: r.Version}
   399  }
   400  
   401  // resolveReplacement returns the module actually used to load the source code
   402  // for m: either m itself, or the replacement for m (iff m is replaced).
   403  // It also returns the modroot of the module providing the replacement if
   404  // one was found.
   405  func resolveReplacement(m module.Version) module.Version {
   406  	if r := Replacement(m); r.Path != "" {
   407  		return r
   408  	}
   409  	return m
   410  }
   411  
   412  func toReplaceMap(replacements []*modfile.Replace) map[module.Version]module.Version {
   413  	replaceMap := make(map[module.Version]module.Version, len(replacements))
   414  	for _, r := range replacements {
   415  		if prev, dup := replaceMap[r.Old]; dup && prev != r.New {
   416  			base.Fatalf("go: conflicting replacements for %v:\n\t%v\n\t%v", r.Old, prev, r.New)
   417  		}
   418  		replaceMap[r.Old] = r.New
   419  	}
   420  	return replaceMap
   421  }
   422  
   423  // indexModFile rebuilds the index of modFile.
   424  // If modFile has been changed since it was first read,
   425  // modFile.Cleanup must be called before indexModFile.
   426  func indexModFile(data []byte, modFile *modfile.File, mod module.Version, needsFix bool) *modFileIndex {
   427  	i := new(modFileIndex)
   428  	i.data = data
   429  	i.dataNeedsFix = needsFix
   430  
   431  	i.module = module.Version{}
   432  	if modFile.Module != nil {
   433  		i.module = modFile.Module.Mod
   434  	}
   435  
   436  	i.goVersion = ""
   437  	if modFile.Go == nil {
   438  		rawGoVersion.Store(mod, "")
   439  	} else {
   440  		i.goVersion = modFile.Go.Version
   441  		rawGoVersion.Store(mod, modFile.Go.Version)
   442  	}
   443  	if modFile.Toolchain != nil {
   444  		i.toolchain = modFile.Toolchain.Name
   445  	}
   446  
   447  	i.require = make(map[module.Version]requireMeta, len(modFile.Require))
   448  	for _, r := range modFile.Require {
   449  		i.require[r.Mod] = requireMeta{indirect: r.Indirect}
   450  	}
   451  
   452  	i.replace = toReplaceMap(modFile.Replace)
   453  
   454  	i.exclude = make(map[module.Version]bool, len(modFile.Exclude))
   455  	for _, x := range modFile.Exclude {
   456  		i.exclude[x.Mod] = true
   457  	}
   458  
   459  	return i
   460  }
   461  
   462  // modFileIsDirty reports whether the go.mod file differs meaningfully
   463  // from what was indexed.
   464  // If modFile has been changed (even cosmetically) since it was first read,
   465  // modFile.Cleanup must be called before modFileIsDirty.
   466  func (i *modFileIndex) modFileIsDirty(modFile *modfile.File) bool {
   467  	if i == nil {
   468  		return modFile != nil
   469  	}
   470  
   471  	if i.dataNeedsFix {
   472  		return true
   473  	}
   474  
   475  	if modFile.Module == nil {
   476  		if i.module != (module.Version{}) {
   477  			return true
   478  		}
   479  	} else if modFile.Module.Mod != i.module {
   480  		return true
   481  	}
   482  
   483  	var goV, toolchain string
   484  	if modFile.Go != nil {
   485  		goV = modFile.Go.Version
   486  	}
   487  	if modFile.Toolchain != nil {
   488  		toolchain = modFile.Toolchain.Name
   489  	}
   490  
   491  	if goV != i.goVersion ||
   492  		toolchain != i.toolchain ||
   493  		len(modFile.Require) != len(i.require) ||
   494  		len(modFile.Replace) != len(i.replace) ||
   495  		len(modFile.Exclude) != len(i.exclude) {
   496  		return true
   497  	}
   498  
   499  	for _, r := range modFile.Require {
   500  		if meta, ok := i.require[r.Mod]; !ok {
   501  			return true
   502  		} else if r.Indirect != meta.indirect {
   503  			if cfg.BuildMod == "readonly" {
   504  				// The module's requirements are consistent; only the "// indirect"
   505  				// comments that are wrong. But those are only guaranteed to be accurate
   506  				// after a "go mod tidy" — it's a good idea to run those before
   507  				// committing a change, but it's certainly not mandatory.
   508  			} else {
   509  				return true
   510  			}
   511  		}
   512  	}
   513  
   514  	for _, r := range modFile.Replace {
   515  		if r.New != i.replace[r.Old] {
   516  			return true
   517  		}
   518  	}
   519  
   520  	for _, x := range modFile.Exclude {
   521  		if !i.exclude[x.Mod] {
   522  			return true
   523  		}
   524  	}
   525  
   526  	return false
   527  }
   528  
   529  // rawGoVersion records the Go version parsed from each module's go.mod file.
   530  //
   531  // If a module is replaced, the version of the replacement is keyed by the
   532  // replacement module.Version, not the version being replaced.
   533  var rawGoVersion sync.Map // map[module.Version]string
   534  
   535  // A modFileSummary is a summary of a go.mod file for which we do not need to
   536  // retain complete information — for example, the go.mod file of a dependency
   537  // module.
   538  type modFileSummary struct {
   539  	module     module.Version
   540  	goVersion  string
   541  	toolchain  string
   542  	pruning    modPruning
   543  	require    []module.Version
   544  	retract    []retraction
   545  	deprecated string
   546  }
   547  
   548  // A retraction consists of a retracted version interval and rationale.
   549  // retraction is like modfile.Retract, but it doesn't point to the syntax tree.
   550  type retraction struct {
   551  	modfile.VersionInterval
   552  	Rationale string
   553  }
   554  
   555  // goModSummary returns a summary of the go.mod file for module m,
   556  // taking into account any replacements for m, exclusions of its dependencies,
   557  // and/or vendoring.
   558  //
   559  // m must be a version in the module graph, reachable from the Target module.
   560  // In readonly mode, the go.sum file must contain an entry for m's go.mod file
   561  // (or its replacement). goModSummary must not be called for the Target module
   562  // itself, as its requirements may change. Use rawGoModSummary for other
   563  // module versions.
   564  //
   565  // The caller must not modify the returned summary.
   566  func goModSummary(m module.Version) (*modFileSummary, error) {
   567  	if m.Version == "" && !inWorkspaceMode() && MainModules.Contains(m.Path) {
   568  		panic("internal error: goModSummary called on a main module")
   569  	}
   570  	if gover.IsToolchain(m.Path) {
   571  		return rawGoModSummary(m)
   572  	}
   573  
   574  	if cfg.BuildMod == "vendor" {
   575  		summary := &modFileSummary{
   576  			module: module.Version{Path: m.Path},
   577  		}
   578  
   579  		readVendorList(VendorDir())
   580  		if vendorVersion[m.Path] != m.Version {
   581  			// This module is not vendored, so packages cannot be loaded from it and
   582  			// it cannot be relevant to the build.
   583  			return summary, nil
   584  		}
   585  
   586  		// For every module other than the target,
   587  		// return the full list of modules from modules.txt.
   588  		// We don't know what versions the vendored module actually relies on,
   589  		// so assume that it requires everything.
   590  		summary.require = vendorList
   591  		return summary, nil
   592  	}
   593  
   594  	actual := resolveReplacement(m)
   595  	if mustHaveSums() && actual.Version != "" {
   596  		key := module.Version{Path: actual.Path, Version: actual.Version + "/go.mod"}
   597  		if !modfetch.HaveSum(key) {
   598  			suggestion := fmt.Sprintf(" for go.mod file; to add it:\n\tgo mod download %s", m.Path)
   599  			return nil, module.VersionError(actual, &sumMissingError{suggestion: suggestion})
   600  		}
   601  	}
   602  	summary, err := rawGoModSummary(actual)
   603  	if err != nil {
   604  		return nil, err
   605  	}
   606  
   607  	if actual.Version == "" {
   608  		// The actual module is a filesystem-local replacement, for which we have
   609  		// unfortunately not enforced any sort of invariants about module lines or
   610  		// matching module paths. Anything goes.
   611  		//
   612  		// TODO(bcmills): Remove this special-case, update tests, and add a
   613  		// release note.
   614  	} else {
   615  		if summary.module.Path == "" {
   616  			return nil, module.VersionError(actual, errors.New("parsing go.mod: missing module line"))
   617  		}
   618  
   619  		// In theory we should only allow mpath to be unequal to m.Path here if the
   620  		// version that we fetched lacks an explicit go.mod file: if the go.mod file
   621  		// is explicit, then it should match exactly (to ensure that imports of other
   622  		// packages within the module are interpreted correctly). Unfortunately, we
   623  		// can't determine that information from the module proxy protocol: we'll have
   624  		// to leave that validation for when we load actual packages from within the
   625  		// module.
   626  		if mpath := summary.module.Path; mpath != m.Path && mpath != actual.Path {
   627  			return nil, module.VersionError(actual,
   628  				fmt.Errorf("parsing go.mod:\n"+
   629  					"\tmodule declares its path as: %s\n"+
   630  					"\t        but was required as: %s", mpath, m.Path))
   631  		}
   632  	}
   633  
   634  	for _, mainModule := range MainModules.Versions() {
   635  		if index := MainModules.Index(mainModule); index != nil && len(index.exclude) > 0 {
   636  			// Drop any requirements on excluded versions.
   637  			// Don't modify the cached summary though, since we might need the raw
   638  			// summary separately.
   639  			haveExcludedReqs := false
   640  			for _, r := range summary.require {
   641  				if index.exclude[r] {
   642  					haveExcludedReqs = true
   643  					break
   644  				}
   645  			}
   646  			if haveExcludedReqs {
   647  				s := new(modFileSummary)
   648  				*s = *summary
   649  				s.require = make([]module.Version, 0, len(summary.require))
   650  				for _, r := range summary.require {
   651  					if !index.exclude[r] {
   652  						s.require = append(s.require, r)
   653  					}
   654  				}
   655  				summary = s
   656  			}
   657  		}
   658  	}
   659  	return summary, nil
   660  }
   661  
   662  // rawGoModSummary returns a new summary of the go.mod file for module m,
   663  // ignoring all replacements that may apply to m and excludes that may apply to
   664  // its dependencies.
   665  //
   666  // rawGoModSummary cannot be used on the main module outside of workspace mode.
   667  // The modFileSummary can still be used for retractions and deprecations
   668  // even if a TooNewError is returned.
   669  func rawGoModSummary(m module.Version) (*modFileSummary, error) {
   670  	if gover.IsToolchain(m.Path) {
   671  		if m.Path == "go" && gover.Compare(m.Version, gover.GoStrictVersion) >= 0 {
   672  			// Declare that go 1.21.3 requires toolchain 1.21.3,
   673  			// so that go get knows that downgrading toolchain implies downgrading go
   674  			// and similarly upgrading go requires upgrading the toolchain.
   675  			return &modFileSummary{module: m, require: []module.Version{{Path: "toolchain", Version: "go" + m.Version}}}, nil
   676  		}
   677  		return &modFileSummary{module: m}, nil
   678  	}
   679  	if m.Version == "" && !inWorkspaceMode() && MainModules.Contains(m.Path) {
   680  		// Calling rawGoModSummary implies that we are treating m as a module whose
   681  		// requirements aren't the roots of the module graph and can't be modified.
   682  		//
   683  		// If we are not in workspace mode, then the requirements of the main module
   684  		// are the roots of the module graph and we expect them to be kept consistent.
   685  		panic("internal error: rawGoModSummary called on a main module")
   686  	}
   687  	if m.Version == "" && inWorkspaceMode() && m.Path == "command-line-arguments" {
   688  		// "go work sync" calls LoadModGraph to make sure the module graph is valid.
   689  		// If there are no modules in the workspace, we synthesize an empty
   690  		// command-line-arguments module, which rawGoModData cannot read a go.mod for.
   691  		return &modFileSummary{module: m}, nil
   692  	}
   693  	return rawGoModSummaryCache.Do(m, func() (*modFileSummary, error) {
   694  		summary := new(modFileSummary)
   695  		name, data, err := rawGoModData(m)
   696  		if err != nil {
   697  			return nil, err
   698  		}
   699  		f, err := modfile.ParseLax(name, data, nil)
   700  		if err != nil {
   701  			return nil, module.VersionError(m, fmt.Errorf("parsing %s: %v", base.ShortPath(name), err))
   702  		}
   703  		if f.Module != nil {
   704  			summary.module = f.Module.Mod
   705  			summary.deprecated = f.Module.Deprecated
   706  		}
   707  		if f.Go != nil {
   708  			rawGoVersion.LoadOrStore(m, f.Go.Version)
   709  			summary.goVersion = f.Go.Version
   710  			summary.pruning = pruningForGoVersion(f.Go.Version)
   711  		} else {
   712  			summary.pruning = unpruned
   713  		}
   714  		if f.Toolchain != nil {
   715  			summary.toolchain = f.Toolchain.Name
   716  		}
   717  		if len(f.Require) > 0 {
   718  			summary.require = make([]module.Version, 0, len(f.Require)+1)
   719  			for _, req := range f.Require {
   720  				summary.require = append(summary.require, req.Mod)
   721  			}
   722  		}
   723  
   724  		if len(f.Retract) > 0 {
   725  			summary.retract = make([]retraction, 0, len(f.Retract))
   726  			for _, ret := range f.Retract {
   727  				summary.retract = append(summary.retract, retraction{
   728  					VersionInterval: ret.VersionInterval,
   729  					Rationale:       ret.Rationale,
   730  				})
   731  			}
   732  		}
   733  
   734  		// This block must be kept at the end of the function because the summary may
   735  		// be used for reading retractions or deprecations even if a TooNewError is
   736  		// returned.
   737  		if summary.goVersion != "" && gover.Compare(summary.goVersion, gover.GoStrictVersion) >= 0 {
   738  			summary.require = append(summary.require, module.Version{Path: "go", Version: summary.goVersion})
   739  			if gover.Compare(summary.goVersion, gover.Local()) > 0 {
   740  				return summary, &gover.TooNewError{What: "module " + m.String(), GoVersion: summary.goVersion}
   741  			}
   742  		}
   743  
   744  		return summary, nil
   745  	})
   746  }
   747  
   748  var rawGoModSummaryCache par.ErrCache[module.Version, *modFileSummary]
   749  
   750  // rawGoModData returns the content of the go.mod file for module m, ignoring
   751  // all replacements that may apply to m.
   752  //
   753  // rawGoModData cannot be used on the main module outside of workspace mode.
   754  //
   755  // Unlike rawGoModSummary, rawGoModData does not cache its results in memory.
   756  // Use rawGoModSummary instead unless you specifically need these bytes.
   757  func rawGoModData(m module.Version) (name string, data []byte, err error) {
   758  	if m.Version == "" {
   759  		dir := m.Path
   760  		if !filepath.IsAbs(dir) {
   761  			if inWorkspaceMode() && MainModules.Contains(m.Path) {
   762  				dir = MainModules.ModRoot(m)
   763  			} else {
   764  				// m is a replacement module with only a file path.
   765  				dir = filepath.Join(replaceRelativeTo(), dir)
   766  			}
   767  		}
   768  		name = filepath.Join(dir, "go.mod")
   769  		if fsys.Replaced(name) {
   770  			// Don't lock go.mod if it's part of the overlay.
   771  			// On Plan 9, locking requires chmod, and we don't want to modify any file
   772  			// in the overlay. See #44700.
   773  			data, err = os.ReadFile(fsys.Actual(name))
   774  		} else {
   775  			data, err = lockedfile.Read(name)
   776  		}
   777  		if err != nil {
   778  			return "", nil, module.VersionError(m, fmt.Errorf("reading %s: %v", base.ShortPath(name), err))
   779  		}
   780  	} else {
   781  		if !gover.ModIsValid(m.Path, m.Version) {
   782  			// Disallow the broader queries supported by fetch.Lookup.
   783  			base.Fatalf("go: internal error: %s@%s: unexpected invalid semantic version", m.Path, m.Version)
   784  		}
   785  		name = "go.mod"
   786  		data, err = modfetch.GoMod(context.TODO(), m.Path, m.Version)
   787  	}
   788  	return name, data, err
   789  }
   790  
   791  // queryLatestVersionIgnoringRetractions looks up the latest version of the
   792  // module with the given path without considering retracted or excluded
   793  // versions.
   794  //
   795  // If all versions of the module are replaced,
   796  // queryLatestVersionIgnoringRetractions returns the replacement without making
   797  // a query.
   798  //
   799  // If the queried latest version is replaced,
   800  // queryLatestVersionIgnoringRetractions returns the replacement.
   801  func queryLatestVersionIgnoringRetractions(ctx context.Context, path string) (latest module.Version, err error) {
   802  	return latestVersionIgnoringRetractionsCache.Do(path, func() (module.Version, error) {
   803  		ctx, span := trace.StartSpan(ctx, "queryLatestVersionIgnoringRetractions "+path)
   804  		defer span.Done()
   805  
   806  		if repl := Replacement(module.Version{Path: path}); repl.Path != "" {
   807  			// All versions of the module were replaced.
   808  			// No need to query.
   809  			return repl, nil
   810  		}
   811  
   812  		// Find the latest version of the module.
   813  		// Ignore exclusions from the main module's go.mod.
   814  		const ignoreSelected = ""
   815  		var allowAll AllowedFunc
   816  		rev, err := Query(ctx, path, "latest", ignoreSelected, allowAll)
   817  		if err != nil {
   818  			return module.Version{}, err
   819  		}
   820  		latest := module.Version{Path: path, Version: rev.Version}
   821  		if repl := resolveReplacement(latest); repl.Path != "" {
   822  			latest = repl
   823  		}
   824  		return latest, nil
   825  	})
   826  }
   827  
   828  var latestVersionIgnoringRetractionsCache par.ErrCache[string, module.Version] // path → queryLatestVersionIgnoringRetractions result
   829  
   830  // ToDirectoryPath adds a prefix if necessary so that path in unambiguously
   831  // an absolute path or a relative path starting with a '.' or '..'
   832  // path component.
   833  func ToDirectoryPath(path string) string {
   834  	if modfile.IsDirectoryPath(path) {
   835  		return path
   836  	}
   837  	// The path is not a relative path or an absolute path, so make it relative
   838  	// to the current directory.
   839  	return "./" + filepath.ToSlash(filepath.Clean(path))
   840  }
   841
View as plain text