Adding upstream version 1.16.10.upstream/1.16.10upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 591 insertions, 0 deletions

diff --git a/src/cmd/go/internal/modload/modfile.go b/src/cmd/go/internal/modload/modfile.go
new file mode 100644
index 0000000..c6667d0
--- /dev/null
+++ b/src/cmd/go/internal/modload/modfile.go
@@ -0,0 +1,591 @@
+// Copyright 2020 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package modload
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"path/filepath"
+	"strings"
+	"sync"
+	"unicode"
+
+	"cmd/go/internal/base"
+	"cmd/go/internal/cfg"
+	"cmd/go/internal/lockedfile"
+	"cmd/go/internal/modfetch"
+	"cmd/go/internal/par"
+	"cmd/go/internal/trace"
+
+	"golang.org/x/mod/modfile"
+	"golang.org/x/mod/module"
+	"golang.org/x/mod/semver"
+)
+
+// narrowAllVersionV is the Go version (plus leading "v") at which the
+// module-module "all" pattern no longer closes over the dependencies of
+// tests outside of the main module.
+const narrowAllVersionV = "v1.16"
+const go116EnableNarrowAll = true
+
+var modFile *modfile.File
+
+// A modFileIndex is an index of data corresponding to a modFile
+// at a specific point in time.
+type modFileIndex struct {
+	data            []byte
+	dataNeedsFix    bool // true if fixVersion applied a change while parsing data
+	module          module.Version
+	goVersionV      string // GoVersion with "v" prefix
+	require         map[module.Version]requireMeta
+	replace         map[module.Version]module.Version
+	highestReplaced map[string]string // highest replaced version of each module path; empty string for wildcard-only replacements
+	exclude         map[module.Version]bool
+}
+
+// index is the index of the go.mod file as of when it was last read or written.
+var index *modFileIndex
+
+type requireMeta struct {
+	indirect bool
+}
+
+// CheckAllowed returns an error equivalent to ErrDisallowed if m is excluded by
+// the main module's go.mod or retracted by its author. Most version queries use
+// this to filter out versions that should not be used.
+func CheckAllowed(ctx context.Context, m module.Version) error {
+	if err := CheckExclusions(ctx, m); err != nil {
+		return err
+	}
+	if err := CheckRetractions(ctx, m); err != nil {
+		return err
+	}
+	return nil
+}
+
+// ErrDisallowed is returned by version predicates passed to Query and similar
+// functions to indicate that a version should not be considered.
+var ErrDisallowed = errors.New("disallowed module version")
+
+// CheckExclusions returns an error equivalent to ErrDisallowed if module m is
+// excluded by the main module's go.mod file.
+func CheckExclusions(ctx context.Context, m module.Version) error {
+	if index != nil && index.exclude[m] {
+		return module.VersionError(m, errExcluded)
+	}
+	return nil
+}
+
+var errExcluded = &excludedError{}
+
+type excludedError struct{}
+
+func (e *excludedError) Error() string     { return "excluded by go.mod" }
+func (e *excludedError) Is(err error) bool { return err == ErrDisallowed }
+
+// CheckRetractions returns an error if module m has been retracted by
+// its author.
+func CheckRetractions(ctx context.Context, m module.Version) error {
+	if m.Version == "" {
+		// Main module, standard library, or file replacement module.
+		// Cannot be retracted.
+		return nil
+	}
+
+	// Look up retraction information from the latest available version of
+	// the module. Cache retraction information so we don't parse the go.mod
+	// file repeatedly.
+	type entry struct {
+		retract []retraction
+		err     error
+	}
+	path := m.Path
+	e := retractCache.Do(path, func() (v interface{}) {
+		ctx, span := trace.StartSpan(ctx, "checkRetractions "+path)
+		defer span.Done()
+
+		if repl := Replacement(module.Version{Path: m.Path}); repl.Path != "" {
+			// All versions of the module were replaced with a local directory.
+			// Don't load retractions.
+			return &entry{nil, nil}
+		}
+
+		// Find the latest version of the module.
+		// Ignore exclusions from the main module's go.mod.
+		const ignoreSelected = ""
+		var allowAll AllowedFunc
+		rev, err := Query(ctx, path, "latest", ignoreSelected, allowAll)
+		if err != nil {
+			return &entry{nil, err}
+		}
+
+		// Load go.mod for that version.
+		// If the version is replaced, we'll load retractions from the replacement.
+		//
+		// If there's an error loading the go.mod, we'll return it here.
+		// These errors should generally be ignored by callers of checkRetractions,
+		// since they happen frequently when we're offline. These errors are not
+		// equivalent to ErrDisallowed, so they may be distinguished from
+		// retraction errors.
+		//
+		// We load the raw file here: the go.mod file may have a different module
+		// path that we expect if the module or its repository was renamed.
+		// We still want to apply retractions to other aliases of the module.
+		rm := module.Version{Path: path, Version: rev.Version}
+		if repl := Replacement(rm); repl.Path != "" {
+			rm = repl
+		}
+		summary, err := rawGoModSummary(rm)
+		if err != nil {
+			return &entry{nil, err}
+		}
+		return &entry{summary.retract, nil}
+	}).(*entry)
+
+	if err := e.err; err != nil {
+		// Attribute the error to the version being checked, not the version from
+		// which the retractions were to be loaded.
+		var mErr *module.ModuleError
+		if errors.As(err, &mErr) {
+			err = mErr.Err
+		}
+		return &retractionLoadingError{m: m, err: err}
+	}
+
+	var rationale []string
+	isRetracted := false
+	for _, r := range e.retract {
+		if semver.Compare(r.Low, m.Version) <= 0 && semver.Compare(m.Version, r.High) <= 0 {
+			isRetracted = true
+			if r.Rationale != "" {
+				rationale = append(rationale, r.Rationale)
+			}
+		}
+	}
+	if isRetracted {
+		return module.VersionError(m, &ModuleRetractedError{Rationale: rationale})
+	}
+	return nil
+}
+
+var retractCache par.Cache
+
+type ModuleRetractedError struct {
+	Rationale []string
+}
+
+func (e *ModuleRetractedError) Error() string {
+	msg := "retracted by module author"
+	if len(e.Rationale) > 0 {
+		// This is meant to be a short error printed on a terminal, so just
+		// print the first rationale.
+		msg += ": " + ShortRetractionRationale(e.Rationale[0])
+	}
+	return msg
+}
+
+func (e *ModuleRetractedError) Is(err error) bool {
+	return err == ErrDisallowed
+}
+
+type retractionLoadingError struct {
+	m   module.Version
+	err error
+}
+
+func (e *retractionLoadingError) Error() string {
+	return fmt.Sprintf("loading module retractions for %v: %v", e.m, e.err)
+}
+
+func (e *retractionLoadingError) Unwrap() error {
+	return e.err
+}
+
+// ShortRetractionRationale returns a retraction rationale string that is safe
+// to print in a terminal. It returns hard-coded strings if the rationale
+// is empty, too long, or contains non-printable characters.
+func ShortRetractionRationale(rationale string) string {
+	const maxRationaleBytes = 500
+	if i := strings.Index(rationale, "\n"); i >= 0 {
+		rationale = rationale[:i]
+	}
+	rationale = strings.TrimSpace(rationale)
+	if rationale == "" {
+		return "retracted by module author"
+	}
+	if len(rationale) > maxRationaleBytes {
+		return "(rationale omitted: too long)"
+	}
+	for _, r := range rationale {
+		if !unicode.IsGraphic(r) && !unicode.IsSpace(r) {
+			return "(rationale omitted: contains non-printable characters)"
+		}
+	}
+	// NOTE: the go.mod parser rejects invalid UTF-8, so we don't check that here.
+	return rationale
+}
+
+// Replacement returns the replacement for mod, if any, from go.mod.
+// If there is no replacement for mod, Replacement returns
+// a module.Version with Path == "".
+func Replacement(mod module.Version) module.Version {
+	if index != nil {
+		if r, ok := index.replace[mod]; ok {
+			return r
+		}
+		if r, ok := index.replace[module.Version{Path: mod.Path}]; ok {
+			return r
+		}
+	}
+	return module.Version{}
+}
+
+// indexModFile rebuilds the index of modFile.
+// If modFile has been changed since it was first read,
+// modFile.Cleanup must be called before indexModFile.
+func indexModFile(data []byte, modFile *modfile.File, needsFix bool) *modFileIndex {
+	i := new(modFileIndex)
+	i.data = data
+	i.dataNeedsFix = needsFix
+
+	i.module = module.Version{}
+	if modFile.Module != nil {
+		i.module = modFile.Module.Mod
+	}
+
+	i.goVersionV = ""
+	if modFile.Go != nil {
+		// We're going to use the semver package to compare Go versions, so go ahead
+		// and add the "v" prefix it expects once instead of every time.
+		i.goVersionV = "v" + modFile.Go.Version
+	}
+
+	i.require = make(map[module.Version]requireMeta, len(modFile.Require))
+	for _, r := range modFile.Require {
+		i.require[r.Mod] = requireMeta{indirect: r.Indirect}
+	}
+
+	i.replace = make(map[module.Version]module.Version, len(modFile.Replace))
+	for _, r := range modFile.Replace {
+		if prev, dup := i.replace[r.Old]; dup && prev != r.New {
+			base.Fatalf("go: conflicting replacements for %v:\n\t%v\n\t%v", r.Old, prev, r.New)
+		}
+		i.replace[r.Old] = r.New
+	}
+
+	i.highestReplaced = make(map[string]string)
+	for _, r := range modFile.Replace {
+		v, ok := i.highestReplaced[r.Old.Path]
+		if !ok || semver.Compare(r.Old.Version, v) > 0 {
+			i.highestReplaced[r.Old.Path] = r.Old.Version
+		}
+	}
+
+	i.exclude = make(map[module.Version]bool, len(modFile.Exclude))
+	for _, x := range modFile.Exclude {
+		i.exclude[x.Mod] = true
+	}
+
+	return i
+}
+
+// allPatternClosesOverTests reports whether the "all" pattern includes
+// dependencies of tests outside the main module (as in Go 1.11–1.15).
+// (Otherwise — as in Go 1.16+ — the "all" pattern includes only the packages
+// transitively *imported by* the packages and tests in the main module.)
+func (i *modFileIndex) allPatternClosesOverTests() bool {
+	if !go116EnableNarrowAll {
+		return true
+	}
+	if i != nil && semver.Compare(i.goVersionV, narrowAllVersionV) < 0 {
+		// The module explicitly predates the change in "all" for lazy loading, so
+		// continue to use the older interpretation. (If i == nil, we not in any
+		// module at all and should use the latest semantics.)
+		return true
+	}
+	return false
+}
+
+// modFileIsDirty reports whether the go.mod file differs meaningfully
+// from what was indexed.
+// If modFile has been changed (even cosmetically) since it was first read,
+// modFile.Cleanup must be called before modFileIsDirty.
+func (i *modFileIndex) modFileIsDirty(modFile *modfile.File) bool {
+	if i == nil {
+		return modFile != nil
+	}
+
+	if i.dataNeedsFix {
+		return true
+	}
+
+	if modFile.Module == nil {
+		if i.module != (module.Version{}) {
+			return true
+		}
+	} else if modFile.Module.Mod != i.module {
+		return true
+	}
+
+	if modFile.Go == nil {
+		if i.goVersionV != "" {
+			return true
+		}
+	} else if "v"+modFile.Go.Version != i.goVersionV {
+		if i.goVersionV == "" && cfg.BuildMod == "readonly" {
+			// go.mod files did not always require a 'go' version, so do not error out
+			// if one is missing — we may be inside an older module in the module
+			// cache, and should bias toward providing useful behavior.
+		} else {
+			return true
+		}
+	}
+
+	if len(modFile.Require) != len(i.require) ||
+		len(modFile.Replace) != len(i.replace) ||
+		len(modFile.Exclude) != len(i.exclude) {
+		return true
+	}
+
+	for _, r := range modFile.Require {
+		if meta, ok := i.require[r.Mod]; !ok {
+			return true
+		} else if r.Indirect != meta.indirect {
+			if cfg.BuildMod == "readonly" {
+				// The module's requirements are consistent; only the "// indirect"
+				// comments that are wrong. But those are only guaranteed to be accurate
+				// after a "go mod tidy" — it's a good idea to run those before
+				// committing a change, but it's certainly not mandatory.
+			} else {
+				return true
+			}
+		}
+	}
+
+	for _, r := range modFile.Replace {
+		if r.New != i.replace[r.Old] {
+			return true
+		}
+	}
+
+	for _, x := range modFile.Exclude {
+		if !i.exclude[x.Mod] {
+			return true
+		}
+	}
+
+	return false
+}
+
+// rawGoVersion records the Go version parsed from each module's go.mod file.
+//
+// If a module is replaced, the version of the replacement is keyed by the
+// replacement module.Version, not the version being replaced.
+var rawGoVersion sync.Map // map[module.Version]string
+
+// A modFileSummary is a summary of a go.mod file for which we do not need to
+// retain complete information — for example, the go.mod file of a dependency
+// module.
+type modFileSummary struct {
+	module     module.Version
+	goVersionV string // GoVersion with "v" prefix
+	require    []module.Version
+	retract    []retraction
+}
+
+// A retraction consists of a retracted version interval and rationale.
+// retraction is like modfile.Retract, but it doesn't point to the syntax tree.
+type retraction struct {
+	modfile.VersionInterval
+	Rationale string
+}
+
+// goModSummary returns a summary of the go.mod file for module m,
+// taking into account any replacements for m, exclusions of its dependencies,
+// and/or vendoring.
+//
+// m must be a version in the module graph, reachable from the Target module.
+// In readonly mode, the go.sum file must contain an entry for m's go.mod file
+// (or its replacement). goModSummary must not be called for the Target module
+// itself, as its requirements may change. Use rawGoModSummary for other
+// module versions.
+//
+// The caller must not modify the returned summary.
+func goModSummary(m module.Version) (*modFileSummary, error) {
+	if m == Target {
+		panic("internal error: goModSummary called on the Target module")
+	}
+
+	if cfg.BuildMod == "vendor" {
+		summary := &modFileSummary{
+			module: module.Version{Path: m.Path},
+		}
+		if vendorVersion[m.Path] != m.Version {
+			// This module is not vendored, so packages cannot be loaded from it and
+			// it cannot be relevant to the build.
+			return summary, nil
+		}
+
+		// For every module other than the target,
+		// return the full list of modules from modules.txt.
+		readVendorList()
+
+		// TODO(#36876): Load the "go" version from vendor/modules.txt and store it
+		// in rawGoVersion with the appropriate key.
+
+		// We don't know what versions the vendored module actually relies on,
+		// so assume that it requires everything.
+		summary.require = vendorList
+		return summary, nil
+	}
+
+	actual := Replacement(m)
+	if actual.Path == "" {
+		actual = m
+	}
+	if HasModRoot() && cfg.BuildMod == "readonly" && actual.Version != "" {
+		key := module.Version{Path: actual.Path, Version: actual.Version + "/go.mod"}
+		if !modfetch.HaveSum(key) {
+			suggestion := fmt.Sprintf("; to add it:\n\tgo mod download %s", m.Path)
+			return nil, module.VersionError(actual, &sumMissingError{suggestion: suggestion})
+		}
+	}
+	summary, err := rawGoModSummary(actual)
+	if err != nil {
+		return nil, err
+	}
+
+	if actual.Version == "" {
+		// The actual module is a filesystem-local replacement, for which we have
+		// unfortunately not enforced any sort of invariants about module lines or
+		// matching module paths. Anything goes.
+		//
+		// TODO(bcmills): Remove this special-case, update tests, and add a
+		// release note.
+	} else {
+		if summary.module.Path == "" {
+			return nil, module.VersionError(actual, errors.New("parsing go.mod: missing module line"))
+		}
+
+		// In theory we should only allow mpath to be unequal to m.Path here if the
+		// version that we fetched lacks an explicit go.mod file: if the go.mod file
+		// is explicit, then it should match exactly (to ensure that imports of other
+		// packages within the module are interpreted correctly). Unfortunately, we
+		// can't determine that information from the module proxy protocol: we'll have
+		// to leave that validation for when we load actual packages from within the
+		// module.
+		if mpath := summary.module.Path; mpath != m.Path && mpath != actual.Path {
+			return nil, module.VersionError(actual, fmt.Errorf(`parsing go.mod:
+	module declares its path as: %s
+	        but was required as: %s`, mpath, m.Path))
+		}
+	}
+
+	if index != nil && len(index.exclude) > 0 {
+		// Drop any requirements on excluded versions.
+		// Don't modify the cached summary though, since we might need the raw
+		// summary separately.
+		haveExcludedReqs := false
+		for _, r := range summary.require {
+			if index.exclude[r] {
+				haveExcludedReqs = true
+				break
+			}
+		}
+		if haveExcludedReqs {
+			s := new(modFileSummary)
+			*s = *summary
+			s.require = make([]module.Version, 0, len(summary.require))
+			for _, r := range summary.require {
+				if !index.exclude[r] {
+					s.require = append(s.require, r)
+				}
+			}
+			summary = s
+		}
+	}
+	return summary, nil
+}
+
+// rawGoModSummary returns a new summary of the go.mod file for module m,
+// ignoring all replacements that may apply to m and excludes that may apply to
+// its dependencies.
+//
+// rawGoModSummary cannot be used on the Target module.
+func rawGoModSummary(m module.Version) (*modFileSummary, error) {
+	if m == Target {
+		panic("internal error: rawGoModSummary called on the Target module")
+	}
+
+	type cached struct {
+		summary *modFileSummary
+		err     error
+	}
+	c := rawGoModSummaryCache.Do(m, func() interface{} {
+		summary := new(modFileSummary)
+		var f *modfile.File
+		if m.Version == "" {
+			// m is a replacement module with only a file path.
+			dir := m.Path
+			if !filepath.IsAbs(dir) {
+				dir = filepath.Join(ModRoot(), dir)
+			}
+			gomod := filepath.Join(dir, "go.mod")
+
+			data, err := lockedfile.Read(gomod)
+			if err != nil {
+				return cached{nil, module.VersionError(m, fmt.Errorf("reading %s: %v", base.ShortPath(gomod), err))}
+			}
+			f, err = modfile.ParseLax(gomod, data, nil)
+			if err != nil {
+				return cached{nil, module.VersionError(m, fmt.Errorf("parsing %s: %v", base.ShortPath(gomod), err))}
+			}
+		} else {
+			if !semver.IsValid(m.Version) {
+				// Disallow the broader queries supported by fetch.Lookup.
+				base.Fatalf("go: internal error: %s@%s: unexpected invalid semantic version", m.Path, m.Version)
+			}
+
+			data, err := modfetch.GoMod(m.Path, m.Version)
+			if err != nil {
+				return cached{nil, err}
+			}
+			f, err = modfile.ParseLax("go.mod", data, nil)
+			if err != nil {
+				return cached{nil, module.VersionError(m, fmt.Errorf("parsing go.mod: %v", err))}
+			}
+		}
+
+		if f.Module != nil {
+			summary.module = f.Module.Mod
+		}
+		if f.Go != nil && f.Go.Version != "" {
+			rawGoVersion.LoadOrStore(m, f.Go.Version)
+			summary.goVersionV = "v" + f.Go.Version
+		}
+		if len(f.Require) > 0 {
+			summary.require = make([]module.Version, 0, len(f.Require))
+			for _, req := range f.Require {
+				summary.require = append(summary.require, req.Mod)
+			}
+		}
+		if len(f.Retract) > 0 {
+			summary.retract = make([]retraction, 0, len(f.Retract))
+			for _, ret := range f.Retract {
+				summary.retract = append(summary.retract, retraction{
+					VersionInterval: ret.VersionInterval,
+					Rationale:       ret.Rationale,
+				})
+			}
+		}
+
+		return cached{summary, nil}
+	}).(cached)
+
+	return c.summary, c.err
+}
+
+var rawGoModSummaryCache par.Cache // module.Version → rawGoModSummary result