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-rw-r--r--src/cmd/go/internal/modfetch/codehost/git.go875
1 files changed, 875 insertions, 0 deletions
diff --git a/src/cmd/go/internal/modfetch/codehost/git.go b/src/cmd/go/internal/modfetch/codehost/git.go
new file mode 100644
index 0000000..72005e2
--- /dev/null
+++ b/src/cmd/go/internal/modfetch/codehost/git.go
@@ -0,0 +1,875 @@
+// Copyright 2018 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 codehost
+
+import (
+ "bytes"
+ "errors"
+ "fmt"
+ exec "internal/execabs"
+ "io"
+ "io/fs"
+ "net/url"
+ "os"
+ "path/filepath"
+ "sort"
+ "strconv"
+ "strings"
+ "sync"
+ "time"
+
+ "cmd/go/internal/lockedfile"
+ "cmd/go/internal/par"
+ "cmd/go/internal/web"
+
+ "golang.org/x/mod/semver"
+)
+
+// LocalGitRepo is like Repo but accepts both Git remote references
+// and paths to repositories on the local file system.
+func LocalGitRepo(remote string) (Repo, error) {
+ return newGitRepoCached(remote, true)
+}
+
+// A notExistError wraps another error to retain its original text
+// but makes it opaquely equivalent to fs.ErrNotExist.
+type notExistError struct {
+ err error
+}
+
+func (e notExistError) Error() string { return e.err.Error() }
+func (notExistError) Is(err error) bool { return err == fs.ErrNotExist }
+
+const gitWorkDirType = "git3"
+
+var gitRepoCache par.Cache
+
+func newGitRepoCached(remote string, localOK bool) (Repo, error) {
+ type key struct {
+ remote string
+ localOK bool
+ }
+ type cached struct {
+ repo Repo
+ err error
+ }
+
+ c := gitRepoCache.Do(key{remote, localOK}, func() interface{} {
+ repo, err := newGitRepo(remote, localOK)
+ return cached{repo, err}
+ }).(cached)
+
+ return c.repo, c.err
+}
+
+func newGitRepo(remote string, localOK bool) (Repo, error) {
+ r := &gitRepo{remote: remote}
+ if strings.Contains(remote, "://") {
+ // This is a remote path.
+ var err error
+ r.dir, r.mu.Path, err = WorkDir(gitWorkDirType, r.remote)
+ if err != nil {
+ return nil, err
+ }
+
+ unlock, err := r.mu.Lock()
+ if err != nil {
+ return nil, err
+ }
+ defer unlock()
+
+ if _, err := os.Stat(filepath.Join(r.dir, "objects")); err != nil {
+ if _, err := Run(r.dir, "git", "init", "--bare"); err != nil {
+ os.RemoveAll(r.dir)
+ return nil, err
+ }
+ // We could just say git fetch https://whatever later,
+ // but this lets us say git fetch origin instead, which
+ // is a little nicer. More importantly, using a named remote
+ // avoids a problem with Git LFS. See golang.org/issue/25605.
+ if _, err := Run(r.dir, "git", "remote", "add", "origin", "--", r.remote); err != nil {
+ os.RemoveAll(r.dir)
+ return nil, err
+ }
+ }
+ r.remoteURL = r.remote
+ r.remote = "origin"
+ } else {
+ // Local path.
+ // Disallow colon (not in ://) because sometimes
+ // that's rcp-style host:path syntax and sometimes it's not (c:\work).
+ // The go command has always insisted on URL syntax for ssh.
+ if strings.Contains(remote, ":") {
+ return nil, fmt.Errorf("git remote cannot use host:path syntax")
+ }
+ if !localOK {
+ return nil, fmt.Errorf("git remote must not be local directory")
+ }
+ r.local = true
+ info, err := os.Stat(remote)
+ if err != nil {
+ return nil, err
+ }
+ if !info.IsDir() {
+ return nil, fmt.Errorf("%s exists but is not a directory", remote)
+ }
+ r.dir = remote
+ r.mu.Path = r.dir + ".lock"
+ }
+ return r, nil
+}
+
+type gitRepo struct {
+ remote, remoteURL string
+ local bool
+ dir string
+
+ mu lockedfile.Mutex // protects fetchLevel and git repo state
+
+ fetchLevel int
+
+ statCache par.Cache
+
+ refsOnce sync.Once
+ // refs maps branch and tag refs (e.g., "HEAD", "refs/heads/master")
+ // to commits (e.g., "37ffd2e798afde829a34e8955b716ab730b2a6d6")
+ refs map[string]string
+ refsErr error
+
+ localTagsOnce sync.Once
+ localTags map[string]bool
+}
+
+const (
+ // How much have we fetched into the git repo (in this process)?
+ fetchNone = iota // nothing yet
+ fetchSome // shallow fetches of individual hashes
+ fetchAll // "fetch -t origin": get all remote branches and tags
+)
+
+// loadLocalTags loads tag references from the local git cache
+// into the map r.localTags.
+// Should only be called as r.localTagsOnce.Do(r.loadLocalTags).
+func (r *gitRepo) loadLocalTags() {
+ // The git protocol sends all known refs and ls-remote filters them on the client side,
+ // so we might as well record both heads and tags in one shot.
+ // Most of the time we only care about tags but sometimes we care about heads too.
+ out, err := Run(r.dir, "git", "tag", "-l")
+ if err != nil {
+ return
+ }
+
+ r.localTags = make(map[string]bool)
+ for _, line := range strings.Split(string(out), "\n") {
+ if line != "" {
+ r.localTags[line] = true
+ }
+ }
+}
+
+// loadRefs loads heads and tags references from the remote into the map r.refs.
+// Should only be called as r.refsOnce.Do(r.loadRefs).
+func (r *gitRepo) loadRefs() {
+ // The git protocol sends all known refs and ls-remote filters them on the client side,
+ // so we might as well record both heads and tags in one shot.
+ // Most of the time we only care about tags but sometimes we care about heads too.
+ out, gitErr := Run(r.dir, "git", "ls-remote", "-q", r.remote)
+ if gitErr != nil {
+ if rerr, ok := gitErr.(*RunError); ok {
+ if bytes.Contains(rerr.Stderr, []byte("fatal: could not read Username")) {
+ rerr.HelpText = "Confirm the import path was entered correctly.\nIf this is a private repository, see https://golang.org/doc/faq#git_https for additional information."
+ }
+ }
+
+ // If the remote URL doesn't exist at all, ideally we should treat the whole
+ // repository as nonexistent by wrapping the error in a notExistError.
+ // For HTTP and HTTPS, that's easy to detect: we'll try to fetch the URL
+ // ourselves and see what code it serves.
+ if u, err := url.Parse(r.remoteURL); err == nil && (u.Scheme == "http" || u.Scheme == "https") {
+ if _, err := web.GetBytes(u); errors.Is(err, fs.ErrNotExist) {
+ gitErr = notExistError{gitErr}
+ }
+ }
+
+ r.refsErr = gitErr
+ return
+ }
+
+ r.refs = make(map[string]string)
+ for _, line := range strings.Split(string(out), "\n") {
+ f := strings.Fields(line)
+ if len(f) != 2 {
+ continue
+ }
+ if f[1] == "HEAD" || strings.HasPrefix(f[1], "refs/heads/") || strings.HasPrefix(f[1], "refs/tags/") {
+ r.refs[f[1]] = f[0]
+ }
+ }
+ for ref, hash := range r.refs {
+ if strings.HasSuffix(ref, "^{}") { // record unwrapped annotated tag as value of tag
+ r.refs[strings.TrimSuffix(ref, "^{}")] = hash
+ delete(r.refs, ref)
+ }
+ }
+}
+
+func (r *gitRepo) Tags(prefix string) ([]string, error) {
+ r.refsOnce.Do(r.loadRefs)
+ if r.refsErr != nil {
+ return nil, r.refsErr
+ }
+
+ tags := []string{}
+ for ref := range r.refs {
+ if !strings.HasPrefix(ref, "refs/tags/") {
+ continue
+ }
+ tag := ref[len("refs/tags/"):]
+ if !strings.HasPrefix(tag, prefix) {
+ continue
+ }
+ tags = append(tags, tag)
+ }
+ sort.Strings(tags)
+ return tags, nil
+}
+
+func (r *gitRepo) Latest() (*RevInfo, error) {
+ r.refsOnce.Do(r.loadRefs)
+ if r.refsErr != nil {
+ return nil, r.refsErr
+ }
+ if r.refs["HEAD"] == "" {
+ return nil, ErrNoCommits
+ }
+ return r.Stat(r.refs["HEAD"])
+}
+
+// findRef finds some ref name for the given hash,
+// for use when the server requires giving a ref instead of a hash.
+// There may be multiple ref names for a given hash,
+// in which case this returns some name - it doesn't matter which.
+func (r *gitRepo) findRef(hash string) (ref string, ok bool) {
+ r.refsOnce.Do(r.loadRefs)
+ for ref, h := range r.refs {
+ if h == hash {
+ return ref, true
+ }
+ }
+ return "", false
+}
+
+// minHashDigits is the minimum number of digits to require
+// before accepting a hex digit sequence as potentially identifying
+// a specific commit in a git repo. (Of course, users can always
+// specify more digits, and many will paste in all 40 digits,
+// but many of git's commands default to printing short hashes
+// as 7 digits.)
+const minHashDigits = 7
+
+// stat stats the given rev in the local repository,
+// or else it fetches more info from the remote repository and tries again.
+func (r *gitRepo) stat(rev string) (*RevInfo, error) {
+ if r.local {
+ return r.statLocal(rev, rev)
+ }
+
+ // Fast path: maybe rev is a hash we already have locally.
+ didStatLocal := false
+ if len(rev) >= minHashDigits && len(rev) <= 40 && AllHex(rev) {
+ if info, err := r.statLocal(rev, rev); err == nil {
+ return info, nil
+ }
+ didStatLocal = true
+ }
+
+ // Maybe rev is a tag we already have locally.
+ // (Note that we're excluding branches, which can be stale.)
+ r.localTagsOnce.Do(r.loadLocalTags)
+ if r.localTags[rev] {
+ return r.statLocal(rev, "refs/tags/"+rev)
+ }
+
+ // Maybe rev is the name of a tag or branch on the remote server.
+ // Or maybe it's the prefix of a hash of a named ref.
+ // Try to resolve to both a ref (git name) and full (40-hex-digit) commit hash.
+ r.refsOnce.Do(r.loadRefs)
+ var ref, hash string
+ if r.refs["refs/tags/"+rev] != "" {
+ ref = "refs/tags/" + rev
+ hash = r.refs[ref]
+ // Keep rev as is: tags are assumed not to change meaning.
+ } else if r.refs["refs/heads/"+rev] != "" {
+ ref = "refs/heads/" + rev
+ hash = r.refs[ref]
+ rev = hash // Replace rev, because meaning of refs/heads/foo can change.
+ } else if rev == "HEAD" && r.refs["HEAD"] != "" {
+ ref = "HEAD"
+ hash = r.refs[ref]
+ rev = hash // Replace rev, because meaning of HEAD can change.
+ } else if len(rev) >= minHashDigits && len(rev) <= 40 && AllHex(rev) {
+ // At the least, we have a hash prefix we can look up after the fetch below.
+ // Maybe we can map it to a full hash using the known refs.
+ prefix := rev
+ // Check whether rev is prefix of known ref hash.
+ for k, h := range r.refs {
+ if strings.HasPrefix(h, prefix) {
+ if hash != "" && hash != h {
+ // Hash is an ambiguous hash prefix.
+ // More information will not change that.
+ return nil, fmt.Errorf("ambiguous revision %s", rev)
+ }
+ if ref == "" || ref > k { // Break ties deterministically when multiple refs point at same hash.
+ ref = k
+ }
+ rev = h
+ hash = h
+ }
+ }
+ if hash == "" && len(rev) == 40 { // Didn't find a ref, but rev is a full hash.
+ hash = rev
+ }
+ } else {
+ return nil, &UnknownRevisionError{Rev: rev}
+ }
+
+ // Protect r.fetchLevel and the "fetch more and more" sequence.
+ unlock, err := r.mu.Lock()
+ if err != nil {
+ return nil, err
+ }
+ defer unlock()
+
+ // Perhaps r.localTags did not have the ref when we loaded local tags,
+ // but we've since done fetches that pulled down the hash we need
+ // (or already have the hash we need, just without its tag).
+ // Either way, try a local stat before falling back to network I/O.
+ if !didStatLocal {
+ if info, err := r.statLocal(rev, hash); err == nil {
+ if strings.HasPrefix(ref, "refs/tags/") {
+ // Make sure tag exists, so it will be in localTags next time the go command is run.
+ Run(r.dir, "git", "tag", strings.TrimPrefix(ref, "refs/tags/"), hash)
+ }
+ return info, nil
+ }
+ }
+
+ // If we know a specific commit we need and its ref, fetch it.
+ // We do NOT fetch arbitrary hashes (when we don't know the ref)
+ // because we want to avoid ever importing a commit that isn't
+ // reachable from refs/tags/* or refs/heads/* or HEAD.
+ // Both Gerrit and GitHub expose every CL/PR as a named ref,
+ // and we don't want those commits masquerading as being real
+ // pseudo-versions in the main repo.
+ if r.fetchLevel <= fetchSome && ref != "" && hash != "" && !r.local {
+ r.fetchLevel = fetchSome
+ var refspec string
+ if ref != "" && ref != "HEAD" {
+ // If we do know the ref name, save the mapping locally
+ // so that (if it is a tag) it can show up in localTags
+ // on a future call. Also, some servers refuse to allow
+ // full hashes in ref specs, so prefer a ref name if known.
+ refspec = ref + ":" + ref
+ } else {
+ // Fetch the hash but give it a local name (refs/dummy),
+ // because that triggers the fetch behavior of creating any
+ // other known remote tags for the hash. We never use
+ // refs/dummy (it's not refs/tags/dummy) and it will be
+ // overwritten in the next command, and that's fine.
+ ref = hash
+ refspec = hash + ":refs/dummy"
+ }
+ _, err := Run(r.dir, "git", "fetch", "-f", "--depth=1", r.remote, refspec)
+ if err == nil {
+ return r.statLocal(rev, ref)
+ }
+ // Don't try to be smart about parsing the error.
+ // It's too complex and varies too much by git version.
+ // No matter what went wrong, fall back to a complete fetch.
+ }
+
+ // Last resort.
+ // Fetch all heads and tags and hope the hash we want is in the history.
+ if err := r.fetchRefsLocked(); err != nil {
+ return nil, err
+ }
+
+ return r.statLocal(rev, rev)
+}
+
+// fetchRefsLocked fetches all heads and tags from the origin, along with the
+// ancestors of those commits.
+//
+// We only fetch heads and tags, not arbitrary other commits: we don't want to
+// pull in off-branch commits (such as rejected GitHub pull requests) that the
+// server may be willing to provide. (See the comments within the stat method
+// for more detail.)
+//
+// fetchRefsLocked requires that r.mu remain locked for the duration of the call.
+func (r *gitRepo) fetchRefsLocked() error {
+ if r.fetchLevel < fetchAll {
+ // NOTE: To work around a bug affecting Git clients up to at least 2.23.0
+ // (2019-08-16), we must first expand the set of local refs, and only then
+ // unshallow the repository as a separate fetch operation. (See
+ // golang.org/issue/34266 and
+ // https://github.com/git/git/blob/4c86140027f4a0d2caaa3ab4bd8bfc5ce3c11c8a/transport.c#L1303-L1309.)
+
+ if _, err := Run(r.dir, "git", "fetch", "-f", r.remote, "refs/heads/*:refs/heads/*", "refs/tags/*:refs/tags/*"); err != nil {
+ return err
+ }
+
+ if _, err := os.Stat(filepath.Join(r.dir, "shallow")); err == nil {
+ if _, err := Run(r.dir, "git", "fetch", "--unshallow", "-f", r.remote); err != nil {
+ return err
+ }
+ }
+
+ r.fetchLevel = fetchAll
+ }
+ return nil
+}
+
+// statLocal returns a RevInfo describing rev in the local git repository.
+// It uses version as info.Version.
+func (r *gitRepo) statLocal(version, rev string) (*RevInfo, error) {
+ out, err := Run(r.dir, "git", "-c", "log.showsignature=false", "log", "-n1", "--format=format:%H %ct %D", rev, "--")
+ if err != nil {
+ return nil, &UnknownRevisionError{Rev: rev}
+ }
+ f := strings.Fields(string(out))
+ if len(f) < 2 {
+ return nil, fmt.Errorf("unexpected response from git log: %q", out)
+ }
+ hash := f[0]
+ if strings.HasPrefix(hash, version) {
+ version = hash // extend to full hash
+ }
+ t, err := strconv.ParseInt(f[1], 10, 64)
+ if err != nil {
+ return nil, fmt.Errorf("invalid time from git log: %q", out)
+ }
+
+ info := &RevInfo{
+ Name: hash,
+ Short: ShortenSHA1(hash),
+ Time: time.Unix(t, 0).UTC(),
+ Version: hash,
+ }
+
+ // Add tags. Output looks like:
+ // ede458df7cd0fdca520df19a33158086a8a68e81 1523994202 HEAD -> master, tag: v1.2.4-annotated, tag: v1.2.3, origin/master, origin/HEAD
+ for i := 2; i < len(f); i++ {
+ if f[i] == "tag:" {
+ i++
+ if i < len(f) {
+ info.Tags = append(info.Tags, strings.TrimSuffix(f[i], ","))
+ }
+ }
+ }
+ sort.Strings(info.Tags)
+
+ // Used hash as info.Version above.
+ // Use caller's suggested version if it appears in the tag list
+ // (filters out branch names, HEAD).
+ for _, tag := range info.Tags {
+ if version == tag {
+ info.Version = version
+ }
+ }
+
+ return info, nil
+}
+
+func (r *gitRepo) Stat(rev string) (*RevInfo, error) {
+ if rev == "latest" {
+ return r.Latest()
+ }
+ type cached struct {
+ info *RevInfo
+ err error
+ }
+ c := r.statCache.Do(rev, func() interface{} {
+ info, err := r.stat(rev)
+ return cached{info, err}
+ }).(cached)
+ return c.info, c.err
+}
+
+func (r *gitRepo) ReadFile(rev, file string, maxSize int64) ([]byte, error) {
+ // TODO: Could use git cat-file --batch.
+ info, err := r.Stat(rev) // download rev into local git repo
+ if err != nil {
+ return nil, err
+ }
+ out, err := Run(r.dir, "git", "cat-file", "blob", info.Name+":"+file)
+ if err != nil {
+ return nil, fs.ErrNotExist
+ }
+ return out, nil
+}
+
+func (r *gitRepo) ReadFileRevs(revs []string, file string, maxSize int64) (map[string]*FileRev, error) {
+ // Create space to hold results.
+ files := make(map[string]*FileRev)
+ for _, rev := range revs {
+ f := &FileRev{Rev: rev}
+ files[rev] = f
+ }
+
+ // Collect locally-known revs.
+ need, err := r.readFileRevs(revs, file, files)
+ if err != nil {
+ return nil, err
+ }
+ if len(need) == 0 {
+ return files, nil
+ }
+
+ // Build list of known remote refs that might help.
+ var redo []string
+ r.refsOnce.Do(r.loadRefs)
+ if r.refsErr != nil {
+ return nil, r.refsErr
+ }
+ for _, tag := range need {
+ if r.refs["refs/tags/"+tag] != "" {
+ redo = append(redo, tag)
+ }
+ }
+ if len(redo) == 0 {
+ return files, nil
+ }
+
+ // Protect r.fetchLevel and the "fetch more and more" sequence.
+ // See stat method above.
+ unlock, err := r.mu.Lock()
+ if err != nil {
+ return nil, err
+ }
+ defer unlock()
+
+ if err := r.fetchRefsLocked(); err != nil {
+ return nil, err
+ }
+
+ if _, err := r.readFileRevs(redo, file, files); err != nil {
+ return nil, err
+ }
+
+ return files, nil
+}
+
+func (r *gitRepo) readFileRevs(tags []string, file string, fileMap map[string]*FileRev) (missing []string, err error) {
+ var stdin bytes.Buffer
+ for _, tag := range tags {
+ fmt.Fprintf(&stdin, "refs/tags/%s\n", tag)
+ fmt.Fprintf(&stdin, "refs/tags/%s:%s\n", tag, file)
+ }
+
+ data, err := RunWithStdin(r.dir, &stdin, "git", "cat-file", "--batch")
+ if err != nil {
+ return nil, err
+ }
+
+ next := func() (typ string, body []byte, ok bool) {
+ var line string
+ i := bytes.IndexByte(data, '\n')
+ if i < 0 {
+ return "", nil, false
+ }
+ line, data = string(bytes.TrimSpace(data[:i])), data[i+1:]
+ if strings.HasSuffix(line, " missing") {
+ return "missing", nil, true
+ }
+ f := strings.Fields(line)
+ if len(f) != 3 {
+ return "", nil, false
+ }
+ n, err := strconv.Atoi(f[2])
+ if err != nil || n > len(data) {
+ return "", nil, false
+ }
+ body, data = data[:n], data[n:]
+ if len(data) > 0 && data[0] == '\r' {
+ data = data[1:]
+ }
+ if len(data) > 0 && data[0] == '\n' {
+ data = data[1:]
+ }
+ return f[1], body, true
+ }
+
+ badGit := func() ([]string, error) {
+ return nil, fmt.Errorf("malformed output from git cat-file --batch")
+ }
+
+ for _, tag := range tags {
+ commitType, _, ok := next()
+ if !ok {
+ return badGit()
+ }
+ fileType, fileData, ok := next()
+ if !ok {
+ return badGit()
+ }
+ f := fileMap[tag]
+ f.Data = nil
+ f.Err = nil
+ switch commitType {
+ default:
+ f.Err = fmt.Errorf("unexpected non-commit type %q for rev %s", commitType, tag)
+
+ case "missing":
+ // Note: f.Err must not satisfy os.IsNotExist. That's reserved for the file not existing in a valid commit.
+ f.Err = fmt.Errorf("no such rev %s", tag)
+ missing = append(missing, tag)
+
+ case "tag", "commit":
+ switch fileType {
+ default:
+ f.Err = &fs.PathError{Path: tag + ":" + file, Op: "read", Err: fmt.Errorf("unexpected non-blob type %q", fileType)}
+ case "missing":
+ f.Err = &fs.PathError{Path: tag + ":" + file, Op: "read", Err: fs.ErrNotExist}
+ case "blob":
+ f.Data = fileData
+ }
+ }
+ }
+ if len(bytes.TrimSpace(data)) != 0 {
+ return badGit()
+ }
+
+ return missing, nil
+}
+
+func (r *gitRepo) RecentTag(rev, prefix string, allowed func(string) bool) (tag string, err error) {
+ info, err := r.Stat(rev)
+ if err != nil {
+ return "", err
+ }
+ rev = info.Name // expand hash prefixes
+
+ // describe sets tag and err using 'git for-each-ref' and reports whether the
+ // result is definitive.
+ describe := func() (definitive bool) {
+ var out []byte
+ out, err = Run(r.dir, "git", "for-each-ref", "--format", "%(refname)", "refs/tags", "--merged", rev)
+ if err != nil {
+ return true
+ }
+
+ // prefixed tags aren't valid semver tags so compare without prefix, but only tags with correct prefix
+ var highest string
+ for _, line := range strings.Split(string(out), "\n") {
+ line = strings.TrimSpace(line)
+ // git do support lstrip in for-each-ref format, but it was added in v2.13.0. Stripping here
+ // instead gives support for git v2.7.0.
+ if !strings.HasPrefix(line, "refs/tags/") {
+ continue
+ }
+ line = line[len("refs/tags/"):]
+
+ if !strings.HasPrefix(line, prefix) {
+ continue
+ }
+
+ semtag := line[len(prefix):]
+ // Consider only tags that are valid and complete (not just major.minor prefixes).
+ // NOTE: Do not replace the call to semver.Compare with semver.Max.
+ // We want to return the actual tag, not a canonicalized version of it,
+ // and semver.Max currently canonicalizes (see golang.org/issue/32700).
+ if c := semver.Canonical(semtag); c == "" || !strings.HasPrefix(semtag, c) || !allowed(semtag) {
+ continue
+ }
+ if semver.Compare(semtag, highest) > 0 {
+ highest = semtag
+ }
+ }
+
+ if highest != "" {
+ tag = prefix + highest
+ }
+
+ return tag != "" && !AllHex(tag)
+ }
+
+ if describe() {
+ return tag, err
+ }
+
+ // Git didn't find a version tag preceding the requested rev.
+ // See whether any plausible tag exists.
+ tags, err := r.Tags(prefix + "v")
+ if err != nil {
+ return "", err
+ }
+ if len(tags) == 0 {
+ return "", nil
+ }
+
+ // There are plausible tags, but we don't know if rev is a descendent of any of them.
+ // Fetch the history to find out.
+
+ unlock, err := r.mu.Lock()
+ if err != nil {
+ return "", err
+ }
+ defer unlock()
+
+ if err := r.fetchRefsLocked(); err != nil {
+ return "", err
+ }
+
+ // If we've reached this point, we have all of the commits that are reachable
+ // from all heads and tags.
+ //
+ // The only refs we should be missing are those that are no longer reachable
+ // (or never were reachable) from any branch or tag, including the master
+ // branch, and we don't want to resolve them anyway (they're probably
+ // unreachable for a reason).
+ //
+ // Try one last time in case some other goroutine fetched rev while we were
+ // waiting on the lock.
+ describe()
+ return tag, err
+}
+
+func (r *gitRepo) DescendsFrom(rev, tag string) (bool, error) {
+ // The "--is-ancestor" flag was added to "git merge-base" in version 1.8.0, so
+ // this won't work with Git 1.7.1. According to golang.org/issue/28550, cmd/go
+ // already doesn't work with Git 1.7.1, so at least it's not a regression.
+ //
+ // git merge-base --is-ancestor exits with status 0 if rev is an ancestor, or
+ // 1 if not.
+ _, err := Run(r.dir, "git", "merge-base", "--is-ancestor", "--", tag, rev)
+
+ // Git reports "is an ancestor" with exit code 0 and "not an ancestor" with
+ // exit code 1.
+ // Unfortunately, if we've already fetched rev with a shallow history, git
+ // merge-base has been observed to report a false-negative, so don't stop yet
+ // even if the exit code is 1!
+ if err == nil {
+ return true, nil
+ }
+
+ // See whether the tag and rev even exist.
+ tags, err := r.Tags(tag)
+ if err != nil {
+ return false, err
+ }
+ if len(tags) == 0 {
+ return false, nil
+ }
+
+ // NOTE: r.stat is very careful not to fetch commits that we shouldn't know
+ // about, like rejected GitHub pull requests, so don't try to short-circuit
+ // that here.
+ if _, err = r.stat(rev); err != nil {
+ return false, err
+ }
+
+ // Now fetch history so that git can search for a path.
+ unlock, err := r.mu.Lock()
+ if err != nil {
+ return false, err
+ }
+ defer unlock()
+
+ if r.fetchLevel < fetchAll {
+ // Fetch the complete history for all refs and heads. It would be more
+ // efficient to only fetch the history from rev to tag, but that's much more
+ // complicated, and any kind of shallow fetch is fairly likely to trigger
+ // bugs in JGit servers and/or the go command anyway.
+ if err := r.fetchRefsLocked(); err != nil {
+ return false, err
+ }
+ }
+
+ _, err = Run(r.dir, "git", "merge-base", "--is-ancestor", "--", tag, rev)
+ if err == nil {
+ return true, nil
+ }
+ if ee, ok := err.(*RunError).Err.(*exec.ExitError); ok && ee.ExitCode() == 1 {
+ return false, nil
+ }
+ return false, err
+}
+
+func (r *gitRepo) ReadZip(rev, subdir string, maxSize int64) (zip io.ReadCloser, err error) {
+ // TODO: Use maxSize or drop it.
+ args := []string{}
+ if subdir != "" {
+ args = append(args, "--", subdir)
+ }
+ info, err := r.Stat(rev) // download rev into local git repo
+ if err != nil {
+ return nil, err
+ }
+
+ unlock, err := r.mu.Lock()
+ if err != nil {
+ return nil, err
+ }
+ defer unlock()
+
+ if err := ensureGitAttributes(r.dir); err != nil {
+ return nil, err
+ }
+
+ // Incredibly, git produces different archives depending on whether
+ // it is running on a Windows system or not, in an attempt to normalize
+ // text file line endings. Setting -c core.autocrlf=input means only
+ // translate files on the way into the repo, not on the way out (archive).
+ // The -c core.eol=lf should be unnecessary but set it anyway.
+ archive, err := Run(r.dir, "git", "-c", "core.autocrlf=input", "-c", "core.eol=lf", "archive", "--format=zip", "--prefix=prefix/", info.Name, args)
+ if err != nil {
+ if bytes.Contains(err.(*RunError).Stderr, []byte("did not match any files")) {
+ return nil, fs.ErrNotExist
+ }
+ return nil, err
+ }
+
+ return io.NopCloser(bytes.NewReader(archive)), nil
+}
+
+// ensureGitAttributes makes sure export-subst and export-ignore features are
+// disabled for this repo. This is intended to be run prior to running git
+// archive so that zip files are generated that produce consistent ziphashes
+// for a given revision, independent of variables such as git version and the
+// size of the repo.
+//
+// See: https://github.com/golang/go/issues/27153
+func ensureGitAttributes(repoDir string) (err error) {
+ const attr = "\n* -export-subst -export-ignore\n"
+
+ d := repoDir + "/info"
+ p := d + "/attributes"
+
+ if err := os.MkdirAll(d, 0755); err != nil {
+ return err
+ }
+
+ f, err := os.OpenFile(p, os.O_CREATE|os.O_APPEND|os.O_RDWR, 0666)
+ if err != nil {
+ return err
+ }
+ defer func() {
+ closeErr := f.Close()
+ if closeErr != nil {
+ err = closeErr
+ }
+ }()
+
+ b, err := io.ReadAll(f)
+ if err != nil {
+ return err
+ }
+ if !bytes.HasSuffix(b, []byte(attr)) {
+ _, err := f.WriteString(attr)
+ return err
+ }
+
+ return nil
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-09-27 04:29:35 +0000