From 571076d5e1a637e4a6d4f2873665f1e4a0cb4c7f Mon Sep 17 00:00:00 2001 From: Stephen Macke Date: Mon, 21 Oct 2024 11:27:07 -0700 Subject: [PATCH] Support Git worktrees for `sync` (#1831) ## Changes This change allows the `sync` command to work from [git worktrees](https://git-scm.com/docs/git-worktree). ## Tests * Added unit tests for traversal of worktree related files. * Manually confirmed that synchronization of files from a main checkout, as well as a worktree, observed the same ignore rules (both locally defined as well as from `$GIT_DIR/info/exclude`). --------- Co-authored-by: Pieter Noordhuis --- libs/git/repository.go | 64 ++++++++++++-------- libs/git/view.go | 2 +- libs/git/worktree.go | 123 ++++++++++++++++++++++++++++++++++++++ libs/git/worktree_test.go | 108 +++++++++++++++++++++++++++++++++ 4 files changed, 271 insertions(+), 26 deletions(-) create mode 100644 libs/git/worktree.go create mode 100644 libs/git/worktree_test.go diff --git a/libs/git/repository.go b/libs/git/repository.go index 82ee7987..0bbd5786 100644 --- a/libs/git/repository.go +++ b/libs/git/repository.go @@ -23,8 +23,21 @@ type Repository struct { // directory where we process .gitignore files. real bool - // root is the absolute path to the repository root. - root vfs.Path + // rootDir is the path to the root of the repository checkout. + // This can be either the main repository checkout or a worktree checkout. + // For more information about worktrees, see: https://git-scm.com/docs/git-worktree#_description. + rootDir vfs.Path + + // gitDir is the equivalent of $GIT_DIR and points to the + // `.git` directory of a repository or a worktree directory. + // See https://git-scm.com/docs/git-worktree#_details for more information. + gitDir vfs.Path + + // gitCommonDir is the equivalent of $GIT_COMMON_DIR and points to the + // `.git` directory of the main working tree (common between worktrees). + // This is equivalent to [gitDir] if this is the main working tree. + // See https://git-scm.com/docs/git-worktree#_details for more information. + gitCommonDir vfs.Path // ignore contains a list of ignore patterns indexed by the // path prefix relative to the repository root. @@ -44,12 +57,11 @@ type Repository struct { // Root returns the absolute path to the repository root. func (r *Repository) Root() string { - return r.root.Native() + return r.rootDir.Native() } func (r *Repository) CurrentBranch() (string, error) { - // load .git/HEAD - ref, err := LoadReferenceFile(r.root, path.Join(GitDirectoryName, "HEAD")) + ref, err := LoadReferenceFile(r.gitDir, "HEAD") if err != nil { return "", err } @@ -65,8 +77,7 @@ func (r *Repository) CurrentBranch() (string, error) { } func (r *Repository) LatestCommit() (string, error) { - // load .git/HEAD - ref, err := LoadReferenceFile(r.root, path.Join(GitDirectoryName, "HEAD")) + ref, err := LoadReferenceFile(r.gitDir, "HEAD") if err != nil { return "", err } @@ -80,12 +91,12 @@ func (r *Repository) LatestCommit() (string, error) { return ref.Content, nil } - // read reference from .git/HEAD + // Read reference from $GIT_DIR/HEAD branchHeadPath, err := ref.ResolvePath() if err != nil { return "", err } - branchHeadRef, err := LoadReferenceFile(r.root, path.Join(GitDirectoryName, branchHeadPath)) + branchHeadRef, err := LoadReferenceFile(r.gitCommonDir, branchHeadPath) if err != nil { return "", err } @@ -125,7 +136,7 @@ func (r *Repository) loadConfig() error { if err != nil { return fmt.Errorf("unable to load user specific gitconfig: %w", err) } - err = config.loadFile(r.root, ".git/config") + err = config.loadFile(r.gitCommonDir, "config") if err != nil { return fmt.Errorf("unable to load repository specific gitconfig: %w", err) } @@ -133,12 +144,6 @@ func (r *Repository) loadConfig() error { return nil } -// newIgnoreFile constructs a new [ignoreRules] implementation backed by -// a file using the specified path relative to the repository root. -func (r *Repository) newIgnoreFile(relativeIgnoreFilePath string) ignoreRules { - return newIgnoreFile(r.root, relativeIgnoreFilePath) -} - // getIgnoreRules returns a slice of [ignoreRules] that apply // for the specified prefix. The prefix must be cleaned by the caller. // It lazily initializes an entry for the specified prefix if it @@ -149,7 +154,7 @@ func (r *Repository) getIgnoreRules(prefix string) []ignoreRules { return fs } - r.ignore[prefix] = append(r.ignore[prefix], r.newIgnoreFile(path.Join(prefix, gitIgnoreFileName))) + r.ignore[prefix] = append(r.ignore[prefix], newIgnoreFile(r.rootDir, path.Join(prefix, gitIgnoreFileName))) return r.ignore[prefix] } @@ -205,21 +210,30 @@ func (r *Repository) Ignore(relPath string) (bool, error) { func NewRepository(path vfs.Path) (*Repository, error) { real := true - rootPath, err := vfs.FindLeafInTree(path, GitDirectoryName) + rootDir, err := vfs.FindLeafInTree(path, GitDirectoryName) if err != nil { if !errors.Is(err, fs.ErrNotExist) { return nil, err } // Cannot find `.git` directory. - // Treat the specified path as a potential repository root. + // Treat the specified path as a potential repository root checkout. real = false - rootPath = path + rootDir = path + } + + // Derive $GIT_DIR and $GIT_COMMON_DIR paths if this is a real repository. + // If it isn't a real repository, they'll point to the (non-existent) `.git` directory. + gitDir, gitCommonDir, err := resolveGitDirs(rootDir) + if err != nil { + return nil, err } repo := &Repository{ - real: real, - root: rootPath, - ignore: make(map[string][]ignoreRules), + real: real, + rootDir: rootDir, + gitDir: gitDir, + gitCommonDir: gitCommonDir, + ignore: make(map[string][]ignoreRules), } err = repo.loadConfig() @@ -253,9 +267,9 @@ func NewRepository(path vfs.Path) (*Repository, error) { ".git", }), // Load repository-wide exclude file. - repo.newIgnoreFile(".git/info/exclude"), + newIgnoreFile(repo.gitCommonDir, "info/exclude"), // Load root gitignore file. - repo.newIgnoreFile(".gitignore"), + newIgnoreFile(repo.rootDir, ".gitignore"), } return repo, nil diff --git a/libs/git/view.go b/libs/git/view.go index 90eed0bb..2d2e39a6 100644 --- a/libs/git/view.go +++ b/libs/git/view.go @@ -80,7 +80,7 @@ func NewView(root vfs.Path) (*View, error) { // Target path must be relative to the repository root path. target := root.Native() - prefix := repo.root.Native() + prefix := repo.rootDir.Native() if !strings.HasPrefix(target, prefix) { return nil, fmt.Errorf("path %q is not within repository root %q", root.Native(), prefix) } diff --git a/libs/git/worktree.go b/libs/git/worktree.go new file mode 100644 index 00000000..964c1c95 --- /dev/null +++ b/libs/git/worktree.go @@ -0,0 +1,123 @@ +package git + +import ( + "bufio" + "errors" + "fmt" + "io/fs" + "path/filepath" + "strings" + + "github.com/databricks/cli/libs/vfs" +) + +func readLines(root vfs.Path, name string) ([]string, error) { + file, err := root.Open(name) + if err != nil { + return nil, err + } + + defer file.Close() + + var lines []string + scanner := bufio.NewScanner(file) + for scanner.Scan() { + lines = append(lines, scanner.Text()) + } + + return lines, scanner.Err() +} + +// readGitDir reads the value of the `.git` file in a worktree. +func readGitDir(root vfs.Path) (string, error) { + lines, err := readLines(root, GitDirectoryName) + if err != nil { + return "", err + } + + var gitDir string + for _, line := range lines { + parts := strings.SplitN(line, ": ", 2) + if len(parts) != 2 { + continue + } + + if parts[0] == "gitdir" { + gitDir = strings.TrimSpace(parts[1]) + } + } + + if gitDir == "" { + return "", fmt.Errorf(`expected %q to contain a line with "gitdir: [...]"`, filepath.Join(root.Native(), GitDirectoryName)) + } + + return gitDir, nil +} + +// readGitCommonDir reads the value of the `commondir` file in the `.git` directory of a worktree. +// This file typically contains "../.." to point to $GIT_COMMON_DIR. +func readGitCommonDir(gitDir vfs.Path) (string, error) { + lines, err := readLines(gitDir, "commondir") + if err != nil { + return "", err + } + + if len(lines) == 0 { + return "", errors.New("file is empty") + } + + return strings.TrimSpace(lines[0]), nil +} + +// resolveGitDirs resolves the paths for $GIT_DIR and $GIT_COMMON_DIR. +// The path argument is the root of the checkout where (supposedly) a `.git` file or directory exists. +func resolveGitDirs(root vfs.Path) (vfs.Path, vfs.Path, error) { + fileInfo, err := root.Stat(GitDirectoryName) + if err != nil { + // If the `.git` file or directory does not exist, then this is not a git repository. + // Return paths that we know don't exist, so we do not need to perform nil checks in the caller. + if errors.Is(err, fs.ErrNotExist) { + gitDir := vfs.MustNew(filepath.Join(root.Native(), GitDirectoryName)) + return gitDir, gitDir, nil + } + return nil, nil, err + } + + // If the path is a directory, then it is the main working tree. + // Both $GIT_DIR and $GIT_COMMON_DIR point to the same directory. + if fileInfo.IsDir() { + gitDir := vfs.MustNew(filepath.Join(root.Native(), GitDirectoryName)) + return gitDir, gitDir, nil + } + + // If the path is not a directory, then it is a worktree. + // Read value for $GIT_DIR. + gitDirValue, err := readGitDir(root) + if err != nil { + return nil, nil, err + } + + // Resolve $GIT_DIR. + var gitDir vfs.Path + if filepath.IsAbs(gitDirValue) { + gitDir = vfs.MustNew(gitDirValue) + } else { + gitDir = vfs.MustNew(filepath.Join(root.Native(), gitDirValue)) + } + + // Read value for $GIT_COMMON_DIR. + gitCommonDirValue, err := readGitCommonDir(gitDir) + if err != nil { + return nil, nil, fmt.Errorf(`expected "commondir" file in worktree git folder at %q: %w`, gitDir.Native(), err) + } + + // Resolve $GIT_COMMON_DIR. + var gitCommonDir vfs.Path + if filepath.IsAbs(gitCommonDirValue) { + gitCommonDir = vfs.MustNew(gitCommonDirValue) + } else { + gitCommonDir = vfs.MustNew(filepath.Join(gitDir.Native(), gitCommonDirValue)) + } + + return gitDir, gitCommonDir, nil +} diff --git a/libs/git/worktree_test.go b/libs/git/worktree_test.go new file mode 100644 index 00000000..3d620c48 --- /dev/null +++ b/libs/git/worktree_test.go @@ -0,0 +1,108 @@ +package git + +import ( + "fmt" + "os" + "path/filepath" + "testing" + + "github.com/databricks/cli/libs/vfs" + "github.com/stretchr/testify/assert" + "github.com/stretchr/testify/require" +) + +func setupWorktree(t *testing.T) string { + var err error + + tmpDir := t.TempDir() + + // Checkout path + err = os.MkdirAll(filepath.Join(tmpDir, "my_worktree"), os.ModePerm) + require.NoError(t, err) + + // Main $GIT_COMMON_DIR + err = os.MkdirAll(filepath.Join(tmpDir, ".git"), os.ModePerm) + require.NoError(t, err) + + // Worktree $GIT_DIR + err = os.MkdirAll(filepath.Join(tmpDir, ".git/worktrees/my_worktree"), os.ModePerm) + require.NoError(t, err) + + return tmpDir +} + +func writeGitDir(t *testing.T, dir, content string) { + err := os.WriteFile(filepath.Join(dir, "my_worktree/.git"), []byte(content), os.ModePerm) + require.NoError(t, err) +} + +func writeGitCommonDir(t *testing.T, dir, content string) { + err := os.WriteFile(filepath.Join(dir, ".git/worktrees/my_worktree/commondir"), []byte(content), os.ModePerm) + require.NoError(t, err) +} + +func verifyCorrectDirs(t *testing.T, dir string) { + gitDir, gitCommonDir, err := resolveGitDirs(vfs.MustNew(filepath.Join(dir, "my_worktree"))) + require.NoError(t, err) + assert.Equal(t, filepath.Join(dir, ".git/worktrees/my_worktree"), gitDir.Native()) + assert.Equal(t, filepath.Join(dir, ".git"), gitCommonDir.Native()) +} + +func TestWorktreeResolveGitDir(t *testing.T) { + dir := setupWorktree(t) + writeGitCommonDir(t, dir, "../..") + + t.Run("relative", func(t *testing.T) { + writeGitDir(t, dir, fmt.Sprintf("gitdir: %s", "../.git/worktrees/my_worktree")) + verifyCorrectDirs(t, dir) + }) + + t.Run("absolute", func(t *testing.T) { + writeGitDir(t, dir, fmt.Sprintf("gitdir: %s", filepath.Join(dir, ".git/worktrees/my_worktree"))) + verifyCorrectDirs(t, dir) + }) + + t.Run("additional spaces", func(t *testing.T) { + writeGitDir(t, dir, fmt.Sprintf("gitdir: %s \n\n\n", "../.git/worktrees/my_worktree")) + verifyCorrectDirs(t, dir) + }) + + t.Run("empty", func(t *testing.T) { + writeGitDir(t, dir, "") + + _, _, err := resolveGitDirs(vfs.MustNew(filepath.Join(dir, "my_worktree"))) + assert.ErrorContains(t, err, ` to contain a line with "gitdir: [...]"`) + }) +} + +func TestWorktreeResolveCommonDir(t *testing.T) { + dir := setupWorktree(t) + writeGitDir(t, dir, fmt.Sprintf("gitdir: %s", "../.git/worktrees/my_worktree")) + + t.Run("relative", func(t *testing.T) { + writeGitCommonDir(t, dir, "../..") + verifyCorrectDirs(t, dir) + }) + + t.Run("absolute", func(t *testing.T) { + writeGitCommonDir(t, dir, filepath.Join(dir, ".git")) + verifyCorrectDirs(t, dir) + }) + + t.Run("additional spaces", func(t *testing.T) { + writeGitCommonDir(t, dir, " ../.. \n\n\n") + verifyCorrectDirs(t, dir) + }) + + t.Run("empty", func(t *testing.T) { + writeGitCommonDir(t, dir, "") + + _, _, err := resolveGitDirs(vfs.MustNew(filepath.Join(dir, "my_worktree"))) + assert.ErrorContains(t, err, `expected "commondir" file in worktree git folder at `) + }) + + t.Run("missing", func(t *testing.T) { + _, _, err := resolveGitDirs(vfs.MustNew(filepath.Join(dir, "my_worktree"))) + assert.ErrorContains(t, err, `expected "commondir" file in worktree git folder at `) + }) +}