fix(trace): reject symlinked tracked paths

Validate every fallback path component before opening tracked files so symlinks and special files stay outside worktree snapshots.

Assisted-by: Vibhav's Pi
Signed-off-by: Vibhav Bobade <vibhav.bobde@gmail.com>

Author: waveywaves

app/cli/internal/trace/git/gogit.go

@@ -332,13 +332,8 @@ func snapshotWorktree(repoRoot string) (map[string]string, error) {
 		if _, ok := sig[path]; ok {
 			continue
 		}
-		f, openErr := root.Open(filepath.FromSlash(path))
-		if openErr != nil {
-			continue
-		}
-		info, statErr := f.Stat()
-		if statErr != nil || !info.Mode().IsRegular() {
-			_ = f.Close()
+		f, ok := openRegularRootFile(root, path)
+		if !ok {
 			continue
 		}
 		hash, hashErr := hashFileReader(f)
@@ -375,6 +370,28 @@ func trackedPaths(repoRoot string) map[string]bool {
 	return tracked
 }
 
+func openRegularRootFile(root *os.Root, path string) (*os.File, bool) {
+	parts := strings.Split(filepath.ToSlash(path), "/")
+	current := ""
+	for i, part := range parts {
+		current = filepath.Join(current, filepath.FromSlash(part))
+		info, err := root.Lstat(current)
+		if err != nil || info.Mode()&os.ModeSymlink != 0 {
+			return nil, false
+		}
+		if i < len(parts)-1 {
+			if !info.IsDir() {
+				return nil, false
+			}
+		} else if !info.Mode().IsRegular() {
+			return nil, false
+		}
+	}
+
+	f, err := root.Open(filepath.FromSlash(path))
+	return f, err == nil
+}
+
 // hashFileContent returns the hex-encoded SHA-256 of the file's content.
 func hashFileContent(path string) (string, error) {
 	f, err := os.Open(path)

app/cli/internal/trace/git/worktree_index_test.go

@@ -134,6 +134,20 @@ func TestGoGitClient_SnapshotWorktree_DoesNotFollowEscapingSymlink(t *testing.T)
 	require.NotContains(t, snapshot, "link/outside.txt")
 }
 
+func TestGoGitClient_SnapshotWorktree_DoesNotFollowInRootSymlink(t *testing.T) {
+	dir := t.TempDir()
+	runIndexGit(t, dir, "init", "-q")
+	require.NoError(t, os.MkdirAll(filepath.Join(dir, "target"), 0o700))
+	require.NoError(t, os.WriteFile(filepath.Join(dir, "target", "file.txt"), []byte("inside\n"), 0o600))
+	require.NoError(t, os.Symlink("target", filepath.Join(dir, "link")))
+	blob := writeGitObject(t, dir, "inside\n")
+	writeGitIndex(t, dir, fmt.Sprintf("100644 %s 0\tlink/file.txt\n", blob))
+
+	snapshot, err := NewGoGitClient().SnapshotWorktree(dir)
+	require.NoError(t, err)
+	require.NotContains(t, snapshot, "link/file.txt")
+}
+
 func TestGoGitClient_UnstagedFiles_ChangedFilterMarksRawEqualityDirty(t *testing.T) {
 	dir := t.TempDir()
 	runIndexGit(t, dir, "init", "-q")