fix: resolve symlink targets in isDirOrSymlink, fix FindClaudeSourceFile parity

isDirOrSymlink now stat-resolves symlink targets to confirm they
point to directories, rejecting symlinks to files and broken links.

FindClaudeSourceFile updated to use isDirOrSymlink instead of
IsDir, matching DiscoverClaudeProjects behavior for symlinked
project directories.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: wesm

internal/sync/discovery.go

@@ -21,9 +21,21 @@ var uuidRe = regexp.MustCompile(
 )
 
 // isDirOrSymlink reports whether the entry is a directory or a
-// symlink (which may point to a directory).
-func isDirOrSymlink(entry os.DirEntry) bool {
-	return entry.IsDir() || entry.Type()&os.ModeSymlink != 0
+// symlink that resolves to a directory. parentDir is needed to
+// build the full path for symlink resolution.
+func isDirOrSymlink(
+	entry os.DirEntry, parentDir string,
+) bool {
+	if entry.IsDir() {
+		return true
+	}
+	if entry.Type()&os.ModeSymlink == 0 {
+		return false
+	}
+	fi, err := os.Stat(
+		filepath.Join(parentDir, entry.Name()),
+	)
+	return err == nil && fi.IsDir()
 }
 
 // DiscoveredFile holds a discovered session JSONL file.
@@ -43,7 +55,7 @@ func DiscoverClaudeProjects(projectsDir string) []DiscoveredFile {
 
 	var files []DiscoveredFile
 	for _, entry := range entries {
-		if !isDirOrSymlink(entry) {
+		if !isDirOrSymlink(entry, projectsDir) {
 			continue
 		}
 
@@ -126,7 +138,7 @@ func FindClaudeSourceFile(
 
 	target := sessionID + ".jsonl"
 	for _, entry := range entries {
-		if !entry.IsDir() {
+		if !isDirOrSymlink(entry, projectsDir) {
 			continue
 		}
 		candidate := filepath.Join(
@@ -277,7 +289,7 @@ func DiscoverGeminiSessions(
 
 	var files []DiscoveredFile
 	for _, hd := range hashDirs {
-		if !isDirOrSymlink(hd) {
+		if !isDirOrSymlink(hd, tmpDir) {
 			continue
 		}
 		hash := hd.Name()
@@ -332,7 +344,7 @@ func FindGeminiSourceFile(
 	}
 
 	for _, hd := range hashDirs {
-		if !isDirOrSymlink(hd) {
+		if !isDirOrSymlink(hd, tmpDir) {
 			continue
 		}
 		chatsDir := filepath.Join(tmpDir, hd.Name(), "chats")

internal/sync/sync_test.go

@@ -709,3 +709,95 @@ func TestFindCopilotSourceFile_DirPreferred(t *testing.T) {
 		t.Errorf("got %q, want dir path %q", got, dirPath)
 	}
 }
+
+// --- Symlink tests ---
+
+func TestIsDirOrSymlink(t *testing.T) {
+	dir := t.TempDir()
+
+	// Real directory
+	realDir := filepath.Join(dir, "real-dir")
+	if err := os.MkdirAll(realDir, 0o755); err != nil {
+		t.Fatalf("mkdir: %v", err)
+	}
+
+	// Regular file
+	realFile := filepath.Join(dir, "file.txt")
+	if err := os.WriteFile(
+		realFile, []byte("hi"), 0o644,
+	); err != nil {
+		t.Fatalf("write: %v", err)
+	}
+
+	// Symlink to directory
+	if err := os.Symlink(
+		realDir, filepath.Join(dir, "link-to-dir"),
+	); err != nil {
+		t.Skipf("symlink not supported: %v", err)
+	}
+
+	// Symlink to file
+	if err := os.Symlink(
+		realFile, filepath.Join(dir, "link-to-file"),
+	); err != nil {
+		t.Fatalf("symlink: %v", err)
+	}
+
+	// Broken symlink
+	if err := os.Symlink(
+		filepath.Join(dir, "gone"),
+		filepath.Join(dir, "broken"),
+	); err != nil {
+		t.Fatalf("symlink: %v", err)
+	}
+
+	entries, err := os.ReadDir(dir)
+	if err != nil {
+		t.Fatalf("readdir: %v", err)
+	}
+
+	want := map[string]bool{
+		"real-dir":     true,
+		"file.txt":     false,
+		"link-to-dir":  true,
+		"link-to-file": false,
+		"broken":       false,
+	}
+
+	for _, e := range entries {
+		expected, ok := want[e.Name()]
+		if !ok {
+			continue
+		}
+		got := isDirOrSymlink(e, dir)
+		if got != expected {
+			t.Errorf("isDirOrSymlink(%q) = %v, want %v",
+				e.Name(), got, expected)
+		}
+	}
+}
+
+func TestFindClaudeSourceFile_Symlink(t *testing.T) {
+	dir := t.TempDir()
+
+	realDir := filepath.Join(dir, "real-project")
+	if err := os.MkdirAll(realDir, 0o755); err != nil {
+		t.Fatalf("mkdir: %v", err)
+	}
+	if err := os.WriteFile(
+		filepath.Join(realDir, "sess-abc.jsonl"),
+		[]byte("{}"), 0o644,
+	); err != nil {
+		t.Fatalf("write: %v", err)
+	}
+
+	linkDir := filepath.Join(dir, "linked-project")
+	if err := os.Symlink(realDir, linkDir); err != nil {
+		t.Skipf("symlink not supported: %v", err)
+	}
+
+	got := FindClaudeSourceFile(dir, "sess-abc")
+	if got == "" {
+		t.Error("expected to find session via symlink")
+	}
+}