fix: resolve backend and test analyzer diagnostics

go_backend/audio_metadata.go

@@ -99,11 +99,6 @@ func readID3TagsAndCover(filePath string, includeCover bool) (*AudioMetadata, []
 	return metadata, cover, mime, nil
 }
 
-func readID3v2(file *os.File) (*AudioMetadata, error) {
-	metadata, _, _, err := readID3v2WithCover(file, false)
-	return metadata, err
-}
-
 func parseID3v22Frames(data []byte, metadata *AudioMetadata, tagUnsync bool) {
 	parseID3Frames(data, metadata, 2, tagUnsync)
 }

go_backend/extension_lifecycle_signed_session_timeout_test.go

@@ -159,7 +159,7 @@ func TestSignedSessionGrantRetryHonorsCancellationAndReleasesCoordinator(t *test
 	lockAcquired := make(chan struct{})
 	go func() {
 		coordinator.mu.Lock()
-		coordinator.mu.Unlock()
+		defer coordinator.mu.Unlock()
 		close(lockAcquired)
 	}()
 	select {

go_backend/extension_runtime.go

@@ -477,13 +477,6 @@ func (w *stallWatchdog) stop() {
 	w.cancel()
 }
 
-// stallError is returned when the watchdog fires. The message is deliberately
-// free of "cancel" and worded to classify as retryable network failure, so the
-// fallback layer retries instead of treating it as a user cancellation.
-func (r *extensionRuntime) stallError() goja.Value {
-	return r.jsError("download stalled: no data received for %ds (network timeout)", int(downloadStallTimeout.Seconds()))
-}
-
 func newExtensionHTTPClient(ext *loadedExtension, jar http.CookieJar, timeout time.Duration, compressResponses bool) *http.Client {
 	// Extension sandbox enforces HTTPS-only domains. Do not apply global
 	// allow_http scheme downgrade here, because some extension APIs (e.g.

go_backend/extension_runtime_stall_test.go

@@ -2,6 +2,7 @@ package gobackend
 
 import (
 	"context"
+	"errors"
 	"net/http"
 	"net/http/httptest"
 	"testing"
@@ -45,8 +46,8 @@ func TestStallWatchdogCancelsOnNoData(t *testing.T) {
 			break
 		}
 	}
-	if readErr == nil {
-		t.Fatal("expected read error from stall cancel")
+	if !errors.Is(readErr, context.Canceled) {
+		t.Fatalf("read error = %v, want watchdog context cancellation", readErr)
 	}
 	if !wd.stalled.Load() {
 		t.Fatalf("watchdog did not mark stalled; err=%v", readErr)

go_backend/extension_runtime_storage.go

@@ -175,23 +175,6 @@ func readJSONMapFile(path string) (map[string]any, error) {
 	return result, nil
 }
 
-func (r *extensionRuntime) refreshStorage() error {
-	path := r.getStoragePath()
-	fileMu := extensionFileMu(path)
-	fileMu.Lock()
-	snapshot, err := readCachedJSONMapLocked(path, func() (map[string]any, error) {
-		return readJSONMapFile(path)
-	})
-	fileMu.Unlock()
-	if err != nil {
-		return err
-	}
-	r.storageMu.Lock()
-	r.storageCache = snapshot
-	r.storageMu.Unlock()
-	return nil
-}
-
 func (r *extensionRuntime) mutateStorage(mutate func(map[string]any) bool) error {
 	r.storageMu.RLock()
 	closed := r.storageClosed

go_backend/extension_runtime_storage_test.go

@@ -167,7 +167,8 @@ func TestExtensionRuntimeStorageConcurrentRuntimesMergeWrites(t *testing.T) {
 		done <- result.ToBoolean()
 	}()
 	close(start)
-	if !<-done || !<-done {
+	firstSucceeded, secondSucceeded := <-done, <-done
+	if !firstSucceeded || !secondSucceeded {
 		t.Fatal("concurrent storage write failed")
 	}
 

go_backend/extension_signed_session.go

@@ -1249,16 +1249,6 @@ func (r *extensionRuntime) refreshSignedSession(config SignedSessionConfig, reco
 	return nil
 }
 
-func (r *extensionRuntime) startSignedSessionVerification(config SignedSessionConfig, reason string) (string, error) {
-	coordinator, err := r.signedSessionCoordinator(config)
-	if err != nil {
-		return "", err
-	}
-	coordinator.mu.Lock()
-	defer coordinator.mu.Unlock()
-	return r.startSignedSessionVerificationLocked(config, coordinator, reason)
-}
-
 func (r *extensionRuntime) startSignedSessionVerificationLocked(
 	config SignedSessionConfig,
 	coordinator *signedSessionCoordinator,

go_backend/extension_signed_session_test.go

@@ -2132,7 +2132,7 @@ func TestRefreshSignedSessionCoalescesWithoutHoldingCoordinatorMutex(t *testing.
 	mutexAvailable := make(chan struct{})
 	go func() {
 		coordinator.mu.Lock()
-		coordinator.mu.Unlock()
+		defer coordinator.mu.Unlock()
 		close(mutexAvailable)
 	}()
 	select {

go_backend/library_scan_formats.go

@@ -7,10 +7,6 @@ import (
 	"strings"
 )
 
-func scanAudioFileWithKnownModTime(filePath, scanTime string, knownModTime int64) (*LibraryScanResult, error) {
-	return scanAudioFileWithKnownModTimeAndDisplayNameAndCoverCacheKey(filePath, "", "", scanTime, knownModTime)
-}
-
 func scanAudioFileWithKnownModTimeAndDisplayNameAndCoverCacheKey(filePath, displayNameHint, coverCacheKey, scanTime string, knownModTime int64) (*LibraryScanResult, error) {
 	ext := resolveLibraryAudioExt(filePath, displayNameHint)
 
@@ -32,13 +28,14 @@ func scanAudioFileWithKnownModTimeAndDisplayNameAndCoverCacheKey(filePath, displ
 	libraryCoverCacheMu.RUnlock()
 	var scanned *LibraryScanResult
 	var scanErr error
-	if ext == ".flac" {
+	switch ext {
+	case ".flac":
 		scanned, scanErr = scanFLACFileWithCoverCache(filePath, result, displayNameHint, coverCacheDir, coverCacheKey)
-	} else if ext == ".m4a" || ext == ".mp4" || ext == ".aac" {
+	case ".m4a", ".mp4", ".aac":
 		scanned, scanErr = scanM4AFileWithCoverCache(filePath, result, displayNameHint, coverCacheDir, coverCacheKey)
-	} else if ext == ".mp3" {
+	case ".mp3":
 		scanned, scanErr = scanMP3FileWithCoverCache(filePath, result, displayNameHint, coverCacheDir, coverCacheKey)
-	} else {
+	default:
 		if coverCacheDir != "" {
 			coverPath, err := SaveCoverToCacheWithHintAndKey(
 				filePath,
@@ -184,10 +181,6 @@ func scanFLACFileWithCoverCache(filePath string, result *LibraryScanResult, disp
 	return result, nil
 }
 
-func scanM4AFile(filePath string, result *LibraryScanResult, displayNameHint string) (*LibraryScanResult, error) {
-	return scanM4AFileWithCoverCache(filePath, result, displayNameHint, "", "")
-}
-
 func scanM4AFileWithCoverCache(filePath string, result *LibraryScanResult, displayNameHint, coverCacheDir, coverCacheKey string) (*LibraryScanResult, error) {
 	f, err := os.Open(filePath)
 	if err != nil {
@@ -276,10 +269,6 @@ func isLosslessLibraryFormat(format string) bool {
 	}
 }
 
-func scanMP3File(filePath string, result *LibraryScanResult, displayNameHint string) (*LibraryScanResult, error) {
-	return scanMP3FileWithCoverCache(filePath, result, displayNameHint, "", "")
-}
-
 func scanMP3FileWithCoverCache(filePath string, result *LibraryScanResult, displayNameHint, cacheDir, cacheKey string) (*LibraryScanResult, error) {
 	wantCover := cacheDir != ""
 	if wantCover {

go_backend/lyrics.go

@@ -623,10 +623,6 @@ func isKnownBuiltInLyricsProvider(providerName string) bool {
 	}
 }
 
-func (c *LyricsClient) fetchBuiltInLyricsProvider(providerName string, request lyricsProviderSearchRequest) (*LyricsResponse, error, bool) {
-	return c.fetchBuiltInLyricsProviderContext(context.Background(), providerName, request)
-}
-
 func (c *LyricsClient) fetchBuiltInLyricsProviderContext(ctx context.Context, providerName string, request lyricsProviderSearchRequest) (*LyricsResponse, error, bool) {
 	clientCopy := *c
 	clientCopy.httpClient = bindLyricsHTTPClientContext(c.httpClient, ctx)

test/local_track_batch_actions_test.dart

@@ -37,12 +37,12 @@ class _BatchSettings extends SettingsNotifier {
 
 class _BatchLibrary extends LocalLibraryNotifier {
   final refreshed = Completer<void>();
-  bool refreshStarted = false;
+  bool _refreshStarted = false;
   @override
   LocalLibraryState build() => LocalLibraryState();
   @override
   Future<void> scanAllSources({bool forceFullScan = false}) {
-    refreshStarted = true;
+    _refreshStarted = true;
     return refreshed.future;
   }
 }
@@ -301,7 +301,7 @@ void main() {
         expect(settings.phases.length, 1);
         await tester.tap(find.text('Apply changes'));
         await tester.pumpAndSettle();
-        expect(library.refreshStarted, isTrue);
+        expect(library._refreshStarted, isTrue);
         expect(settings.phases.length, 2);
         active = !leaveDuringRefresh;
         library.refreshed.complete();