harden manifest detection and downloader failure coverage

internal/download/downloader.go

@@ -386,7 +386,7 @@ func isManifestResponse(contentType string, peek []byte) bool {
 		return true
 	}
 	s := strings.TrimSpace(strings.ToLower(string(peek)))
-	if strings.HasPrefix(s, "<?xml") && strings.Contains(s, "<mpd") {
+	if (strings.HasPrefix(s, "<?xml") && strings.Contains(s, "<mpd")) || strings.HasPrefix(s, "<mpd") {
 		return true
 	}
 	if strings.HasPrefix(s, "#extm3u") {

internal/download/downloader_test.go

@@ -8,8 +8,11 @@ import (
 	"net/http"
 	"net/http/httptest"
 	"os"
+	"os/exec"
 	"path/filepath"
+	"strings"
 	"testing"
+	"time"
 
 	"golang.org/x/crypto/blowfish"
 )
@@ -46,9 +49,15 @@ func TestManifestDetection(t *testing.T) {
 	if !isManifestResponse("application/dash+xml", []byte("x")) {
 		t.Fatalf("expected dash content-type to be manifest")
 	}
+	if !isManifestResponse("application/vnd.apple.mpegurl", []byte("x")) {
+		t.Fatalf("expected mpegurl content-type to be manifest")
+	}
 	if !isManifestResponse("application/octet-stream", []byte("<?xml version='1.0'?><MPD></MPD>")) {
 		t.Fatalf("expected MPD XML body to be manifest")
 	}
+	if !isManifestResponse("application/octet-stream", []byte("<MPD type='static'></MPD>")) {
+		t.Fatalf("expected MPD body without xml prolog to be manifest")
+	}
 	if !isManifestResponse("text/plain", []byte("#EXTM3U\n#EXT-X-VERSION:3")) {
 		t.Fatalf("expected HLS body to be manifest")
 	}
@@ -158,3 +167,67 @@ func TestFileDeezerEncryptedTruncatedResponseRemovesPartialFile(t *testing.T) {
 		t.Fatalf("expected no partial file, stat err=%v", statErr)
 	}
 }
+
+func TestFileDeezerEncryptedBadStatus(t *testing.T) {
+	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
+		w.WriteHeader(http.StatusForbidden)
+	}))
+	defer ts.Close()
+
+	d := NewWithOptions(true, false)
+	out := filepath.Join(t.TempDir(), "x", "a.flac")
+	err := d.FileDeezerEncrypted(context.Background(), ts.URL, out, "3135556")
+	if err == nil || !strings.Contains(err.Error(), "status=403") {
+		t.Fatalf("expected status error, got %v", err)
+	}
+}
+
+func TestDownloaderFileContextCancellationRemovesPartialFile(t *testing.T) {
+	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("Content-Type", "application/octet-stream")
+		_, _ = w.Write([]byte("partial-data"))
+		if f, ok := w.(http.Flusher); ok {
+			f.Flush()
+		}
+		<-r.Context().Done()
+	}))
+	defer ts.Close()
+
+	d := NewWithOptions(true, false)
+	out := filepath.Join(t.TempDir(), "x", "cancel.bin")
+	ctx, cancel := context.WithTimeout(context.Background(), 60*time.Millisecond)
+	defer cancel()
+	err := d.File(ctx, ts.URL, out)
+	if err == nil {
+		t.Fatalf("expected context cancellation error")
+	}
+	if _, statErr := os.Stat(out); !errors.Is(statErr, os.ErrNotExist) {
+		t.Fatalf("expected no partial file, stat err=%v", statErr)
+	}
+}
+
+func TestStreamManifestWithFFmpegMissing(t *testing.T) {
+	d := NewWithOptions(true, false)
+	t.Setenv("PATH", "")
+	err := d.streamManifestWithFFmpeg(context.Background(), "https://example.com/live.m3u8", filepath.Join(t.TempDir(), "out.m4a"), false)
+	if err == nil || !strings.Contains(strings.ToLower(err.Error()), "ffmpeg not found") {
+		t.Fatalf("expected ffmpeg missing error, got %v", err)
+	}
+}
+
+func TestStreamManifestWithFFmpegFailureRemovesPartialFile(t *testing.T) {
+	if _, err := exec.LookPath("ffmpeg"); err != nil {
+		t.Skip("ffmpeg not installed")
+	}
+	d := NewWithOptions(true, false)
+	out := filepath.Join(t.TempDir(), "out.m4a")
+	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+	defer cancel()
+	err := d.streamManifestWithFFmpeg(ctx, "https://127.0.0.1:1/unreachable.m3u8", out, false)
+	if err == nil || !strings.Contains(err.Error(), "ffmpeg stream copy failed") {
+		t.Fatalf("expected ffmpeg failure error, got %v", err)
+	}
+	if _, statErr := os.Stat(out); !errors.Is(statErr, os.ErrNotExist) {
+		t.Fatalf("expected no partial file after ffmpeg failure, stat err=%v", statErr)
+	}
+}