fix(audio): ignore stale CUE sheets whose referenced files are gone

Adopt a CUE only when at least one FILE reference resolves to a real
file in the audio directory. Legacy WAV-era cue sheets shipped inside
FLAC split-track releases previously blocked every track transfer with
"CUE 引用的文件名与当前音频不一致" (and broken-index cues did the same);
they are now ignored with an info log and organization falls back to
the files' own tags. Cross-directory references and cues that still
point at existing files keep the current strict behavior.

Refs: https://github.com/jxxghp/MoviePilot/issues/6888

app/application/audio.py

@@ -174,6 +174,28 @@ def _cue_mentions_audio(text: str, path: Path) -> bool:
     return False
 
 
+def _cue_file_references(text: str) -> list[str]:
+    """从原始 CUE 文本提取 FILE 引用名，供解析失败时判断引用是否仍然存在。"""
+    references = []
+    for line in text.splitlines():
+        match = re.match(r'\s*FILE\s+(?:"([^"\r\n]+)"|(\S+))', line, re.IGNORECASE)
+        if match:
+            references.append(match.group(1) or match.group(2))
+    return references
+
+
+def _cue_references_existing_audio(path: Path, names: Any) -> bool:
+    """CUE 至少引用一个目录中真实存在的音频才可采信；跨目录引用保守视为存在。"""
+    for name in names:
+        try:
+            reference = _cue_reference_name(name)
+        except ValueError:
+            return True
+        if (path.parent / reference).is_file():
+            return True
+    return False
+
+
 def _cue_candidates(path: Path) -> list[Path]:
     """只扫描音频同目录的有限 CUE，不遍历全集或其它目录。"""
     candidates = []
@@ -206,10 +228,14 @@ def _find_audio_cue(path: Path) -> Optional[tuple[Path, MusicCueSheet]]:
         try:
             sheet = parse_music_cue(text)
         except ValueError as error:
-            if candidate.stem.casefold() == path.stem.casefold() or _cue_mentions_audio(text, path):
+            mentions = candidate.stem.casefold() == path.stem.casefold() or _cue_mentions_audio(text, path)
+            if mentions and _cue_references_existing_audio(path, _cue_file_references(text)):
                 raise ValueError(f"关联 CUE 无法解析：{candidate.name} - {error}") from error
             continue
         references = {track.file_name for track in sheet.tracks}
+        if not _cue_references_existing_audio(path, references):
+            logger.info(f"CUE 引用的音频文件均已不存在，按陈旧索引忽略：{candidate}")
+            continue
         related = [name for name in references if PurePosixPath(name.replace("\\", "/")).stem.casefold() == path.stem.casefold()]
         if not related:
             continue

tests/test_music_cue.py

@@ -122,9 +122,9 @@ def test_image_cue_never_runs_recording_fingerprint(tmp_path, monkeypatch, async
     async_fingerprint.assert_not_called()
 
 
-@pytest.mark.parametrize("bad_reference", ["../image.flac", "image.wav", "IMAGE.flac", "C:\\music\\image.flac"])
+@pytest.mark.parametrize("bad_reference", ["../image.flac", "C:\\music\\image.flac"])
 def test_cue_reference_errors_block_even_without_category_folders(tmp_path, bad_reference):
-    """跨目录、错误后缀和大小写等引用不能靠关闭分类目录绕过检查。"""
+    """跨目录引用不能靠关闭分类目录绕过检查；同目录引用交给存在性判定。"""
     audio, _ = _image_pair(tmp_path, text=CUE.replace('"image.flac"', f'"{bad_reference}"'))
     meta = AudioMetadataHelper.read(audio)
     task = TransferTask(fileitem=make_fileitem(str(audio)), meta=meta, mediainfo=MusicInfo.from_meta(meta),
@@ -135,6 +135,58 @@ def test_cue_reference_errors_block_even_without_category_folders(tmp_path, bad_
     assert meta.organization_error
 
 
+@pytest.mark.parametrize("stale_reference", ["image.wav"])
+def test_cue_reference_missing_from_directory_falls_back_to_tags(tmp_path, stale_reference):
+    """引用文件已不存在的陈旧索引（转制未更新扩展名等）不得阻断整理，回退标签。"""
+    audio, _ = _image_pair(tmp_path, text=CUE.replace('"image.flac"', f'"{stale_reference}"'))
+    tags = FLAC(audio)
+    tags.update(title=["独立单曲"], artist=["测试歌手"], album=["专辑示例"], tracknumber=["2"])
+    tags.save()
+
+    meta = AudioMetadataHelper.read(audio)
+
+    assert not meta.organization_error
+    assert meta.music_layout != "cue_invalid"
+    assert meta.title == "独立单曲"
+    assert meta.track_number == 2
+
+
+def test_stale_wav_cue_does_not_block_flac_split_album(tmp_path):
+    """WAV 时代留档 CUE 全部引用不存在的 .wav 时，FLAC 分轨按自带标签正常整理。"""
+    source = tmp_path / "source"
+    source.mkdir()
+    for name in ("01 - 以父之名.flac", "02 - 懦夫.flac"):
+        shutil.copyfile(Path(__file__).parent / "fixtures/audio/silence.flac", source / name)
+    (source / "album.cue").write_text('''PERFORMER "周杰倫"
+TITLE "葉惠美"
+FILE "01 - 以父之名.wav" WAVE
+  TRACK 01 AUDIO
+    TITLE "以父之名"
+    INDEX 01 00:00:00
+FILE "02 - 懦夫.wav" WAVE
+  TRACK 02 AUDIO
+    TITLE "懦夫"
+    INDEX 01 00:00:00
+''')
+
+    meta = AudioMetadataHelper.read(source / "01 - 以父之名.flac")
+
+    assert not meta.organization_error
+    assert meta.music_layout != "cue_invalid"
+    assert not meta.cue_tracks
+
+
+def test_broken_index_without_existing_references_is_ignored(tmp_path):
+    """结构损坏且引用文件全部不存在的 CUE 同样按陈旧索引忽略，不再阻断。"""
+    audio, _ = _image_pair(tmp_path, text=CUE.replace('"image.flac"', '"image.wav"')
+                           .replace("    INDEX 01 00:01:00\n", ""))
+
+    meta = AudioMetadataHelper.read(audio)
+
+    assert not meta.organization_error
+    assert meta.music_layout != "cue_invalid"
+
+
 def test_single_audio_collects_nonmatching_stem_cue_companion(tmp_path, monkeypatch):
     """FILE 关联有效时，CUE 文件名无需与音频同主干，且应在音频后加入归档。"""
     audio, cue = _image_pair(tmp_path, cue_name="album-index.cue")