[BACKEND] Better error message for music_tags recieving a video (#413)

* [BACKEND] Better error message for music_tags recieving a video

* test and better message

src/ytdl_sub/plugins/music_tags.py

@@ -11,6 +11,7 @@ from ytdl_sub.plugins.plugin import PluginOptions
 from ytdl_sub.utils.file_handler import FileMetadata
 from ytdl_sub.utils.logger import Logger
 from ytdl_sub.utils.thumbnail import convert_download_thumbnail
+from ytdl_sub.validators.audo_codec_validator import AUDIO_CODEC_EXTS
 from ytdl_sub.validators.strict_dict_validator import StrictDictValidator
 from ytdl_sub.validators.string_formatter_validators import ListFormatterValidator
 from ytdl_sub.validators.string_formatter_validators import StringFormatterValidator
@@ -116,6 +117,13 @@ class MusicTagsPlugin(Plugin[MusicTagsOptions]):
         """
         Tags the entry's audio file using values defined in the metadata options
         """
+        if entry.ext not in AUDIO_CODEC_EXTS:
+            raise self.plugin_options.validation_exception(
+                f"music_tags plugin received a video with the extension '{entry.ext}'. Only audio "
+                f"files are supported for setting music tags. Ensure you are converting the video "
+                f"to audio using the audio_extract plugin."
+            )
+
         # Resolve the tags into this dict
         tags_to_write: Dict[str, List[str]] = defaultdict(list)
         for tag_name, tag_formatters in self.plugin_options.tags.as_lists.items():

src/ytdl_sub/plugins/plugin.py

@@ -10,6 +10,7 @@ from typing import TypeVar
 from ytdl_sub.config.preset_options import AddsVariablesMixin
 from ytdl_sub.config.preset_options import Overrides
 from ytdl_sub.entries.entry import Entry
+from ytdl_sub.utils.exceptions import ValidationException
 from ytdl_sub.utils.file_handler import FileMetadata
 from ytdl_sub.utils.logger import Logger
 from ytdl_sub.validators.strict_dict_validator import StrictDictValidator
@@ -44,6 +45,23 @@ class PluginOptions(StrictDictValidator, AddsVariablesMixin, ABC):
     Class that defines the parameters to a plugin
     """
 
+    def validation_exception(
+        self,
+        error_message: str | Exception,
+    ) -> ValidationException:
+        """
+        Parameters
+        ----------
+        error_message
+            Error message to include in the validation exception
+
+        Returns
+        -------
+        Validation exception that points to the location in the config. To be used for plugins
+        to throw good validation exceptions at runtime.
+        """
+        return self._validation_exception(error_message=error_message)
+
 
 PluginOptionsT = TypeVar("PluginOptionsT", bound=PluginOptions)
 

tests/e2e/plugins/test_music_tags.py

@@ -0,0 +1,51 @@
+import re
+
+import pytest
+from expected_download import assert_expected_downloads
+from expected_transaction_log import assert_transaction_log_matches
+
+from ytdl_sub.subscriptions.subscription import Subscription
+from ytdl_sub.utils.exceptions import ValidationException
+
+
+@pytest.fixture
+def single_song_video_dict(output_directory):
+    return {
+        "download": {
+            "download_strategy": "url",
+            "url": "https://www.youtube.com/watch?v=2lAe1cqCOXo",
+        },
+        "output_options": {"output_directory": output_directory, "file_name": "will_error.mp4"},
+        # test multi-tags
+        "music_tags": {"embed_thumbnail": True, "tags": {"genres": ["multi_tag_1", "multi_tag_2"]}},
+        # download the worst format so it is fast
+        "ytdl_options": {
+            "format": "worst[ext=mp4]",
+            "postprocessor_args": {"ffmpeg": ["-bitexact"]},  # Must add this for reproducibility
+        },
+    }
+
+
+class TestMusicTags:
+    def test_music_tags_errors_on_video(
+        self,
+        youtube_audio_config,
+        single_song_video_dict,
+        output_directory,
+    ):
+        subscription = Subscription.from_dict(
+            config=youtube_audio_config,
+            preset_name="single_song_test",
+            preset_dict=single_song_video_dict,
+        )
+
+        with pytest.raises(
+            ValidationException,
+            match=re.escape(
+                "Validation error in single_song_test.music_tags: music_tags plugin received a "
+                "video with the extension 'mp4'. Only audio files are supported for setting music "
+                "tags. Ensure you are converting the video to audio using the audio_extract "
+                "plugin."
+            ),
+        ):
+            subscription.download(dry_run=True)