fix: handle null/missing fields in Video API responses (#295)

* fix: handle null/missing fields in Video API responses

Tidal's API returns some Video objects (lyric/visualiser videos on
artist pages) with fields that don't match the current strict models:

- `imageId` can be null instead of a string
- The nested `album` object can be present but missing `id`, `title`,
  and `cover`

These validation failures cause the entire `ArtistVideosItems` page
to be rejected by Pydantic before any video can be parsed, resulting
in 0 downloads when targeting an artist with `--videos`.

A second independent bug causes an `AttributeError` on every video:
the default template `{album.artist}/{album.title}/{item.title}` is
shared with videos, but many videos have no album. When `album=None`
is passed to `format_template`, Python's `str.format()` evaluates
`None.artist` and raises `AttributeError: 'NoneType' object has no
attribute 'artist'`, which is caught and printed as an error for
every single video.

Fix:
- `resources.py`: make `Video.imageId` and `Video.Album.{id,title,
  cover}` optional so incomplete API responses pass validation
- `format.py`: give `AlbumTemplate` field defaults so it can be
  instantiated empty; use `AlbumTemplate()` as fallback instead of
  `None` when no album is present, so `{album.*}` tokens render as
  empty strings rather than raising AttributeError
- `download/__init__.py`: guard `video.album.id` accesses against
  `None` (now possible after the model fix) in both video code paths

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

* test: add tests for Video model null fields and AlbumTemplate fallback

Covers the two bugs fixed in the previous commit:

- Video model accepts null/missing imageId and partial album objects
- format_template does not raise AttributeError when album is None
  and the template references {album.*} tokens

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

---------

Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>

tests/core/api/test_api_models_resources.py

@@ -0,0 +1,86 @@
+import pytest
+from pydantic import ValidationError
+
+from tiddl.core.api.models.resources import Video
+
+
+# Minimal valid payload shared across tests
+BASE_VIDEO = {
+    "id": 123,
+    "title": "Test Video",
+    "volumeNumber": 1,
+    "trackNumber": 1,
+    "duration": 180,
+    "quality": "MP4_1080P",
+    "streamReady": True,
+    "adSupportedStreamReady": False,
+    "djReady": False,
+    "stemReady": False,
+    "allowStreaming": True,
+    "explicit": False,
+    "popularity": 50,
+    "type": "Music Video",
+    "adsPrePaywallOnly": False,
+    "artists": [],
+}
+
+
+def test_video_null_image_id():
+    """imageId=null should be accepted (Tidal returns this for some videos)."""
+    video = Video.model_validate({**BASE_VIDEO, "imageId": None})
+    assert video.imageId is None
+
+
+def test_video_missing_image_id():
+    """imageId absent entirely should default to None."""
+    video = Video.model_validate(BASE_VIDEO)
+    assert video.imageId is None
+
+
+def test_video_valid_image_id():
+    """A normal imageId string should still be accepted."""
+    video = Video.model_validate({**BASE_VIDEO, "imageId": "abc123"})
+    assert video.imageId == "abc123"
+
+
+def test_video_album_missing_required_fields():
+    """album object present but missing id/title/cover should be accepted."""
+    payload = {
+        **BASE_VIDEO,
+        "album": {"vibrantColor": None},
+    }
+    video = Video.model_validate(payload)
+    assert video.album is not None
+    assert video.album.id is None
+    assert video.album.title is None
+    assert video.album.cover is None
+
+
+def test_video_album_none():
+    """album=null should still be accepted (existing behaviour)."""
+    video = Video.model_validate({**BASE_VIDEO, "album": None})
+    assert video.album is None
+
+
+def test_video_album_fully_populated():
+    """A fully populated album object should still parse correctly."""
+    payload = {
+        **BASE_VIDEO,
+        "album": {
+            "id": 42,
+            "title": "Greatest Hits",
+            "cover": "cover-uuid",
+        },
+    }
+    video = Video.model_validate(payload)
+    assert video.album is not None
+    assert video.album.id == 42
+    assert video.album.title == "Greatest Hits"
+    assert video.album.cover == "cover-uuid"
+
+
+def test_video_still_requires_core_fields():
+    """Removing a genuinely required field (title) should still raise."""
+    payload = {k: v for k, v in BASE_VIDEO.items() if k != "title"}
+    with pytest.raises(ValidationError):
+        Video.model_validate(payload)

tests/core/utils/test_utils_format.py

@@ -0,0 +1,103 @@
+from datetime import datetime
+
+import pytest
+
+from tiddl.core.utils.format import AlbumTemplate, format_template, generate_template_data
+from tiddl.core.api.models.resources import Video
+
+
+# Minimal Video instance used across format tests
+BASE_VIDEO = Video.model_validate(
+    {
+        "id": 1,
+        "title": "My Video",
+        "volumeNumber": 1,
+        "trackNumber": 1,
+        "duration": 200,
+        "quality": "MP4_1080P",
+        "streamReady": True,
+        "adSupportedStreamReady": False,
+        "djReady": False,
+        "stemReady": False,
+        "allowStreaming": True,
+        "explicit": False,
+        "popularity": 10,
+        "type": "Music Video",
+        "adsPrePaywallOnly": False,
+        "artists": [{"id": 1, "name": "Gorillaz", "type": "MAIN"}],
+        "artist": {"id": 1, "name": "Gorillaz", "type": "MAIN"},
+    }
+)
+
+
+class TestAlbumTemplateDefaults:
+    def test_can_be_instantiated_with_no_args(self):
+        t = AlbumTemplate()
+        assert t.id == 0
+        assert t.title == ""
+        assert t.artist == ""
+        assert t.artists == ""
+        assert t.release == ""
+
+    def test_date_defaults_to_datetime_min(self):
+        assert AlbumTemplate().date == datetime.min
+
+    def test_explicit_formats_to_empty_string(self):
+        assert f"{AlbumTemplate().explicit}" == ""
+
+    def test_master_formats_to_empty_string(self):
+        assert f"{AlbumTemplate().master:MASTER}" == ""
+
+
+class TestFormatTemplateNoAlbum:
+    def test_album_artist_token_does_not_raise(self):
+        """Default template must not raise AttributeError when album is None."""
+        result = format_template(
+            template="{album.artist}/{album.title}/{item.title}",
+            item=BASE_VIDEO,
+            album=None,
+            with_asterisk_ext=False,
+        )
+        # album tokens render as "_" (empty string → sanitised fallback)
+        assert result == "_/_/My Video"
+
+    def test_album_title_token_does_not_raise(self):
+        result = format_template(
+            template="{album.title}",
+            item=BASE_VIDEO,
+            album=None,
+            with_asterisk_ext=False,
+        )
+        assert result == "_"
+
+    def test_item_title_still_rendered(self):
+        result = format_template(
+            template="{item.title}",
+            item=BASE_VIDEO,
+            album=None,
+            with_asterisk_ext=False,
+        )
+        assert result == "My Video"
+
+    def test_item_artist_still_rendered(self):
+        result = format_template(
+            template="{item.artist}",
+            item=BASE_VIDEO,
+            album=None,
+            with_asterisk_ext=False,
+        )
+        assert result == "Gorillaz"
+
+
+class TestGenerateTemplateDataAlbumFallback:
+    def test_album_template_is_never_none(self):
+        """generate_template_data should always return an AlbumTemplate, never None."""
+        data = generate_template_data(item=BASE_VIDEO, album=None)
+        assert data["album"] is not None
+        assert isinstance(data["album"], AlbumTemplate)
+
+    def test_album_template_has_empty_fields_when_no_album(self):
+        data = generate_template_data(item=BASE_VIDEO, album=None)
+        album = data["album"]
+        assert album.title == ""
+        assert album.artist == ""

tiddl/cli/commands/download/__init__.py

@@ -414,7 +414,7 @@ def download_callback(
                     video = ctx.obj.api.get_video(resource.id)
                     template = TEMPLATE or CONFIG.templates.video
 
-                    if "{album" in template and video.album:
+                    if "{album" in template and video.album and video.album.id is not None:
                         album = ctx.obj.api.get_album(video.album.id)
                     else:
                         album = None

tiddl/core/api/models/resources.py

@@ -69,9 +69,9 @@ class Video(BaseModel):
         picture: Optional[str] = None
 
     class Album(BaseModel):
-        id: int
-        title: str
-        cover: str
+        id: Optional[int] = None
+        title: Optional[str] = None
+        cover: Optional[str] = None
         vibrantColor: Optional[str] = None
         videoCover: Optional[str] = None
 
@@ -81,7 +81,7 @@ class Video(BaseModel):
     trackNumber: int
     streamStartDate: Optional[datetime] = None
     imagePath: Optional[str] = None
-    imageId: str
+    imageId: Optional[str] = None
     vibrantColor: Optional[str] = None
     duration: int
     quality: Literal["MP4_1080P"] | str

tiddl/core/utils/format.py

@@ -1,5 +1,5 @@
 import re
-from dataclasses import dataclass
+from dataclasses import dataclass, field
 from datetime import datetime
 
 from tiddl.core.api.models import Track, Video, Album, Playlist
@@ -67,14 +67,14 @@ class UserFormat:
 
 @dataclass(slots=True)
 class AlbumTemplate:
-    id: int
-    title: str
-    artist: str
-    artists: str
-    date: datetime
-    explicit: Explicit
-    master: UserFormat
-    release: str
+    id: int = 0
+    title: str = ""
+    artist: str = ""
+    artists: str = ""
+    date: datetime = datetime.min
+    explicit: Explicit = field(default_factory=lambda: Explicit(None))
+    master: UserFormat = field(default_factory=lambda: UserFormat(False))
+    release: str = ""
 
 
 @dataclass(slots=True)
@@ -156,7 +156,7 @@ def generate_template_data(
             dolby=dolby,
         )
 
-    album_template = None
+    album_template = AlbumTemplate()
     if album:
         album_template = AlbumTemplate(
             id=album.id,