Fixes TypeError in the Discogs plugin (#5415)

Handles the case when discogs return `None` for format descriptions.

---------

Co-authored-by: Šarūnas Nejus <snejus@protonmail.com>

beetsplug/discogs.py

@@ -16,6 +16,8 @@
 python3-discogs-client library.
 """
 
+from __future__ import annotations
+
 import http.client
 import json
 import os
@@ -30,6 +32,7 @@ from discogs_client import Client, Master, Release
 from discogs_client import __version__ as dc_string
 from discogs_client.exceptions import DiscogsAPIError
 from requests.exceptions import ConnectionError
+from typing_extensions import TypedDict
 
 import beets
 import beets.ui
@@ -52,6 +55,12 @@ CONNECTION_ERRORS = (
 )
 
 
+class ReleaseFormat(TypedDict):
+    name: str
+    qty: int
+    descriptions: list[str] | None
+
+
 class DiscogsPlugin(BeetsPlugin):
     def __init__(self):
         super().__init__()
@@ -363,6 +372,18 @@ class DiscogsPlugin(BeetsPlugin):
             )
             return None
 
+    @staticmethod
+    def get_media_and_albumtype(
+        formats: list[ReleaseFormat] | None,
+    ) -> tuple[str | None, str | None]:
+        media = albumtype = None
+        if formats and (first_format := formats[0]):
+            if descriptions := first_format["descriptions"]:
+                albumtype = ", ".join(descriptions)
+            media = first_format["name"]
+
+        return media, albumtype
+
     def get_album_info(self, result):
         """Returns an AlbumInfo object for a discogs Release object."""
         # Explicitly reload the `Release` fields, as they might not be yet
@@ -413,13 +434,11 @@ class DiscogsPlugin(BeetsPlugin):
 
         # Extract information for the optional AlbumInfo fields that are
         # contained on nested discogs fields.
-        albumtype = media = label = catalogno = labelid = None
-        if result.data.get("formats"):
-            albumtype = (
-                ", ".join(result.data["formats"][0].get("descriptions", []))
-                or None
-            )
-            media = result.data["formats"][0]["name"]
+        media, albumtype = self.get_media_and_albumtype(
+            result.data.get("formats")
+        )
+
+        label = catalogno = labelid = None
         if result.data.get("labels"):
             label = result.data["labels"][0].get("name")
             catalogno = result.data["labels"][0].get("catno")

docs/changelog.rst

@@ -23,9 +23,9 @@ New features:
 
 Bug fixes:
 
-* Improved naming of temporary files by separating the random part with the file extension.
-* Fixed the ``auto`` value for the :ref:`reflink` config option.
-* Fixed lyrics plugin only getting part of the lyrics from ``Genius.com`` :bug:`4815`
+* Improve naming of temporary files by separating the random part with the file extension.
+* Fix the ``auto`` value for the :ref:`reflink` config option.
+* Fix lyrics plugin only getting part of the lyrics from ``Genius.com`` :bug:`4815`
 * Album flexible fields are now correctly saved. For instance MusicBrainz external links
   such as `bandcamp_album_id` will be available on albums in addition to tracks.
   For albums already in your library, a re-import is required for the fields to be added.
@@ -34,6 +34,7 @@ Bug fixes:
   as a numpy array. Update ``librosa`` dependency constraint to prevent similar
   issues in the future.
   :bug:`5289`
+* :doc:`plugins/discogs`: Fix the ``TypeError`` when there is no description.
 
 For packagers:
 

test/plugins/test_discogs.py

@@ -12,9 +12,9 @@
 # The above copyright notice and this permission notice shall be
 # included in all copies or substantial portions of the Software.
 
-"""Tests for discogs plugin.
-"""
+"""Tests for discogs plugin."""
 
+import pytest
 
 from beets import config
 from beets.test._common import Bag
@@ -423,3 +423,26 @@ class DGAlbumInfoTest(BeetsTestCase):
         d = DiscogsPlugin().get_album_info(release)
         assert d.genre == "GENRE1, GENRE2"
         assert d.style is None
+
+
+@pytest.mark.parametrize(
+    "formats, expected_media, expected_albumtype",
+    [
+        (None, None, None),
+        (
+            [
+                {
+                    "descriptions": ['7"', "Single", "45 RPM"],
+                    "name": "Vinyl",
+                    "qty": 1,
+                }
+            ],
+            "Vinyl",
+            '7", Single, 45 RPM',
+        ),
+    ],
+)
+def test_get_media_and_albumtype(formats, expected_media, expected_albumtype):
+    result = DiscogsPlugin.get_media_and_albumtype(formats)
+
+    assert result == (expected_media, expected_albumtype)