refactor: convert _queries from class attributes to cached properties

Convert _queries from mutable class attributes to cached class properties
that dynamically fetch plugin queries. This eliminates the need for manual
query registration and cleanup in plugin loading/unloading logic.

beets/dbcore/db.py

@@ -299,10 +299,12 @@ class Model(ABC, Generic[D]):
     are subclasses of `Sort`.
     """
 
-    _queries: dict[str, FieldQueryType] = {}
-    """Named queries that use a field-like `name:value` syntax but which
-    do not relate to any specific field.
-    """
+    @cached_classproperty
+    def _queries(cls) -> dict[str, FieldQueryType]:
+        """Named queries that use a field-like `name:value` syntax but which
+        do not relate to any specific field.
+        """
+        return {}
 
     _always_dirty = False
     """By default, fields only become "dirty" when their value actually

beets/library/models.py

@@ -49,6 +49,10 @@ class LibModel(dbcore.Model["Library"]):
             "data_source": types.STRING,
         }
 
+    @cached_classproperty
+    def _queries(cls) -> dict[str, FieldQueryType]:
+        return plugins.named_queries(cls)  # type: ignore[arg-type]
+
     @cached_classproperty
     def writable_media_fields(cls) -> set[str]:
         return set(MediaFile.fields()) & cls._fields.keys()
@@ -740,7 +744,9 @@ class Item(LibModel):
 
     _sorts = {"artist": dbcore.query.SmartArtistSort}
 
-    _queries = {"singleton": dbcore.query.SingletonQuery}
+    @cached_classproperty
+    def _queries(cls) -> dict[str, FieldQueryType]:
+        return {**super()._queries, "singleton": dbcore.query.SingletonQuery}
 
     _format_config_key = "format_item"
 

beets/plugins.py

@@ -379,13 +379,13 @@ def types(model_cls: type[AnyModel]) -> dict[str, Type]:
 
 
 def named_queries(model_cls: type[AnyModel]) -> dict[str, FieldQueryType]:
-    # Gather `item_queries` and `album_queries` from the plugins.
+    """Return mapping between field names and queries for the given model."""
     attr_name = f"{model_cls.__name__.lower()}_queries"
-    queries: dict[str, FieldQueryType] = {}
-    for plugin in find_plugins():
-        plugin_queries = getattr(plugin, attr_name, {})
-        queries.update(plugin_queries)
-    return queries
+    return {
+        field: query
+        for plugin in find_plugins()
+        for field, query in getattr(plugin, attr_name, {}).items()
+    }
 
 
 def notify_info_yielded(event: str) -> Callable[[IterF[P, Ret]], IterF[P, Ret]]:

beets/test/helper.py

@@ -52,7 +52,7 @@ import beets.plugins
 from beets import importer, logging, util
 from beets.autotag.hooks import AlbumInfo, TrackInfo
 from beets.importer import ImportSession
-from beets.library import Album, Item, Library
+from beets.library import Item, Library
 from beets.test import _common
 from beets.ui.commands import TerminalImportSession
 from beets.util import (
@@ -472,9 +472,6 @@ class PluginMixin(ConfigMixin):
     plugin: ClassVar[str]
     preload_plugin: ClassVar[bool] = True
 
-    original_item_queries = dict(Item._queries)
-    original_album_queries = dict(Album._queries)
-
     def setup_beets(self):
         super().setup_beets()
         if self.preload_plugin:
@@ -498,10 +495,6 @@ class PluginMixin(ConfigMixin):
         beets.plugins.send("pluginload")
         beets.plugins.find_plugins()
 
-        # Take a backup of the original _queries to restore when unloading.
-        Item._queries.update(beets.plugins.named_queries(Item))
-        Album._queries.update(beets.plugins.named_queries(Album))
-
     def unload_plugins(self) -> None:
         """Unload all plugins and remove them from the configuration."""
         # FIXME this should eventually be handled by a plugin manager
@@ -510,8 +503,6 @@ class PluginMixin(ConfigMixin):
         self.config["plugins"] = []
         beets.plugins._classes = set()
         beets.plugins._instances = {}
-        Item._queries = self.original_item_queries
-        Album._queries = self.original_album_queries
 
     @contextmanager
     def configure_plugin(self, config: Any):

beets/ui/__init__.py

@@ -1609,10 +1609,6 @@ def _setup(options, lib=None):
 
     plugins = _load_plugins(options, config)
 
-    # Add queries defined by plugins.
-    library.Item._queries.update(plugins.named_queries(library.Item))
-    library.Album._queries.update(plugins.named_queries(library.Album))
-
     plugins.send("pluginload")
 
     # Get the default subcommands.