dbcore: replace _check_db by db cached attribute

beets/dbcore/db.py

@@ -34,6 +34,7 @@ from collections.abc import (
     Mapping,
     Sequence,
 )
+from functools import cached_property
 from sqlite3 import Connection, sqlite_version_info
 from typing import TYPE_CHECKING, Any, AnyStr, Generic
 
@@ -360,6 +361,10 @@ class Model(ABC, Generic[D]):
         """Fields in the related table."""
         return cls._relation._fields.keys() - cls.shared_db_fields
 
+    @cached_property
+    def db(self) -> D:
+        return self._check_db()
+
     @classmethod
     def _getters(cls: type[Model]):
         """Return a mapping from field names to getter functions."""
@@ -599,7 +604,6 @@ class Model(ABC, Generic[D]):
         """
         if fields is None:
             fields = self._fields
-        db = self._check_db()
 
         # Build assignments for query.
         assignments = []
@@ -611,7 +615,7 @@ class Model(ABC, Generic[D]):
                 value = self._type(key).to_sql(self[key])
                 subvars.append(value)
 
-        with db.transaction() as tx:
+        with self.db.transaction() as tx:
             # Main table update.
             if assignments:
                 query = f"UPDATE {self._table} SET {','.join(assignments)} WHERE id=?"
@@ -645,11 +649,10 @@ class Model(ABC, Generic[D]):
         If check_revision is true, the database is only queried loaded when a
         transaction has been committed since the item was last loaded.
         """
-        db = self._check_db()
-        if not self._dirty and db.revision == self._revision:
+        if not self._dirty and self.db.revision == self._revision:
             # Exit early
             return
-        stored_obj = db._get(type(self), self.id)
+        stored_obj = self.db._get(type(self), self.id)
         assert stored_obj is not None, f"object {self.id} not in DB"
         self._values_fixed = LazyConvertDict(self)
         self._values_flex = LazyConvertDict(self)
@@ -658,8 +661,7 @@ class Model(ABC, Generic[D]):
 
     def remove(self):
         """Remove the object's associated rows from the database."""
-        db = self._check_db()
-        with db.transaction() as tx:
+        with self.db.transaction() as tx:
             tx.mutate(f"DELETE FROM {self._table} WHERE id=?", (self.id,))
             tx.mutate(
                 f"DELETE FROM {self._flex_table} WHERE entity_id=?", (self.id,)
@@ -675,7 +677,7 @@ class Model(ABC, Generic[D]):
         """
         if db:
             self._db = db
-        db = self._check_db(False)
+        db = self._check_db(need_id=False)
 
         with db.transaction() as tx:
             new_id = tx.mutate(f"INSERT INTO {self._table} DEFAULT VALUES")
@@ -742,6 +744,7 @@ class Model(ABC, Generic[D]):
         """
         state = self.__dict__.copy()
         state["_db"] = None
+        state["db"] = None
         return state
 
 

beets/library/models.py

@@ -1143,7 +1143,6 @@ class Item(LibModel):
         If `store` is `False` however, the item won't be stored and it will
         have to be manually stored after invoking this method.
         """
-        self._check_db()
         dest = self.destination(basedir=basedir)
 
         # Create necessary ancestry for the move.
@@ -1183,9 +1182,8 @@ class Item(LibModel):
         is true, returns just the fragment of the path underneath the library
         base directory.
         """
-        db = self._check_db()
-        basedir = basedir or db.directory
-        path_formats = path_formats or db.path_formats
+        basedir = basedir or self.db.directory
+        path_formats = path_formats or self.db.path_formats
 
         # Use a path format based on a query, falling back on the
         # default.
@@ -1224,7 +1222,7 @@ class Item(LibModel):
             )
 
         lib_path_str, fallback = util.legalize_path(
-            subpath, db.replacements, self.filepath.suffix
+            subpath, self.db.replacements, self.filepath.suffix
         )
         if fallback:
             # Print an error message if legalization fell back to