Fix bug of same dict being used for different Classes' caches.

[plomtask] / plomtask / db.py

diff --git a/plomtask/db.py b/plomtask/db.py
index e8a542e6176937a7c205a9a5909a5c776bdbd7db..1753da43cee71ca2204bbbdfd27c69aa52bd93fe 100644 (file)
--- a/plomtask/db.py
+++ b/plomtask/db.py
@@ -112,22 +112,22 @@ class DatabaseConnection:
         return '(' + ','.join(['?'] * len(values)) + ')'
 
 
-X = TypeVar('X', int, str)
-T = TypeVar('T', bound='BaseModel[Any]')
+BaseModelId = TypeVar('BaseModelId', int, str)
+BaseModelInstance = TypeVar('BaseModelInstance', bound='BaseModel[Any]')
 
 
-class BaseModel(Generic[X]):
+class BaseModel(Generic[BaseModelId]):
     """Template for most of the models we use/derive from the DB."""
     table_name = ''
     to_save: list[str] = []
-    id_: None | X
-    cache_: dict[X, Self] = {}
+    id_: None | BaseModelId
+    cache_: dict[BaseModelId, Self]
 
     @classmethod
-    def from_table_row(cls: type[T],
+    def from_table_row(cls: type[BaseModelInstance],
                        # pylint: disable=unused-argument
                        db_conn: DatabaseConnection,
-                       row: Row | list[Any]) -> T:
+                       row: Row | list[Any]) -> BaseModelInstance:
         """Make from DB row, write to DB cache."""
         obj = cls(*row)
         obj.cache()
@@ -136,7 +136,7 @@ class BaseModel(Generic[X]):
     @classmethod
     def _by_id(cls,
                db_conn: DatabaseConnection,
-               id_: X) -> tuple[Self | None, bool]:
+               id_: BaseModelId) -> tuple[Self | None, bool]:
         """Return instance found by ID, or None, and if from cache or not."""
         from_cache = False
         obj = cls.get_cached(id_)
@@ -145,7 +145,6 @@ class BaseModel(Generic[X]):
         else:
             for row in db_conn.row_where(cls.table_name, 'id', id_):
                 obj = cls.from_table_row(db_conn, row)
-                assert isinstance(obj, cls)
                 obj.cache()
                 break
         return obj, from_cache
@@ -171,11 +170,13 @@ class BaseModel(Generic[X]):
         self.cache()
 
     @classmethod
-    def get_cached(cls: type[T], id_: X) -> T | None:
+    def get_cached(cls: type[BaseModelInstance],
+                   id_: BaseModelId) -> BaseModelInstance | None:
         """Get object of id_ from class's cache, or None if not found."""
         # pylint: disable=consider-iterating-dictionary
-        if id_ in cls.cache_.keys():
-            obj = cls.cache_[id_]
+        cache = cls.get_cache()
+        if id_ in cache.keys():
+            obj = cache[id_]
             assert isinstance(obj, cls)
             return obj
         return None
@@ -184,15 +185,41 @@ class BaseModel(Generic[X]):
         """Update object in class's cache."""
         if self.id_ is None:
             raise HandledException('Cannot cache object without ID.')
-        self.__class__.cache_[self.id_] = self
+        cache = self.__class__.get_cache()
+        cache[self.id_] = self
 
     def uncache(self) -> None:
         """Remove self from cache."""
         if self.id_ is None:
             raise HandledException('Cannot un-cache object without ID.')
-        del self.__class__.cache_[self.id_]
+        cache = self.__class__.get_cache()
+        del cache[self.id_]
 
     @classmethod
     def empty_cache(cls) -> None:
         """Empty class's cache."""
         cls.cache_ = {}
+
+    @classmethod
+    def all(cls: type[BaseModelInstance],
+            db_conn: DatabaseConnection) -> list[BaseModelInstance]:
+        """Collect all objects of class."""
+        items: dict[BaseModelId, BaseModelInstance] = {}
+        for k, v in cls.get_cache().items():
+            assert isinstance(v, cls)
+            items[k] = v
+        already_recorded = items.keys()
+        for id_ in db_conn.column_all(cls.table_name, 'id'):
+            if id_ not in already_recorded:
+                # pylint: disable=no-member
+                item = cls.by_id(db_conn, id_)  # type: ignore[attr-defined]
+                items[item.id_] = item
+        return list(items.values())
+
+    @classmethod
+    def get_cache(cls: type[BaseModelInstance]) -> dict[Any, BaseModel[Any]]:
+        """Get cache dictionary, create it if not yet existing."""
+        if not hasattr(cls, 'cache_'):
+            d: dict[Any, BaseModel[Any]] = {}
+            cls.cache_ = d
+        return cls.cache_