fix broken list deletions when cards are contained in the list

resources/migrations/00021_check_for_deleted_list_in_update_lists_card_quantities.down.sql

@@ -0,0 +1,56 @@
+CREATE OR REPLACE FUNCTION update_lists_card_quantities()
+	RETURNS TRIGGER
+AS $update_lists_card_quantities$
+DECLARE
+	update_card_id TEXT;
+	update_list_id INT;
+	new_quantity INT;
+	new_foil_quantity INT;
+BEGIN
+	-- get card_id and list_id of the lists_card_quantities row to insert/update
+	IF (TG_OP = 'DELETE') THEN
+		update_card_id = OLD.card_id;
+		update_list_id = OLD.list_id;
+	ELSE
+		update_card_id = NEW.card_id;
+		update_list_id = NEW.list_id;
+	END IF;
+
+	-- get quantities for both foil and non-foil to insert/update in the lists_card_quantities row
+
+	SELECT COALESCE(SUM(cl.quantity), 0) INTO STRICT new_quantity
+	FROM collection cl
+	WHERE cl.card_id = update_card_id
+	      AND cl.list_id = update_list_id;
+
+	SELECT COALESCE(SUM(cl.quantity), 0) INTO STRICT new_foil_quantity
+	FROM collection cl
+	WHERE cl.card_id = update_card_id
+	      AND cl.list_id = update_list_id
+	      AND cl.foil = TRUE;
+
+	-- poor man's upsert equivalent
+	LOOP
+		UPDATE lists_card_quantities
+		SET quantity = new_quantity,
+			foil_quantity = new_foil_quantity
+		WHERE card_id = update_card_id
+		      AND list_id = update_list_id;
+		IF FOUND THEN
+			-- update succeeded (existing row was present). exit loop
+			RETURN NULL;
+		END IF;
+
+		-- if we get here, an existing row was not present so we should try to insert one
+		BEGIN
+			INSERT INTO lists_card_quantities (card_id, list_id, quantity, foil_quantity)
+			VALUES (update_card_id, update_list_id, new_quantity, new_foil_quantity);
+			-- insert succeeded. exit loop
+			RETURN NULL;
+			EXCEPTION WHEN UNIQUE_VIOLATION THEN
+			-- insert failed because another operation finished first.
+			-- do nothing and just loop and retry the update
+		END;
+	END LOOP;
+END;
+$update_lists_card_quantities$ LANGUAGE plpgsql;

resources/migrations/00021_check_for_deleted_list_in_update_lists_card_quantities.up.sql

@@ -0,0 +1,62 @@
+CREATE OR REPLACE FUNCTION update_lists_card_quantities()
+	RETURNS TRIGGER
+AS $update_lists_card_quantities$
+DECLARE
+	update_card_id TEXT;
+	update_list_id INT;
+	new_quantity INT;
+	new_foil_quantity INT;
+BEGIN
+	-- get card_id and list_id of the lists_card_quantities row to insert/update
+	IF (TG_OP = 'DELETE') THEN
+		update_card_id = OLD.card_id;
+		update_list_id = OLD.list_id;
+	ELSE
+		update_card_id = NEW.card_id;
+		update_list_id = NEW.list_id;
+	END IF;
+
+	-- don't proceed if the list was deleted (this function does get called in response
+	-- to list deletions due to the DELETE CASCADE table relationships)
+	IF NOT EXISTS (SELECT 1 FROM lists WHERE id = update_list_id) THEN
+		RETURN NULL;
+	END IF;
+
+	-- get quantities for both foil and non-foil to insert/update in the lists_card_quantities row
+
+	SELECT COALESCE(SUM(cl.quantity), 0) INTO STRICT new_quantity
+	FROM collection cl
+	WHERE cl.card_id = update_card_id
+	      AND cl.list_id = update_list_id;
+
+	SELECT COALESCE(SUM(cl.quantity), 0) INTO STRICT new_foil_quantity
+	FROM collection cl
+	WHERE cl.card_id = update_card_id
+	      AND cl.list_id = update_list_id
+	      AND cl.foil = TRUE;
+
+	-- poor man's upsert equivalent
+	LOOP
+		UPDATE lists_card_quantities
+		SET quantity = new_quantity,
+			foil_quantity = new_foil_quantity
+		WHERE card_id = update_card_id
+		      AND list_id = update_list_id;
+		IF FOUND THEN
+			-- update succeeded (existing row was present). exit loop
+			RETURN NULL;
+		END IF;
+
+		-- if we get here, an existing row was not present so we should try to insert one
+		BEGIN
+			INSERT INTO lists_card_quantities (card_id, list_id, quantity, foil_quantity)
+			VALUES (update_card_id, update_list_id, new_quantity, new_foil_quantity);
+			-- insert succeeded. exit loop
+			RETURN NULL;
+			EXCEPTION WHEN UNIQUE_VIOLATION THEN
+			-- insert failed because another operation finished first.
+			-- do nothing and just loop and retry the update
+		END;
+	END LOOP;
+END;
+$update_lists_card_quantities$ LANGUAGE plpgsql;