Try every event database file on delete and say which was left (closes #275)

DeleteDB returned on the first event database file it failed to remove, so with WAL sidecars present a failure could be reported as "the file was left behind" after the events themselves were already gone. It now tries the database file and both sidecars, and its error says which case happened and names each file left: the database file is still on disk, or it is gone (the events are lost) and only a -wal or -shm sidecar remains. The webhook delete handler logs a different message for each and never says the events survive when they do not. Tests cover a normal delete with both sidecars, and a failed removal of the database file or a sidecar, through DeleteDB and the handler.

Model: opus-5-5

internal/database/webhook_db_manager.go

@@ -33,6 +33,19 @@ var errInvalidCachedDBType = errors.New(
 	"invalid cached database type",
 )
 
+// ErrEventDBNotRemoved is in DeleteDB's error when the event
+// database file itself could not be removed: it is still on disk.
+var ErrEventDBNotRemoved = errors.New(
+	"event database file not removed",
+)
+
+// ErrSidecarNotRemoved is in DeleteDB's error when the event
+// database file was removed, so its events are gone, but its -wal
+// or -shm sidecar could not be.
+var ErrSidecarNotRemoved = errors.New(
+	"event database file removed, but a -wal or -shm sidecar was not",
+)
+
 // WebhookDBManager manages per-webhook SQLite database files
 // for event storage. Each webhook gets its own dedicated
 // database containing Events, Deliveries, DeliveryResults and the
@@ -151,7 +164,10 @@ func (m *WebhookDBManager) DBExists(
 }
 
 // DeleteDB closes the connection and deletes the database file
-// for a webhook. The file is permanently removed.
+// for a webhook, with its -wal and -shm sidecars. The files are
+// permanently removed. Each file is tried even when another could
+// not be removed, and the error wraps ErrEventDBNotRemoved or
+// ErrSidecarNotRemoved to say which was left, naming each file.
 func (m *WebhookDBManager) DeleteDB(
 	webhookID string,
 ) error {
@@ -170,16 +186,23 @@ func (m *WebhookDBManager) DeleteDB(
 		}
 	}
 
-	// Delete the main DB file and WAL/SHM files
 	path := m.dbPath(webhookID)
-	for _, suffix := range []string{"", "-wal", "-shm"} {
-		err := os.Remove(path + suffix)
-		if err != nil && !os.IsNotExist(err) {
-			return fmt.Errorf(
-				"deleting webhook database file %s%s: %w",
-				path, suffix, err,
-			)
-		}
+
+	dbErr := removeFile(path)
+	sidecarErr := errors.Join(
+		removeFile(path+"-wal"),
+		removeFile(path+"-shm"),
+	)
+
+	if dbErr != nil {
+		return fmt.Errorf(
+			"%w: %w",
+			ErrEventDBNotRemoved, errors.Join(dbErr, sidecarErr),
+		)
+	}
+
+	if sidecarErr != nil {
+		return fmt.Errorf("%w: %w", ErrSidecarNotRemoved, sidecarErr)
 	}
 
 	m.log.Info(
@@ -190,6 +213,17 @@ func (m *WebhookDBManager) DeleteDB(
 	return nil
 }
 
+// removeFile removes path. A file that is already gone counts as
+// removed; the error from any other failure names the file.
+func removeFile(path string) error {
+	err := os.Remove(path)
+	if errors.Is(err, os.ErrNotExist) {
+		return nil
+	}
+
+	return err
+}
+
 // CloseAll closes all open per-webhook database connections.
 // Called during application shutdown.
 func (m *WebhookDBManager) CloseAll() error {