db: roll back the request transaction on handler panic

The middleware only committed or rolled back after the handler returned.
If the handler panicked, control jumped to the recoverer and the open
transaction was leaked. Add a deferred rollback that runs unless one of
the normal commit/rollback paths already handled it.

Signed-off-by: Robin Jarry <robin@jarry.cc>

Author: rjarry

pkg/db/middleware.go

@@ -52,7 +52,19 @@ func Middleware(database *bun.DB, bus EventBus) func(http.Handler) http.Handler
 			}
 			ctx = context.WithValue(ctx, queriesKey{}, q)
 			rw := &statusWriter{ResponseWriter: w}
+			// Ensure the transaction is rolled back if the handler
+			// panics (the panic then propagates to the recoverer);
+			// the normal paths below set handled and take over.
+			handled := false
+			defer func() {
+				if !handled {
+					if err := q.Rollback(); err != nil {
+						log.Printf("rollback: %v", err)
+					}
+				}
+			}()
 			next.ServeHTTP(rw, r.WithContext(ctx))
+			handled = true
 			if rw.status >= 400 {
 				if err := q.Rollback(); err != nil {
 					log.Printf("rollback: %v", err)