Improved Window.flip error message when no surface is associated with it

Author: Matiiss

src_c/window.c

@@ -183,11 +183,19 @@ window_flip(pgWindowObject *self)
 {
     int result;
 
+    VIDEO_INIT_CHECK();
+
     Py_BEGIN_ALLOW_THREADS;
     result = SDL_UpdateWindowSurface(self->_win);
     Py_END_ALLOW_THREADS;
-    if (result)
+    if (result) {
+        if (!self->surf) {
+            return RAISE(pgExc_SDLError,
+                         "the Window has no surface associated with it, did "
+                         "you forget to call Window.get_surface()");
+        }
         return RAISE(pgExc_SDLError, SDL_GetError());
+    }
     Py_RETURN_NONE;
 }
 

test/window_test.py

@@ -360,6 +360,15 @@ def test_window_flip(self):
         self.assertIs(win.flip(), None)
         win.destroy()
 
+        # creates a new window with no surface associated
+        win = Window(size=(640, 480))
+        self.assertRaisesRegex(
+            pygame.error,
+            "the Window has no surface associated with it, did you forget to call Window.get_surface()",
+            win.flip,
+        )
+        win.destroy()
+
     def tearDown(self):
         self.win.destroy()