Merge pull request #2633 from Matiiss/matiiss-improve-window-flip-err…

…-msg

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

src_c/window.c

@@ -183,11 +183,18 @@ window_flip(pgWindowObject *self)
 {
     int result;
 
+    if (!self->surf) {
+        return RAISE(pgExc_SDLError,
+                     "the Window has no surface associated with it, did "
+                     "you forget to call Window.get_surface()");
+    }
+
     Py_BEGIN_ALLOW_THREADS;
     result = SDL_UpdateWindowSurface(self->_win);
     Py_END_ALLOW_THREADS;
-    if (result)
+    if (result) {
         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()