Move check before

Author: damusss

src_c/transform.c

@@ -3266,6 +3266,11 @@ blur(pgSurfaceObject *srcobj, pgSurfaceObject *dstobj, int radius,
         retsurf = pgSurface_AsSurface(dstobj);
     }
 
+    if ((retsurf->w) != (src->w) || (retsurf->h) != (src->h)) {
+        return RAISE(PyExc_ValueError,
+                     "Destination surface not the same size.");
+    }
+    
     if (retsurf->w == 0 || retsurf->h == 0) {
         return retsurf;
     }
@@ -3283,11 +3288,6 @@ blur(pgSurfaceObject *srcobj, pgSurfaceObject *dstobj, int radius,
             "of them is a subsurface, or they are sharing the same buffer.");
     }
 
-    if ((retsurf->w) != (src->w) || (retsurf->h) != (src->h)) {
-        return RAISE(PyExc_ValueError,
-                     "Destination surface not the same size.");
-    }
-
     if (PG_SURF_BytesPerPixel(src) != PG_SURF_BytesPerPixel(retsurf)) {
         return (SDL_Surface *)(RAISE(
             PyExc_ValueError,