Merge pull request #2276 from oddbookworm/zero_area_surface

fixed pixelarray indexing to prevent segfault reported in #2275

Author: MyreMylar

src_c/pixelarray.c

@@ -354,6 +354,10 @@ _pxarray_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
     stride0 = (Py_ssize_t)surf->format->BytesPerPixel;
     stride1 = (Py_ssize_t)surf->pitch;
     pixels = surf->pixels;
+    if (pixels == NULL) {
+        return RAISE(PyExc_ValueError,
+                     "Cannot create pixelarray on zero-sized Surface");
+    }
     if (stride0 < 1 || stride0 > 4) {
         return RAISE(PyExc_ValueError,
                      "unsupported bit depth for reference array");

src_c/pixelarray_methods.c

@@ -102,7 +102,6 @@ _get_single_pixel(pgPixelArrayObject *array, Py_ssize_t x, Py_ssize_t y)
     if (array->surface == NULL) {
         return RAISE(PyExc_ValueError, "Operation on closed PixelArray.");
     }
-
     pixel_p = (array->pixels + x * array->strides[0] + y * array->strides[1]);
     surf = pgSurface_AsSurface(array->surface);
 

test/pixelarray_test.py

@@ -1309,6 +1309,16 @@ def test_repr(self):
         pixel = sf.get_at_mapped((0, 0))
         self.assertEqual(repr(ar), type(ar).__name__ + "([\n  [42, 42, 42]]\n)")
 
+    def test_zero_size_surface(self):
+        """Should not be able to create PixelArray on a surface with a width or height of 0
+        Regression test for pygame-ce issue 2275 (https://github.com/pygame-community/pygame-ce/issues/2275)
+        """
+        weird_surface = pygame.Surface((5, 0))
+        self.assertRaises(ValueError, lambda: pygame.PixelArray(weird_surface))
+
+        weird_surface = pygame.Surface((0, 5))
+        self.assertRaises(ValueError, lambda: pygame.PixelArray(weird_surface))
+
 
 @unittest.skipIf(IS_PYPY, "pypy having issues")
 class PixelArrayArrayInterfaceTest(unittest.TestCase, TestMixin):