Start QOI decoding with a zero-initialized array of previously seen pixels (#9008)

Author: radarhere

Tests/images/op_index.qoi

@@ -28,3 +28,9 @@ def test_invalid_file() -> None:
 
     with pytest.raises(SyntaxError):
         QoiImagePlugin.QoiImageFile(invalid_file)
+
+
+def test_op_index() -> None:
+    # QOI_OP_INDEX as the first chunk
+    with Image.open("Tests/images/op_index.qoi") as im:
+        assert im.getpixel((0, 0)) == (0, 0, 0, 0)

Tests/test_file_qoi.py

@@ -51,7 +51,7 @@ def decode(self, buffer: bytes | Image.SupportsArrayInterface) -> tuple[int, int
         assert self.fd is not None
 
         self._previously_seen_pixels = {}
-        self._add_to_previous_pixels(bytearray((0, 0, 0, 255)))
+        self._previous_pixel = bytearray((0, 0, 0, 255))
 
         data = bytearray()
         bands = Image.getmodebands(self.mode)