Allow rawmode None to return the palette in the current mode

Tests/test_image_getpalette.py

@@ -25,9 +25,10 @@ def test_palette_rawmode():
     im = Image.new("P", (1, 1))
     im.putpalette((1, 2, 3))
 
-    rgb = im.getpalette("RGB")
-    assert len(rgb) == 256 * 3
-    assert rgb[:3] == [1, 2, 3]
+    for rawmode in ("RGB", None):
+        rgb = im.getpalette(rawmode)
+        assert len(rgb) == 256 * 3
+        assert rgb[:3] == [1, 2, 3]
 
     # Convert the RGB palette to RGBA
     rgba = im.getpalette("RGBA")
@@ -41,6 +42,7 @@ def test_palette_rawmode():
     assert len(rgb) == 256 * 3
     assert rgb[:3] == [1, 2, 3]
 
-    rgba = im.getpalette("RGBA")
-    assert len(rgba) == 256 * 4
-    assert rgba[:4] == [1, 2, 3, 4]
+    for rawmode in ("RGBA", None):
+        rgba = im.getpalette(rawmode)
+        assert len(rgba) == 256 * 4
+        assert rgba[:4] == [1, 2, 3, 4]

src/PIL/Image.py

@@ -1405,7 +1405,8 @@ def getpalette(self, rawmode="RGB"):
         """
         Returns the image palette as a list.
 
-        :param rawmode: The mode in which to return the palette.
+        :param rawmode: The mode in which to return the palette. ``None`` will
+        return the palette in its current mode.
         :returns: A list of color values [r, g, b, ...], or None if the
            image has no palette.
         """
@@ -1415,6 +1416,8 @@ def getpalette(self, rawmode="RGB"):
             mode = self.im.getpalettemode()
         except ValueError:
             return None  # no palette
+        if rawmode is None:
+            rawmode = mode
         return list(self.im.getpalette(mode, rawmode))
 
     def getpixel(self, xy):