fix(converter): restrict ColourConverter to valid factory methods

changelog/1488.bugfix.rst

@@ -0,0 +1 @@
+Fix :class:`~disnake.ext.commands.ColourConverter` accepting ``classmethod`` names that do not return :class:`Colour`, for example ``holographic_style``.

disnake/colour.py

@@ -328,6 +328,9 @@ def dark_embed(cls) -> Self:
         """
         return cls(0x2B2D31)
 
+    # NOTE: when adding new factory methods, also update _COLOUR_FACTORY_NAMES
+    # in disnake/ext/commands/converter.py
+
     @classmethod
     def holographic_style(cls) -> tuple[Self, Self, Self]:
         """A factory method that returns a tuple of :class:`Colour` with values of

disnake/ext/commands/converter.py

@@ -669,6 +669,50 @@ async def convert(self, ctx: AnyContext, argument: str) -> disnake.Thread:
         return GuildChannelConverter._resolve_thread(ctx, argument, "threads", disnake.Thread)
 
 
+# set of Colour.xyz() method names supported by ColourConverter
+_COLOUR_FACTORY_NAMES: frozenset[str] = frozenset(
+    {
+        "default",
+        "random",
+        "teal",
+        "dark_teal",
+        "brand_green",
+        "green",
+        "dark_green",
+        "blue",
+        "dark_blue",
+        "purple",
+        "dark_purple",
+        "magenta",
+        "dark_magenta",
+        "gold",
+        "dark_gold",
+        "orange",
+        "dark_orange",
+        "brand_red",
+        "red",
+        "dark_red",
+        "lighter_grey",
+        "lighter_gray",
+        "dark_grey",
+        "dark_gray",
+        "light_grey",
+        "light_gray",
+        "darker_grey",
+        "darker_gray",
+        "og_blurple",
+        "old_blurple",
+        "blurple",
+        "greyple",
+        "dark_theme",
+        "fuchsia",
+        "yellow",
+        "light_embed",
+        "dark_embed",
+    }
+)
+
+
 class ColourConverter(Converter[disnake.Colour]):
     """Converts to a :class:`~disnake.Colour`.
 
@@ -748,10 +792,9 @@ async def convert(self, ctx: AnyContext, argument: str) -> disnake.Color:
             return self.parse_rgb(arg)
 
         arg = arg.replace(" ", "_")
-        method = getattr(disnake.Colour, arg, None)
-        if arg.startswith("from_") or method is None or not inspect.ismethod(method):
+        if arg not in _COLOUR_FACTORY_NAMES:
             raise BadColourArgument(arg)
-        return method()
+        return getattr(disnake.Colour, arg)()
 
 
 ColorConverter = ColourConverter

tests/ext/commands/test_converter.py

@@ -0,0 +1,70 @@
+# SPDX-License-Identifier: MIT
+
+from unittest import mock
+
+import pytest
+
+import disnake
+from disnake.ext.commands import BadColourArgument
+from disnake.ext.commands.converter import ColourConverter
+
+
+@pytest.fixture
+def converter() -> ColourConverter:
+    return ColourConverter()
+
+
+@pytest.fixture
+def ctx() -> mock.Mock:
+    return mock.Mock()
+
+
+class TestColourConverter:
+    @pytest.mark.asyncio
+    @pytest.mark.parametrize(
+        ("arg", "expected_value"),
+        [
+            ("red", 0xE74C3C),
+            ("dark_green", 0x1F8B4C),
+            ("blurple", 0x5865F2),
+            ("dark theme", 0x313338),
+            ("og blurple", 0x7289DA),
+        ],
+    )
+    async def test_valid_colour_names(
+        self, converter: ColourConverter, ctx: mock.Mock, arg: str, expected_value: int
+    ) -> None:
+        result = await converter.convert(ctx, arg)
+        assert isinstance(result, disnake.Colour)
+        assert result.value == expected_value
+
+    @pytest.mark.asyncio
+    @pytest.mark.parametrize(
+        "arg",
+        [
+            "holographic_style",
+            "holographic style",
+            "from_rgb",
+            "from_hsv",
+            "from_hex",
+            "to_rgb",
+            "value",
+            "__init__",
+            "nonexistent",
+        ],
+    )
+    async def test_invalid_colour_names(
+        self, converter: ColourConverter, ctx: mock.Mock, arg: str
+    ) -> None:
+        with pytest.raises(BadColourArgument):
+            await converter.convert(ctx, arg)
+
+    @pytest.mark.asyncio
+    async def test_hex_format(self, converter: ColourConverter, ctx: mock.Mock) -> None:
+        result = await converter.convert(ctx, "#ff0000")
+        assert result.value == 0xFF0000
+
+    @pytest.mark.asyncio
+    async def test_rgb_format(self, converter: ColourConverter, ctx: mock.Mock) -> None:
+        result = await converter.convert(ctx, "rgb(255, 0, 0)")
+        assert result.value == 0xFF0000