Bring back removed features, add deprecations and Release notes

Tests/test_features.py

@@ -46,6 +46,18 @@ def test(name: str, function: Callable[[str], str | None]) -> None:
         test(feature, features.version_feature)
 
 
+def test_webp_transparency() -> None:
+    assert features.check("transp_webp") == features.check_module("webp")
+
+
+def test_webp_mux() -> None:
+    assert features.check("webp_mux") == features.check_module("webp")
+
+
+def test_webp_anim() -> None:
+    assert features.check("webp_anim") == features.check_module("webp")
+
+
 @skip_unless_feature("libjpeg_turbo")
 def test_libjpeg_turbo_version() -> None:
     version = features.version("libjpeg_turbo")

docs/reference/features.rst

@@ -57,6 +57,9 @@ Support for the following features can be checked:
 * ``raqm``: Raqm library, required for ``ImageFont.Layout.RAQM`` in :py:func:`PIL.ImageFont.truetype`. Run-time version number is available for Raqm 0.7.0 or newer.
 * ``libimagequant``: (compile time) ImageQuant quantization support in :py:func:`PIL.Image.Image.quantize`. Run-time version number is available.
 * ``xcb``: (compile time) Support for X11 in :py:func:`PIL.ImageGrab.grab` via the XCB library.
+* ``transp_webp``: Deprecated. Always ``True`` if WebP module is installed.
+* ``webp_mux``: Deprecated. Always ``True`` if WebP module is installed.
+* ``webp_anim``: Deprecated. Always ``True`` if WebP module is installed.
 
 .. autofunction:: PIL.features.check_feature
 .. autofunction:: PIL.features.version_feature

docs/releasenotes/11.0.0.rst

@@ -43,10 +43,13 @@ similarly removed.
 Deprecations
 ============
 
-TODO
-^^^^
+WebP Features Test
+^^^^^^^^^^^^^^^^^^
 
-TODO
+The following features ``features.check("transp_webp")``,
+``features.check("webp_mux")``, and ``features.check("webp_anim")`` are now 
+always ``True`` if the WebP module is installed and sohuld not be used.
+These checks wil be removed in Pillow 12.0.0 (2025-10-15).
 
 API Changes
 ===========

src/PIL/features.py

@@ -7,6 +7,7 @@
 from typing import IO
 
 import PIL
+from PIL import _deprecate
 
 from . import Image
 
@@ -119,6 +120,9 @@ def get_supported_codecs() -> list[str]:
 
 
 features = {
+    "webp_anim": ("PIL._webp", True, None),
+    "webp_mux": ("PIL._webp", True, None),
+    "transp_webp": ("PIL._webp", True, None),
     "raqm": ("PIL._imagingft", "HAVE_RAQM", "raqm_version"),
     "fribidi": ("PIL._imagingft", "HAVE_FRIBIDI", "fribidi_version"),
     "harfbuzz": ("PIL._imagingft", "HAVE_HARFBUZZ", "harfbuzz_version"),
@@ -144,7 +148,11 @@ def check_feature(feature: str) -> bool | None:
 
     try:
         imported_module = __import__(module, fromlist=["PIL"])
-        return getattr(imported_module, flag)
+        if isinstance(flag, str):
+            return getattr(imported_module, flag)
+        else:
+            _deprecate.deprecate(f'check_feature("{feature}")', 12)
+            return flag
     except ModuleNotFoundError:
         return None
     except ImportError as ex: