Suggestions for deprecating older WebP versions

Tests/test_features.py

@@ -18,7 +18,11 @@ def test_check() -> None:
     for codec in features.codecs:
         assert features.check_codec(codec) == features.check(codec)
     for feature in features.features:
-        assert features.check_feature(feature) == features.check(feature)
+        if "webp" in feature:
+            with pytest.warns(DeprecationWarning):
+                assert features.check_feature(feature) == features.check(feature)
+        else:
+            assert features.check_feature(feature) == features.check(feature)
 
 
 def test_version() -> None:
@@ -43,19 +47,26 @@ def test(name: str, function: Callable[[str], str | None]) -> None:
     for codec in features.codecs:
         test(codec, features.version_codec)
     for feature in features.features:
-        test(feature, features.version_feature)
+        if "webp" in feature:
+            with pytest.warns(DeprecationWarning):
+                test(feature, features.version_feature)
+        else:
+            test(feature, features.version_feature)
 
 
 def test_webp_transparency() -> None:
-    assert features.check("transp_webp") == features.check_module("webp")
+    with pytest.warns(DeprecationWarning):
+        assert features.check("transp_webp") == features.check_module("webp")
 
 
 def test_webp_mux() -> None:
-    assert features.check("webp_mux") == features.check_module("webp")
+    with pytest.warns(DeprecationWarning):
+        assert features.check("webp_mux") == features.check_module("webp")
 
 
 def test_webp_anim() -> None:
-    assert features.check("webp_anim") == features.check_module("webp")
+    with pytest.warns(DeprecationWarning):
+        assert features.check("webp_anim") == features.check_module("webp")
 
 
 @skip_unless_feature("libjpeg_turbo")

Tests/test_file_webp.py

@@ -166,7 +166,7 @@ def test_WebPEncode_with_invalid_args(self) -> None:
         with pytest.raises(TypeError):
             _webp.WebPEncode()
 
-    def test_WebPDecode_with_invalid_args(self) -> None:
+    def test_WebPAnimDecoder_with_invalid_args(self) -> None:
         """
         Calling decoder functions with no arguments should result in an error.
         """

Tests/test_file_webp_alpha.py

@@ -13,7 +13,7 @@
     hopper,
 )
 
-_webp = pytest.importorskip("PIL._webp", reason="WebP support not installed")
+pytest.importorskip("PIL._webp", reason="WebP support not installed")
 
 
 def test_read_rgba() -> None:

Tests/test_file_webp_lossless.py

@@ -8,7 +8,7 @@
 
 from .helper import assert_image_equal, hopper
 
-_webp = pytest.importorskip("PIL._webp", reason="WebP support not installed")
+pytest.importorskip("PIL._webp", reason="WebP support not installed")
 RGB_MODE = "RGB"
 
 

docs/deprecations.rst

@@ -126,6 +126,16 @@ JpegImageFile.huffman_ac and JpegImageFile.huffman_dc
 The ``huffman_ac`` and ``huffman_dc`` dictionaries on JPEG images were unused. They
 have been deprecated, and will be removed in Pillow 12 (2025-10-15).
 
+Specific WebP Feature Checks
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+.. deprecated:: 11.0.0
+
+``features.check("transp_webp")``, ``features.check("webp_mux")`` and
+``features.check("webp_anim")`` are now deprecated. They will always return
+``True`` if the WebP module is installed, until they are removed in Pillow
+12.0.0 (2025-10-15).
+
 Removed features
 ----------------
 

docs/releasenotes/11.0.0.rst

@@ -61,10 +61,10 @@ have been deprecated, and will be removed in Pillow 12 (2025-10-15).
 Specific WebP Feature Checks
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-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 should not be used.
-These checks will be removed in Pillow 12.0.0 (2025-10-15).
+``features.check("transp_webp")``, ``features.check("webp_mux")`` and
+``features.check("webp_anim")`` are now deprecated. They will always return
+``True`` if the WebP module is installed, until they are removed in Pillow
+12.0.0 (2025-10-15).
 
 API Changes
 ===========

setup.py

@@ -794,25 +794,17 @@ def build_extensions(self):
         if feature.want("webp"):
             _dbg("Looking for webp")
             if all(
-                _find_include_file(self, src)
-                for src in [
-                    "webp/encode.h",
-                    "webp/decode.h",
-                    "webp/mux.h",
-                    "webp/demux.h",
-                ]
+                _find_include_file(self, "webp/" + include)
+                for include in ("encode.h", "decode.h", "mux.h", "demux.h")
             ):
-                # In Google's precompiled zip it is call "libwebp":
-                if all(
-                    _find_library_file(self, lib)
-                    for lib in ["webp", "webpmux", "webpdemux"]
-                ):
-                    feature.webp = "webp"
-                elif all(
-                    _find_library_file(self, lib)
-                    for lib in ["libwebp", "libwebpmux", "libwebpdemux"]
-                ):
-                    feature.webp = "libwebp"
+                # In Google's precompiled zip it is called "libwebp"
+                for prefix in ("", "lib"):
+                    if all(
+                        _find_library_file(self, prefix + library)
+                        for library in ("webp", "webpmux", "webpdemux")
+                    ):
+                        feature.webp = prefix + "webp"
+                        break
 
         if feature.want("xcb"):
             _dbg("Looking for xcb")
@@ -901,12 +893,8 @@ def build_extensions(self):
             self._remove_extension("PIL._imagingcms")
 
         if feature.webp:
-            libs = [
-                feature.webp,
-                feature.webp + "mux",
-                feature.webp + "demux",
-            ]
-            self._update_extension("PIL._webp", libs, [])
+            libs = [feature.webp, feature.webp + "mux", feature.webp + "demux"]
+            self._update_extension("PIL._webp", libs)
         else:
             self._remove_extension("PIL._webp")
 

src/PIL/features.py

@@ -7,9 +7,9 @@
 from typing import IO
 
 import PIL
-from PIL import _deprecate
 
 from . import Image
+from ._deprecate import deprecate
 
 modules = {
     "pil": ("PIL._imaging", "PILLOW_VERSION"),
@@ -149,7 +149,7 @@ def check_feature(feature: str) -> bool | None:
     try:
         imported_module = __import__(module, fromlist=["PIL"])
         if isinstance(flag, bool):
-            _deprecate.deprecate(f'check_feature("{feature}")', 12)
+            deprecate(f'check_feature("{feature}")', 12)
             return flag
         return getattr(imported_module, flag)
     except ModuleNotFoundError:
@@ -180,7 +180,17 @@ def get_supported_features() -> list[str]:
     """
     :returns: A list of all supported features.
     """
-    return [f for f in features if check_feature(f)]
+    supported_features = []
+    for f, (module, flag, _) in features.items():
+        if flag is True:
+            for feature, (feature_module, _) in modules.items():
+                if feature_module == module:
+                    if check_module(feature):
+                        supported_features.append(f)
+                    break
+        elif check_feature(f):
+            supported_features.append(f)
+    return supported_features
 
 
 def check(feature: str) -> bool | None:

src/_webp.c

@@ -11,7 +11,7 @@
  * Check the versions from mux.h and demux.h, to ensure the WebPAnimEncoder and
  * WebPAnimDecoder APIs are present (initial support was added in 0.5.0). The
  * very early versions had some significant differences, so we require later
- * versions, before enabling animation support.
+ * versions.
  */
 #if WEBP_MUX_ABI_VERSION < 0x0106 || WEBP_DEMUX_ABI_VERSION < 0x0107
 #error libwebp 0.5.0 and above is required. Upgrade libwebp or build Pillow with --disable-webp flag