Add type hints

Tests/helper.py

@@ -101,6 +101,7 @@ def assert_image_equal_tofile(
     msg: str | None = None,
     mode: str | None = None,
 ) -> None:
+    img: Image.Image
     with Image.open(filename) as img:
         if mode:
             img = img.convert(mode)
@@ -144,6 +145,7 @@ def assert_image_similar_tofile(
     epsilon: float,
     msg: str | None = None,
 ) -> None:
+    img: Image.Image
     with Image.open(filename) as img:
         assert_image_similar(a, img, epsilon, msg)
 

Tests/test_bmp_reference.py

@@ -94,8 +94,11 @@ def get_compare(f: str) -> str:
 
     for f in get_files("g"):
         try:
+            im: Image.Image
             with Image.open(f) as im:
                 im.load()
+
+                compare: Image.Image
                 with Image.open(get_compare(f)) as compare:
                     compare.load()
                     if im.mode == "P":

Tests/test_file_apng.py

@@ -277,25 +277,25 @@ def test_apng_mode() -> None:
         assert isinstance(im, PngImagePlugin.PngImageFile)
         assert im.mode == "P"
         im.seek(im.n_frames - 1)
-        im = im.convert("RGB")
-        assert im.getpixel((0, 0)) == (0, 255, 0)
-        assert im.getpixel((64, 32)) == (0, 255, 0)
+        rgb_im = im.convert("RGB")
+        assert rgb_im.getpixel((0, 0)) == (0, 255, 0)
+        assert rgb_im.getpixel((64, 32)) == (0, 255, 0)
 
     with Image.open("Tests/images/apng/mode_palette_alpha.png") as im:
         assert isinstance(im, PngImagePlugin.PngImageFile)
         assert im.mode == "P"
         im.seek(im.n_frames - 1)
-        im = im.convert("RGBA")
-        assert im.getpixel((0, 0)) == (0, 255, 0, 255)
-        assert im.getpixel((64, 32)) == (0, 255, 0, 255)
+        rgb_im = im.convert("RGBA")
+        assert rgb_im.getpixel((0, 0)) == (0, 255, 0, 255)
+        assert rgb_im.getpixel((64, 32)) == (0, 255, 0, 255)
 
     with Image.open("Tests/images/apng/mode_palette_1bit_alpha.png") as im:
         assert isinstance(im, PngImagePlugin.PngImageFile)
         assert im.mode == "P"
         im.seek(im.n_frames - 1)
-        im = im.convert("RGBA")
-        assert im.getpixel((0, 0)) == (0, 0, 255, 128)
-        assert im.getpixel((64, 32)) == (0, 0, 255, 128)
+        rgb_im = im.convert("RGBA")
+        assert rgb_im.getpixel((0, 0)) == (0, 0, 255, 128)
+        assert rgb_im.getpixel((64, 32)) == (0, 0, 255, 128)
 
 
 def test_apng_chunk_errors() -> None:

Tests/test_file_avif.py

@@ -14,6 +14,7 @@
 
 from PIL import (
     AvifImagePlugin,
+    GifImagePlugin,
     Image,
     ImageDraw,
     ImageFile,
@@ -220,6 +221,7 @@ def test_file_pointer_could_be_reused(self) -> None:
     def test_background_from_gif(self, tmp_path: Path) -> None:
         with Image.open("Tests/images/chi.gif") as im:
             original_value = im.convert("RGB").getpixel((1, 1))
+            assert isinstance(original_value, tuple)
 
             # Save as AVIF
             out_avif = tmp_path / "temp.avif"
@@ -232,6 +234,7 @@ def test_background_from_gif(self, tmp_path: Path) -> None:
 
         with Image.open(out_gif) as reread:
             reread_value = reread.convert("RGB").getpixel((1, 1))
+        assert isinstance(reread_value, tuple)
         difference = sum([abs(original_value[i] - reread_value[i]) for i in range(3)])
         assert difference <= 6
 
@@ -240,6 +243,7 @@ def test_save_single_frame(self, tmp_path: Path) -> None:
         with Image.open("Tests/images/chi.gif") as im:
             im.save(temp_file)
         with Image.open(temp_file) as im:
+            assert isinstance(im, AvifImagePlugin.AvifImageFile)
             assert im.n_frames == 1
 
     def test_invalid_file(self) -> None:
@@ -598,10 +602,12 @@ def test_n_frames(self) -> None:
         """
 
         with Image.open(TEST_AVIF_FILE) as im:
+            assert isinstance(im, AvifImagePlugin.AvifImageFile)
             assert im.n_frames == 1
             assert not im.is_animated
 
         with Image.open("Tests/images/avif/star.avifs") as im:
+            assert isinstance(im, AvifImagePlugin.AvifImageFile)
             assert im.n_frames == 5
             assert im.is_animated
 
@@ -612,11 +618,13 @@ def test_write_animation_P(self, tmp_path: Path) -> None:
         """
 
         with Image.open("Tests/images/avif/star.gif") as original:
+            assert isinstance(original, GifImagePlugin.GifImageFile)
             assert original.n_frames > 1
 
             temp_file = tmp_path / "temp.avif"
             original.save(temp_file, save_all=True)
             with Image.open(temp_file) as im:
+                assert isinstance(im, AvifImagePlugin.AvifImageFile)
                 assert im.n_frames == original.n_frames
 
                 # Compare first frame in P mode to frame from original GIF
@@ -636,6 +644,7 @@ def test_write_animation_RGBA(self, tmp_path: Path) -> None:
 
         def check(temp_file: Path) -> None:
             with Image.open(temp_file) as im:
+                assert isinstance(im, AvifImagePlugin.AvifImageFile)
                 assert im.n_frames == 4
 
                 # Compare first frame to original
@@ -708,6 +717,7 @@ def test_timestamp_and_duration(self, tmp_path: Path) -> None:
             )
 
         with Image.open(temp_file) as im:
+            assert isinstance(im, AvifImagePlugin.AvifImageFile)
             assert im.n_frames == 5
             assert im.is_animated
 
@@ -737,6 +747,7 @@ def test_seeking(self, tmp_path: Path) -> None:
             )
 
         with Image.open(temp_file) as im:
+            assert isinstance(im, AvifImagePlugin.AvifImageFile)
             assert im.n_frames == 5
             assert im.is_animated
 

Tests/test_file_bmp.py

@@ -160,9 +160,9 @@ def test_save_dib(tmp_path: Path) -> None:
 def test_rgba_bitfields() -> None:
     # This test image has been manually hexedited
     # to change the bitfield compression in the header from XBGR to RGBA
-    with Image.open("Tests/images/rgb32bf-rgba.bmp") as im:
+    with Image.open("Tests/images/rgb32bf-rgba.bmp") as bmp_im:
         # So before the comparing the image, swap the channels
-        b, g, r = im.split()[1:]
+        b, g, r = bmp_im.split()[1:]
         im = Image.merge("RGB", (r, g, b))
 
     assert_image_equal_tofile(im, "Tests/images/bmp/q/rgb32bf-xbgr.bmp")

Tests/test_file_bufrstub.py

@@ -61,6 +61,7 @@ def open(self, im: ImageFile.StubImageFile) -> None:
 
         def load(self, im: ImageFile.StubImageFile) -> Image.Image:
             self.loaded = True
+            assert im.fp is not None
             im.fp.close()
             return Image.new("RGB", (1, 1))
 

Tests/test_file_cur.py

@@ -26,6 +26,7 @@ def test_invalid_file() -> None:
     no_cursors_file = "Tests/images/no_cursors.cur"
 
     cur = CurImagePlugin.CurImageFile(TEST_FILE)
+    assert cur.fp is not None
     cur.fp.close()
     with open(no_cursors_file, "rb") as cur.fp:
         with pytest.raises(TypeError):

Tests/test_file_dds.py

@@ -56,6 +56,7 @@
 )
 def test_sanity_dxt1_bc1(image_path: str) -> None:
     """Check DXT1 and BC1 images can be opened"""
+    target: Image.Image
     with Image.open(TEST_FILE_DXT1.replace(".dds", ".png")) as target:
         target = target.convert("RGBA")
     with Image.open(image_path) as im:
@@ -504,9 +505,9 @@ def test_save_dxt5(tmp_path: Path) -> None:
 
 def test_save_dx10_bc5(tmp_path: Path) -> None:
     out = tmp_path / "temp.dds"
-    with Image.open(TEST_FILE_DX10_BC5_TYPELESS) as im:
-        im.save(out, pixel_format="BC5")
-    assert_image_similar_tofile(im, out, 9.56)
+    with Image.open(TEST_FILE_DX10_BC5_TYPELESS) as img:
+        img.save(out, pixel_format="BC5")
+    assert_image_similar_tofile(img, out, 9.56)
 
     im = hopper("L")
     with pytest.raises(OSError, match="only RGB mode can be written as BC5"):

Tests/test_file_eps.py

@@ -256,8 +256,8 @@ def test_bytesio_object() -> None:
     with Image.open(img_bytes) as img:
         img.load()
 
-        with Image.open(FILE1_COMPARE) as image1_scale1_compare:
-            image1_scale1_compare = image1_scale1_compare.convert("RGB")
+        with Image.open(FILE1_COMPARE) as im:
+            image1_scale1_compare = im.convert("RGB")
         image1_scale1_compare.load()
         assert_image_similar(img, image1_scale1_compare, 5)
 
@@ -292,16 +292,16 @@ def test_render_scale1() -> None:
     # Zero bounding box
     with Image.open(FILE1) as image1_scale1:
         image1_scale1.load()
-        with Image.open(FILE1_COMPARE) as image1_scale1_compare:
-            image1_scale1_compare = image1_scale1_compare.convert("RGB")
+        with Image.open(FILE1_COMPARE) as im:
+            image1_scale1_compare = im.convert("RGB")
         image1_scale1_compare.load()
         assert_image_similar(image1_scale1, image1_scale1_compare, 5)
 
     # Non-zero bounding box
     with Image.open(FILE2) as image2_scale1:
         image2_scale1.load()
-        with Image.open(FILE2_COMPARE) as image2_scale1_compare:
-            image2_scale1_compare = image2_scale1_compare.convert("RGB")
+        with Image.open(FILE2_COMPARE) as im:
+            image2_scale1_compare = im.convert("RGB")
         image2_scale1_compare.load()
         assert_image_similar(image2_scale1, image2_scale1_compare, 10)
 
@@ -315,17 +315,17 @@ def test_render_scale2() -> None:
     with Image.open(FILE1) as image1_scale2:
         assert isinstance(image1_scale2, EpsImagePlugin.EpsImageFile)
         image1_scale2.load(scale=2)
-        with Image.open(FILE1_COMPARE_SCALE2) as image1_scale2_compare:
-            image1_scale2_compare = image1_scale2_compare.convert("RGB")
+        with Image.open(FILE1_COMPARE_SCALE2) as im:
+            image1_scale2_compare = im.convert("RGB")
         image1_scale2_compare.load()
         assert_image_similar(image1_scale2, image1_scale2_compare, 5)
 
     # Non-zero bounding box
     with Image.open(FILE2) as image2_scale2:
         assert isinstance(image2_scale2, EpsImagePlugin.EpsImageFile)
         image2_scale2.load(scale=2)
-        with Image.open(FILE2_COMPARE_SCALE2) as image2_scale2_compare:
-            image2_scale2_compare = image2_scale2_compare.convert("RGB")
+        with Image.open(FILE2_COMPARE_SCALE2) as im:
+            image2_scale2_compare = im.convert("RGB")
         image2_scale2_compare.load()
         assert_image_similar(image2_scale2, image2_scale2_compare, 10)
 
@@ -335,9 +335,9 @@ def test_render_scale2() -> None:
     "filename", (FILE1, FILE2, "Tests/images/eps/illu10_preview.eps")
 )
 def test_resize(filename: str) -> None:
-    with Image.open(filename) as im:
+    with Image.open(filename) as img:
         new_size = (100, 100)
-        im = im.resize(new_size)
+        im = img.resize(new_size)
         assert im.size == new_size
 
 

Tests/test_file_fli.py

@@ -48,13 +48,16 @@ def test_sanity() -> None:
 def test_prefix_chunk(monkeypatch: pytest.MonkeyPatch) -> None:
     monkeypatch.setattr(ImageFile, "LOAD_TRUNCATED_IMAGES", True)
     with Image.open(animated_test_file_with_prefix_chunk) as im:
+        assert isinstance(im, FliImagePlugin.FliImageFile)
+
         assert im.mode == "P"
         assert im.size == (320, 200)
         assert im.format == "FLI"
         assert im.info["duration"] == 171
         assert im.is_animated
 
         palette = im.getpalette()
+        assert palette is not None
         assert palette[3:6] == [255, 255, 255]
         assert palette[381:384] == [204, 204, 12]
         assert palette[765:] == [252, 0, 0]

Tests/test_file_gif.py

@@ -281,6 +281,7 @@ def test_roundtrip_save_all(tmp_path: Path) -> None:
         im.save(out, save_all=True)
 
     with Image.open(out) as reread:
+        assert isinstance(reread, GifImagePlugin.GifImageFile)
         assert reread.n_frames == 5
 
 
@@ -306,6 +307,7 @@ def test_roundtrip_save_all_1(tmp_path: Path) -> None:
     ),
 )
 def test_loading_multiple_palettes(path: str, mode: str) -> None:
+    im: Image.Image
     with Image.open(path) as im:
         assert im.mode == "P"
         assert im.palette is not None
@@ -339,7 +341,7 @@ def test_headers_saving_for_animated_gifs(tmp_path: Path) -> None:
 
 def test_palette_handling(tmp_path: Path) -> None:
     # see https://github.com/python-pillow/Pillow/issues/513
-
+    im: Image.Image
     with Image.open(TEST_GIF) as im:
         im = im.convert("RGB")
 
@@ -363,8 +365,8 @@ def roundtrip(im: Image.Image, **kwargs: bool) -> Image.Image:
 
         return reloaded
 
-    orig = "Tests/images/test.colors.gif"
-    with Image.open(orig) as im:
+    im: Image.Image
+    with Image.open("Tests/images/test.colors.gif") as im:
         with roundtrip(im) as reloaded:
             assert_image_similar(im, reloaded, 1)
         with roundtrip(im, optimize=True) as reloaded:
@@ -379,6 +381,7 @@ def roundtrip(im: Image.Image, **kwargs: bool) -> Image.Image:
 
 @pytest.mark.skipif(not netpbm_available(), reason="Netpbm not available")
 def test_save_netpbm_bmp_mode(tmp_path: Path) -> None:
+    img: Image.Image
     with Image.open(TEST_GIF) as img:
         img = img.convert("RGB")
 
@@ -391,6 +394,7 @@ def test_save_netpbm_bmp_mode(tmp_path: Path) -> None:
 
 @pytest.mark.skipif(not netpbm_available(), reason="Netpbm not available")
 def test_save_netpbm_l_mode(tmp_path: Path) -> None:
+    img: Image.Image
     with Image.open(TEST_GIF) as img:
         img = img.convert("L")
 
@@ -1020,9 +1024,9 @@ def test_webp_background(tmp_path: Path) -> None:
 
     # Test opaque WebP background
     if features.check("webp"):
-        with Image.open("Tests/images/hopper.webp") as im:
-            assert im.info["background"] == (255, 255, 255, 255)
-            im.save(out)
+        with Image.open("Tests/images/hopper.webp") as img:
+            assert img.info["background"] == (255, 255, 255, 255)
+            img.save(out)
 
     # Test non-opaque WebP background
     im = Image.new("L", (100, 100), "#000")
@@ -1031,6 +1035,7 @@ def test_webp_background(tmp_path: Path) -> None:
 
 
 def test_comment(tmp_path: Path) -> None:
+    im: Image.Image
     with Image.open(TEST_GIF) as im:
         assert im.info["comment"] == b"File written by Adobe Photoshop\xa8 4.0"
 
@@ -1361,6 +1366,7 @@ def test_palette_save_all_P(tmp_path: Path) -> None:
     with Image.open(out) as im:
         # Assert that the frames are correct, and each frame has the same palette
         assert_image_equal(im.convert("RGB"), frames[0].convert("RGB"))
+        assert isinstance(im, GifImagePlugin.GifImageFile)
         assert im.palette is not None
         assert im.global_palette is not None
         assert im.palette.palette == im.global_palette.palette

Tests/test_file_gribstub.py

@@ -59,8 +59,9 @@ class TestHandler(ImageFile.StubHandler):
         def open(self, im: Image.Image) -> None:
             self.opened = True
 
-        def load(self, im: Image.Image) -> Image.Image:
+        def load(self, im: ImageFile.ImageFile) -> Image.Image:
             self.loaded = True
+            assert im.fp is not None
             im.fp.close()
             return Image.new("RGB", (1, 1))
 

Tests/test_file_hdf5stub.py

@@ -61,8 +61,9 @@ class TestHandler(ImageFile.StubHandler):
         def open(self, im: Image.Image) -> None:
             self.opened = True
 
-        def load(self, im: Image.Image) -> Image.Image:
+        def load(self, im: ImageFile.ImageFile) -> Image.Image:
             self.loaded = True
+            assert im.fp is not None
             im.fp.close()
             return Image.new("RGB", (1, 1))
 

Tests/test_file_iptc.py

@@ -31,7 +31,7 @@ def test_getiptcinfo_jpg_none() -> None:
     # Arrange
     with hopper() as im:
         # Act
-        iptc = IptcImagePlugin.getiptcinfo(im)
+        iptc = IptcImagePlugin.getiptcinfo(im)  # type: ignore[arg-type]
 
     # Assert
     assert iptc is None