Use different variables for Image and ImageFile instances (#9316)

Author: radarhere

Tests/helper.py

@@ -104,10 +104,9 @@ def assert_image_equal_tofile(
     msg: str | None = None,
     mode: str | None = None,
 ) -> None:
-    with Image.open(filename) as img:
-        if mode:
-            img = img.convert(mode)
-        assert_image_equal(a, img, msg)
+    with Image.open(filename) as im:
+        converted_im = im.convert(mode) if mode else im
+        assert_image_equal(a, converted_im, msg)
 
 
 def assert_image_similar(

Tests/test_bmp_reference.py

@@ -95,16 +95,16 @@ def get_compare(f: str) -> str:
     for f in get_files("g"):
         try:
             with Image.open(f) as im:
-                im.load()
                 with Image.open(get_compare(f)) as compare:
-                    compare.load()
-                    if im.mode == "P":
-                        # assert image similar doesn't really work
-                        # with paletized image, since the palette might
-                        # be differently ordered for an equivalent image.
-                        im = im.convert("RGBA")
-                        compare = compare.convert("RGBA")
-                    assert_image_similar(im, compare, 5)
+                    # assert image similar doesn't really work
+                    # with paletized image, since the palette might
+                    # be differently ordered for an equivalent image.
+                    im_converted = im.convert("RGBA") if im.mode == "P" else im
+                    compare_converted = (
+                        compare.convert("RGBA") if im.mode == "P" else compare
+                    )
+
+                    assert_image_similar(im_converted, compare_converted, 5)
 
         except Exception as msg:
             # there are three here that are unsupported:

Tests/test_file_apng.py

@@ -278,25 +278,25 @@ 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)
+        im_rgb = im.convert("RGB")
+    assert im_rgb.getpixel((0, 0)) == (0, 255, 0)
+    assert im_rgb.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)
+        im_rgba = im.convert("RGBA")
+    assert im_rgba.getpixel((0, 0)) == (0, 255, 0, 255)
+    assert im_rgba.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)
+        im_rgba = im.convert("RGBA")
+    assert im_rgba.getpixel((0, 0)) == (0, 0, 255, 128)
+    assert im_rgba.getpixel((64, 32)) == (0, 0, 255, 128)
 
 
 def test_apng_chunk_errors() -> None:

Tests/test_file_bmp.py

@@ -165,9 +165,9 @@ def test_rgba_bitfields() -> None:
     with Image.open("Tests/images/rgb32bf-rgba.bmp") as im:
         # So before the comparing the image, swap the channels
         b, g, r = im.split()[1:]
-        im = Image.merge("RGB", (r, g, b))
+        im_rgb = Image.merge("RGB", (r, g, b))
 
-    assert_image_equal_tofile(im, "Tests/images/bmp/q/rgb32bf-xbgr.bmp")
+    assert_image_equal_tofile(im_rgb, "Tests/images/bmp/q/rgb32bf-xbgr.bmp")
 
     # This test image has been manually hexedited
     # to change the bitfield compression in the header from XBGR to ABGR

Tests/test_file_dds.py

@@ -57,15 +57,15 @@
 def test_sanity_dxt1_bc1(image_path: str) -> None:
     """Check DXT1 and BC1 images can be opened"""
     with Image.open(TEST_FILE_DXT1.replace(".dds", ".png")) as target:
-        target = target.convert("RGBA")
+        target_rgba = target.convert("RGBA")
     with Image.open(image_path) as im:
         im.load()
 
         assert im.format == "DDS"
         assert im.mode == "RGBA"
         assert im.size == (256, 256)
 
-        assert_image_equal(im, target)
+        assert_image_equal(im, target_rgba)
 
 
 def test_sanity_dxt3() -> None:
@@ -520,9 +520,9 @@ def test_save_dx10_bc5(tmp_path: Path) -> None:
         im.save(out, pixel_format="BC5")
     assert_image_similar_tofile(im, out, 9.56)
 
-    im = hopper("L")
+    im_l = hopper("L")
     with pytest.raises(OSError, match="only RGB mode can be written as BC5"):
-        im.save(out, pixel_format="BC5")
+        im_l.save(out, pixel_format="BC5")
 
 
 @pytest.mark.parametrize(

Tests/test_file_eps.py

@@ -265,9 +265,9 @@ def test_bytesio_object() -> None:
         img.load()
 
         with Image.open(FILE1_COMPARE) as image1_scale1_compare:
-            image1_scale1_compare = image1_scale1_compare.convert("RGB")
-        image1_scale1_compare.load()
-        assert_image_similar(img, image1_scale1_compare, 5)
+            image1_scale1_compare_rgb = image1_scale1_compare.convert("RGB")
+        image1_scale1_compare_rgb.load()
+        assert_image_similar(img, image1_scale1_compare_rgb, 5)
 
 
 @pytest.mark.skipif(not HAS_GHOSTSCRIPT, reason="Ghostscript not available")
@@ -301,17 +301,17 @@ def test_render_scale1() -> None:
     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")
-        image1_scale1_compare.load()
-        assert_image_similar(image1_scale1, image1_scale1_compare, 5)
+            image1_scale1_compare_rgb = image1_scale1_compare.convert("RGB")
+        image1_scale1_compare_rgb.load()
+        assert_image_similar(image1_scale1, image1_scale1_compare_rgb, 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")
-        image2_scale1_compare.load()
-        assert_image_similar(image2_scale1, image2_scale1_compare, 10)
+            image2_scale1_compare_rgb = image2_scale1_compare.convert("RGB")
+        image2_scale1_compare_rgb.load()
+        assert_image_similar(image2_scale1, image2_scale1_compare_rgb, 10)
 
 
 @pytest.mark.skipif(not HAS_GHOSTSCRIPT, reason="Ghostscript not available")
@@ -324,18 +324,16 @@ def test_render_scale2() -> None:
         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")
-        image1_scale2_compare.load()
-        assert_image_similar(image1_scale2, image1_scale2_compare, 5)
+            image1_scale2_compare_rgb = image1_scale2_compare.convert("RGB")
+        assert_image_similar(image1_scale2, image1_scale2_compare_rgb, 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")
-        image2_scale2_compare.load()
-        assert_image_similar(image2_scale2, image2_scale2_compare, 10)
+            image2_scale2_compare_rgb = image2_scale2_compare.convert("RGB")
+        assert_image_similar(image2_scale2, image2_scale2_compare_rgb, 10)
 
 
 @pytest.mark.skipif(not HAS_GHOSTSCRIPT, reason="Ghostscript not available")
@@ -345,8 +343,8 @@ def test_render_scale2() -> None:
 def test_resize(filename: str) -> None:
     with Image.open(filename) as im:
         new_size = (100, 100)
-        im = im.resize(new_size)
-        assert im.size == new_size
+        im_resized = im.resize(new_size)
+        assert im_resized.size == new_size
 
 
 @pytest.mark.skipif(not HAS_GHOSTSCRIPT, reason="Ghostscript not available")

Tests/test_file_gif.py

@@ -327,14 +327,13 @@ def test_loading_multiple_palettes(path: str, mode: str) -> None:
 
         im.seek(1)
         assert im.mode == mode
-        if mode == "RGBA":
-            im = im.convert("RGB")
+        im_rgb = im.convert("RGB") if mode == "RGBA" else im
 
         # Check a color only from the old palette
-        assert im.getpixel((0, 0)) == original_color
+        assert im_rgb.getpixel((0, 0)) == original_color
 
         # Check a color from the new palette
-        assert im.getpixel((24, 24)) not in first_frame_colors
+        assert im_rgb.getpixel((24, 24)) not in first_frame_colors
 
 
 def test_headers_saving_for_animated_gifs(tmp_path: Path) -> None:
@@ -354,16 +353,16 @@ def test_palette_handling(tmp_path: Path) -> None:
     # see https://github.com/python-pillow/Pillow/issues/513
 
     with Image.open(TEST_GIF) as im:
-        im = im.convert("RGB")
+        im_rgb = im.convert("RGB")
 
-        im = im.resize((100, 100), Image.Resampling.LANCZOS)
-        im2 = im.convert("P", palette=Image.Palette.ADAPTIVE, colors=256)
+    im_rgb = im_rgb.resize((100, 100), Image.Resampling.LANCZOS)
+    im_p = im_rgb.convert("P", palette=Image.Palette.ADAPTIVE, colors=256)
 
-        f = tmp_path / "temp.gif"
-        im2.save(f, optimize=True)
+    f = tmp_path / "temp.gif"
+    im_p.save(f, optimize=True)
 
     with Image.open(f) as reloaded:
-        assert_image_similar(im, reloaded.convert("RGB"), 10)
+        assert_image_similar(im_rgb, reloaded.convert("RGB"), 10)
 
 
 def test_palette_434(tmp_path: Path) -> None:
@@ -383,35 +382,36 @@ def roundtrip(im: Image.Image, **kwargs: bool) -> Image.Image:
         with roundtrip(im, optimize=True) as reloaded:
             assert_image_similar(im, reloaded, 1)
 
-        im = im.convert("RGB")
-        # check automatic P conversion
-        with roundtrip(im) as reloaded:
-            reloaded = reloaded.convert("RGB")
-            assert_image_equal(im, reloaded)
+        im_rgb = im.convert("RGB")
+
+    # check automatic P conversion
+    with roundtrip(im_rgb) as reloaded:
+        reloaded = reloaded.convert("RGB")
+        assert_image_equal(im_rgb, reloaded)
 
 
 @pytest.mark.skipif(not netpbm_available(), reason="Netpbm not available")
 def test_save_netpbm_bmp_mode(tmp_path: Path) -> None:
     with Image.open(TEST_GIF) as img:
-        img = img.convert("RGB")
+        img_rgb = img.convert("RGB")
 
-        tempfile = str(tmp_path / "temp.gif")
-        b = BytesIO()
-        GifImagePlugin._save_netpbm(img, b, tempfile)
-        with Image.open(tempfile) as reloaded:
-            assert_image_similar(img, reloaded.convert("RGB"), 0)
+    tempfile = str(tmp_path / "temp.gif")
+    b = BytesIO()
+    GifImagePlugin._save_netpbm(img_rgb, b, tempfile)
+    with Image.open(tempfile) as reloaded:
+        assert_image_similar(img_rgb, reloaded.convert("RGB"), 0)
 
 
 @pytest.mark.skipif(not netpbm_available(), reason="Netpbm not available")
 def test_save_netpbm_l_mode(tmp_path: Path) -> None:
     with Image.open(TEST_GIF) as img:
-        img = img.convert("L")
+        img_l = img.convert("L")
 
         tempfile = str(tmp_path / "temp.gif")
         b = BytesIO()
-        GifImagePlugin._save_netpbm(img, b, tempfile)
+        GifImagePlugin._save_netpbm(img_l, b, tempfile)
         with Image.open(tempfile) as reloaded:
-            assert_image_similar(img, reloaded.convert("L"), 0)
+            assert_image_similar(img_l, reloaded.convert("L"), 0)
 
 
 def test_seek() -> None:
@@ -1038,26 +1038,26 @@ def test_webp_background(tmp_path: Path) -> None:
             im.save(out)
 
     # Test non-opaque WebP background
-    im = Image.new("L", (100, 100), "#000")
-    im.info["background"] = (0, 0, 0, 0)
-    im.save(out)
+    im2 = Image.new("L", (100, 100), "#000")
+    im2.info["background"] = (0, 0, 0, 0)
+    im2.save(out)
 
 
 def test_comment(tmp_path: Path) -> None:
     with Image.open(TEST_GIF) as im:
         assert im.info["comment"] == b"File written by Adobe Photoshop\xa8 4.0"
 
     out = tmp_path / "temp.gif"
-    im = Image.new("L", (100, 100), "#000")
-    im.info["comment"] = b"Test comment text"
-    im.save(out)
+    im2 = Image.new("L", (100, 100), "#000")
+    im2.info["comment"] = b"Test comment text"
+    im2.save(out)
     with Image.open(out) as reread:
-        assert reread.info["comment"] == im.info["comment"]
+        assert reread.info["comment"] == im2.info["comment"]
 
-    im.info["comment"] = "Test comment text"
-    im.save(out)
+    im2.info["comment"] = "Test comment text"
+    im2.save(out)
     with Image.open(out) as reread:
-        assert reread.info["comment"] == im.info["comment"].encode()
+        assert reread.info["comment"] == im2.info["comment"].encode()
 
         # Test that GIF89a is used for comments
         assert reread.info["version"] == b"GIF89a"

Tests/test_file_libtiff.py

@@ -516,12 +516,12 @@ def test_blur(self, tmp_path: Path) -> None:
         # and save to compressed tif.
         out = tmp_path / "temp.tif"
         with Image.open("Tests/images/pport_g4.tif") as im:
-            im = im.convert("L")
+            im_l = im.convert("L")
 
-        im = im.filter(ImageFilter.GaussianBlur(4))
-        im.save(out, compression="tiff_adobe_deflate")
+        im_l = im_l.filter(ImageFilter.GaussianBlur(4))
+        im_l.save(out, compression="tiff_adobe_deflate")
 
-        assert_image_equal_tofile(im, out)
+        assert_image_equal_tofile(im_l, out)
 
     def test_compressions(self, tmp_path: Path) -> None:
         # Test various tiff compressions and assert similar image content but reduced
@@ -1087,8 +1087,10 @@ def test_old_style_jpeg_orientation(self) -> None:
         data = data[:102] + b"\x02" + data[103:]
 
         with Image.open(io.BytesIO(data)) as im:
-            im = im.transpose(Image.Transpose.FLIP_LEFT_RIGHT)
-        assert_image_equal_tofile(im, "Tests/images/old-style-jpeg-compression.png")
+            im_transposed = im.transpose(Image.Transpose.FLIP_LEFT_RIGHT)
+        assert_image_equal_tofile(
+            im_transposed, "Tests/images/old-style-jpeg-compression.png"
+        )
 
     def test_open_missing_samplesperpixel(self) -> None:
         with Image.open(