Added type hints

Tests/check_imaging_leaks.py

@@ -23,7 +23,10 @@ def _get_mem_usage() -> float:
 
 
 def _test_leak(
-    min_iterations: int, max_iterations: int, fn: Callable[..., None], *args: Any
+    min_iterations: int,
+    max_iterations: int,
+    fn: Callable[..., Image.Image | None],
+    *args: Any,
 ) -> None:
     mem_limit = None
     for i in range(max_iterations):

Tests/check_png_dos.py

@@ -17,6 +17,7 @@ def test_ignore_dos_text() -> None:
     finally:
         ImageFile.LOAD_TRUNCATED_IMAGES = False
 
+    assert isinstance(im, PngImagePlugin.PngImageFile)
     for s in im.text.values():
         assert len(s) < 1024 * 1024, "Text chunk larger than 1M"
 
@@ -32,6 +33,7 @@ def test_dos_text() -> None:
         assert msg, "Decompressed Data Too Large"
         return
 
+    assert isinstance(im, PngImagePlugin.PngImageFile)
     for s in im.text.values():
         assert len(s) < 1024 * 1024, "Text chunk larger than 1M"
 
@@ -57,6 +59,7 @@ def test_dos_total_memory() -> None:
         return
 
     total_len = 0
+    assert isinstance(im2, PngImagePlugin.PngImageFile)
     for txt in im2.text.values():
         total_len += len(txt)
     assert total_len < 64 * 1024 * 1024, "Total text chunks greater than 64M"

Tests/helper.py

@@ -351,7 +351,7 @@ def is_mingw() -> bool:
 
 
 class CachedProperty:
-    def __init__(self, func: Callable[[Any], None]) -> None:
+    def __init__(self, func: Callable[[Any], Any]) -> None:
         self.func = func
 
     def __get__(self, instance: Any, cls: type[Any] | None = None) -> Any:

Tests/test_file_container.py

@@ -1,5 +1,7 @@
 from __future__ import annotations
 
+from typing import Literal
+
 import pytest
 
 from PIL import ContainerIO, Image
@@ -22,14 +24,14 @@ def test_isatty() -> None:
 
 
 @pytest.mark.parametrize(
-    "mode, expected_value",
+    "mode, expected_position",
     (
         (0, 33),
         (1, 66),
         (2, 100),
     ),
 )
-def test_seek_mode(mode: int, expected_value: int) -> None:
+def test_seek_mode(mode: Literal[0, 1, 2], expected_position: int) -> None:
     # Arrange
     with open(TEST_FILE, "rb") as fh:
         container = ContainerIO.ContainerIO(fh, 22, 100)
@@ -39,7 +41,7 @@ def test_seek_mode(mode: int, expected_value: int) -> None:
         container.seek(33, mode)
 
         # Assert
-        assert container.tell() == expected_value
+        assert container.tell() == expected_position
 
 
 @pytest.mark.parametrize("bytesmode", (True, False))

Tests/test_file_jpeg.py

@@ -6,7 +6,7 @@
 from io import BytesIO
 from pathlib import Path
 from types import ModuleType
-from typing import Any
+from typing import Any, cast
 
 import pytest
 
@@ -45,14 +45,20 @@
 
 @skip_unless_feature("jpg")
 class TestFileJpeg:
-    def roundtrip(self, im: Image.Image, **options: Any) -> Image.Image:
+    def roundtrip_with_bytes(
+        self, im: Image.Image, **options: Any
+    ) -> tuple[JpegImagePlugin.JpegImageFile, int]:
         out = BytesIO()
         im.save(out, "JPEG", **options)
         test_bytes = out.tell()
         out.seek(0)
-        im = Image.open(out)
-        im.bytes = test_bytes  # for testing only
-        return im
+        reloaded = cast(JpegImagePlugin.JpegImageFile, Image.open(out))
+        return reloaded, test_bytes
+
+    def roundtrip(
+        self, im: Image.Image, **options: Any
+    ) -> JpegImagePlugin.JpegImageFile:
+        return self.roundtrip_with_bytes(im, **options)[0]
 
     def gen_random_image(self, size: tuple[int, int], mode: str = "RGB") -> Image.Image:
         """Generates a very hard to compress file
@@ -246,13 +252,13 @@ def test_large_icc_meta(self, tmp_path: Path) -> None:
             im.save(f, progressive=True, quality=94, exif=b" " * 43668)
 
     def test_optimize(self) -> None:
-        im1 = self.roundtrip(hopper())
-        im2 = self.roundtrip(hopper(), optimize=0)
-        im3 = self.roundtrip(hopper(), optimize=1)
+        im1, im1_bytes = self.roundtrip_with_bytes(hopper())
+        im2, im2_bytes = self.roundtrip_with_bytes(hopper(), optimize=0)
+        im3, im3_bytes = self.roundtrip_with_bytes(hopper(), optimize=1)
         assert_image_equal(im1, im2)
         assert_image_equal(im1, im3)
-        assert im1.bytes >= im2.bytes
-        assert im1.bytes >= im3.bytes
+        assert im1_bytes >= im2_bytes
+        assert im1_bytes >= im3_bytes
 
     def test_optimize_large_buffer(self, tmp_path: Path) -> None:
         # https://github.com/python-pillow/Pillow/issues/148
@@ -262,15 +268,15 @@ def test_optimize_large_buffer(self, tmp_path: Path) -> None:
         im.save(f, format="JPEG", optimize=True)
 
     def test_progressive(self) -> None:
-        im1 = self.roundtrip(hopper())
+        im1, im1_bytes = self.roundtrip_with_bytes(hopper())
         im2 = self.roundtrip(hopper(), progressive=False)
-        im3 = self.roundtrip(hopper(), progressive=True)
+        im3, im3_bytes = self.roundtrip_with_bytes(hopper(), progressive=True)
         assert not im1.info.get("progressive")
         assert not im2.info.get("progressive")
         assert im3.info.get("progressive")
 
         assert_image_equal(im1, im3)
-        assert im1.bytes >= im3.bytes
+        assert im1_bytes >= im3_bytes
 
     def test_progressive_large_buffer(self, tmp_path: Path) -> None:
         f = str(tmp_path / "temp.jpg")
@@ -341,6 +347,7 @@ def test_empty_exif_gps(self) -> None:
             assert exif.get_ifd(0x8825) == {}
 
             transposed = ImageOps.exif_transpose(im)
+        assert transposed is not None
         exif = transposed.getexif()
         assert exif.get_ifd(0x8825) == {}
 
@@ -419,14 +426,14 @@ def test_progressive_compat(self) -> None:
         assert im3.info.get("progression")
 
     def test_quality(self) -> None:
-        im1 = self.roundtrip(hopper())
-        im2 = self.roundtrip(hopper(), quality=50)
+        im1, im1_bytes = self.roundtrip_with_bytes(hopper())
+        im2, im2_bytes = self.roundtrip_with_bytes(hopper(), quality=50)
         assert_image(im1, im2.mode, im2.size)
-        assert im1.bytes >= im2.bytes
+        assert im1_bytes >= im2_bytes
 
-        im3 = self.roundtrip(hopper(), quality=0)
+        im3, im3_bytes = self.roundtrip_with_bytes(hopper(), quality=0)
         assert_image(im1, im3.mode, im3.size)
-        assert im2.bytes > im3.bytes
+        assert im2_bytes > im3_bytes
 
     def test_smooth(self) -> None:
         im1 = self.roundtrip(hopper())

Tests/test_file_jpeg2k.py

@@ -40,10 +40,8 @@
 def roundtrip(im: Image.Image, **options: Any) -> Image.Image:
     out = BytesIO()
     im.save(out, "JPEG2000", **options)
-    test_bytes = out.tell()
     out.seek(0)
     with Image.open(out) as im:
-        im.bytes = test_bytes  # for testing only
         im.load()
     return im
 
@@ -77,7 +75,9 @@ def test_invalid_file() -> None:
 def test_bytesio() -> None:
     with open("Tests/images/test-card-lossless.jp2", "rb") as f:
         data = BytesIO(f.read())
-    assert_image_similar_tofile(test_card, data, 1.0e-3)
+    with Image.open(data) as im:
+        im.load()
+        assert_image_similar(im, test_card, 1.0e-3)
 
 
 # These two test pre-written JPEG 2000 files that were not written with
@@ -340,6 +340,7 @@ def test_parser_feed() -> None:
     p.feed(data)
 
     # Assert
+    assert p.image is not None
     assert p.image.size == (640, 480)
 
 

Tests/test_file_libtiff.py

@@ -27,7 +27,7 @@
 
 @skip_unless_feature("libtiff")
 class LibTiffTestCase:
-    def _assert_noerr(self, tmp_path: Path, im: Image.Image) -> None:
+    def _assert_noerr(self, tmp_path: Path, im: TiffImagePlugin.TiffImageFile) -> None:
         """Helper tests that assert basic sanity about the g4 tiff reading"""
         # 1 bit
         assert im.mode == "1"
@@ -524,7 +524,8 @@ def test_bw_compression_w_rgb(self, compression: str, tmp_path: Path) -> None:
             im.save(out, compression=compression)
 
     def test_fp_leak(self) -> None:
-        im = Image.open("Tests/images/hopper_g4_500.tif")
+        im: Image.Image | None = Image.open("Tests/images/hopper_g4_500.tif")
+        assert im is not None
         fn = im.fp.fileno()
 
         os.fstat(fn)
@@ -716,6 +717,7 @@ def test_fd_duplication(self, tmp_path: Path) -> None:
                 f.write(src.read())
 
         im = Image.open(tmpfile)
+        assert isinstance(im, TiffImagePlugin.TiffImageFile)
         im.n_frames
         im.close()
         # Should not raise PermissionError.
@@ -1097,6 +1099,7 @@ def test_save_multistrip(self, compression: str, tmp_path: Path) -> None:
 
         with Image.open(out) as im:
             # Assert that there are multiple strips
+            assert isinstance(im, TiffImagePlugin.TiffImageFile)
             assert len(im.tag_v2[STRIPOFFSETS]) > 1
 
     @pytest.mark.parametrize("argument", (True, False))
@@ -1113,6 +1116,7 @@ def test_save_single_strip(self, argument: bool, tmp_path: Path) -> None:
             im.save(out, **arguments)
 
             with Image.open(out) as im:
+                assert isinstance(im, TiffImagePlugin.TiffImageFile)
                 assert len(im.tag_v2[STRIPOFFSETS]) == 1
         finally:
             TiffImagePlugin.STRIP_SIZE = 65536

Tests/test_file_mpo.py

@@ -2,11 +2,11 @@
 
 import warnings
 from io import BytesIO
-from typing import Any
+from typing import Any, cast
 
 import pytest
 
-from PIL import Image
+from PIL import Image, MpoImagePlugin
 
 from .helper import (
     assert_image_equal,
@@ -20,14 +20,11 @@
 pytestmark = skip_unless_feature("jpg")
 
 
-def roundtrip(im: Image.Image, **options: Any) -> Image.Image:
+def roundtrip(im: Image.Image, **options: Any) -> MpoImagePlugin.MpoImageFile:
     out = BytesIO()
     im.save(out, "MPO", **options)
-    test_bytes = out.tell()
     out.seek(0)
-    im = Image.open(out)
-    im.bytes = test_bytes  # for testing only
-    return im
+    return cast(MpoImagePlugin.MpoImageFile, Image.open(out))
 
 
 @pytest.mark.parametrize("test_file", test_files)

Tests/test_file_png.py

@@ -7,7 +7,7 @@
 from io import BytesIO
 from pathlib import Path
 from types import ModuleType
-from typing import Any
+from typing import Any, cast
 
 import pytest
 
@@ -59,11 +59,11 @@ def load(data: bytes) -> Image.Image:
     return Image.open(BytesIO(data))
 
 
-def roundtrip(im: Image.Image, **options: Any) -> Image.Image:
+def roundtrip(im: Image.Image, **options: Any) -> PngImagePlugin.PngImageFile:
     out = BytesIO()
     im.save(out, "PNG", **options)
     out.seek(0)
-    return Image.open(out)
+    return cast(PngImagePlugin.PngImageFile, Image.open(out))
 
 
 @skip_unless_feature("zlib")

Tests/test_file_spider.py

@@ -9,7 +9,7 @@
 
 from PIL import Image, ImageSequence, SpiderImagePlugin
 
-from .helper import assert_image_equal_tofile, hopper, is_pypy
+from .helper import assert_image_equal, hopper, is_pypy
 
 TEST_FILE = "Tests/images/hopper.spider"
 
@@ -152,12 +152,13 @@ def test_nonstack_dos() -> None:
             assert i <= 1, "Non-stack DOS file test failed"
 
 
-# for issue #4093
+# for issue #4093s
 def test_odd_size() -> None:
     data = BytesIO()
     width = 100
     im = Image.new("F", (width, 64))
     im.save(data, format="SPIDER")
 
     data.seek(0)
-    assert_image_equal_tofile(im, data)
+    with Image.open(data) as im2:
+        assert_image_equal(im, im2)

Tests/test_file_tiff.py

@@ -623,6 +623,7 @@ def test_rowsperstrip(self, tmp_path: Path) -> None:
         im.save(outfile, tiffinfo={278: 256})
 
         with Image.open(outfile) as im:
+            assert isinstance(im, TiffImagePlugin.TiffImageFile)
             assert im.tag_v2[278] == 256
 
     def test_strip_raw(self) -> None:

Tests/test_image.py

@@ -138,13 +138,13 @@ def test_width_height(self) -> None:
         assert im.height == 2
 
         with pytest.raises(AttributeError):
-            im.size = (3, 4)
+            im.size = (3, 4)  # type: ignore[misc]
 
     def test_set_mode(self) -> None:
         im = Image.new("RGB", (1, 1))
 
         with pytest.raises(AttributeError):
-            im.mode = "P"
+            im.mode = "P"  # type: ignore[misc]
 
     def test_invalid_image(self) -> None:
         im = io.BytesIO(b"")

Tests/test_image_access.py

@@ -14,6 +14,7 @@
 
 # CFFI imports pycparser which doesn't support PYTHONOPTIMIZE=2
 # https://github.com/eliben/pycparser/pull/198#issuecomment-317001670
+cffi: ModuleType | None
 if os.environ.get("PYTHONOPTIMIZE") == "2":
     cffi = None
 else: