Deprecate IptcImagePlugin helpers

Tests/test_file_iptc.py

@@ -87,24 +87,28 @@ def test_i():
     c = b"a"
 
     # Act
-    ret = IptcImagePlugin.i(c)
+    with pytest.warns(DeprecationWarning):
+        ret = IptcImagePlugin.i(c)
 
     # Assert
     assert ret == 97
 
 
-def test_dump():
+def test_dump(monkeypatch):
     # Arrange
     c = b"abc"
     # Temporarily redirect stdout
-    old_stdout = sys.stdout
-    sys.stdout = mystdout = StringIO()
+    mystdout = StringIO()
+    monkeypatch.setattr(sys, "stdout", mystdout)
 
     # Act
-    IptcImagePlugin.dump(c)
-
-    # Reset stdout
-    sys.stdout = old_stdout
+    with pytest.warns(DeprecationWarning):
+        IptcImagePlugin.dump(c)
 
     # Assert
     assert mystdout.getvalue() == "61 62 63 \n"
+
+
+def test_pad_deprecation():
+    with pytest.warns(DeprecationWarning):
+        assert IptcImagePlugin.PAD == b"\0\0\0\0"

docs/deprecations.rst

@@ -44,6 +44,17 @@ ImageFile.raise_oserror
 error codes returned by a codec's ``decode()`` method, which ImageFile already does
 automatically.
 
+IptcImageFile helper functions
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. deprecated:: 10.2.0
+
+The functions ``IptcImageFile.dump`` and ``IptcImageFile.i``, and the constant
+``IptcImageFile.PAD`` have been deprecated and will be removed in Pillow
+12.0.0 (2025-10-15). These are undocumented helper functions intended
+for internal use, so there is no replacement. They can each be replaced
+by a single line of code using builtin functions in Python.
+
 Removed features
 ----------------
 

docs/releasenotes/10.2.0.rst

@@ -20,10 +20,14 @@ ImageFile.raise_oserror
 error codes returned by a codec's ``decode()`` method, which ImageFile already does
 automatically.
 
-TODO
-^^^^
-
-TODO
+IptcImageFile helper functions
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+The functions ``IptcImageFile.dump`` and ``IptcImageFile.i``, and the constant
+``IptcImageFile.PAD`` have been deprecated and will be removed in Pillow
+12.0.0 (2025-10-15). These are undocumented helper functions intended
+for internal use, so there is no replacement. They can each be replaced
+by a single line of code using builtin functions in Python.
 
 API Changes
 ===========

src/PIL/Image.py

@@ -3190,7 +3190,7 @@ def _decompression_bomb_check(size):
         )
 
 
-def open(fp, mode="r", formats=None):
+def open(fp, mode="r", formats=None) -> Image:
     """
     Opens and identifies the given image file.
 
@@ -3415,7 +3415,7 @@ def merge(mode, bands):
 # Plugin registry
 
 
-def register_open(id, factory, accept=None):
+def register_open(id, factory, accept=None) -> None:
     """
     Register an image file plugin.  This function should not be used
     in application code.
@@ -3469,7 +3469,7 @@ def register_save_all(id, driver):
     SAVE_ALL[id.upper()] = driver
 
 
-def register_extension(id, extension):
+def register_extension(id, extension) -> None:
     """
     Registers an image extension.  This function should not be
     used in application code.

src/PIL/IptcImagePlugin.py

@@ -18,29 +18,45 @@
 
 import os
 import tempfile
+from typing import Sequence
 
 from . import Image, ImageFile
 from ._binary import i16be as i16
 from ._binary import i32be as i32
+from ._deprecate import deprecate
 
 COMPRESSION = {1: "raw", 5: "jpeg"}
 
-PAD = b"\0\0\0\0"
+
+def __getattr__(name: str) -> bytes:
+    if name == "PAD":
+        deprecate("IptcImagePlugin.PAD", 12)
+        return b"\0\0\0\0"
+    msg = f"module '{__name__}' has no attribute '{name}'"
+    raise AttributeError(msg)
 
 
 #
 # Helpers
 
 
+def _i(c: bytes) -> int:
+    return i32((b"\0\0\0\0" + c)[-4:])
+
+
 def _i8(c: int | bytes) -> int:
     return c if isinstance(c, int) else c[0]
 
 
-def i(c):
-    return i32((PAD + c)[-4:])
+def i(c: bytes) -> int:
+    """.. deprecated:: 10.2.0"""
+    deprecate("IptcImagePlugin.i", 12)
+    return _i(c)
 
 
-def dump(c):
+def dump(c: Sequence[int | bytes]) -> None:
+    """.. deprecated:: 10.2.0"""
+    deprecate("IptcImagePlugin.dump", 12)
     for i in c:
         print("%02x" % _i8(i), end=" ")
     print()
@@ -55,10 +71,10 @@ class IptcImageFile(ImageFile.ImageFile):
     format = "IPTC"
     format_description = "IPTC/NAA"
 
-    def getint(self, key):
-        return i(self.info[key])
+    def getint(self, key: tuple[int, int]) -> int:
+        return _i(self.info[key])
 
-    def field(self):
+    def field(self) -> tuple[tuple[int, int] | None, int]:
         #
         # get a IPTC field header
         s = self.fp.read(5)
@@ -80,13 +96,13 @@ def field(self):
         elif size == 128:
             size = 0
         elif size > 128:
-            size = i(self.fp.read(size - 128))
+            size = _i(self.fp.read(size - 128))
         else:
             size = i16(s, 3)
 
         return tag, size
 
-    def _open(self):
+    def _open(self) -> None:
         # load descriptive fields
         while True:
             offset = self.fp.tell()