chg: [typing] Make Mypy Happy Again.

.pre-commit-config.yaml

@@ -21,7 +21,7 @@ repos:
         additional_dependencies:
           - flake8-bugbear
           - flake8-implicit-str-concat
-        args: ["--max-line-length=125"]
+        args: ["--max-line-length=125", "--ignore=E203"]
   - repo: https://github.com/pre-commit/pre-commit-hooks
     rev: v4.1.0
     hooks:

pyproject.toml

@@ -73,7 +73,7 @@ optional = true
 
 
 [tool.mypy]
-python_version = "3.12"
+python_version = "3.13"
 check_untyped_defs = true
 ignore_errors = false
 ignore_missing_imports = true
@@ -87,7 +87,12 @@ warn_unreachable = true
 show_error_context = true
 pretty = true
 
-exclude = "build|dist|docs|stegano.egg-info"
+exclude = "build|dist|docs"
+
 
 [tool.isort]
 profile = "black"
+
+
+[tool.flake8]
+ignore = ["E203"]

stegano/red/red.py

@@ -23,7 +23,7 @@ __date__ = "$Date: 2010/10/01 $"
 __revision__ = "$Date: 2017/02/06 $"
 __license__ = "GPLv3"
 
-from typing import IO, Union
+from typing import IO, Union, cast
 
 from stegano import tools
 
@@ -40,13 +40,17 @@ def hide(input_image: Union[str, IO[bytes]], message: str):
     assert message_length != 0, "message message_length is zero"
     assert message_length < 255, "message is too long"
     img = tools.open_image(input_image)
+    # Ensure image mode is RGB
+    if img.mode != "RGB":
+        img = img.convert("RGB")
     # Use a copy of image to hide the text in
     encoded = img.copy()
     width, height = img.size
     index = 0
     for row in range(height):
         for col in range(width):
-            (r, g, b) = img.getpixel((col, row))
+            pixel = cast(tuple[int, int, int], img.getpixel((col, row)))
+            r, g, b = pixel
             # first value is message_length of message
             if row == 0 and col == 0 and index < message_length:
                 asc = message_length
@@ -70,12 +74,16 @@ def reveal(input_image: Union[str, IO[bytes]]):
     The red value of the first pixel is used for message_length of string.
     """
     img = tools.open_image(input_image)
+    # Ensure image mode is RGB
+    if img.mode != "RGB":
+        img = img.convert("RGB")
     width, height = img.size
     message = ""
     index = 0
     for row in range(height):
         for col in range(width):
-            r, g, b = img.getpixel((col, row))
+            pixel = cast(tuple[int, int, int], img.getpixel((col, row)))
+            r, g, b = pixel
             # First pixel r value is length of message
             if row == 0 and col == 0:
                 message_length = r

stegano/steganalysis/parity.py

@@ -23,6 +23,8 @@ __date__ = "$Date: 2010/10/01 $"
 __revision__ = "$Date: 2019/06/06 $"
 __license__ = "GPLv3"
 
+from typing import cast
+
 from PIL import Image
 
 
@@ -34,7 +36,7 @@ def steganalyse(img: Image.Image) -> Image.Image:
     width, height = img.size
     for row in range(height):
         for col in range(width):
-            if pixel := img.getpixel((col, row)):
+            if pixel := cast(tuple[int, int, int], img.getpixel((col, row))):
                 r, g, b = pixel[0:3]
             else:
                 raise Exception("Error during steganlysis.")

stegano/tools.py

@@ -26,7 +26,7 @@ __license__ = "GPLv3"
 import base64
 import itertools
 from functools import reduce
-from typing import IO, List, Union
+from typing import IO, List, Union, cast
 
 from PIL import Image
 
@@ -101,11 +101,12 @@ def base642binary(b64_fname: str) -> bytes:
     return base64.b64decode(b64_fname)
 
 
-def open_image(fname_or_instance: Union[str, IO[bytes]]):
-    """Opens a Image and returns it.
+def open_image(fname_or_instance: Union[str, IO[bytes], Image.Image]) -> Image.Image:
+    """Opens an image and returns it.
 
-    :param fname_or_instance: Can either be the location of the image as a
-                              string or the Image.Image instance itself.
+    :param fname_or_instance: Can be a path to the image (str),
+                              a file-like object (IO[bytes]),
+                              or a PIL Image instance.
     """
     if isinstance(fname_or_instance, Image.Image):
         return fname_or_instance
@@ -157,8 +158,15 @@ class Hider:
         return True if self._index + 3 <= self._len_message_bits else False
 
     def encode_pixel(self, coordinate: tuple):
-        # Get the colour component.
-        r, g, b, *a = self.encoded_image.getpixel(coordinate)
+        # Determine expected pixel format based on mode
+        if self.encoded_image.mode == "RGBA":
+            r, g, b, *a = cast(
+                tuple[int, int, int, int], self.encoded_image.getpixel(coordinate)
+            )
+        else:
+            r, g, b, *a = cast(
+                tuple[int, int, int], self.encoded_image.getpixel(coordinate)
+            )
 
         # Change the Least Significant Bit of each colour component.
         r = setlsb(r, self._message_bits[self._index])
@@ -190,8 +198,11 @@ class Revealer:
         self.close_file = close_file
 
     def decode_pixel(self, coordinate: tuple):
-        # pixel = [r, g, b] or [r,g,b,a]
-        pixel = self.encoded_image.getpixel(coordinate)
+        # Tell mypy that this will be a 3- or 4-tuple of ints
+        pixel = cast(
+            tuple[int, int, int] | tuple[int, int, int, int],
+            self.encoded_image.getpixel(coordinate),
+        )
 
         if self.encoded_image.mode == "RGBA":
             pixel = pixel[:3]  # ignore the alpha
@@ -211,13 +222,9 @@ class Revealer:
                         raise IndexError("Impossible to detect message.")
 
         if len(self._bitab) - len(str(self._limit)) - 1 == self._limit:
-            self.secret_message = "".join(self._bitab)[
-                len(str(self._limit)) + 1 :  # noqa: E203
-            ]
+            self.secret_message = "".join(self._bitab)[len(str(self._limit)) + 1 :]
             if self.close_file:
                 self.encoded_image.close()
-
             return True
-
         else:
             return False