Merge branch 'main' into branch_deekshu

.coveragerc

@@ -23,4 +23,4 @@ omit =
     # Tests/check_*.py
     # Tests/createfontdatachunk.py
     Tests/*
-    # src/*
+    src/*

README.md

@@ -1,115 +1,136 @@
-<p align="center">
+# Report for Assignment 1
-    <img width="248" height="250" src="https://raw.githubusercontent.com/python-pillow/pillow-logo/main/pillow-logo-248x250.png" alt="Pillow logo">
-</p>
 
-# Pillow
+## Project chosen
 
-## Python Imaging Library (Fork)
+Name: Pillow
 
-Pillow is the friendly PIL fork by [Jeffrey A. Clark and
+URL of our repository: https://github.com/jovanovicisidora/Pillow-SEP.git
-contributors](https://github.com/python-pillow/Pillow/graphs/contributors).
-PIL is the Python Imaging Library by Fredrik Lundh and contributors.
-As of 2019, Pillow development is
-[supported by Tidelift](https://tidelift.com/subscription/pkg/pypi-pillow?utm_source=pypi-pillow&utm_medium=readme&utm_campaign=enterprise).
 
-<table>
+URL of the original repo: https://github.com/python-pillow/Pillow.git
-    <tr>
-        <th>docs</th>
-        <td>
-            <a href="https://pillow.readthedocs.io/?badge=latest"><img
-                alt="Documentation Status"
-                src="https://readthedocs.org/projects/pillow/badge/?version=latest"></a>
-        </td>
-    </tr>
-    <tr>
-        <th>tests</th>
-        <td>
-            <a href="https://github.com/python-pillow/Pillow/actions/workflows/lint.yml"><img
-                alt="GitHub Actions build status (Lint)"
-                src="https://github.com/python-pillow/Pillow/workflows/Lint/badge.svg"></a>
-            <a href="https://github.com/python-pillow/Pillow/actions/workflows/test.yml"><img
-                alt="GitHub Actions build status (Test Linux and macOS)"
-                src="https://github.com/python-pillow/Pillow/workflows/Test/badge.svg"></a>
-            <a href="https://github.com/python-pillow/Pillow/actions/workflows/test-windows.yml"><img
-                alt="GitHub Actions build status (Test Windows)"
-                src="https://github.com/python-pillow/Pillow/workflows/Test%20Windows/badge.svg"></a>
-            <a href="https://github.com/python-pillow/Pillow/actions/workflows/test-mingw.yml"><img
-                alt="GitHub Actions build status (Test MinGW)"
-                src="https://github.com/python-pillow/Pillow/workflows/Test%20MinGW/badge.svg"></a>
-            <a href="https://github.com/python-pillow/Pillow/actions/workflows/test-cygwin.yml"><img
-                alt="GitHub Actions build status (Test Cygwin)"
-                src="https://github.com/python-pillow/Pillow/workflows/Test%20Cygwin/badge.svg"></a>
-            <a href="https://github.com/python-pillow/Pillow/actions/workflows/test-docker.yml"><img
-                alt="GitHub Actions build status (Test Docker)"
-                src="https://github.com/python-pillow/Pillow/workflows/Test%20Docker/badge.svg"></a>
-            <a href="https://ci.appveyor.com/project/python-pillow/Pillow"><img
-                alt="AppVeyor CI build status (Windows)"
-                src="https://img.shields.io/appveyor/build/python-pillow/Pillow/main.svg?label=Windows%20build"></a>
-            <a href="https://github.com/python-pillow/Pillow/actions/workflows/wheels.yml"><img
-                alt="GitHub Actions build status (Wheels)"
-                src="https://github.com/python-pillow/Pillow/workflows/Wheels/badge.svg"></a>
-            <a href="https://app.codecov.io/gh/python-pillow/Pillow"><img
-                alt="Code coverage"
-                src="https://codecov.io/gh/python-pillow/Pillow/branch/main/graph/badge.svg"></a>
-            <a href="https://bugs.chromium.org/p/oss-fuzz/issues/list?sort=-opened&can=1&q=proj:pillow"><img
-                alt="Fuzzing Status"
-                src="https://oss-fuzz-build-logs.storage.googleapis.com/badges/pillow.svg"></a>
-        </td>
-    </tr>
-    <tr>
-        <th>package</th>
-        <td>
-            <a href="https://zenodo.org/badge/latestdoi/17549/python-pillow/Pillow"><img
-                alt="Zenodo"
-                src="https://zenodo.org/badge/17549/python-pillow/Pillow.svg"></a>
-            <a href="https://tidelift.com/subscription/pkg/pypi-pillow?utm_source=pypi-pillow&utm_medium=badge"><img
-                alt="Tidelift"
-                src="https://tidelift.com/badges/package/pypi/pillow?style=flat"></a>
-            <a href="https://pypi.org/project/pillow/"><img
-                alt="Newest PyPI version"
-                src="https://img.shields.io/pypi/v/pillow.svg"></a>
-            <a href="https://pypi.org/project/pillow/"><img
-                alt="Number of PyPI downloads"
-                src="https://img.shields.io/pypi/dm/pillow.svg"></a>
-            <a href="https://www.bestpractices.dev/projects/6331"><img
-                alt="OpenSSF Best Practices"
-                src="https://www.bestpractices.dev/projects/6331/badge"></a>
-        </td>
-    </tr>
-    <tr>
-        <th>social</th>
-        <td>
-            <a href="https://gitter.im/python-pillow/Pillow?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge"><img
-                alt="Join the chat at https://gitter.im/python-pillow/Pillow"
-                src="https://badges.gitter.im/python-pillow/Pillow.svg"></a>
-            <a href="https://fosstodon.org/@pillow"><img
-                alt="Follow on https://fosstodon.org/@pillow"
-                src="https://img.shields.io/badge/publish-on%20Mastodon-595aff.svg"
-                rel="me"></a>
-        </td>
-    </tr>
-</table>
 
-## Overview
+Number of lines of code and the tool used to count it:
+- Tool used: coverage.py
+- Number of lines of code: 82 KLOC
 
-The Python Imaging Library adds image processing capabilities to your Python interpreter.
+Programming language: Python
 
-This library provides extensive file format support, an efficient internal representation, and fairly powerful image processing capabilities.
+## Coverage measurement
 
-The core image library is designed for fast access to data stored in a few basic pixel formats. It should provide a solid foundation for a general image processing tool.
+### Existing tool
 
-## More Information
+<Inform the name of the existing tool that was executed and how it was executed>
 
-- [Documentation](https://pillow.readthedocs.io/)
+<Show the coverage results provided by the existing tool with a screenshot>
-  - [Installation](https://pillow.readthedocs.io/en/latest/installation/basic-installation.html)
-  - [Handbook](https://pillow.readthedocs.io/en/latest/handbook/index.html)
-- [Contribute](https://github.com/python-pillow/Pillow/blob/main/.github/CONTRIBUTING.md)
-  - [Issues](https://github.com/python-pillow/Pillow/issues)
-  - [Pull requests](https://github.com/python-pillow/Pillow/pulls)
-- [Release notes](https://pillow.readthedocs.io/en/stable/releasenotes/index.html)
-- [Changelog](https://github.com/python-pillow/Pillow/blob/main/CHANGES.rst)
-  - [Pre-fork](https://github.com/python-pillow/Pillow/blob/main/CHANGES.rst#pre-fork)
 
-## Report a Vulnerability
+We used Coverage.py. We executed the coverage tool by running the following command:
 
-To report a security vulnerability, please follow the procedure described in the [Tidelift security policy](https://tidelift.com/docs/security).
+`python3 -bb -m pytest -v -x -W always --cov PIL --cov Tests --cov-report term Tests $REVERSE`
+
+This resulted in the following output:
+
+![Coverage Tool Result](report_images/isidora_images/[BEFORE]overall_coverage.png)
+
+### Your own coverage tool
+
+<The following is supposed to be repeated for each group member>
+
+<Group member name>
+
+<Function 1 name>
+
+<Show a patch (diff) or a link to a commit made in your forked repository that shows the instrumented code to gather
+coverage measurements>
+
+<Provide a screenshot of the coverage results output by the instrumentation>
+
+<Function 2 name>
+
+<Provide the same kind of information provided for Function 1>
+
+Each member of out group has chosen two functions and has instrumented our own coverage tool. For each function we
+created a dictionary with the branch ID as key, and a boolean as the value. If the branch was accessed by the tests,
+the boolean value would be changed from False to True. In order to calculate and display the coverage, all tests use
+the shared code in **conftest.py**.
+
+**1. Deekshu**
+
+**2. Duru**
+
+**3. Isidora**
+
+- Function 1: `_save()` from **SpiderImagePlugin.py**
+
+    [Link to the commit](https://github.com/jovanovicisidora/Pillow-SEP/commit/5701d33cbb789342ca781769d4ba7cd323c9255e#diff-44debbfd4d0c5a80130a15bdcd9e0b28c1b4fef6eda0eaaef48838c954589d15)
+
+    <img src="report_images/isidora_images/our_tool_save.png" alt="Implemented Coverage Tool" width="600" />
+
+- Function 2: `Bitstream.peek()` from **MpegImagePlugin.py**
+
+    [Link to the commit](https://github.com/jovanovicisidora/Pillow-SEP/commit/70f6735620d2f8e469cbe5b60a4586c5db95624a#diff-0272f0c6b5871be3364fe2062e50944fba30dad9625c74d13340de7d3ad8d367)
+
+    <img src="report_images/isidora_images/our_tool_peek.png" alt="Implemented Coverage Tool" width="600" />
+
+**4. Sofija**
+
+## Coverage improvement
+
+### Individual tests
+
+<The following is supposed to be repeated for each group member>
+
+<Group member name>
+
+<Test 1>
+
+<Show a patch (diff) or a link to a commit made in your forked repository that shows the new/enhanced test>
+
+<Provide a screenshot of the old coverage results (the same as you already showed above)>
+
+<Provide a screenshot of the new coverage results>
+
+<State the coverage improvement with a number and elaborate on why the coverage is improved>
+
+<Test 2>
+
+<Provide the same kind of information provided for Test 1>
+
+**1. Deekshu**
+
+**2. Duru**
+
+**3. Isidora**
+
+- Function 1: `_save()` from **SpiderImagePlugin.py**
+
+    [Link to the commit](https://github.com/jovanovicisidora/Pillow-SEP/commit/70f6735620d2f8e469cbe5b60a4586c5db95624a#diff-f0eb82b90cfc005f681c774b3bf87f19b1db010750e49f850883005f4f623202)
+
+    <img src="report_images/isidora_images/[BEFORE]_save.png" alt="Coverage Before" width="600" />
+
+    <img src="report_images/isidora_images/[AFTER]_save.png" alt="Coverage After" width="600" />
+
+- Function 2: `Bitstream.peek()` from **MpegImagePlugin.py**
+
+    [Link to the commit](https://github.com/jovanovicisidora/Pillow-SEP/commit/70f6735620d2f8e469cbe5b60a4586c5db95624a#diff-48e5b5451c5cab3fbb758ae58649082b62ae6f2850393a332949643d75bd4ad2)
+
+    <img src="report_images/isidora_images/[BEFORE]peek.png" alt="Coverage Before" width="600" />
+
+    <img src="report_images/isidora_images/[AFTER]peek.png" alt="Coverage After" width="600" />
+
+**4. Sofija**
+
+### Overall
+
+First we provide a screenshot of the old coverage results by running an existing tool:
+
+![Coverage Results Before](report_images/isidora_images/[BEFORE]overall_coverage.png)
+
+Here we show the improved overall coverage with all test modifications made by out group:
+
+![Coverage Results After](path/to/image)
+
+## Statement of individual contributions
+
+Each group member had an equal contribution to the assignment. We first met together to determine
+how we can make a coverage tool that can be used across all functions (in conftest.py). Then, each
+member chose two functions to instrument our coverage tool on and to make/enhance tests for them.
+The specific functions each member chose can be seen in the report above.

README_original.md

@@ -0,0 +1,115 @@
+<p align="center">
+    <img width="248" height="250" src="https://raw.githubusercontent.com/python-pillow/pillow-logo/main/pillow-logo-248x250.png" alt="Pillow logo">
+</p>
+
+# Pillow
+
+## Python Imaging Library (Fork)
+
+Pillow is the friendly PIL fork by [Jeffrey A. Clark and
+contributors](https://github.com/python-pillow/Pillow/graphs/contributors).
+PIL is the Python Imaging Library by Fredrik Lundh and contributors.
+As of 2019, Pillow development is
+[supported by Tidelift](https://tidelift.com/subscription/pkg/pypi-pillow?utm_source=pypi-pillow&utm_medium=readme&utm_campaign=enterprise).
+
+<table>
+    <tr>
+        <th>docs</th>
+        <td>
+            <a href="https://pillow.readthedocs.io/?badge=latest"><img
+                alt="Documentation Status"
+                src="https://readthedocs.org/projects/pillow/badge/?version=latest"></a>
+        </td>
+    </tr>
+    <tr>
+        <th>tests</th>
+        <td>
+            <a href="https://github.com/python-pillow/Pillow/actions/workflows/lint.yml"><img
+                alt="GitHub Actions build status (Lint)"
+                src="https://github.com/python-pillow/Pillow/workflows/Lint/badge.svg"></a>
+            <a href="https://github.com/python-pillow/Pillow/actions/workflows/test.yml"><img
+                alt="GitHub Actions build status (Test Linux and macOS)"
+                src="https://github.com/python-pillow/Pillow/workflows/Test/badge.svg"></a>
+            <a href="https://github.com/python-pillow/Pillow/actions/workflows/test-windows.yml"><img
+                alt="GitHub Actions build status (Test Windows)"
+                src="https://github.com/python-pillow/Pillow/workflows/Test%20Windows/badge.svg"></a>
+            <a href="https://github.com/python-pillow/Pillow/actions/workflows/test-mingw.yml"><img
+                alt="GitHub Actions build status (Test MinGW)"
+                src="https://github.com/python-pillow/Pillow/workflows/Test%20MinGW/badge.svg"></a>
+            <a href="https://github.com/python-pillow/Pillow/actions/workflows/test-cygwin.yml"><img
+                alt="GitHub Actions build status (Test Cygwin)"
+                src="https://github.com/python-pillow/Pillow/workflows/Test%20Cygwin/badge.svg"></a>
+            <a href="https://github.com/python-pillow/Pillow/actions/workflows/test-docker.yml"><img
+                alt="GitHub Actions build status (Test Docker)"
+                src="https://github.com/python-pillow/Pillow/workflows/Test%20Docker/badge.svg"></a>
+            <a href="https://ci.appveyor.com/project/python-pillow/Pillow"><img
+                alt="AppVeyor CI build status (Windows)"
+                src="https://img.shields.io/appveyor/build/python-pillow/Pillow/main.svg?label=Windows%20build"></a>
+            <a href="https://github.com/python-pillow/Pillow/actions/workflows/wheels.yml"><img
+                alt="GitHub Actions build status (Wheels)"
+                src="https://github.com/python-pillow/Pillow/workflows/Wheels/badge.svg"></a>
+            <a href="https://app.codecov.io/gh/python-pillow/Pillow"><img
+                alt="Code coverage"
+                src="https://codecov.io/gh/python-pillow/Pillow/branch/main/graph/badge.svg"></a>
+            <a href="https://bugs.chromium.org/p/oss-fuzz/issues/list?sort=-opened&can=1&q=proj:pillow"><img
+                alt="Fuzzing Status"
+                src="https://oss-fuzz-build-logs.storage.googleapis.com/badges/pillow.svg"></a>
+        </td>
+    </tr>
+    <tr>
+        <th>package</th>
+        <td>
+            <a href="https://zenodo.org/badge/latestdoi/17549/python-pillow/Pillow"><img
+                alt="Zenodo"
+                src="https://zenodo.org/badge/17549/python-pillow/Pillow.svg"></a>
+            <a href="https://tidelift.com/subscription/pkg/pypi-pillow?utm_source=pypi-pillow&utm_medium=badge"><img
+                alt="Tidelift"
+                src="https://tidelift.com/badges/package/pypi/pillow?style=flat"></a>
+            <a href="https://pypi.org/project/pillow/"><img
+                alt="Newest PyPI version"
+                src="https://img.shields.io/pypi/v/pillow.svg"></a>
+            <a href="https://pypi.org/project/pillow/"><img
+                alt="Number of PyPI downloads"
+                src="https://img.shields.io/pypi/dm/pillow.svg"></a>
+            <a href="https://www.bestpractices.dev/projects/6331"><img
+                alt="OpenSSF Best Practices"
+                src="https://www.bestpractices.dev/projects/6331/badge"></a>
+        </td>
+    </tr>
+    <tr>
+        <th>social</th>
+        <td>
+            <a href="https://gitter.im/python-pillow/Pillow?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge"><img
+                alt="Join the chat at https://gitter.im/python-pillow/Pillow"
+                src="https://badges.gitter.im/python-pillow/Pillow.svg"></a>
+            <a href="https://fosstodon.org/@pillow"><img
+                alt="Follow on https://fosstodon.org/@pillow"
+                src="https://img.shields.io/badge/publish-on%20Mastodon-595aff.svg"
+                rel="me"></a>
+        </td>
+    </tr>
+</table>
+
+## Overview
+
+The Python Imaging Library adds image processing capabilities to your Python interpreter.
+
+This library provides extensive file format support, an efficient internal representation, and fairly powerful image processing capabilities.
+
+The core image library is designed for fast access to data stored in a few basic pixel formats. It should provide a solid foundation for a general image processing tool.
+
+## More Information
+
+- [Documentation](https://pillow.readthedocs.io/)
+  - [Installation](https://pillow.readthedocs.io/en/latest/installation/basic-installation.html)
+  - [Handbook](https://pillow.readthedocs.io/en/latest/handbook/index.html)
+- [Contribute](https://github.com/python-pillow/Pillow/blob/main/.github/CONTRIBUTING.md)
+  - [Issues](https://github.com/python-pillow/Pillow/issues)
+  - [Pull requests](https://github.com/python-pillow/Pillow/pulls)
+- [Release notes](https://pillow.readthedocs.io/en/stable/releasenotes/index.html)
+- [Changelog](https://github.com/python-pillow/Pillow/blob/main/CHANGES.rst)
+  - [Pre-fork](https://github.com/python-pillow/Pillow/blob/main/CHANGES.rst#pre-fork)
+
+## Report a Vulnerability
+
+To report a security vulnerability, please follow the procedure described in the [Tidelift security policy](https://tidelift.com/docs/security).

Tests/test_file_mpeg.py

@@ -6,6 +6,8 @@ import pytest
 
 from PIL import Image, MpegImagePlugin
 
+from unittest.mock import MagicMock, patch
+
 
 def test_identify() -> None:
     # Arrange
@@ -37,3 +39,15 @@ def test_load() -> None:
         # Act / Assert: cannot load
         with pytest.raises(OSError):
             im.load()
+
+
+def test_peek_with_negative_c() -> None:
+    fp = MagicMock()
+
+    return_values = [-1, 255]
+
+    with patch.object(MpegImagePlugin.BitStream, 'next', side_effect=return_values):
+        bitstream = MpegImagePlugin.BitStream(fp)
+        result = bitstream.peek(8)
+
+        assert result == 255

Tests/test_file_spider.py

@@ -4,6 +4,9 @@ import tempfile
 import warnings
 from io import BytesIO
 from pathlib import Path
+from unittest.mock import MagicMock, patch
+import unittest
+import struct
 
 import pytest
 
@@ -162,3 +165,27 @@ def test_odd_size() -> None:
     data.seek(0)
     with Image.open(data) as im2:
         assert_image_equal(im, im2)
+
+
+def test_seek_no_frame() -> None:
+    with Image.open(TEST_FILE) as im:
+        im.istack = 1
+        im.seek(0)
+
+
+def test_save_small_header() -> None:
+    width, height = 10, 10
+    im = Image.new("F", (width, height))
+
+    fp = BytesIO()
+
+    corrupted_header = [b'\x00' * 4] * 22
+
+    with patch("PIL.SpiderImagePlugin.makeSpiderHeader", return_value=corrupted_header):
+        try:
+            im.save(fp, format="SPIDER")
+        except OSError as e:
+            assert str(e) == "Error creating Spider header"
+        else:
+            assert False, "Expected an OSError due to corrupted header"
+

conftest.py

@@ -4,6 +4,10 @@ import sys
 
 from PIL import Image
 from PIL import PdfParser
+from PIL import SpiderImagePlugin
+from PIL import MpegImagePlugin
+from PIL import ImageCms
+from PIL import McIdasImagePlugin
 from PIL import ImageTk
 from PIL import ImageFile
 
@@ -12,10 +16,12 @@ pytest_plugins = ["Tests.helper"]
 
 def calculate_coverage(test_name):
     all_branches = {
-        "branches1": Image.branches,
+        "branches1": Image.branches,                        # duru
-        "branches2": PdfParser.XrefTable.branches,
+        "branches2": PdfParser.XrefTable.branches,          # duru
-        "branches3": ImageTk.BitmapImage.branches,
+        "branches3": SpiderImagePlugin.branches,            # isidora
-        "branches4": ImageFile.PyEncoder.branches,
+        "branches4": MpegImagePlugin.BitStream.branches,    # isidora
+        "branches5": ImageTk.BitmapImage.branches,          # deekshu
+        "branches6": ImageFile.PyEncoder.branches,          # deekshu
         # Add more
     }
 

myenv/lib64

@@ -0,0 +1 @@
+lib

myenv/pyvenv.cfg

@@ -0,0 +1,5 @@
+home = /usr/bin
+include-system-site-packages = false
+version = 3.12.3
+executable = /usr/bin/python3.12
+command = /usr/bin/python3 -m venv /home/duru/Documents/Period_6/Pillow-SEP/myenv

pillowenv/lib64

@@ -0,0 +1 @@
+lib

pillowenv/pyvenv.cfg

@@ -0,0 +1,5 @@
+home = /usr/bin
+include-system-site-packages = false
+version = 3.12.3
+executable = /usr/bin/python3.12
+command = /usr/bin/python3 -m venv /home/duru/Documents/Period_6/Pillow-SEP/pillowenv

src/PIL/ImageCms.py

@@ -242,6 +242,17 @@ _FLAGS = {
 
 
 class ImageCmsProfile:
+    branches = {
+        "1": False,
+        "2": False,
+        "3": False,
+        "4": False,
+        "5": False,
+        "6": False,
+        "7": False,
+        "8": False,
+    }
+
     def __init__(self, profile: str | SupportsRead[bytes] | core.CmsProfile) -> None:
         """
         :param profile: Either a string representing a filename,
@@ -251,20 +262,28 @@ class ImageCmsProfile:
         """
 
         if isinstance(profile, str):
+            ImageCmsProfile.branches["1"] = True
             if sys.platform == "win32":
+                ImageCmsProfile.branches["2"] = True
                 profile_bytes_path = profile.encode()
                 try:
+                    ImageCmsProfile.branches["3"] = True
                     profile_bytes_path.decode("ascii")
                 except UnicodeDecodeError:
+                    ImageCmsProfile.branches["4"] = True
                     with open(profile, "rb") as f:
+                        ImageCmsProfile.branches["5"] = True
                         self._set(core.profile_frombytes(f.read()))
                     return
             self._set(core.profile_open(profile), profile)
         elif hasattr(profile, "read"):
+            ImageCmsProfile.branches["6"] = True
             self._set(core.profile_frombytes(profile.read()))
         elif isinstance(profile, core.CmsProfile):
+            ImageCmsProfile.branches["7"] = True
             self._set(profile)
         else:
+            ImageCmsProfile.branches["8"] = True
             msg = "Invalid type for Profile"  # type: ignore[unreachable]
             raise TypeError(msg)
 

src/PIL/McIdasImagePlugin.py

@@ -30,6 +30,14 @@ def _accept(prefix: bytes) -> bool:
 
 
 class McIdasImageFile(ImageFile.ImageFile):
+    branches = {
+        "1": False,
+        "2": False,
+        "3": False,
+        "4": False,
+        "5": False,
+        }
+
     format = "MCIDAS"
     format_description = "McIdas area file"
 
@@ -39,6 +47,7 @@ class McIdasImageFile(ImageFile.ImageFile):
 
         s = self.fp.read(256)
         if not _accept(s) or len(s) != 256:
+            McIdasImageFile.branches["1"] = True
             msg = "not an McIdas area file"
             raise SyntaxError(msg)
 
@@ -47,16 +56,20 @@ class McIdasImageFile(ImageFile.ImageFile):
 
         # get mode
         if w[11] == 1:
+            McIdasImageFile.branches["2"] = True
             mode = rawmode = "L"
         elif w[11] == 2:
+            McIdasImageFile.branches["3"] = True
             # FIXME: add memory map support
             mode = "I"
             rawmode = "I;16B"
         elif w[11] == 4:
+            McIdasImageFile.branches["4"] = True
             # FIXME: add memory map support
             mode = "I"
             rawmode = "I;32B"
         else:
+            McIdasImageFile.branches["5"] = True
             msg = "unsupported McIdas format"
             raise SyntaxError(msg)
 

src/PIL/MpegImagePlugin.py

@@ -21,8 +21,13 @@ from ._typing import SupportsRead
 #
 # Bitstream parser
 
-
 class BitStream:
+    branches = {
+        "1": False,
+        "2": False,
+        "3": False,
+    }
+
     def __init__(self, fp: SupportsRead[bytes]) -> None:
         self.fp = fp
         self.bits = 0
@@ -33,12 +38,19 @@ class BitStream:
 
     def peek(self, bits: int) -> int:
         while self.bits < bits:
+            BitStream.branches["1"] = True
             c = self.next()
+
             if c < 0:
+                BitStream.branches["2"] = True
                 self.bits = 0
                 continue
+            else:
+                BitStream.branches["3"] = True
+
             self.bitbuffer = (self.bitbuffer << 8) + c
             self.bits += 8
+
         return self.bitbuffer >> (self.bits - bits) & (1 << bits) - 1
 
     def skip(self, bits: int) -> None:

src/PIL/SpiderImagePlugin.py

@@ -42,6 +42,7 @@ from typing import IO, TYPE_CHECKING
 from . import Image, ImageFile
 
 
+
 def isInt(f):
     try:
         i = int(f)
@@ -55,6 +56,13 @@ def isInt(f):
 
 iforms = [1, 3, -11, -12, -21, -22]
 
+branches = {
+    "1": False,
+    "2": False,
+    "3": False,
+    "4": False
+}
+
 
 # There is no magic number to identify Spider files, so just check a
 # series of header locations to see if they have reasonable values.
@@ -107,19 +115,23 @@ class SpiderImageFile(ImageFile.ImageFile):
             self.bigendian = 1
             t = struct.unpack(">27f", f)  # try big-endian first
             hdrlen = isSpiderHeader(t)
+
             if hdrlen == 0:
                 self.bigendian = 0
                 t = struct.unpack("<27f", f)  # little-endian
                 hdrlen = isSpiderHeader(t)
+
             if hdrlen == 0:
                 msg = "not a valid Spider file"
                 raise SyntaxError(msg)
+
         except struct.error as e:
             msg = "not a valid Spider file"
             raise SyntaxError(msg) from e
 
         h = (99,) + t  # add 1 value : spider header index starts at 1
         iform = int(h[5])
+
         if iform != 1:
             msg = "not a Spider 2D image"
             raise SyntaxError(msg)
@@ -176,8 +188,10 @@ class SpiderImageFile(ImageFile.ImageFile):
         if self.istack == 0:
             msg = "attempt to seek in a non-stack file"
             raise EOFError(msg)
+
         if not self._seek_check(frame):
             return
+
         self.stkoffset = self.hdrlen + frame * (self.hdrlen + self.imgbytes)
         self.fp = self._fp
         self.fp.seek(self.stkoffset)
@@ -265,12 +279,18 @@ def makeSpiderHeader(im: Image.Image) -> list[bytes]:
 
 def _save(im: Image.Image, fp: IO[bytes], filename: str | bytes) -> None:
     if im.mode[0] != "F":
+        branches["1"] = True
         im = im.convert("F")
+    else:
+        branches["2"] = True
 
     hdr = makeSpiderHeader(im)
     if len(hdr) < 256:
+        branches["3"] = True
         msg = "Error creating Spider header"
         raise OSError(msg)
+    else:
+        branches["4"] = True
 
     # write the SPIDER header
     fp.writelines(hdr)