whatthepatch
A patch parsing and application library.
Decision gist · record as of 2026-08-14
Yes. The library is stable, has no dependencies, and solves a clear problem—parsing and applying patches—with low friction. The permissive license and active repository maintenance make it safe to rely on. The caveat is that the maintainer does not actively fix reported issues, so verify that the documented formats cover your use case before adopting it.AI-flagged interpretation of the facts on this page — verify before relying
Before you install
- Low install friction with no runtime dependencies.
- Maintenance is active but minimal—the library has been stable for years with infrequent updates; pull requests are accepted and released, but issues may not be addressed by the maintainer.
License · maintenance · safety
permissive license (permissive) — Licensed under MIT (permissive), allowing free use, modification, and distribution with minimal restrictions.
last release 2024-11-16 (636 days) · last repo commit 2026-08-04 · 78 stars
0 known vulnerabilities (OSV.dev, 2026-08-14) · 2,648,129 downloads/mo, #2,962 on PyPI
Alternatives
Verify before relying
pip install whatthepatch
import whatthepatch
with open('somechanges.patch') as f:
text = f.read()
for diff in whatthepatch.parse_patch(text):
result = whatthepatch.apply_diff(diff, original_text)- Whether the library handles all real-world patch edge cases or only the documented diff formats
- Performance characteristics when parsing or applying very large patch files
What it is and what it does
What The Patch is a Python library for parsing patch files and applying them to text. It reads diffs in standard formats (unified, context, normal, ed, rcs) and from source control systems (Git, SVN, CVS), extracting the changes into structured data that describes which lines were added, removed, or kept unchanged. You can then apply those changes to a file's text to reconstruct the patched version.
The library has been stable since its 1.0 release and requires no external dependencies. It works by default without needing the system patch command, though you can opt to use it if available. The maintainer notes that while the functions are reliable, they are not ideally implemented and active development is minimal—pull requests are welcome and will be merged and released, but reported issues may not be fixed.
Use it for
- Parse a patch file to inspect what changes it contains before applying it to your codebase.
- Apply a Git, SVN, or CVS patch to text in memory without invoking external tools.
- Build a tool that needs to understand or manipulate diffs programmatically.
- Validate patch compatibility or extract metadata from patch files.
- Reconstruct a modified version of a file by applying a stored patch to the original text.
Worth the install?
AI-flagged interpretation of the facts on this page. Verify before relying on it.
Yes.
The library is stable, has no dependencies, and solves a clear problem—parsing and applying patches—with low friction. The permissive license and active repository maintenance make it safe to rely on. The caveat is that the maintainer does not actively fix reported issues, so verify that the documented formats cover your use case before adopting it.
Install
whatthepatch on PyPI
Before you install
Low install friction with no runtime dependencies. Maintenance is active but minimal—the library has been stable for years with infrequent updates; pull requests are accepted and released, but issues may not be addressed by the maintainer.
License in practice
Licensed under MIT (permissive), allowing free use, modification, and distribution with minimal restrictions.
Quickstart
pip install whatthepatch
import whatthepatch
with open('somechanges.patch') as f:
text = f.read()
for diff in whatthepatch.parse_patch(text):
result = whatthepatch.apply_diff(diff, original_text)Verify before relying
- Whether the library handles all real-world patch edge cases or only the documented diff formats
- Performance characteristics when parsing or applying very large patch files
Package facts
| License | permissive license permissive |
| Python support | Supports the current Python release >=3.9 |
| Install friction | Low. Pure-Python wheel |
| Runtime dependencies | None |
| Maintenance | Actively maintained 636 days since the last release |
| Last repo commit | |
| First released | |
| Downloads | 2,648,129 / month, #2,962 on PyPI 30-day window, as of 2026-08-14 |
| Known vulnerabilities | None known OSV.dev, checked 2026-08-14 |
| Classifiers | Development Status :: 5 - Production/StableIntended Audience :: DevelopersIntended Audience :: Science/ResearchLicense :: OSI Approved :: MIT LicenseOperating System :: OS IndependentProgramming Language :: Python :: 3Programming Language :: Python :: 3 :: OnlyProgramming Language :: Python :: 3.10Programming Language :: Python :: 3.11Programming Language :: Python :: 3.12Programming Language :: Python :: 3.13Programming Language :: Python :: 3.9Programming Language :: Python :: Implementation :: CPythonTopic :: Software DevelopmentTopic :: Software Development :: Libraries :: Python ModulesTopic :: Software Development :: Version ControlTopic :: Text Processing |
Evidence: whatthepatch-1.0.7-py3-none-any.whl
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See also patch · patch-ng · unidiff2 · diff-match-patch · unidiff · dictdiffer · fast-diff-match-patch · bsdiff4 · moreorless · daff