whatthepatch

Warnings

• breaking Version 1.0.0 dropped support for Python 2 and Python 3.4. Users on these older Python versions must use `whatthepatch<1.0.0` or upgrade their Python environment.
  Fix: Upgrade Python to 3.9+ or pin `whatthepatch` version to `<1.0.0`.
• gotcha An incorrect regular expression matching `diffcmd` was fixed in version 1.0.7. Older versions might misinterpret diff commands in some patch files, leading to parsing errors.
  Fix: Upgrade to `whatthepatch` version 1.0.7 or newer.
• gotcha Issues with parsing binary diffs and context diffs were fixed in versions 1.0.5 and 1.0.1 respectively. Users dealing with these specific patch formats in older library versions might encounter parsing failures.
  Fix: Upgrade to `whatthepatch` version 1.0.5 or newer to ensure correct parsing of binary and context diffs.
• gotcha The project's maintainer notes limited active development; while pull requests are considered, direct issue fixes by the maintainer are not guaranteed. Users encountering bugs may need to contribute fixes.
  Fix: Be prepared to contribute pull requests for bug fixes or rely on community contributions.
• gotcha Open issues exist regarding the parser not discarding 'a/' and 'b/' prefixes in paths for certain Git patches (issue #43) and incorrect parsing of colored diffs (issue #28). These might affect specific Git patch workflows or diff outputs.
  Fix: Check relevant GitHub issues for workarounds or community-contributed solutions if encountering these specific parsing challenges.

Install

• pip install whatthepatch Install stable version

Imports

• whatthepatch

  import whatthepatch

• parse_patch

  from whatthepatch import parse_patch

  Often accessed via `whatthepatch.parse_patch` after `import whatthepatch`.
• apply_diff

  from whatthepatch import apply_diff

  Often accessed via `whatthepatch.apply_diff` after `import whatthepatch`.

Quickstart

This example demonstrates how to parse a patch string and then apply the first detected diff to an original file's content. It prints the parsed changes and the resulting patched content.

import whatthepatch
import io

patch_content = """--- lao\t2012-12-26 23:16:54.000000000 -0600
+++ tzu\t2012-12-26 23:16:50.000000000 -0600
@@ -1,7 +1,6 @@
-The Way that can be told of is not the eternal Way;
-The name that can be named is not the eternal name.
 The Nameless is the origin of Heaven and Earth;
-The Named is the mother of all things.
+The named is the mother of all things.
 Therefore let there always be non-being, so we may see their subtlety,
 And let there always be being,
@@ -9,3 +8,6 @@
 The two are the same,
 But after they are produced,
 they have different names.
+They both may be called deep and profound.
+Deeper and more profound,
+The door of all subtleties!"""

original_file_content = """The Way that can be told of is not the eternal Way;
The name that can be named is not the eternal name.
The Nameless is the origin of Heaven and Earth;
The Named is the mother of all things.
Therefore let there always be non-being, so we may see their subtlety,
And let there always be being,
The two are the same,
But after they are produced,
they have different names."""

# Parse the patch
print("--- Parsing Patch ---")
patches = list(whatthepatch.parse_patch(patch_content))
for diff in patches:
    print(f"Diff for file: {diff.header.old_path} -> {diff.header.new_path}")
    for change in diff.changes:
        print(f"  Change: old={change.old}, new={change.new}, line='{change.line.strip()}'")

# Apply the patch (example for the first diff in the patch)
if patches:
    first_diff = patches[0]
    print("\n--- Applying Patch ---")
    
    # Simulate reading the original file lines
    original_lines = original_file_content.splitlines(keepends=True)
    
    try:
        patched_lines = whatthepatch.apply_diff(first_diff, original_lines)
        print("Patch applied successfully. New content:")
        print("".join(patched_lines))
    except whatthepatch.exceptions.PatchException as e:
        print(f"Failed to apply patch: {e}")