Unidiff

Simple Python library to parse and interact with unified diff data.

Installing unidiff

$ pip install unidiff

Quick start

>>> import urllib.request
>>> from unidiff import PatchSet
>>> diff = urllib.request.urlopen('https://github.com/matiasb/python-unidiff/pull/3.diff')
>>> encoding = diff.headers.get_charsets()[0]
>>> patch = PatchSet(diff, encoding=encoding)
>>> patch
<PatchSet: [<PatchedFile: .gitignore>, <PatchedFile: unidiff/patch.py>, <PatchedFile: unidiff/utils.py>]>
>>> patch[0]
<PatchedFile: .gitignore>
>>> patch[0].is_added_file
True
>>> patch[0].added
6
>>> patch[1]
<PatchedFile: unidiff/patch.py>
>>> patch[1].added, patch[1].removed
(20, 11)
>>> len(patch[1])
6
>>> patch[1][2]
<Hunk: @@ 109,14 110,21 @@ def __repr__(self):>
>>> patch[2]
<PatchedFile: unidiff/utils.py>
>>> print(patch[2])
diff --git a/unidiff/utils.py b/unidiff/utils.py
index eae63e6..29c896a 100644
--- a/unidiff/utils.py
+++ b/unidiff/utils.py
@@ -37,4 +37,3 @@
# - deleted line
# \ No newline case (ignore)
RE_HUNK_BODY_LINE = re.compile(r'^([- \+\\])')
-

Load unified diff data by instantiating PatchSet with a file-like object as argument, or using PatchSet.from_filename class method to read diff from file.

A PatchSet is a list of files updated by the given patch. For each PatchedFile you can get stats (if it is a new, removed or modified file; the source/target lines; etc), besides having access to each hunk (also like a list) and its respective info.

At any point you can get the string representation of the current object, and that will return the unified diff data of it.

As a quick example of what can be done, check bin/unidiff file.

Also, once installed, unidiff provides a command-line program that displays information from diff data (a file, or stdin). For example:

$ git diff | unidiff
Summary
-------
README.md: +6 additions, -0 deletions

1 modified file(s), 0 added file(s), 0 removed file(s)
Total: 6 addition(s), 0 deletion(s)

Load a local diff file

To instantiate PatchSet from a local file, you can use:

>>> from unidiff import PatchSet
>>> patch = PatchSet.from_filename('tests/samples/bzr.diff', encoding='utf-8')
>>> patch
<PatchSet: [<PatchedFile: added_file>, <PatchedFile: modified_file>, <PatchedFile: removed_file>]>

Notice the (optional) encoding parameter. If not specified, unicode input will be expected. Or alternatively:

>>> import codecs
>>> from unidiff import PatchSet
>>> with codecs.open('tests/samples/bzr.diff', 'r', encoding='utf-8') as diff:
...     patch = PatchSet(diff)
...
>>> patch
<PatchSet: [<PatchedFile: added_file>, <PatchedFile: modified_file>, <PatchedFile: removed_file>]>

Finally, you can also instantiate PatchSet passing any iterable (and encoding, if needed):

>>> from unidiff import PatchSet
>>> with open('tests/samples/bzr.diff', 'r') as diff:
...     data = diff.readlines()
...
>>> patch = PatchSet(data)
>>> patch
<PatchSet: [<PatchedFile: added_file>, <PatchedFile: modified_file>, <PatchedFile: removed_file>]>

If you don't need to be able to rebuild the original unified diff input, you can pass metadata_only=True (defaults to False), which should help making the parsing more efficient:

>>> from unidiff import PatchSet
>>> patch = PatchSet.from_filename('tests/samples/bzr.diff', encoding='utf-8', metadata_only=True)

References

• https://en.wikipedia.org/wiki/Diff_utility
• https://www.artima.com/weblogs/viewpost.jsp?thread=164293