Fix filename parsing in clang-format-diff.py for paths with spaces

[selimkeles]

Summary: This PR resolves an issue in clang-format-diff.py where filenames containing spaces were not correctly extracted from Git diffs. Due to the previous regex implementation, filenames were being truncated, causing the script to fail when processing diffs with such filenames.

Fixes #135619.

Details:

• Adjusted the regex pattern to correctly capture the filename, including spaces.
• Ensured compatibility across Linux and Windows environments (tested on WSL and Windows).

Steps to Reproduce:

Modify a file with spaces in its name, stage the changes, and generate a diff.

Run git diff --cached -U0 --no-color | python3 clang-format-diff.py -p1.

Before the fix, filenames with spaces are incorrectly extracted or cause errors.

After the fix, filenames with spaces are correctly recognized, and formatting differences are processed properly.

Impact:

Users relying on clang-format-diff.py in their automated workflows and pre-commit hooks will now be able to format files without filename parsing issues.

No changes are made to formatting behavior—only improved filename handling in diffs.

Maintainer Mentions: Tagging @mydeveloperday and @owenca for review since they maintain clang-format and also @owenca reviewed my issue earlier.

Note: Also attached the patch file clang-format-space-fix.patch

Would love any feedback or suggestions for further refinements! 🚀

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[llvmbot]

@llvm/pr-subscribers-lldb

@llvm/pr-subscribers-clang-format

Author: Selim Keles (selimkeles)

Changes

Summary: This PR resolves an issue in clang-format-diff.py where filenames containing spaces were not correctly extracted from Git diffs. Due to the previous regex implementation, filenames were being truncated, causing the script to fail when processing diffs with such filenames.

Details:

• Adjusted the regex pattern to correctly capture the filename, including spaces.
• Ensured compatibility across Linux and Windows environments (tested on WSL and Windows).

Steps to Reproduce:

Modify a file with spaces in its name, stage the changes, and generate a diff.

Run git diff --cached -U0 --no-color | python3 clang-format-diff.py -p1.

Before the fix, filenames with spaces are incorrectly extracted or cause errors.

After the fix, filenames with spaces are correctly recognized, and formatting differences are processed properly.

Impact:

Users relying on clang-format-diff.py in their automated workflows and pre-commit hooks will now be able to format files without filename parsing issues.

No changes are made to formatting behavior—only improved filename handling in diffs.

Maintainer Mentions: Tagging @mydeveloperday and @owenca for review since they maintain clang-format and also @owenca reviewed my issue earlier.

Note: Also attached the patch file clang-format-space-fix.patch

Would love any feedback or suggestions for further refinements! 🚀

---

Full diff: https://github.com/llvm/llvm-project/pull/135779.diff

1 Files Affected:

• (modified) clang/tools/clang-format/clang-format-diff.py (+2-2)

diff --git a/clang/tools/clang-format/clang-format-diff.py b/clang/tools/clang-format/clang-format-diff.py
index c82b41e8bd031..e1d635fc85ffb 100755
--- a/clang/tools/clang-format/clang-format-diff.py
+++ b/clang/tools/clang-format/clang-format-diff.py
@@ -102,9 +102,9 @@ def main():
     filename = None
     lines_by_file = {}
     for line in sys.stdin:
-        match = re.search(r"^\+\+\+\ (.*?/){%s}(\S*)" % args.p, line)
+        match = re.search(r"^\+\+\+\s+(?:.*?/){%s}(.+)$" % args.p, line)
         if match:
-            filename = match.group(2)
+            filename = match.group(1).strip()
         if filename is None:
             continue
 

[github-actions]

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