[bug] the file mode is ignorred when applying patches

[markvmk]

If a patch creates new file, the file mode is ignored and default permissions (0644) are applied for the created file.
This results in loosing the executable permission for the generated file even though that permission was present in the patch file.

The issue was spotted when using conan's apply_conandata_patches() function which uses patch-ng to implement the patching functionality.

When a patch creates new file, it is generated in this part of the implementation:

python-patch-ng/patch_ng.py

Line 914 in 2354804

if old == b'/dev/null':

The 'new file mode' in the patch file is only referenced here in the source, while detecting the patch type:

python-patch-ng/patch_ng.py

Line 765 in 2354804

and re.match(b'(?:index \\w{7}..\\w{7} \\d{6}|new file mode \\d*)', p.header[idx+1])):

but it is not referenced or consumed further to set the correct file mode of a new generated file.

[uilianries]

Fixed by PR #46. Please, feel free to give your feedback!

[uilianries]

@markvmk Hello! Release 1.19.0 just arrived with a proper fix for this issue.

You can find its changelog at https://github.com/conan-io/python-patch-ng/releases/tag/1.19.0

Please, update your local version of Python Patch-NG and feel free to give us your feedback:

pip install -U patch-ng

Regards!

[markvmk]

Hi @uilianries! Thanks for providing a fix for this bug!

I was able to quickly test this with conan using conan source command for a package that has patches which add new files with the executable bit set.

Using the default patch-ng version that comes with conan (1.18.1) the files added by the patch file are having the default permissions as it was described before (0644).
After updating to version 1.19.0 of patch-ng the files were created with the executable bit in the permissions added (0755) which is the expected behavior.

For me, this confirms that the bug was fixed!

Probably it will take some time until the new version of patch-ng makes it into the official conan package.

Regards!

[uilianries]

Thank you for sharing your feedback!! : 😁