C-format check doesn't allow positional values

[sethhillbrand]

When the C-format check is enabled, positional arguments such as %1$s raise an error.

I already tried

• I've read and searched the docs and did not find the answer there.
• The weblate documentation states that this format is supported (https://docs.weblate.org/en/latest/user/checks.html#c-format)

To Reproduce the issue

Steps to reproduce the behavior:

1. Go to 'https://hosted.weblate.org/translate/kicad/master-source/zh_Hans/?checksum=65ad27d657ff921f'
2. Note that the source string uses default position format (%s)
3. When translating to Chinese, the position of the arguments needs to change, so the positional format it used
4. Note that this fails the c-format check

Expected behavior

We expect that default order variables can be replaced in translation with positional variables without error

Screenshots

Server configuration and status

Observed on Weblate hosted instance

[nijel]

The check currently looks for same format strings as in the source. While this is the correct approach in most cases, it is better to use position-based format in the source string as well to make sure it is really supported by the printf engine (there used to be implementations which did not support this).

[sethhillbrand]

Thank you for looking into this.

Please note that even on systems where printf does not support this (and so it should not exist in the source string), libintl.a provides a replacement function that is activated for translations [1].

[1] https://www.gnu.org/software/gettext/manual/html_node/c_002dformat.html

[nijel]

I know it's possible to use libintl, but whether it is being used the translator typically does not know, that's why it's good to be explicit in the source string in this.

Still, Weblate probably should not complain on this, as most platforms these days will support it.