Snippet trimleft option does not handle newlines well

[Lucan11]

Describe the bug
The trimleft option for the \snippet command does not work well with newlines and stripped spaces. Specifically, it requires that the newlines have the same indentation (e.g. 4 spaces) as the rest of the code. However, newlines typically have a indentation of 0 due to the fact that all trailing spaces are stripped by auto-formatters.

Screenshots
See the output of the attached project:

To Reproduce
See the attached project:
doxygen_snippet_trimleft_example.zip

Tested with Doxygen 1.13.0 downloaded from the website. The config used is generated with doxygen.exe -g and adjusted the following two settings:
EXAMPLE_PATH = .
EXAMPLE_RECURSIVE = YES

Expected behavior
I expect the trimleft option to ignore newlines (lines with only whitespaces and line termination characters), such that code snippets with newlines are trimmed correctly.

Version
Tested with Doxygen 1.13.0 downloaded from the website on Windows 11 64 bit.

[albert-github]

The fundamental question here is should a line with just a \n on it be considered in the calculation of the indentation or not.
(same might apply for lines with just white space!).

@doxygen what do you think (or do we need an extra option e.g. trimleftblank)

In case the "empty" line (just \n) it would be sufficient to add

      if (*ss == '\n') { ss++; continue;}

just before the call to lineIndent in codefragment.cpp.

When white space should be considered as well, a small change to the lambda (and its call) would be required.

[albert-github]

With the comment:

       // Does work because the indentation of line 27 does match the rest.
        // However, this results in messy code

I assume that you mean that it is all a bit cramped together and empty lines would increase readability.

[albert-github]

I've just pushed a proposed patch, pull request #11331 with the "white space lines" not contributing to the indentation calculation.

[Lucan11]

With the comment:

       // Does work because the indentation of line 27 does match the rest.
        // However, this results in messy code

I assume that you mean that it is all a bit cramped together and empty lines would increase readability.

Yes that's correct.

Thanks for picking this up so quickly! I'll download the fix once it's released 👍

[albert-github]

@Lucan11
Might take while before a release is available. I don't know which platform you use but you could already look at the patch as in the GitHub actions there are some executable artifacts (see: https://github.com/doxygen/doxygen/actions/runs/12669350933)

[Lucan11]

@Lucan11 Might take while before a release is available. I don't know which platform you use but you could already look at the patch as in the GitHub actions there are some executable artifacts (see: https://github.com/doxygen/doxygen/actions/runs/12669350933)

👍 Thanks. I've downloaded the Windows Release Artifacts and everything seems to work, all the snippets are now indented correctly. The executable is tagged with version 1.14.0.

[albert-github]

Code has been integrated in master on GitHub (please don't close the issue as this will be done at the moment of an official release).