clang-format and checkpatch have contradictory requirements

[nordic-krch]

Describe the bug

After running clang-format on drivers/serial/uart_nrfx_uarte.c (#78179) I'm getting checkpatch errors.

There are 2 types of errors:

• SPACING: space prohibited before that close parenthesis ')' clang-format added space after VAL, in a statement like below

  COND_CODE_1(FLAG, (.elem = VAL, ), ())

• TABSTOP: Statements should start on a tabstop clang-format reformatted macro with code generation in a way that is not accepted by checkpath.

To Reproduce

1. run clang-format on drivers/serial/uart_nrfx_uarte.c and then run checkpatch
2. See error

Expected behavior

Running clang-format shall not violate checkpatch rules.

Impact

Red CI after running clang-format. Manual code adjustment must be used which discourage user from using clang-format.

Environment (please complete the following information):

• OS: Linux
• Commit SHA 056d5a354bc

[pdgendt]

FYI clang-format reports checkpatch issues on the "notice" level, these aren't blocking PRs.

[nordic-krch]

yes, but if i run clang-format on a file and commit that I will get red CI because checkpatch reports those as errors. https://docs.zephyrproject.org/latest/contribute/guidelines.html#clang-format suggests to use it. On the other hand it states that

When there are differences between the Coding Style guidelines and the formatting generated by code formatting tools, the Coding Style guidelines take precedence.

but it would be best to configure it in a way so that there are as few differences as possible.

[nordic-krch]

If it's not recommended to run clang-format on entire existing file (https://github.com/zephyrproject-rtos/zephyr/pull/78179#issuecomment-2340255925) then maybe it's worth adding it to the guidelines section about clang-format. It's not clear how to treat those notices left by clang-format in the PR? Is it obligatory to fix them?