Formatting with clang-format ignores `BreakAfterAttributes`

[maxime-modulopi]

Take these files for example:

shader.slang

[[SpecializationConstant]] const uint32_t MY_CONSTANT;

.clang-format

BreakAfterAttributes: Leave

Formatting the slang file with the Format Document action will format it to the following code instead of letting it as-is:

[[SpecializationConstant]]
const uint32_t MY_CONSTANT;

However, manually invoking clang-format with clang-format.exe shader.slang does not exhibit the same issue.

[jhelferty-nv]

@csyonghe or @expipiplus1 Can you comment on whether this is supposed to work?

[szihs]

I am not sure but it looks like configuration issue where the .clang-format file is not getting picked up by the vscode. @expipiplus1 do you have guidance ?

[expipiplus1]

@maxime-modulopi can you verify if the config file is being picked up by both clang format invocations, and also let us know the versions of the two clang format? Thank you

[maxime-modulopi]

Testing Format Document with the AllowShortIfStatementsOnASingleLine rule works as expected, so the .clang-format file is correctly read.

Both Format Document and manual cli invocation uses the same clang-format from https://pypi.org/project/clang-format/, which is version 21.1.8 at the time of writing.
I added it to PATH, but I also tested setting it explicitly via slang.format.clangFormatLocation.

I found that performing Format Document without a .clang-format file also adds a line break before const uint32_t MY_CONSTANT; (and replaces tab indentation with spaces), could it be that this default formatter is ran on top of the clang-format output?

I'm on Windows 11 x64, if that can help.