We can't run v1 in the test repo because the test repo's CI now uses all platforms supported. Whereas, v1 (as an action not a pkg) can only run on Linux because Github doesn't allow/use docker-based actions on anything but Linux runners.

• The error message about the unsupported extra-args input option is probably from trying to use the submodule that contains the older version of cpp-linter src (which doesn't support that input option).

Given that this still passed on the Linux runners in the test repo, it's ok to merge this.

OK. I'm going to merge it.
I also update tag v1 to the latest commit of the master branch with the job

It also looks like powershell is having a problem with the multiline input that invokes the cpp-linter exe script. I think there's a better YAML fix for that where each line is joined with spaces instead of \n:

      - name: Run linter as package
        id: linter
        env:
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
        run: >
          cpp-linter 
            -s=file 
            -v=9 
            -i=build 
            -p=build 
            -V=${{ runner.temp }}/llvm 
            -f=false 
            --extra-arg="-std=c++14 -Wall" 
            --thread-comments=${{ matrix.clang-version == '12' }} 
            -a=${{ matrix.clang-version == '12' }} 

notice run: option using the > syntax instead of |.

OK, so my update to the master branch of test-cpp-linter-action repo is incorrect, I thought it maybe not support --extra-arg at that moment.

It definitely installed the right version, so I doubt that's a problem with the cpp-linter exe script. Only 1 way to find out...

yep, that fixed it, but I had to use a consistent indentation.

        run: >
          cpp-linter 
          -s=file 
          -v=9 
          -i=build 
          -p=build 
          -V=${{ runner.temp }}/llvm 
          -f=false 
          --extra-arg="-std=c++14 -Wall" 
          --thread-comments=${{ matrix.clang-version == '12' }} 
          -a=${{ matrix.clang-version == '12' }}

which looks kinda ugly IMHO, but its YAML... I'm not a huge fan of YAML syntax despite my widespread use of it.