Warning: "1 issue was detected with this workflow: git checkout HEAD^2 is no longer necessary"

About this warning

Warning: 1 issue was detected with this workflow: git checkout HEAD^2 is no longer
necessary. Please remove this step as Code Scanning recommends analyzing the merge
commit for best results.

If you're using an old CodeQL workflow you may receive this warning from the "Initialize CodeQL" action.

Confirm the cause of the problem

Check for the following lines from the CodeQL workflow. These lines were included in the steps section of the Analyze job in initial versions of the CodeQL workflow.

        with:
          # We must fetch at least the immediate parents so that if this is
          # a pull request then we can checkout the head.
          fetch-depth: 2

      # If this run was triggered by a pull request event, then checkout
      # the head of the pull request instead of the merge commit.
      - run: git checkout HEAD^2
        if: ${{ github.event_name == 'pull_request' }}

Fixing the problem

Remove the lines from the CodeQL workflow. The revised steps section of the workflow should now look like this:

    steps:
      - name: Checkout repository
        uses: actions/checkout@v4

      # Initializes the CodeQL tools for scanning.
      - name: Initialize CodeQL
        uses: github/codeql-action/init@v3

      # ...

For more information about editing the CodeQL workflow file, see "Customizing your advanced setup for code scanning."