Hello @matthewhughes-uw , thank you for the input. We are starting to investigate the problem.

Hello @matthewhughes-uw , thank you for the input. We are starting to investigate the problem.

do you have any updates around this to share?

I'll chime in here to bump this thread, explain my issue, and a solution.

Situation:

1. We had a go and different toolchain version specified in our go.mod.
2. We had cache: false when calling this action.
3. We were caching go modules separately for when installing/building our projects

Problem:

1. Installing the go version (and not the toolchain) with this action
2. Running a go command would then cache the toolchain's modules
3. Running actions/cache on our go mod cache directory would
   • Saving: Caches the toolchain's modules
   • Restore: Attempt to extract the toolchain's modules over a directory that already contained them (The cause of the errors)

Solutions:

I think both of the solutions I've shown here are rather hacky and this action should support installing the toolchain version instead.

    - name: Get Go Version
      shell: bash
      id: go-version
      run: |
        version=$(sed -ne '/^toolchain /s/^toolchain go//p' ${{ inputs.go-version-file }})
        if [ -z "$version" ]; then
          version=$(sed -ne '/^go /s/^go //p' ${{ inputs.go-version-file }})
          echo "Toolchain version not found in ${{ inputs.go-version-file }}, using go directive instead."
        fi
        echo "Go Version: $version"
        echo "version=$version" >> "$GITHUB_OUTPUT"
    - name: Set up Go
      uses: actions/setup-go@v5.0.2
      with:
        go-version: ${{ steps.go-version.outputs.version }}
        cache: false
        check-latest: true

    - name: Setup tar default options
      shell: bash
      # Do not overwrite existing files when extracting files from a cache archive.
      # Since actions/cache does not support this option, we set it here as a default.
      run: echo "TAR_OPTIONS=--skip-old-files" >> $GITHUB_ENV

Hi @matthewhughes-uw,

Thank you for opening this issue and bringing this to our attention!

We are still investigating this as there are multiple related issues that we are consolidating alongside this one. Your input is very valuable in helping us address this comprehensively. We appreciate your patience as we work towards a resolution.

Meanwhile, As a workaround, you can use an environment variable to suppress tar errors specifically by setting TAR_OPTIONS=--skip-old-files. This will help to resolve conflicts during cache extraction. The --skip-old-files option prevents tar from overwriting existing files when extracting files from a cache archive. This ensures that any existing files are not replaced, which can be useful in avoiding conflicts during concurrent cache operations.

Below is a code snippet for your reference:

- name: Setup tar default options
shell: bash
run: echo "TAR_OPTIONS=--skip-old-files" >> $GITHUB_ENV
- name: Checkout
uses: actions/checkout@v4

If you have any additional details or observations, feel free to share them here. Thanks again for your contribution!

If you have any additional details or observations, feel free to share them here. Thanks again for your contribution!

Per my comment above (#424 (comment)) I think the solution here is to avoid Go toolchain installs (since these are what cause the duplicate files), see also:

• More specific handling/detection of Go toolchain versions #457
• Improve toolchain handling #460