Provide pnpm workflow caching without action enhancement

[MikeMcC399]

• Relates to discussions in Add dependency caching to pnpm #1044

What would you like

Provide tested recommendations and examples for pnpm workflow caching in the absence of built-in pnpm workflow caching in cypress-io/github-action.

This should be implemented in the workflows:

• .github/workflows/example-basic-pnpm.yml
• .github/workflows/example-start-and-pnpm-workspaces.yml

and documented in the README > pnpm section.

Why is this needed

• Lack of pnpm caching can cause a performance impact on workflows, negatively affecting the usability of cypress-io/github-action.
• PR test: remove pnpm store caching #1188 removed pnpm caching due to reliability issues.
• Although the title of the original community-contribution PR feat: add support for pnpm (install and cache deps) #586 suggested that pnpm dependencies were being cached, in fact there was no additional caching of the pnpm store implemented in this PR.
• The enhancement request Add dependency caching to pnpm #1044 remains open.

[MikeMcC399]

The pnpm documentation recommends the following:

GitHub Actions

On GitHub Actions, you can use pnpm for installing and caching your dependencies
like so (belongs in .github/workflows/NAME.yml):

name: pnpm Example Workflow
on:
  push:

jobs:
  build:
    runs-on: ubuntu-22.04
    strategy:
      matrix:
        node-version: [20]
    steps:
    - uses: actions/checkout@v4
    - name: Install pnpm
      uses: pnpm/action-setup@v4
      with:
        version: 9
    - name: Use Node.js ${{ matrix.node-version }}
      uses: actions/setup-node@v4
      with:
        node-version: ${{ matrix.node-version }}
        cache: 'pnpm'
    - name: Install dependencies
      run: pnpm install

It remains open how applicable the above recommendations are for use together with cypress-io/github-action.

[MikeMcC399]

• The previous recommendation for pnpm caching came from an earlier recommendation of the pnpm documentation.

• Testing again with the relevant commit 8c3db3a before caching was removed through PR test: remove pnpm store caching #1188 shows that it sometimes works and sometimes does not work. When the example-basic-pnpm fails, the Linux workflows are affected, and there are 3 of them running in parallel. The failure mechanism is however not clear. Before the test all GitHub Action caches were cleared.

https://github.com/cypress-io/github-action/blob/8c3db3a4795a005ea7de1f04087c97a3b9ddda84/README.md#pnpm

name: example-basic-pnpm
on: push
jobs:
  basic-pnpm:
    runs-on: ubuntu-22.04
    steps:
      - name: Checkout
        uses: actions/checkout@v4
      - name: Install pnpm
        run: npm install -g pnpm@9
      - name: Get pnpm store directory
        shell: bash
        run: |
          echo "STORE_PATH=$(pnpm store path --silent)" >> $GITHUB_ENV
      - name: Setup pnpm cache
        uses: actions/cache@v4
        with:
          path: ${{ env.STORE_PATH }}
          key: ${{ runner.os }}-pnpm-store-${{ hashFiles('examples/basic-pnpm/pnpm-lock.yaml') }}
      - name: Cypress run
        uses: cypress-io/github-action@v6
        with:
          working-directory: examples/basic-pnpm

[MikeMcC399]

• PR test: implement example pnpm workflow caching #1228 resolves this issue as far as caching for pnpm in non-workspace setups is concerned.
• Currently cypress-io/github-action does not inherently support pnpm workspaces. See enhancement request Add workspace support for pnpm #1144. This leads to issues when attempting to apply the pnpm caching recommendations. I will follow this up with separate issue descriptions.

[MikeMcC399]

• I successfully verified a test version of the workflow .github/workflows/example-start-and-pnpm-workspaces.yml modified to run mixed older Cypress versions and using actions/setup-node for pnpm caching. For the moment I will not update the production version of the workflow .github/workflows/example-start-and-pnpm-workspaces.yml to use caching. It is still a valid example without caching.

• On first run of .github/workflows/example-start-and-pnpm-workspaces.yml cypress-io/github-action attempts to verify the installation of Cypress using npx cypress verify. Since there is no Cypress installed in the root of the workspace it downloads the latest version of Cypress, which is then cached in the npm cache for subsequent runs. This issue is similar to cypress cache list and verify using wrong Cypress version for Yarn Modern pnp #971.

• PR test: implement example pnpm workflow caching #1228 already added pnpm caching to .github/workflows/example-basic-pnpm.yml and updated the README > pnpm section to describe pnpm caching. So, I'm now closing this issue as resolved.