caching a folder on ubuntu and restore it on macos doesn't work

when you try to cache a folder between two different jobs which are on a different operating system runner, it seems like the caching mechanism doesn’t work.

i am using this pipeline to reproduce the issue:

name: Build Unity TestProject
on: [pull_request]

jobs:
  buildAndTestForSomePlatforms:
    name: Build for ${{ matrix.targetPlatform }}
    runs-on: ubuntu-latest
    strategy:
      fail-fast: false
      matrix:
        unityVersion:
          - 2020.3.25f1
        targetPlatform:
          - Android
    steps:
      - uses: actions/checkout@v2
        with:
          fetch-depth: 0
          lfs: true
      - run: mkdir build && mkdir build/Android && touch build/Android/Android.apk
      
      - name: cache build folder
        uses: actions/cache@v2
        with:
          path: build/${{ matrix.targetPlatform }}
          key: build-${{ matrix.targetPlatform }}-${{ github.run_id }}
      - run: ls build
  testOnAndroidEmulator:
    name: execute tests
    needs: buildAndTestForSomePlatforms
    runs-on: macos-latest
    steps:
      - name: restore 'Android' build folder
        uses: actions/cache@v2
        with:
          path: build/Android
          key: build-Android-${{ github.run_id }}
      - run: ls 

[megetron]

@vsvipul - YES! installing zstd in linux-latest runner solved the issue for me: sudo apt install zstd

maybe it would be best to document that sceario? when a user wants to cache from linux to mac he should install zstd in the linux machine.

[vsvipul]

@megetron zstd should have been installed by default when you used the action. I’m not sure why that was not done in this case. Added this to our backlog. We will look into how we can fix this. Thank you for opening this.