rea/.github/actions/portable-build-cache/action.yml

name: Portable build cache
description: Reuse Turbo build outputs without serializing verification jobs.
inputs:
  save:
    description: Save newly built outputs after the job succeeds.
    default: "false"
runs:
  using: composite
  steps:
    - name: Resolve portable build task hashes
      id: plan
      shell: bash
      env:
        BUILD_CACHE_PREFIX: rea-portable-build-v1-${{ runner.os }}-${{ runner.arch }}-${{ hashFiles('.npmrc') }}
      run: |
        npm run --silent test:prepare -- --dry=json |
          node --input-type=module -e '
            import { createHash } from "node:crypto";
            import { readFileSync } from "node:fs";
            const { tasks } = JSON.parse(readFileSync(0, "utf8"));
            const hashes = tasks.map(({ taskId, hash }) => {
              if (typeof hash !== "string")
                throw new Error(`Build task ${taskId} must have an eager Turbo hash`);
              return `${taskId}:${hash}`;
            }).sort();
            const hash = createHash("sha256").update(hashes.join("\n")).digest("hex");
            console.log(`key=${process.env.BUILD_CACHE_PREFIX}-${hash}`);
          ' >> "$GITHUB_OUTPUT"
    - name: Restore portable build outputs
      if: inputs.save != 'true'
      uses: actions/cache/restore@v4
      with:
        path: .turbo/cache/
        key: ${{ steps.plan.outputs.key }}
    - name: Restore and save portable build outputs
      if: inputs.save == 'true'
      uses: actions/cache@v4
      with:
        path: .turbo/cache/
        key: ${{ steps.plan.outputs.key }}