name: PostgreSQL 19
description: >
  The PostgreSQL 19 server (scripts/pg19-build.sh) in ~/pg19, from the cache of the newest commit of the branch. With exact set, the commit
  that is the head of the branch now (the nightly run and the pre-warm workflow); otherwise any build of the same recipe is good enough, so
  that a pull request never waits for a build and PostgreSQL 19 is at most as old as the last pre-warm run.

inputs:
  ref:
    description: The branch of the git tree
    default: REL_19_STABLE
  exact:
    description: Build the head of the branch when the cache has no build of that very commit
    default: 'false'

outputs:
  commit:
    description: The commit the server in ~/pg19 was built from
    value: ${{ steps.commit.outputs.commit }}

runs:
  using: composite
  steps:
    # the full ref: a bare name can match several refs, and two lines would break GITHUB_OUTPUT
    - id: head
      shell: bash
      run: echo "sha=$(git ls-remote --exit-code https://github.com/postgres/postgres.git "refs/heads/${{ inputs.ref }}" | cut -f1)" >> "$GITHUB_OUTPUT"

    # a build of the same recipe (the hash of the script) of an older commit is the fallback: the newest one the cache has
    - id: cache
      uses: actions/cache/restore@v5
      with:
        path: ~/pg19
        key: pg19-${{ runner.os }}-${{ hashFiles('scripts/pg19-build.sh') }}-${{ steps.head.outputs.sha }}
        restore-keys: pg19-${{ runner.os }}-${{ hashFiles('scripts/pg19-build.sh') }}-

    - id: build
      if: ${{ steps.cache.outputs.cache-matched-key == '' || (inputs.exact == 'true' && steps.cache.outputs.cache-hit != 'true') }}
      shell: bash
      run: echo "needed=true" >> "$GITHUB_OUTPUT"

    # the objects of the last build: a new commit of the branch recompiles the few files it touched
    - id: ccache
      if: ${{ steps.build.outputs.needed == 'true' }}
      uses: actions/cache@v5
      with:
        path: ~/.cache/ccache
        key: ccache-pg19-${{ runner.os }}-${{ steps.head.outputs.sha }}
        restore-keys: ccache-pg19-${{ runner.os }}-

    - if: ${{ steps.build.outputs.needed == 'true' }}
      shell: bash
      run: |
        scripts/apt-install.sh --update bison flex libipc-run-perl libicu-dev libxml2-dev ccache
        export CCACHE_DIR="$HOME/.cache/ccache"
        ccache --max-size=200M
        scripts/pg19-build.sh "$HOME/pg19" "${{ steps.head.outputs.sha }}"
        ccache --show-stats

    - if: ${{ steps.build.outputs.needed == 'true' }}
      uses: actions/cache/save@v5
      with:
        path: ~/pg19
        key: pg19-${{ runner.os }}-${{ hashFiles('scripts/pg19-build.sh') }}-${{ steps.head.outputs.sha }}

    - id: commit
      shell: bash
      run: echo "commit=$(cat ~/pg19/.commit)" | tee -a "$GITHUB_OUTPUT"