build-cache.yml

name: Build cache

# Saves the build cache of the C# repositories on develop, where every pull request can read it. A cache saved by a pull request run is only
# visible to that pull request, so after a PR run this checks whether develop already has the current state, and builds it from develop when not.
# It never uses what the pull request built: the refresh clones and builds the C# repositories itself, with the code on develop.

on:
  workflow_run:
    workflows: [PR]
    types: [completed]
  workflow_dispatch:

permissions:
  contents: read

# The running refresh finishes, and a newer pending one replaces an older pending one
concurrency:
  group: build-cache
  cancel-in-progress: false

jobs:
  gate:
    name: Does develop need a refresh?
    # Never for a pull request from a fork, and only for develop when started by hand
    if: >-
      (github.event_name == 'workflow_run' && github.event.workflow_run.head_repository.full_name == github.repository)
      || (github.event_name == 'workflow_dispatch' && github.ref == 'refs/heads/develop')
    runs-on: ubuntu-latest
    permissions:
      contents: read
      actions: read
    outputs:
      refresh: ${{ steps.lookup.outputs.refresh }}

    steps:
      - uses: actions/checkout@v4
        with:
          ref: develop

      # The plan is made for the Windows build. Its state prefix leaves out the build tools, which only the Windows runner knows
      - name: Plan the build
        id: plan
        shell: pwsh
        run: ./.github/scripts/Build-Repositories.ps1 -List Included-repositories.txt -Plan -OS Windows -ToolsVersion ubuntu

      - name: Look for the current state on develop
        id: lookup
        shell: pwsh
        env:
          GH_TOKEN: ${{ github.token }}
          STATE_PREFIX: ${{ steps.plan.outputs.state-prefix }}
          MANUAL: ${{ github.event_name == 'workflow_dispatch' }}
        run: |
          $found = gh cache list --repo $env:GITHUB_REPOSITORY --ref refs/heads/develop --key $env:STATE_PREFIX --json key --jq '.[].key'
          if ($LASTEXITCODE -ne 0) { exit $LASTEXITCODE }

          $refresh = $env:MANUAL -eq "true" -or -not $found
          Write-Host $(if ($found) { "develop has: $found" } else { "develop has no entry starting with $env:STATE_PREFIX" })
          "refresh=$("$refresh".ToLower())" >> $env:GITHUB_OUTPUT

  refresh:
    name: Build and save on develop
    needs: gate
    if: needs.gate.outputs.refresh == 'true'
    runs-on: windows-latest

    steps:
      - uses: actions/checkout@v4
        with:
          ref: develop

      - name: Install the built BHoM assemblies
        uses: ./.github/actions/bhom-assemblies