# Guards the checked-in .llvm-version file, which CI reads (via the get-llvm
# action) to select the prebuilt LLVM release to build against. Whenever the
# llvm submodule pin or the file changes, this derives the version from the
# pinned commit and fails if the file was not updated to match.

name: Check LLVM Version

on:
  push:
    branches: ["main"]
    paths:
      - "llvm"
      - ".llvm-version"
      - ".gitmodules"
      - ".github/workflows/check-llvm-version.yml"
      - ".github/actions/get-llvm/action.yml"
  pull_request:
    types: [opened, synchronize]
    paths:
      - "llvm"
      - ".llvm-version"
      - ".gitmodules"
      - ".github/workflows/check-llvm-version.yml"
      - ".github/actions/get-llvm/action.yml"

jobs:
  check-llvm-version:
    runs-on: ubuntu-24.04
    steps:
      - name: Checkout revive
        uses: actions/checkout@v6

      - name: Verify .llvm-version Matches the Submodule Pin
        env:
          GH_TOKEN: ${{ github.token }}
        run: |
          set -euo pipefail

          LLVM_SHA=$(git ls-tree HEAD llvm | awk '{print $3}')
          LLVM_URL=$(git config -f .gitmodules submodule.llvm.url)

          # Do a treeless clone to avoid unnecessarily fetching source files.
          git clone --filter=tree:0 --no-checkout \
            "https://x-access-token:${GH_TOKEN}@${LLVM_URL#https://}" llvm-tmp

          # Try to get the most recent tag (e.g., "llvmorg-18.1.8").
          DETECTED_LLVM_TAG=$(git -C llvm-tmp describe --tags --abbrev=0 "$LLVM_SHA")

          # Convert "llvmorg-x.y.z" to "llvm-x.y.z".
          DETECTED_LLVM_VERSION=$(echo "$DETECTED_LLVM_TAG" | sed 's/^llvmorg-/llvm-/')
          RECORDED_LLVM_VERSION=$(cat .llvm-version)

          if [ "$DETECTED_LLVM_VERSION" != "$RECORDED_LLVM_VERSION" ]; then
            echo "::error file=.llvm-version::.llvm-version contains '$RECORDED_LLVM_VERSION' but the submodule pin describes to '$DETECTED_LLVM_VERSION'."
            exit 1
          fi
          echo "OK: .llvm-version ($RECORDED_LLVM_VERSION) matches the submodule pin."