update-subtree.yml

name: Subtree Update

on:
  schedule:
    - cron: '0 14 * * *'  # Run at 14:00 UTC every day
  workflow_dispatch:

defaults:
  run:
    shell: bash

jobs:
  update-subtree-library:
    runs-on: ubuntu-latest

    steps:
    - name: Checkout Repository
      uses: actions/checkout@v4
      with:
        fetch-depth: 0
        path: verify-rust-std

    - name: Checkout Kani
      uses: actions/checkout@v4
      with:
        repository: model-checking/kani
        path: kani-tmp

    - name: Checkout Rust
      uses: actions/checkout@v4
      with:
        repository: rust-lang/rust
        fetch-depth: 0
        path: rust-tmp

    - name: Checkout git-filter-repo
      uses: actions/checkout@v4
      with:
        repository: newren/git-filter-repo
        path: git-filter-repo

    - name: Fetch Kani toolchain version
      run: |
        cd kani-tmp
        TOOLCHAIN_DATE=$(grep -oP 'channel = "nightly-\K\d{4}-\d{2}-\d{2}' rust-toolchain.toml)
        COMMIT_HASH=$(curl https://static.rust-lang.org/dist/$TOOLCHAIN_DATE/channel-rust-nightly-git-commit-hash.txt)
        if [ -z "$COMMIT_HASH" ]; then
          echo "Could not find commit hash on static.rust-lang.org"
          exit 1
        fi
        echo "Kani toolchain date: ${TOOLCHAIN_DATE}"
        echo "TOOLCHAIN_DATE=${TOOLCHAIN_DATE}" >> $GITHUB_ENV
        echo "Kani toolchain hash: ${COMMIT_HASH}"
        echo "COMMIT_HASH=${COMMIT_HASH}" >> $GITHUB_ENV

    - name: Update subtree/library locally
      run: |
        cd rust-tmp

        # Ensure "upstream/master" branch contains the target commit
        if ! git show ${COMMIT_HASH} --oneline --no-patch; then
          echo "Rust commit ${COMMIT_HASH} cannot be found."
          exit 1
        fi

        git checkout ${COMMIT_HASH}
        ../git-filter-repo/git-filter-repo --subdirectory-filter library --force
        git checkout -b subtree/library

        cd ../verify-rust-std
        git remote add rust-filtered ../rust-tmp/
        git fetch rust-filtered
        git checkout -t -b update-subtree/library origin/subtree/library
        SUBTREE_HEAD_MSG=$(git log --format=%s -n 1 origin/subtree/library)
        UPSTREAM_FROM=$(git log --grep="${SUBTREE_HEAD_MSG}" -n 1 --format=%H rust-filtered/subtree/library)
        UPSTREAM_HEAD=$(git log --format=%H -n 1 rust-filtered/subtree/library)
        if [ "${UPSTREAM_HEAD}" = "${UPSTREAM_FROM}" ]; then
          echo "Nothing to cherry-pick, ${UPSTREAM_FROM} matches ${UPSTREAM_HEAD} (${SUBTREE_HEAD_MSG})"
          echo "MERGE_CONFLICTS=noop" >> $GITHUB_ENV
        else
          git cherry-pick ${UPSTREAM_FROM}..rust-filtered/subtree/library
          echo "MERGE_CONFLICTS=maybe" >> $GITHUB_ENV
        fi

    - name: Create Pull Request
      if: ${{ env.MERGE_CONFLICTS != 'noop' }}
      uses: peter-evans/create-pull-request@v7
      with:
        title: 'Update subtree/library'
        body: |
          This is an automated PR to update the subtree/library branch to the changes
          up to and including ${{ env.COMMIT_HASH }} of ${{ env.TOOLCHAIN_DATE }}.
        branch: update-subtree/library
        delete-branch: true
        base: subtree/library
        path: verify-rust-std

    - name: Merge subtree/library changes
      if: ${{ env.MERGE_CONFLICTS != 'noop' }}
      run: |
        cd verify-rust-std
        SYNC_BRANCH="sync-$TOOLCHAIN_DATE"
        git checkout -t -b ${SYNC_BRANCH} origin/main
        git submodule update --init

        # This command may fail, which will require human intervention.
        if ! git subtree merge --prefix=library update-subtree/library --squash; then
          echo "MERGE_CONFLICTS=yes" >> $GITHUB_ENV
          git commit -a -m "Merge from $COMMIT_HASH with conflicts"
        else
          echo "MERGE_CONFLICTS=no" >> $GITHUB_ENV
        fi

        sed -i "s/^channel = \"nightly-.*\"/channel = \"${TOOLCHAIN_DATE}\"/" rust-toolchain.toml
        git commit "Update toolchain to ${TOOLCHAIN_DATE}" rust-toolchain.toml

    - name: Create Pull Request without conflicts
      if: ${{ env.MERGE_CONFLICTS == 'no' }}
      uses: peter-evans/create-pull-request@v7
      with:
        title: 'Merge subtree update'
        body: |
          This is an automated PR to merge library subtree updates
          up to and including ${{ env.COMMIT_HASH }} of ${{ env.TOOLCHAIN_DATE }}
          into main. This is a clean merge, no conflicts were detected.
        delete-branch: true
        path: verify-rust-std

    - name: Create Pull Request with conflicts
      if: ${{ env.MERGE_CONFLICTS == 'yes' }}
      uses: peter-evans/create-pull-request@v7
      with:
        title: 'Merge subtree update'
        body: |
          This is an automated PR to merge library subtree updates
          up to and including ${{ env.COMMIT_HASH }} of ${{ env.TOOLCHAIN_DATE }}
          into main. `git merge` resulted in conflicts, which require manual resolution.
          Files were commited with merge conflict markers.
        delete-branch: true
        path: verify-rust-std