lean4-htt/.github/workflows/pr-release.yml

# Push a release to the lean4-pr-releases repository, whenever someone pushes to a PR branch.

# This needs to run with the `secrets.PR_RELEASES_TOKEN` token available,
# but PR branches will generally come from forks,
# so it is not possible to run this using the `pull_request` or `pull_request_target` workflows.
# Instead we use `workflow_run`, which essentially allows us to escalate privileges
# (but only runs the CI as described in the `master` branch, not in the PR branch).

# The main specification/documentation for this workflow is at
# https://leanprover-community.github.io/contribute/tags_and_branches.html
# Keep that in sync!

name: PR release

on:
  workflow_run: # https://docs.github.com/en/actions/using-workflows/events-that-trigger-workflows#workflow_run
    workflows: [CI]
    types: [completed]

jobs:
  on-success:
    runs-on: ubuntu-latest
    if: github.event.workflow_run.conclusion == 'success' && github.event.workflow_run.event == 'pull_request' && github.repository == 'leanprover/lean4'
    steps:
      - name: Retrieve information about the original workflow
        uses: potiuk/get-workflow-origin@v1_1 # https://github.com/marketplace/actions/get-workflow-origin
        # This action is deprecated and archived, but it seems hard to find a better solution for getting the PR number
        # see https://github.com/orgs/community/discussions/25220 for some discussion
        id: workflow-info
        with:
          token: ${{ secrets.GITHUB_TOKEN }}
          sourceRunId: ${{ github.event.workflow_run.id }}

      - name: Download artifact from the previous workflow.
        if: ${{ steps.workflow-info.outputs.pullRequestNumber != '' }}
        id: download-artifact
        uses: dawidd6/action-download-artifact@v11 # https://github.com/marketplace/actions/download-workflow-artifact
        with:
          run_id: ${{ github.event.workflow_run.id }}
          path: artifacts
          name: build-.*
          name_is_regexp: true

      - name: Push tag
        if: ${{ steps.workflow-info.outputs.pullRequestNumber != '' }}
        run: |
          git init --bare lean4.git
          git -C lean4.git remote add origin https://github.com/${{ github.repository_owner }}/lean4.git
          git -C lean4.git fetch -n origin master
          git -C lean4.git fetch -n origin "${{ steps.workflow-info.outputs.sourceHeadSha }}"
          
          # Create both the original tag and the SHA-suffixed tag
          SHORT_SHA="${{ steps.workflow-info.outputs.sourceHeadSha }}"
          SHORT_SHA="${SHORT_SHA:0:7}"
          
          # Export the short SHA for use in subsequent steps
          echo "SHORT_SHA=${SHORT_SHA}" >> "$GITHUB_ENV"

          git -C lean4.git tag -f pr-release-${{ steps.workflow-info.outputs.pullRequestNumber }} "${{ steps.workflow-info.outputs.sourceHeadSha }}"
          git -C lean4.git tag -f pr-release-${{ steps.workflow-info.outputs.pullRequestNumber }}-"${SHORT_SHA}" "${{ steps.workflow-info.outputs.sourceHeadSha }}"
          
          git -C lean4.git remote add pr-releases https://foo:'${{ secrets.PR_RELEASES_TOKEN }}'@github.com/${{ github.repository_owner }}/lean4-pr-releases.git
          git -C lean4.git push -f pr-releases pr-release-${{ steps.workflow-info.outputs.pullRequestNumber }}
          git -C lean4.git push -f pr-releases pr-release-${{ steps.workflow-info.outputs.pullRequestNumber }}-"${SHORT_SHA}"
      - name: Delete existing release if present
        if: ${{ steps.workflow-info.outputs.pullRequestNumber != '' }}
        run: |
          # Try to delete any existing release for the current PR (just the version without the SHA suffix).
          gh release delete --repo ${{ github.repository_owner }}/lean4-pr-releases pr-release-${{ steps.workflow-info.outputs.pullRequestNumber }} -y || true
        env:
          GH_TOKEN: ${{ secrets.PR_RELEASES_TOKEN }}
      - name: Release (short format)
        if: ${{ steps.workflow-info.outputs.pullRequestNumber != '' }}
        uses: softprops/action-gh-release@72f2c25fcb47643c292f7107632f7a47c1df5cd8
        with:
          name: Release for PR ${{ steps.workflow-info.outputs.pullRequestNumber }}
          # There are coredumps files here as well, but all in deeper subdirectories.
          files: artifacts/*/*
          fail_on_unmatched_files: true
          draft: false
          tag_name: pr-release-${{ steps.workflow-info.outputs.pullRequestNumber }}
          repository: ${{ github.repository_owner }}/lean4-pr-releases
        env:
          # The token used here must have `workflow` privileges.
          GITHUB_TOKEN: ${{ secrets.PR_RELEASES_TOKEN }}

      - name: Release (SHA-suffixed format)
        if: ${{ steps.workflow-info.outputs.pullRequestNumber != '' }}
        uses: softprops/action-gh-release@72f2c25fcb47643c292f7107632f7a47c1df5cd8
        with:
          name: Release for PR ${{ steps.workflow-info.outputs.pullRequestNumber }} (${{ steps.workflow-info.outputs.sourceHeadSha }})
          # There are coredumps files here as well, but all in deeper subdirectories.
          files: artifacts/*/*
          fail_on_unmatched_files: true
          draft: false
          tag_name: pr-release-${{ steps.workflow-info.outputs.pullRequestNumber }}-${{ env.SHORT_SHA }}
          repository: ${{ github.repository_owner }}/lean4-pr-releases
        env:
          # The token used here must have `workflow` privileges.
          GITHUB_TOKEN: ${{ secrets.PR_RELEASES_TOKEN }}

      - name: Report release status (short format)
        if: ${{ steps.workflow-info.outputs.pullRequestNumber != '' }}
        uses: actions/github-script@v7
        with:
          script: |
            await github.rest.repos.createCommitStatus({
              owner: context.repo.owner,
              repo: context.repo.repo,
              sha: "${{ steps.workflow-info.outputs.sourceHeadSha }}",
              state: "success",
              context: "PR toolchain",
              description: "${{ github.repository_owner }}/lean4-pr-releases:pr-release-${{ steps.workflow-info.outputs.pullRequestNumber }}",
            });

      - name: Report release status (SHA-suffixed format)
        if: ${{ steps.workflow-info.outputs.pullRequestNumber != '' }}
        uses: actions/github-script@v7
        with:
          script: |
            await github.rest.repos.createCommitStatus({
              owner: context.repo.owner,
              repo: context.repo.repo,
              sha: "${{ steps.workflow-info.outputs.sourceHeadSha }}",
              state: "success",
              context: "PR toolchain (SHA-suffixed)",
              description: "${{ github.repository_owner }}/lean4-pr-releases:pr-release-${{ steps.workflow-info.outputs.pullRequestNumber }}-${{ env.SHORT_SHA }}",
            });

      - name: Add label
        if: ${{ steps.workflow-info.outputs.pullRequestNumber != '' }}
        uses: actions/github-script@v7
        with:
          script: |
            await github.rest.issues.addLabels({
              issue_number: ${{ steps.workflow-info.outputs.pullRequestNumber }},
              owner: context.repo.owner,
              repo: context.repo.repo,
              labels: ['toolchain-available']
            })

      # Next, determine the most recent nightly release in this PR's history.
      - name: Find most recent nightly in feature branch
        id: most-recent-nightly-tag
        if: ${{ steps.workflow-info.outputs.pullRequestNumber != '' }}
        run: |
          git -C lean4.git remote add nightly https://github.com/leanprover/lean4-nightly.git
          git -C lean4.git fetch nightly '+refs/tags/nightly-*:refs/tags/nightly-*'
          git -C lean4.git tag --merged "${{ steps.workflow-info.outputs.sourceHeadSha }}" --list "nightly-*" \
            | sort -rV | head -n 1 | sed "s/^nightly-*/MOST_RECENT_NIGHTLY=/" | tee -a "$GITHUB_ENV"

      - name: 'Setup jq'
        if: ${{ steps.workflow-info.outputs.pullRequestNumber != '' }}
        uses: dcarbone/install-jq-action@v3.2.0

      # Check that the most recently nightly coincides with 'git merge-base HEAD master'
      - name: Check merge-base and nightly-testing-YYYY-MM-DD for Mathlib/Batteries
        if: ${{ steps.workflow-info.outputs.pullRequestNumber != '' }}
        id: ready
        run: |
          echo "Most recent nightly release in your branch: $MOST_RECENT_NIGHTLY"
          NIGHTLY_SHA=$(git -C lean4.git rev-parse "nightly-$MOST_RECENT_NIGHTLY^{commit}")
          echo "SHA of most recent nightly release: $NIGHTLY_SHA"
          MERGE_BASE_SHA=$(git -C lean4.git merge-base origin/master "${{ steps.workflow-info.outputs.sourceHeadSha }}")
          echo "SHA of merge-base: $MERGE_BASE_SHA"
          if [ "$NIGHTLY_SHA" = "$MERGE_BASE_SHA" ]; then
            echo "The merge base of this PR coincides with the nightly release"

            BATTERIES_REMOTE_TAGS="$(git ls-remote https://github.com/leanprover-community/batteries.git nightly-testing-"$MOST_RECENT_NIGHTLY")"
            MATHLIB_REMOTE_TAGS="$(git ls-remote https://github.com/leanprover-community/mathlib4-nightly-testing.git nightly-testing-"$MOST_RECENT_NIGHTLY")"

            if [[ -n "$BATTERIES_REMOTE_TAGS" ]]; then
              echo "... and Batteries has a 'nightly-testing-$MOST_RECENT_NIGHTLY' tag."
              MESSAGE=""

              if [[ -n "$MATHLIB_REMOTE_TAGS" ]]; then
                echo "... and Mathlib has a 'nightly-testing-$MOST_RECENT_NIGHTLY' tag."
              else
                echo "... but Mathlib does not yet have a 'nightly-testing-$MOST_RECENT_NIGHTLY' tag."
                MESSAGE="- ❗ Mathlib CI can not be attempted yet, as the \`nightly-testing-$MOST_RECENT_NIGHTLY\` tag does not exist there yet. We will retry when you push more commits. If you rebase your branch onto \`nightly-with-mathlib\`, Mathlib CI should run now."
              fi
            else
              echo "... but Batteries does not yet have a 'nightly-testing-$MOST_RECENT_NIGHTLY' tag."
              MESSAGE="- ❗ Batteries CI can not be attempted yet, as the \`nightly-testing-$MOST_RECENT_NIGHTLY\` tag does not exist there yet. We will retry when you push more commits. If you rebase your branch onto \`nightly-with-mathlib\`, Batteries CI should run now."
            fi
          else
            echo "The most recently nightly tag on this branch has SHA: $NIGHTLY_SHA"
            echo "but 'git merge-base origin/master HEAD' reported: $MERGE_BASE_SHA"
            git -C lean4.git log -10 origin/master

            git -C lean4.git fetch origin nightly-with-mathlib
            NIGHTLY_WITH_MATHLIB_SHA="$(git -C lean4.git rev-parse "origin/nightly-with-mathlib")"
            MESSAGE="- ❗ Batteries/Mathlib CI will not be attempted unless your PR branches off the \`nightly-with-mathlib\` branch. Try \`git rebase $MERGE_BASE_SHA --onto $NIGHTLY_WITH_MATHLIB_SHA\`."
          fi

          if [[ -n "$MESSAGE" ]]; then
            # Check if force-mathlib-ci label is present
            LABELS="$(curl --retry 3 --location --silent \
                          -H "Authorization: token ${{ secrets.MATHLIB4_COMMENT_BOT }}" \
                          -H "Accept: application/vnd.github.v3+json" \
                          "https://api.github.com/repos/leanprover/lean4/issues/${{ steps.workflow-info.outputs.pullRequestNumber }}/labels" \
                          | jq -r '.[].name')"
            
            if echo "$LABELS" | grep -q "^force-mathlib-ci$"; then
              echo "force-mathlib-ci label detected, forcing CI despite issues"
              MESSAGE="Forcing Mathlib CI because the \`force-mathlib-ci\` label is present, despite problem: $MESSAGE"
              FORCE_CI=true
            else
              MESSAGE="$MESSAGE You can force Mathlib CI using the \`force-mathlib-ci\` label."
            fi

            echo "Checking existing messages"

            # The code for updating comments is duplicated in mathlib's
            # scripts/lean-pr-testing-comments.sh
            # so keep in sync

            # Use GitHub API to check if a comment already exists
            existing_comment="$(curl --retry 3 --location --silent \
                                    -H "Authorization: token ${{ secrets.MATHLIB4_COMMENT_BOT }}" \
                                    -H "Accept: application/vnd.github.v3+json" \
                                    "https://api.github.com/repos/leanprover/lean4/issues/${{ steps.workflow-info.outputs.pullRequestNumber }}/comments" \
                                    | jq 'first(.[] | select(.body | test("^- . Mathlib") or startswith("Mathlib CI status")) | select(.user.login == "leanprover-community-bot"))')"
            existing_comment_id="$(echo "$existing_comment" | jq -r .id)"
            existing_comment_body="$(echo "$existing_comment" | jq -r .body)"

            if [[ "$existing_comment_body" != *"$MESSAGE"* ]]; then
              MESSAGE="$MESSAGE ($(date "+%Y-%m-%d %H:%M:%S"))"

              echo "Posting message to the comments: $MESSAGE"

              # Append new result to the existing comment or post a new comment
              # It's essential we use the MATHLIB4_COMMENT_BOT token here, so that Mathlib CI can subsequently edit the comment.
              if [ -z "$existing_comment_id" ]; then
                INTRO="Mathlib CI status ([docs](https://leanprover-community.github.io/contribute/tags_and_branches.html)):"
                # Post new comment with a bullet point
                echo "Posting as new comment at leanprover/lean4/issues/${{ steps.workflow-info.outputs.pullRequestNumber }}/comments"
                curl -L -s \
                  -X POST \
                  -H "Authorization: token ${{ secrets.MATHLIB4_COMMENT_BOT }}" \
                  -H "Accept: application/vnd.github.v3+json" \
                  -d "$(jq --null-input --arg intro "$INTRO" --arg val "$MESSAGE" '{"body":($intro + "\n" + $val)}')" \
                  "https://api.github.com/repos/leanprover/lean4/issues/${{ steps.workflow-info.outputs.pullRequestNumber }}/comments"
              else
                # Append new result to the existing comment
                echo "Appending to existing comment at leanprover/lean4/issues/${{ steps.workflow-info.outputs.pullRequestNumber }}/comments"
                curl -L -s \
                  -X PATCH \
                  -H "Authorization: token ${{ secrets.MATHLIB4_COMMENT_BOT }}" \
                  -H "Accept: application/vnd.github.v3+json" \
                  -d "$(jq --null-input --arg existing "$existing_comment_body" --arg message "$MESSAGE" '{"body":($existing + "\n" + $message)}')" \
                  "https://api.github.com/repos/leanprover/lean4/issues/comments/$existing_comment_id"
              fi
            else
              echo "The message already exists in the comment body."
            fi

            if [[ "$FORCE_CI" == "true" ]]; then
              echo "mathlib_ready=true" >> "$GITHUB_OUTPUT"
            else
              echo "mathlib_ready=false" >> "$GITHUB_OUTPUT"
            fi
          else
            echo "mathlib_ready=true" >> "$GITHUB_OUTPUT"
          fi

      - name: Check merge-base and nightly-testing-YYYY-MM-DD for reference manual
        if: ${{ steps.workflow-info.outputs.pullRequestNumber != '' }}
        id: reference-manual-ready
        run: |
          echo "Most recent nightly release in your branch: $MOST_RECENT_NIGHTLY"
          NIGHTLY_SHA=$(git -C lean4.git rev-parse "nightly-$MOST_RECENT_NIGHTLY^{commit}")
          echo "SHA of most recent nightly release: $NIGHTLY_SHA"
          MERGE_BASE_SHA=$(git -C lean4.git merge-base origin/master "${{ steps.workflow-info.outputs.sourceHeadSha }}")
          echo "SHA of merge-base: $MERGE_BASE_SHA"
          if [ "$NIGHTLY_SHA" = "$MERGE_BASE_SHA" ]; then
            echo "The merge base of this PR coincides with the nightly release"

            MANUAL_REMOTE_TAGS="$(git ls-remote https://github.com/leanprover/reference-manual.git nightly-testing-"$MOST_RECENT_NIGHTLY")"
            if [[ -n "$MANUAL_REMOTE_TAGS" ]]; then
              echo "... and the reference manual has a 'nightly-testing-$MOST_RECENT_NIGHTLY' tag."
              MESSAGE=""
            else
              echo "... but the reference manual does not yet have a 'nightly-testing-$MOST_RECENT_NIGHTLY' tag."
              MESSAGE="- ❗ Reference manual CI can not be attempted yet, as the \`nightly-testing-$MOST_RECENT_NIGHTLY\` tag does not exist there yet. We will retry when you push more commits. If you rebase your branch onto \`nightly-with-manual\`, reference manual CI should run now."
            fi
          else
            echo "The most recently nightly tag on this branch has SHA: $NIGHTLY_SHA"
            echo "but 'git merge-base origin/master HEAD' reported: $MERGE_BASE_SHA"
            git -C lean4.git log -10 origin/master

            git -C lean4.git fetch origin nightly-with-manual
            NIGHTLY_WITH_MANUAL_SHA="$(git -C lean4.git rev-parse "origin/nightly-with-manual")"
            MESSAGE="- ❗ Reference manual CI will not be attempted unless your PR branches off the \`nightly-with-manual\` branch. Try \`git rebase $MERGE_BASE_SHA --onto $NIGHTLY_WITH_MANUAL_SHA\`."
          fi

          if [[ -n "$MESSAGE" ]]; then
            # Check if force-manual-ci label is present
            LABELS="$(curl --retry 3 --location --silent \
                          -H "Authorization: token ${{ secrets.MANUAL_COMMENT_BOT }}" \
                          -H "Accept: application/vnd.github.v3+json" \
                          "https://api.github.com/repos/leanprover/lean4/issues/${{ steps.workflow-info.outputs.pullRequestNumber }}/labels" \
                          | jq -r '.[].name')"
            
            if echo "$LABELS" | grep -q "^force-manual-ci$"; then
              echo "force-manual-ci label detected, forcing CI despite issues"
              MESSAGE="Forcing reference manual CI because the \`force-manual-ci\` label is present, despite problem: $MESSAGE"
              FORCE_CI=true
            else
              MESSAGE="$MESSAGE You can force reference manual CI using the \`force-manual-ci\` label."
            fi

            echo "Checking existing messages"

            # The code for updating comments is duplicated in the reference manual's
            # scripts/lean-pr-testing-comments.sh
            # so keep in sync

            # Use GitHub API to check if a comment already exists
            existing_comment="$(curl --retry 3 --location --silent \
                                    -H "Authorization: token ${{ secrets.MANUAL_COMMENT_BOT }}" \
                                    -H "Accept: application/vnd.github.v3+json" \
                                    "https://api.github.com/repos/leanprover/lean4/issues/${{ steps.workflow-info.outputs.pullRequestNumber }}/comments" \
                                    | jq 'first(.[] | select(.body | test("^- . Manual") or startswith("Reference manual CI status")) | select(.user.login == "leanprover-bot"))')"
            existing_comment_id="$(echo "$existing_comment" | jq -r .id)"
            existing_comment_body="$(echo "$existing_comment" | jq -r .body)"

            if [[ "$existing_comment_body" != *"$MESSAGE"* ]]; then
              MESSAGE="$MESSAGE ($(date "+%Y-%m-%d %H:%M:%S"))"

              echo "Posting message to the comments: $MESSAGE"

              # Append new result to the existing comment or post a new comment
              # It's essential we use the MANUAL_COMMENT_BOT token here, so that reference manual CI can subsequently edit the comment.
              if [ -z "$existing_comment_id" ]; then
                INTRO="Reference manual CI status:"
                # Post new comment with a bullet point
                echo "Posting as new comment at leanprover/lean4/issues/${{ steps.workflow-info.outputs.pullRequestNumber }}/comments"
                curl -L -s \
                  -X POST \
                  -H "Authorization: token ${{ secrets.MANUAL_COMMENT_BOT }}" \
                  -H "Accept: application/vnd.github.v3+json" \
                  -d "$(jq --null-input --arg intro "$INTRO" --arg val "$MESSAGE" '{"body":($intro + "\n" + $val)}')" \
                  "https://api.github.com/repos/leanprover/lean4/issues/${{ steps.workflow-info.outputs.pullRequestNumber }}/comments"
              else
                # Append new result to the existing comment
                echo "Appending to existing comment at leanprover/lean4/issues/${{ steps.workflow-info.outputs.pullRequestNumber }}/comments"
                curl -L -s \
                  -X PATCH \
                  -H "Authorization: token ${{ secrets.MANUAL_COMMENT_BOT }}" \
                  -H "Accept: application/vnd.github.v3+json" \
                  -d "$(jq --null-input --arg existing "$existing_comment_body" --arg message "$MESSAGE" '{"body":($existing + "\n" + $message)}')" \
                  "https://api.github.com/repos/leanprover/lean4/issues/comments/$existing_comment_id"
              fi
            else
              echo "The message already exists in the comment body."
            fi

            if [[ "$FORCE_CI" == "true" ]]; then
              echo "manual_ready=true" >> "$GITHUB_OUTPUT"
            else
              echo "manual_ready=false" >> "$GITHUB_OUTPUT"
            fi
          else
            echo "manual_ready=true" >> "$GITHUB_OUTPUT"
          fi


      - name: Report mathlib base
        if: ${{ steps.workflow-info.outputs.pullRequestNumber != '' && steps.ready.outputs.mathlib_ready == 'true' }}
        uses: actions/github-script@v7
        with:
          script: |
            const description =
              process.env.MOST_RECENT_NIGHTLY ?
              "nightly-" + process.env.MOST_RECENT_NIGHTLY :
              "not branched off nightly";
            await github.rest.repos.createCommitStatus({
              owner: context.repo.owner,
              repo: context.repo.repo,
              sha: "${{ steps.workflow-info.outputs.sourceHeadSha }}",
              state: "success",
              context: "PR branched off:",
              description: description,
            });

      # We next automatically create a Batteries branch using this toolchain.
      # Batteries doesn't itself have a mechanism to report results of CI from this branch back to Lean
      # Instead this is taken care of by Mathlib CI, which will fail if Batteries fails.
      - name: Cleanup workspace
        if: steps.workflow-info.outputs.pullRequestNumber != '' && steps.ready.outputs.mathlib_ready == 'true'
        run: |
          sudo rm -rf ./*

      # Checkout the Batteries repository with all branches
      - name: Checkout Batteries repository
        if: steps.workflow-info.outputs.pullRequestNumber != '' && steps.ready.outputs.mathlib_ready == 'true'
        uses: actions/checkout@v5
        with:
          repository: leanprover-community/batteries
          token: ${{ secrets.MATHLIB4_BOT }}
          ref: nightly-testing
          fetch-depth: 0 # This ensures we check out all tags and branches.

      - name: Check if tag exists
        if: steps.workflow-info.outputs.pullRequestNumber != '' && steps.ready.outputs.mathlib_ready == 'true'
        id: check_batteries_tag
        run: |
          git config user.name "leanprover-community-mathlib4-bot"
          git config user.email "leanprover-community-mathlib4-bot@users.noreply.github.com"

          if git ls-remote --heads --tags --exit-code origin "nightly-testing-${MOST_RECENT_NIGHTLY}" >/dev/null; then
            BASE="nightly-testing-${MOST_RECENT_NIGHTLY}"
          else
            echo "Couldn't find a 'nightly-testing-${MOST_RECENT_NIGHTLY}' tag at Batteries. Falling back to 'nightly-testing'."
            BASE=nightly-testing
          fi

          echo "Using base branch: $BASE"

          EXISTS="$(git ls-remote --heads origin lean-pr-testing-${{ steps.workflow-info.outputs.pullRequestNumber }} | wc -l)"
          echo "Branch exists: $EXISTS"
          if [ "$EXISTS" = "0" ]; then
            echo "Branch does not exist, creating it."
            git switch -c lean-pr-testing-${{ steps.workflow-info.outputs.pullRequestNumber }} "$BASE"
            echo "leanprover/lean4-pr-releases:pr-release-${{ steps.workflow-info.outputs.pullRequestNumber }}-${{ env.SHORT_SHA }}" > lean-toolchain
            git add lean-toolchain
            git commit -m "Update lean-toolchain for testing https://github.com/leanprover/lean4/pull/${{ steps.workflow-info.outputs.pullRequestNumber }}"
          else
            echo "Branch already exists, updating lean-toolchain."
            git switch lean-pr-testing-${{ steps.workflow-info.outputs.pullRequestNumber }}
            # The Batteries `nightly-testing` or `nightly-testing-YYYY-MM-DD` branch may have moved since this branch was created, so merge their changes.
            # (This should no longer be possible once `nightly-testing-YYYY-MM-DD` is a tag, but it is still safe to merge.)
            git merge "$BASE" --strategy-option ours --no-commit --allow-unrelated-histories
            echo "leanprover/lean4-pr-releases:pr-release-${{ steps.workflow-info.outputs.pullRequestNumber }}-${{ env.SHORT_SHA }}" > lean-toolchain
            git add lean-toolchain
            git commit -m "Update lean-toolchain for https://github.com/leanprover/lean4/pull/${{ steps.workflow-info.outputs.pullRequestNumber }}"
          fi

      - name: Push changes
        if: steps.workflow-info.outputs.pullRequestNumber != '' && steps.ready.outputs.mathlib_ready == 'true'
        run: |
          git push origin lean-pr-testing-${{ steps.workflow-info.outputs.pullRequestNumber }}


      # We next automatically create a Mathlib branch using this toolchain.
      # Mathlib CI will be responsible for reporting back success or failure
      # to the PR comments asynchronously.
      - name: Cleanup workspace
        if: steps.workflow-info.outputs.pullRequestNumber != '' && steps.ready.outputs.mathlib_ready == 'true'
        run: |
          sudo rm -rf ./*

      # Checkout the mathlib4 repository with all branches
      - name: Checkout mathlib4 repository
        if: steps.workflow-info.outputs.pullRequestNumber != '' && steps.ready.outputs.mathlib_ready == 'true'
        uses: actions/checkout@v5
        with:
          repository: leanprover-community/mathlib4-nightly-testing
          token: ${{ secrets.MATHLIB4_BOT }}
          ref: nightly-testing
          fetch-depth: 0 # This ensures we check out all tags and branches.

      - name: install elan
        run: |
          set -o pipefail
          curl -sSfL https://github.com/leanprover/elan/releases/download/v3.0.0/elan-x86_64-unknown-linux-gnu.tar.gz | tar xz
          ./elan-init -y --default-toolchain none
          echo "$HOME/.elan/bin" >> "${GITHUB_PATH}"

      - name: Check if tag exists
        if: steps.workflow-info.outputs.pullRequestNumber != '' && steps.ready.outputs.mathlib_ready == 'true'
        id: check_mathlib_tag
        run: |
          git config user.name "leanprover-community-mathlib4-bot"
          git config user.email "leanprover-community-mathlib4-bot@users.noreply.github.com"

          if git ls-remote --heads --tags --exit-code origin "nightly-testing-${MOST_RECENT_NIGHTLY}" >/dev/null; then
            BASE="nightly-testing-${MOST_RECENT_NIGHTLY}"
          else
            echo "Couldn't find a 'nightly-testing-${MOST_RECENT_NIGHTLY}' branch at Mathlib. Falling back to 'nightly-testing'."
            BASE=nightly-testing
          fi

          echo "Using base tag: $BASE"

          EXISTS="$(git ls-remote --heads origin lean-pr-testing-${{ steps.workflow-info.outputs.pullRequestNumber }} | wc -l)"
          echo "Branch exists: $EXISTS"
          if [ "$EXISTS" = "0" ]; then
            echo "Branch does not exist, creating it."
            git switch -c lean-pr-testing-${{ steps.workflow-info.outputs.pullRequestNumber }} "$BASE"
            echo "leanprover/lean4-pr-releases:pr-release-${{ steps.workflow-info.outputs.pullRequestNumber }}-${{ env.SHORT_SHA }}" > lean-toolchain
            git add lean-toolchain
            sed -i 's,require "leanprover-community" / "batteries" @ git ".\+",require "leanprover-community" / "batteries" @ git "lean-pr-testing-${{ steps.workflow-info.outputs.pullRequestNumber }}",' lakefile.lean
            lake update batteries
            git add lakefile.lean lake-manifest.json
            git commit -m "Update lean-toolchain for testing https://github.com/leanprover/lean4/pull/${{ steps.workflow-info.outputs.pullRequestNumber }}"
          else
            echo "Branch already exists, updating lean-toolchain and bumping Batteries."
            git switch lean-pr-testing-${{ steps.workflow-info.outputs.pullRequestNumber }}
            # The Mathlib `nightly-testing` branch or `nightly-testing-YYYY-MM-DD` tag may have moved since this branch was created, so merge their changes.
            # (This should no longer be possible once `nightly-testing-YYYY-MM-DD` is a tag, but it is still safe to merge.)
            git merge "$BASE" --strategy-option ours --no-commit --allow-unrelated-histories
            echo "leanprover/lean4-pr-releases:pr-release-${{ steps.workflow-info.outputs.pullRequestNumber }}-${{ env.SHORT_SHA }}" > lean-toolchain
            git add lean-toolchain
            lake update batteries
            git add lake-manifest.json
            git commit -m "Update lean-toolchain for https://github.com/leanprover/lean4/pull/${{ steps.workflow-info.outputs.pullRequestNumber }}"
          fi

      - name: Push changes
        if: steps.workflow-info.outputs.pullRequestNumber != '' && steps.ready.outputs.mathlib_ready == 'true'
        run: |
          git push origin lean-pr-testing-${{ steps.workflow-info.outputs.pullRequestNumber }}

      # We next automatically create a reference manual branch using this toolchain.
      # Reference manual CI will be responsible for reporting back success or failure
      # to the PR comments asynchronously (and thus transitively SubVerso/Verso).
      - name: Cleanup workspace
        if: steps.workflow-info.outputs.pullRequestNumber != '' && steps.reference-manual-ready.outputs.manual_ready == 'true'
        run: |
          sudo rm -rf ./*

      # Checkout the reference manual repository with all branches
      - name: Checkout mathlib4 repository
        if: steps.workflow-info.outputs.pullRequestNumber != '' && steps.reference-manual-ready.outputs.manual_ready == 'true'
        uses: actions/checkout@v5
        with:
          repository: leanprover/reference-manual
          token: ${{ secrets.MANUAL_PR_BOT }}
          ref: nightly-testing
          fetch-depth: 0 # This ensures we check out all tags and branches.

      - name: Check if tag in reference manual exists
        if: steps.workflow-info.outputs.pullRequestNumber != '' && steps.reference-manual-ready.outputs.manual_ready == 'true'
        id: check_manual_tag
        run: |
          git config user.name "leanprover-bot"
          git config user.email "leanprover-bot@lean-fro.org"

          if git ls-remote --heads --tags --exit-code origin "nightly-testing-${MOST_RECENT_NIGHTLY}" >/dev/null; then
            BASE="nightly-testing-${MOST_RECENT_NIGHTLY}"
          else
            echo "Couldn't find a 'nightly-testing-${MOST_RECENT_NIGHTLY}' branch in the reference manual. Falling back to 'nightly-testing'."
            BASE=nightly-testing
          fi

          echo "Using base tag: $BASE"

          EXISTS="$(git ls-remote --heads origin lean-pr-testing-${{ steps.workflow-info.outputs.pullRequestNumber }} | wc -l)"
          echo "Branch exists: $EXISTS"
          if [ "$EXISTS" = "0" ]; then
            echo "Branch does not exist, creating it."
            git switch -c lean-pr-testing-${{ steps.workflow-info.outputs.pullRequestNumber }} "$BASE"
            echo "leanprover/lean4-pr-releases:pr-release-${{ steps.workflow-info.outputs.pullRequestNumber }}-${{ env.SHORT_SHA }}" > lean-toolchain
            git add lean-toolchain
            git add lakefile.lean lake-manifest.json
            git commit -m "Update lean-toolchain for testing https://github.com/leanprover/lean4/pull/${{ steps.workflow-info.outputs.pullRequestNumber }}"
          else
            echo "Branch already exists, updating lean-toolchain."
            git switch lean-pr-testing-${{ steps.workflow-info.outputs.pullRequestNumber }}
            # The reference manual's `nightly-testing` branch or `nightly-testing-YYYY-MM-DD` tag may have moved since this branch was created, so merge their changes.
            # (This should no longer be possible once `nightly-testing-YYYY-MM-DD` is a tag, but it is still safe to merge.)
            git merge "$BASE" --strategy-option ours --no-commit --allow-unrelated-histories
            echo "leanprover/lean4-pr-releases:pr-release-${{ steps.workflow-info.outputs.pullRequestNumber }}-${{ env.SHORT_SHA }}" > lean-toolchain
            git add lean-toolchain
            git add lake-manifest.json
            git commit -m "Update lean-toolchain for https://github.com/leanprover/lean4/pull/${{ steps.workflow-info.outputs.pullRequestNumber }}"
          fi

      - name: Push changes
        if: steps.workflow-info.outputs.pullRequestNumber != '' && steps.reference-manual-ready.outputs.manual_ready == 'true'
        run: |
          git push origin lean-pr-testing-${{ steps.workflow-info.outputs.pullRequestNumber }}