auto-rebase-upstream.yml

name: Auto-rebase saga branches

# Two-stage scheduled rebase chain.
#
# Stage 1 ("rebase-master"): rebase this fork's master onto
#   locationtech/jts:master, force-push on success, open/update a
#   "Auto-rebase conflict on master" issue on failure.
#
# Stage 2 ("rebase-saga", matrix, needs: stage 1): for every saga
#   branch in the matrix, rebase onto the (now upstream-current) fork
#   master, force-push on success, open/update a per-branch conflict
#   issue on failure. Branches run in parallel; one branch's conflict
#   doesn't block the others (fail-fast: false).
#
# RULE-OUT spike branches (F-CP-spike-optionB, F-CP-spike-optionC) are
# intentionally NOT in the matrix — they're frozen records of failed
# experiments and force-pushing would erase the audit trail. Add them
# below if you decide they should follow master.
#
# All knobs are in the env block; the matrix list below is the second
# place to edit when the saga grows.

on:
  schedule:
    - cron: '0 6 * * *'   # 06:00 UTC daily
  workflow_dispatch:       # manual trigger from the Actions tab

permissions:
  contents: write
  issues: write

env:
  UPSTREAM_REPO: locationtech/jts
  UPSTREAM_BRANCH: master
  CONFLICT_LABEL: upstream-rebase-conflict

jobs:
  # ---------------------------------------------------------------
  # Stage 1: fork master  <-  locationtech/jts:master
  # ---------------------------------------------------------------
  rebase-master:
    runs-on: ubuntu-latest
    steps:
      - name: Checkout master with full history
        uses: actions/checkout@v4
        with:
          ref: master
          fetch-depth: 0
          token: ${{ secrets.GITHUB_TOKEN }}

      - name: Configure git identity
        run: |
          git config user.name  "github-actions[bot]"
          git config user.email "41898282+github-actions[bot]@users.noreply.github.com"

      - name: Add upstream remote and fetch
        run: |
          git remote remove upstream 2>/dev/null || true
          git remote add upstream "https://github.com/${UPSTREAM_REPO}.git"
          git fetch upstream "${UPSTREAM_BRANCH}"

      - name: Attempt rebase
        id: rebase
        run: |
          set +e
          git rebase "upstream/${UPSTREAM_BRANCH}"
          RC=$?
          if [ $RC -ne 0 ]; then
            CONFLICTS=$(git diff --name-only --diff-filter=U)
            git rebase --abort
            {
              echo "status=conflict"
              echo "conflicts<<EOF"
              echo "$CONFLICTS"
              echo "EOF"
            } >> "$GITHUB_OUTPUT"
            exit 0
          fi
          echo "status=clean" >> "$GITHUB_OUTPUT"

      - name: Force-push if ahead of origin
        if: steps.rebase.outputs.status == 'clean'
        run: |
          if ! git diff --quiet origin/master..HEAD; then
            git push --force-with-lease origin HEAD:master
          fi

      - name: Ensure conflict label exists
        if: steps.rebase.outputs.status == 'conflict'
        env:
          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
        run: |
          gh label create "${CONFLICT_LABEL}" \
            --description "Auto-rebase against ${UPSTREAM_REPO} hit a conflict" \
            --color "B60205" \
          || true

      - name: Open or update master conflict issue
        if: steps.rebase.outputs.status == 'conflict'
        env:
          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
          CONFLICTS: ${{ steps.rebase.outputs.conflicts }}
        run: |
          UPSTREAM_SHA=$(git rev-parse "upstream/${UPSTREAM_BRANCH}")
          TITLE_PREFIX="Auto-rebase conflict on master"
          BODY_FILE=$(mktemp)
          cat > "$BODY_FILE" <<EOF
          The scheduled rebase of \`master\` onto \`upstream/${UPSTREAM_BRANCH}\` (${UPSTREAM_REPO}) hit a conflict and was aborted. \`master\` is unchanged.

          **Upstream HEAD:** \`${UPSTREAM_SHA}\`
          **Workflow run:** ${{ github.server_url }}/${{ github.repository }}/actions/runs/${{ github.run_id }}

          **Conflicting paths:**
          \`\`\`
          ${CONFLICTS}
          \`\`\`

          Resolve locally:
          \`\`\`
          git fetch upstream
          git checkout master
          git rebase upstream/${UPSTREAM_BRANCH}
          # resolve files, then:
          git add -A && git rebase --continue
          git push --force-with-lease origin master
          \`\`\`

          This issue auto-updates on each subsequent failed run. Close it once the rebase has been resolved manually.
          EOF
          EXISTING=$(gh issue list \
            --label "${CONFLICT_LABEL}" \
            --state open \
            --search "${TITLE_PREFIX}" \
            --json number,title \
            --jq ".[] | select(.title | startswith(\"${TITLE_PREFIX}\")) | .number" \
            | head -1)
          if [ -n "$EXISTING" ]; then
            gh issue comment "$EXISTING" --body-file "$BODY_FILE"
          else
            gh issue create \
              --title "${TITLE_PREFIX} ($(date -u +%Y-%m-%d))" \
              --label "${CONFLICT_LABEL}" \
              --body-file "$BODY_FILE"
          fi

  # ---------------------------------------------------------------
  # Stage 2: every saga branch  <-  fork master
  # Runs after stage 1 so each saga branch sees the freshly updated
  # master. fail-fast: false so one branch's conflict doesn't block
  # the others.
  # ---------------------------------------------------------------
  rebase-saga:
    needs: rebase-master
    runs-on: ubuntu-latest
    strategy:
      fail-fast: false
      matrix:
        branch:
          - feature/sfa-curve-AT-NS-spike
          - feature/sfa-curve-F-CP-spike
          - feature/sfa-curve-F-CP-spike-optionA
          - feature/sfa-curve-F-MC-F-MS-spike
          - feature/sfa-curve-PRC-SN-spike
          - feature/sfa-curve-R-EQ-spike
          - feature/sfa-curve-buffer-spike
          - feature/sfa-curve-clothoid-playground
          - feature/sfa-curve-compoundcurve-members
          - feature/sfa-curve-extension-points
          - feature/sfa-curve-multisurface-function
          - feature/sfa-curve-testbuilder-ui
          - feature/sfa-curve-tin-tool
          - feature/sfa-curve-toLinear-densification
          - feature/sfa-curve-triangle-tool
    steps:
      - name: Checkout ${{ matrix.branch }}
        uses: actions/checkout@v4
        with:
          ref: ${{ matrix.branch }}
          fetch-depth: 0
          token: ${{ secrets.GITHUB_TOKEN }}

      - name: Configure git identity
        run: |
          git config user.name  "github-actions[bot]"
          git config user.email "41898282+github-actions[bot]@users.noreply.github.com"

      - name: Fetch latest master
        run: git fetch origin master

      - name: Attempt rebase onto origin/master
        id: rebase
        run: |
          set +e
          git rebase origin/master
          RC=$?
          if [ $RC -ne 0 ]; then
            CONFLICTS=$(git diff --name-only --diff-filter=U)
            git rebase --abort
            {
              echo "status=conflict"
              echo "conflicts<<EOF"
              echo "$CONFLICTS"
              echo "EOF"
            } >> "$GITHUB_OUTPUT"
            exit 0
          fi
          echo "status=clean" >> "$GITHUB_OUTPUT"

      - name: Force-push if ahead of origin
        if: steps.rebase.outputs.status == 'clean'
        run: |
          BRANCH="${{ matrix.branch }}"
          if ! git diff --quiet "origin/${BRANCH}..HEAD"; then
            git push --force-with-lease origin "HEAD:${BRANCH}"
          fi

      - name: Ensure conflict label exists
        if: steps.rebase.outputs.status == 'conflict'
        env:
          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
        run: |
          gh label create "${CONFLICT_LABEL}" \
            --description "Auto-rebase against ${UPSTREAM_REPO} hit a conflict" \
            --color "B60205" \
          || true

      - name: Open or update conflict issue for ${{ matrix.branch }}
        if: steps.rebase.outputs.status == 'conflict'
        env:
          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
          CONFLICTS: ${{ steps.rebase.outputs.conflicts }}
          BRANCH: ${{ matrix.branch }}
        run: |
          MASTER_SHA=$(git rev-parse origin/master)
          TITLE_PREFIX="Auto-rebase conflict on ${BRANCH}"
          BODY_FILE=$(mktemp)
          cat > "$BODY_FILE" <<EOF
          The scheduled rebase of \`${BRANCH}\` onto fresh \`origin/master\` hit a conflict and was aborted. \`${BRANCH}\` is unchanged.

          **Master HEAD:** \`${MASTER_SHA}\`
          **Workflow run:** ${{ github.server_url }}/${{ github.repository }}/actions/runs/${{ github.run_id }}

          **Conflicting paths:**
          \`\`\`
          ${CONFLICTS}
          \`\`\`

          Resolve locally:
          \`\`\`
          git fetch origin
          git checkout ${BRANCH}
          git rebase origin/master
          # resolve files, then:
          git add -A && git rebase --continue
          git push --force-with-lease origin ${BRANCH}
          \`\`\`

          This issue auto-updates on each subsequent failed run. Close it once the rebase has been resolved manually.
          EOF
          EXISTING=$(gh issue list \
            --label "${CONFLICT_LABEL}" \
            --state open \
            --search "${TITLE_PREFIX}" \
            --json number,title \
            --jq ".[] | select(.title | startswith(\"${TITLE_PREFIX}\")) | .number" \
            | head -1)
          if [ -n "$EXISTING" ]; then
            gh issue comment "$EXISTING" --body-file "$BODY_FILE"
          else
            gh issue create \
              --title "${TITLE_PREFIX} ($(date -u +%Y-%m-%d))" \
              --label "${CONFLICT_LABEL}" \
              --body-file "$BODY_FILE"
          fi