Gt 367 GitHub workflow to merge main into develop (#282) (#284)

* ci: adding a workflow to autogen main to develop sync pr

* ci: adding a work dispatch trigger for testing

* chore: adjusting bool check for consistency

Author: alocay

.github/workflows/sync-develop.yml

@@ -0,0 +1,116 @@
+name: Sync main → develop
+
+on:
+  pull_request:
+    types: [closed]
+    branches: [main]
+  workflow_dispatch:
+    inputs:
+      head_branch:
+        description: "Branch to merge FROM (default: main)."
+        required: false
+        default: "main"
+      base_branch:
+        description: "Branch to merge INTO (default: develop)."
+        required: false
+        default: "develop"
+      source_pr_number:
+        description: "If testing, the PR number to comment on (optional)."
+        required: false
+      test_mode:
+        description: "Bypass PR/push guards for manual testing"
+        required: false
+        default: "true"
+
+permissions:
+  contents: write
+  pull-requests: write
+  issues: write
+
+concurrency:
+  group: sync-main-into-develop
+  cancel-in-progress: false
+
+jobs:
+  open-sync-pr:
+    if: |
+      github.actor != 'github-actions[bot]' && (
+        (
+            github.event_name == 'pull_request' && github.event.pull_request.merged == true
+        ) || (
+            github.event_name == 'workflow_dispatch' && (inputs.test_mode == 'true')
+        )
+      )
+    runs-on: ubuntu-latest
+
+    env:
+      # Use inputs for dispatch (testing), defaults for normal triggers
+      HEAD_BRANCH: ${{ (github.event_name == 'workflow_dispatch' && inputs.head_branch) || 'main' }}
+      BASE_BRANCH: ${{ (github.event_name == 'workflow_dispatch' && inputs.base_branch) || 'develop' }}
+      SOURCE_PR: ${{ (github.event_name == 'pull_request' && github.event.pull_request.number) || inputs.source_pr_number || '' }}
+
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+
+      # Generate branch name from PR# when available, otherwise use first 7 commit SHA characters
+      - name: Compute branch/name metadata
+        id: meta
+        run: |
+          if [ -n "${SOURCE_PR}" ]; then
+            echo "branch=sync/${HEAD_BRANCH}-into-${BASE_BRANCH}-pr-${SOURCE_PR}" >> $GITHUB_OUTPUT
+            echo "title=Sync ${HEAD_BRANCH} → ${BASE_BRANCH} (PR #${SOURCE_PR})" >> $GITHUB_OUTPUT
+            echo "body=Auto-opened to merge \`${HEAD_BRANCH}\` into \`${BASE_BRANCH}\`. Source PR: #${SOURCE_PR}." >> $GITHUB_OUTPUT
+          else
+            short_sha=${GITHUB_SHA::7}
+            echo "branch=sync/${HEAD_BRANCH}-into-${BASE_BRANCH}-${short_sha}" >> $GITHUB_OUTPUT
+            echo "title=Sync ${HEAD_BRANCH} → ${BASE_BRANCH} (${short_sha})" >> $GITHUB_OUTPUT
+            echo "body=Auto-opened to merge \`${HEAD_BRANCH}\` into \`${BASE_BRANCH}\` at \`${GITHUB_SHA}\`." >> $GITHUB_OUTPUT
+          fi
+
+      # Short-lived sync branch from develop and merge main into it (do NOT rebase)
+      # use +e to stop errors from short-circuiting the script
+      - name: Prepare sync branch
+        id: prep
+        run: |
+          git fetch origin "${BASE_BRANCH}" "${HEAD_BRANCH}"
+          git switch -c "${{ steps.meta.outputs.branch }}" "origin/${BASE_BRANCH}"
+          set +e
+          git merge --no-ff "origin/${HEAD_BRANCH}"
+          rc=$?
+          set -e
+          git add -A || true
+          git commit -m "WIP: merge ${HEAD_BRANCH} into ${BASE_BRANCH} via ${{ steps.meta.outputs.branch }}" || true
+          git push origin HEAD
+          echo "merge_status=$rc" >> "$GITHUB_OUTPUT"
+
+      # Open the PR targeting develop
+      - name: Open PR to develop
+        id: syncpr
+        uses: peter-evans/create-pull-request@v6
+        with:
+          branch: ${{ steps.meta.outputs.branch }}
+          base: ${{ env.BASE_BRANCH }}
+          title: ${{ steps.meta.outputs.title }}
+          body:  |
+            ${{ steps.meta.outputs.body }}
+
+            Merge status: ${{ steps.prep.outputs.merge_status == '0' && 'clean ✅' || 'conflicts ❗' }}
+          labels: ${{ steps.prep.outputs.merge_status == '0' && 'back-merge,automation' || 'back-merge,automation,conflicts' }}
+
+      # Comment back on the ORIGINAL merged PR with a link to the sync PR
+      - name: Comment on source PR with sync PR link
+        if: github.event_name == 'pull_request' && steps.syncpr.outputs.pull-request-number != ''
+        uses: actions/github-script@v7
+        with:
+          script: |
+            const issue_number = Number(process.env.SOURCE_PR);
+            const syncUrl = `${{ toJson(steps.syncpr.outputs['pull-request-url']) }}`.replace(/^"|"$/g, '');
+            const body = `Opened sync PR **${process.env.HEAD_BRANCH} → ${process.env.BASE_BRANCH}**: ${syncUrl}`;
+            await github.rest.issues.createComment({
+              owner: context.repo.owner,
+              repo: context.repo.repo,
+              issue_number,
+              body,
+            });