Reuse existing branch and PR for stops data updates

- Check for existing open PR before creating new branch
- Checkout and update existing branch instead of creating timestamped ones
- Use force-with-lease to safely update branch with new data
- Add timestamped comment to existing PR instead of closing/recreating
- Fetch all branches to ensure existing branch is available

1 files changed, 69 insertions, 31 deletions

diff --git a/.github/workflows/update-stops-data.yml b/.github/workflows/update-stops-data.yml
index 619f7dd..6268b5f 100644
--- a/.github/workflows/update-stops-data.yml
+++ b/.github/workflows/update-stops-data.yml
@@ -10,55 +10,93 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout code
-        uses: actions/checkout@v3
+        uses: actions/checkout@v5
+        with:
+          fetch-depth: 0  # Fetch all branches
+      
+      - name: Check for existing branch and PR
+        id: check_existing
+        env:
+          GH_TOKEN: ${{ github.token }}
+        run: |
+          # Look for existing open PR with our title
+          existing_pr=$(gh pr list --json number,headRefName --search "Update stops data in:title author:app/github-actions is:open" --limit 1)
+          
+          if [[ $(echo "$existing_pr" | jq length) -gt 0 ]]; then
+            branch_name=$(echo "$existing_pr" | jq -r '.[0].headRefName')
+            pr_number=$(echo "$existing_pr" | jq -r '.[0].number')
+            echo "branch_name=$branch_name" >> $GITHUB_OUTPUT
+            echo "pr_number=$pr_number" >> $GITHUB_OUTPUT
+            echo "has_existing=true" >> $GITHUB_OUTPUT
+            echo "Found existing PR #$pr_number with branch $branch_name"
+          else
+            branch_name="update-stops-data"
+            echo "branch_name=$branch_name" >> $GITHUB_OUTPUT
+            echo "has_existing=false" >> $GITHUB_OUTPUT
+            echo "No existing PR found, will use branch $branch_name"
+          fi
+
+      - name: Setup branch
+        env:
+          BRANCH_NAME: ${{ steps.check_existing.outputs.branch_name }}
+          HAS_EXISTING: ${{ steps.check_existing.outputs.has_existing }}
+        run: |
+          git config user.name "github-actions[bot]"
+          git config user.email "41898282+github-actions[bot]@users.noreply.github.com"
+          
+          if [[ "$HAS_EXISTING" == "true" ]]; then
+            # Checkout existing branch
+            git fetch origin $BRANCH_NAME
+            git checkout $BRANCH_NAME
+            echo "Checked out existing branch $BRANCH_NAME"
+          else
+            # Create new branch
+            git checkout -b $BRANCH_NAME
+            echo "Created new branch $BRANCH_NAME"
+          fi
 
       - name: Install uv
-        uses: astral-sh/setup-uv@v5
+        uses: astral-sh/setup-uv@v7
 
       - name: Run download script
         run: uv run data/download-stops.py
 
-      - name: Commit changes if any
+      - name: Commit and push changes if any
         id: commit
+        env:
+          BRANCH_NAME: ${{ steps.check_existing.outputs.branch_name }}
+          HAS_EXISTING: ${{ steps.check_existing.outputs.has_existing }}
         run: |
-          git config user.name "github-actions[bot]"
-          git config user.email "41898282+github-actions[bot]@users.noreply.github.com"
           git add src/frontend/public/stops.json
+          
           if git diff --staged --exit-code; then
             echo "No changes to commit"
             echo "changes_made=false" >> $GITHUB_OUTPUT
           else
-            # Create a new branch with timestamp
-            BRANCH_NAME="update-stops-data-$(date +%Y-%m-%d-%H%M%S)"
-            git checkout -b $BRANCH_NAME
             git commit -m "Update stops data"
-            git push origin $BRANCH_NAME
-            echo "branch_name=$BRANCH_NAME" >> $GITHUB_OUTPUT
+            git push origin $BRANCH_NAME --force-with-lease
             echo "changes_made=true" >> $GITHUB_OUTPUT
+            echo "Committed and pushed changes to $BRANCH_NAME"
           fi
-
-      - name: Create Pull Request
+      
+      - name: Create or update Pull Request
         if: steps.commit.outputs.changes_made == 'true'
         env:
           GH_TOKEN: ${{ github.token }}
-          BRANCH_NAME: ${{ steps.commit.outputs.branch_name }}
+          BRANCH_NAME: ${{ steps.check_existing.outputs.branch_name }}
+          HAS_EXISTING: ${{ steps.check_existing.outputs.has_existing }}
+          PR_NUMBER: ${{ steps.check_existing.outputs.pr_number }}
         run: |
-          # Close any existing PRs created by this action
-          existing_prs=$(gh pr list --json number,title,headRefName --search "Update stops data in:title head:update-stops-data- author:app/github-actions is:open")
-
-          if [[ $(echo "$existing_prs" | jq length) -gt 0 ]]; then
-            echo "Found existing PRs to close"
-            echo "$existing_prs" | jq -c '.[]' | while read pr; do
-              pr_number=$(echo "$pr" | jq -r '.number')
-              echo "Closing PR #$pr_number"
-              gh pr close $pr_number --comment "Superseded by a new PR with updated data"
-              git push origin --delete $(echo "$pr" | jq -r '.headRefName')
-            done
+          if [[ "$HAS_EXISTING" == "true" ]]; then
+            # Update existing PR with a comment
+            gh pr comment $PR_NUMBER --body "🔄 Stops data updated on $(date -u +"%Y-%m-%d %H:%M:%S UTC")"
+            echo "Updated existing PR #$PR_NUMBER"
+          else
+            # Create new PR
+            gh pr create \
+              --title "Update stops data" \
+              --body "Automatically generated PR with updated stops data from scheduled fetch." \
+              --base main \
+              --head "$BRANCH_NAME"
+            echo "Created new PR"
           fi
-
-          # Create new PR
-          gh pr create \
-            --title "Update stops data" \
-            --body "Automatically generated PR with updated stops data from scheduled fetch." \
-            --base main \
-            --head "$BRANCH_NAME"