ci: add backport label on PR creation (#365)

* ci: improve backport workflow
* chore: ignore tmp files
* ci: add exact match
* ci: target main branch
* ci: rewrite workflows

---------

Signed-off-by: Yi-Ya Chen <yiya.chen@suse.com>

.eslintignore

@@ -14,3 +14,4 @@ dist-pkg
 pkg/harvester/index.ts
 pkg/harvester/store/*
 scripts/pkgfile.js
+tmp

.github/mergify.yml

@@ -1,43 +1,4 @@
 pull_request_rules:
-- name: Automatically open backport PR to release-harvester-v1.6
-  conditions:
-    - base=main
-  actions:
-    backport:
-      branches:
-        - "release-harvester-v1.6"
-      assignees:
-        - "{{ author }}"
-      labels:
-        - "v1.6 backport PR"
-
-pull_request_rules:
-- name: Automatically open backport PR to release-harvester-v1.5
-  conditions:
-    - base=main
-    - label="require backport 1.5"
-  actions:
-    backport:
-      branches:
-        - "release-harvester-v1.5"
-      assignees:
-        - "{{ author }}"
-      labels:
-        - "v1.5 backport PR"
-
-- name: Automatically open backport PR to release-harvester-v1.0
-  conditions:
-    - base=main
-    - label="require backport 1.0"
-  actions:
-    backport:
-      branches:
-        - "release-harvester-v1.0"
-      assignees:
-        - "{{ author }}"
-      labels:
-        - "v1.0 backport PR"
-
 - name: Ask to resolve conflict
   conditions:
     - conflict

.github/workflows/backport-label.yaml

@@ -0,0 +1,58 @@
+name: "[PR Management] Add Backport Label"
+
+on:
+  pull_request:
+    types: [opened, reopened]
+    branches: [main]
+
+permissions:
+  pull-requests: write
+
+jobs:
+  add-backport-label:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Fetch release branches and PR labels
+        id: fetch_info
+        env:
+          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        run: |
+          set -euo pipefail
+
+          repo="${{ github.repository }}"
+          pr_number=${{ github.event.pull_request.number }}
+
+          release_branches=$(gh api "repos/${repo}/branches" --paginate --jq '.[].name' | grep -E '^release-harvester-v[0-9]+\.[0-9]+$' || true)
+
+          if [[ -z "$release_branches" ]]; then
+            echo "should_label=false" >> "$GITHUB_OUTPUT"
+            exit 0
+          fi
+
+          latest_branch=$(echo "$release_branches" | sort -Vr | head -n1)
+          version="${latest_branch#release-harvester-v}"
+          release_tag="v${version}.0"
+
+          tags=$(gh api "repos/${repo}/releases" --paginate --jq '.[].tag_name')
+          if echo "$tags" | grep -Fxq "$release_tag"; then
+            echo "should_label=false" >> "$GITHUB_OUTPUT"
+            exit 0
+          fi
+
+          label="require backport/v${version}"
+          echo "should_label=true" >> "$GITHUB_OUTPUT"
+          echo "backport_label=$label" >> "$GITHUB_OUTPUT"
+
+          pr_labels=$(gh pr view "$pr_number" --repo "$repo" --json labels --jq '.labels[].name' || echo "")
+          pr_labels_csv=$(echo "$pr_labels" | tr '\n' ',' | sed 's/,$//')
+          echo "pr_labels=$pr_labels_csv" >> "$GITHUB_OUTPUT"
+
+      - name: Add backport label if needed
+        if: steps.fetch_info.outputs.should_label == 'true' && !contains(steps.fetch_info.outputs.pr_labels, steps.fetch_info.outputs.backport_label)
+        uses: actions-ecosystem/action-add-labels@v1
+        with:
+          github_token: ${{ secrets.GITHUB_TOKEN }}
+          labels: ${{ steps.fetch_info.outputs.backport_label }}

.github/workflows/backport-request.yaml

@@ -0,0 +1,44 @@
+name: "[PR Management] Request Backport via Mergify"
+
+on:
+  pull_request:
+    types: [closed]
+    branches: [main]
+
+permissions:
+  pull-requests: write
+
+jobs:
+  comment-backport:
+    if: github.event.pull_request.merged == true
+    runs-on: ubuntu-latest
+    steps:
+      - name: Post Mergify backport command
+        env:
+          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        run: |
+          set -euo pipefail
+
+          pr_number=${{ github.event.pull_request.number }}
+          repo="${{ github.repository }}"
+
+          labels_json='${{ toJson(github.event.pull_request.labels.*.name) }}'
+          labels=$(echo "$labels_json" | jq -r '.[] // empty')
+
+          echo "Labels on PR: $labels"
+
+          matches=$(echo "$labels" | grep -oE '^require backport/v[0-9]+\.[0-9]+$' || true)
+
+          if [[ -z "$matches" ]]; then
+            echo "No back‑port labels found — skipping."
+            exit 0
+          fi
+
+          branches=$(echo "$matches" \
+            | sed -E 's/^require backport\/v/release-harvester-v/' \
+            | sort -u | tr '\n' ' ')
+          branches=${branches%% }
+
+          cmd="@Mergifyio backport $branches"
+          echo "Posting Mergify command: $cmd"
+          gh pr comment "$pr_number" --repo "$repo" --body "$cmd"