🏃 Verify PR titles with shell script

.github/workflows/verify.yml

@@ -1,17 +1,17 @@
+name: PR title verifier
+
 on:
   pull_request_target:
-    types: [opened, edited, reopened, synchronize]
-
-permissions:
-  checks: write # Allow access to checks to write check runs.
+    types: [opened, edited, synchronize, reopened]
 
 jobs:
   verify:
     runs-on: ubuntu-latest
-    name: verify PR contents
+
     steps:
-    - name: Verifier action
-      id: verifier
-      uses: kubernetes-sigs/kubebuilder-release-tools@012269a88fa4c034a0acf1ba84c26b195c0dbab4 # tag=v0.4.3
-      with:
-        github_token: ${{ secrets.GITHUB_TOKEN }}
+    - uses: actions/checkout@692973e3d937129bcbf40652eb9f2f61becf3332 # tag=v4.1.7
+
+    - name: Check if PR title is valid
+      run: |
+        ./hack/verify-pr-title.sh "${{ github.event.pull_request.title }}"
+

hack/verify-pr-title.sh

@@ -0,0 +1,54 @@
+#!/bin/bash
+
+# Copyright 2024 The Kubernetes Authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# Define regex patterns
+WIP_REGEX="^\W?WIP\W"
+TAG_REGEX="^\[[[:alnum:]\._-]*\]"
+PR_TITLE="$1"
+
+# Trim WIP and tags from title
+trimmed_title=$(echo "$PR_TITLE" | sed -E "s/$WIP_REGEX//" | sed -E "s/$TAG_REGEX//" | xargs)
+
+# Normalize common emojis in text form to actual emojis
+trimmed_title=$(echo "$trimmed_title" | sed -E "s/:warning:/⚠/g")
+trimmed_title=$(echo "$trimmed_title" | sed -E "s/:sparkles:/✨/g")
+trimmed_title=$(echo "$trimmed_title" | sed -E "s/:bug:/🐛/g")
+trimmed_title=$(echo "$trimmed_title" | sed -E "s/:book:/📖/g")
+trimmed_title=$(echo "$trimmed_title" | sed -E "s/:rocket:/🚀/g")
+trimmed_title=$(echo "$trimmed_title" | sed -E "s/:seedling:/🌱/g")
+
+# Check PR type prefix
+if [[ "$trimmed_title" =~ ^(⚠|✨|🐛|📖|🚀|🌱) ]]; then
+    echo "PR title is valid: $trimmed_title"
+else
+    echo "Error: No matching PR type indicator found in title."
+    echo "You need to have one of these as the prefix of your PR title:"
+    echo "- Breaking change: ⚠ (:warning:)"
+    echo "- Non-breaking feature: ✨ (:sparkles:)"
+    echo "- Patch fix: 🐛 (:bug:)"
+    echo "- Docs: 📖 (:book:)"
+    echo "- Release: 🚀 (:rocket:)"
+    echo "- Infra/Tests/Other: 🌱 (:seedling:)"
+    exit 1
+fi
+
+# Check that PR title does not contain Issue or PR number
+if [[ "$trimmed_title" =~ \#[0-9]+ ]]; then
+    echo "Error: PR title should not contain issue or PR number."
+    echo "Issue numbers belong in the PR body as either \"Fixes #XYZ\" (if it closes the issue or PR), or something like \"Related to #XYZ\" (if it's just related)."
+    exit 1
+fi
+