Testing: add GitHub Actions workflow to run SpotBugs on pull requests

Author: cconlon

.github/workflows/spotbugs.yml

@@ -0,0 +1,95 @@
+name: SpotBugs Static Analysis
+
+on:
+  pull_request:
+    branches: [ '*' ]
+    paths:
+      - '**/*.java'
+      - 'build.xml'
+      - 'spotbugs-exclude.xml'
+
+jobs:
+  spotbugs:
+    runs-on: ubuntu-latest
+    name: Run SpotBugs
+
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+
+      - name: Set up Java 17
+        uses: actions/setup-java@v4
+        with:
+          distribution: 'temurin'
+          java-version: '17'
+
+      - name: Set up Ant
+        run: |
+          sudo apt-get update
+          sudo apt-get install -y ant
+
+      - name: Download JUnit
+        run: |
+          mkdir -p /tmp/junit
+          wget -q -P /tmp/junit \
+            "https://repo1.maven.org/maven2/junit/junit/4.13.2/junit-4.13.2.jar"
+          echo "JUNIT_HOME=/tmp/junit" >> $GITHUB_ENV
+
+      - name: Download and set up SpotBugs
+        run: |
+          SPOTBUGS_VERSION="4.9.3"
+          wget -q "https://github.com/spotbugs/spotbugs/releases/download/${SPOTBUGS_VERSION}/spotbugs-${SPOTBUGS_VERSION}.tgz"
+          tar xzf "spotbugs-${SPOTBUGS_VERSION}.tgz"
+          echo "SPOTBUGS_HOME=${GITHUB_WORKSPACE}/spotbugs-${SPOTBUGS_VERSION}" >> $GITHUB_ENV
+
+      - name: Run SpotBugs
+        run: |
+          ant spotbugs
+
+      - name: Check for SpotBugs warnings
+        if: always()
+        run: |
+          REPORT="build/reports/spotbugs.html"
+          if [ ! -f "$REPORT" ]; then
+            echo "SpotBugs report not found"
+            exit 1
+          fi
+
+          # Extract warning count from report
+          COUNT=$(python3 -c "
+          import re
+          with open('$REPORT', 'r') as f:
+              content = f.read()
+          m = re.search(r'<b>Total Warnings</b>.*?<b>(\d+)</b>', content, re.DOTALL)
+          print(m.group(1) if m else '0')
+          ")
+
+          if [ "$COUNT" -eq 0 ]; then
+            echo "=================================="
+            echo "SpotBugs: 0 warnings found"
+            echo "=================================="
+            exit 0
+          fi
+
+          echo "=================================="
+          echo "SpotBugs: $COUNT warning(s) found"
+          echo "=================================="
+          echo ""
+
+          # Print each warning
+          python3 -c "
+          import re
+          with open('$REPORT', 'r') as f:
+              content = f.read()
+          pattern = r'priority-(\d)\">([\w]+)</span>.*?</td>\s*<td>(.*?)</td>.*?Bug type (\w+).*?</p>'
+          warnings = re.findall(pattern, content, re.DOTALL)
+          for pri, code, desc, full_type in warnings:
+              d = re.sub(r'<[^>]+>', '', desc).strip()
+              loc = ''
+              m2 = re.search(r'At ([\w.]+:\[line \d+\])', d)
+              print(f'[P{pri}] {full_type}')
+              print(f'  {d[:200]}')
+              print()
+          "
+
+          exit 1