ci: configure dynamic build matrix for PRs, tags, and main

Update the GitHub Actions workflow to optimize CI runner usage by dynamically scaling the build matrix based on the event trigger:
- Main branch pushes: Full matrix (Ubuntu, Windows, macOS) with Java 21 and 25.
- Tags (v*): Reduced matrix to only Ubuntu with Java 21.
- Pull Requests: Ubuntu and Windows with Java 21.

Author: jknack

.github/workflows/full-build.yml

@@ -3,58 +3,60 @@ name: Full Build
 on:
   push:
     branches:
-      - main  # Only run push on main (merges/direct pushes)
+      - main
     tags:
-      - 'v*' # Triggers on any tag starting with 'v' (e.g., v1.0, v2.1.3)
+      - 'v*'
   pull_request:
     branches:
-      - main  # Run on any PR targeting main
+      - main
 
 jobs:
   build:
-    runs-on: ${{ matrix.os }}
     strategy:
       matrix:
-        os: [ubuntu-latest, windows-latest, macos-latest]
-        java-version: [21]
-        include:
-          - os: ubuntu-latest
-            java-version: 25
+        # 1. If PR -> [ubuntu, windows]
+        # 2. Else If Tag -> [ubuntu]
+        # 3. Else (Main Push) -> [ubuntu, windows, macos]
+        os: ${{ github.event_name == 'pull_request' && fromJSON('["ubuntu-latest", "windows-latest"]') || (startsWith(github.ref, 'refs/tags/') && fromJSON('["ubuntu-latest"]') || fromJSON('["ubuntu-latest", "windows-latest", "macos-latest"]')) }}
+
+        # 1. If Main Push -> [21, 25]
+        # 2. Else (PR or Tag) -> [21]
+        java-version: ${{ github.event_name == 'push' && github.ref == 'refs/heads/main' && fromJSON('[21, 25]') || fromJSON('[21]') }}
+
+    runs-on: ${{ matrix.os }}
     steps:
       - name: Checkout
         uses: actions/checkout@v6
+
       - name: Set up JDK ${{ matrix.java-version }}
         uses: actions/setup-java@v5
         with:
           java-version: ${{ matrix.java-version }}
           distribution: 'temurin'
           cache: maven
 
-      # 1. Set up Go (cross-platform)
       - name: Set up Go
         uses: actions/setup-go@v6
         with:
           go-version: 'stable'
 
-      # 2. Install grpcurl (this places it in the $PATH automatically)
       - name: Install grpcurl
         run: go install github.com/fullstorydev/grpcurl/cmd/grpcurl@latest
 
       - name: Build
         run: mvn -B install -P gradlePlugin --no-transfer-progress
         env:
           BUILD_LOG_LEVEL: 'ERROR'
+
       - name: 📊 Test Report
         if: always()
         run: |
-          echo "## 🧪 Test Summary (${{ matrix.os }} - Java ${{ matrix.java-version }})" >> $GITHUB_STEP_SUMMARY
+          echo "## 🧪 Test Summary (${{ matrix.os }} Java ${{ matrix.java-version }})" >> $GITHUB_STEP_SUMMARY
 
-          # Use Python to safely parse the JUnit XML files and write to the summary
           python3 -c '
           import xml.etree.ElementTree as ET
           import glob, os
 
-          # Find all JUnit XML reports
           files = glob.glob("**/target/**/TEST-*.xml", recursive=True)
 
           tests, failures, errors, skipped = 0, 0, 0, 0
@@ -66,7 +68,6 @@ jobs:
                   tree = ET.parse(f)
                   root = tree.getroot()
 
-                  # Handle both <testsuite> and <testsuites> root elements
                   suites = [root] if root.tag == "testsuite" else root.findall(".//testsuite")
 
                   for suite in suites:
@@ -75,10 +76,8 @@ jobs:
                       errors += int(suite.attrib.get("errors", 0))
                       skipped += int(suite.attrib.get("skipped", 0))
 
-                      # Collect names of failing and skipped tests
                       for case in suite.findall("testcase"):
                           if case.find("failure") is not None or case.find("error") is not None:
-                              # Strip the package path from the classname for a cleaner display
                               cls = case.attrib.get("classname", "UnknownClass").split(".")[-1]
                               name = case.attrib.get("name", "UnknownMethod")
                               failed_tests.add(f"- `{cls}.{name}`")
@@ -96,15 +95,13 @@ jobs:
               if not files:
                   f.write("⚠️ **Could not find any `TEST-*.xml` files.**\n")
               else:
-                  # Draw the Markdown Table
                   f.write("| Result | Count |\n")
                   f.write("|--------|-------|\n")
                   f.write(f"| ✅ **Passed** | **{passed}** |\n")
                   f.write(f"| ❌ **Failed/Errors** | **{failures + errors}** |\n")
                   f.write(f"| ⚠️ **Skipped** | **{skipped}** |\n")
                   f.write(f"| 📊 **Total Tests** | **{tests}** |\n\n")
 
-                  # Provide specific feedback for failures
                   if failures > 0 or errors > 0:
                       f.write("### 🚨 Test Failures Detected!\n")
                       f.write("The following tests did not pass:\n")
@@ -114,7 +111,6 @@ jobs:
                       f.write("### 🎉 100% Pass Rate!\n")
                       f.write(f"The build is green across all {tests} tests.\n")
 
-                  # Provide specific feedback for skips
                   if skipped > 0:
                       f.write("\n### ⚠️ Skipped Tests\n")
                       for test in sorted(skipped_tests):
@@ -127,7 +123,6 @@ jobs:
           python3 -c '
           import csv, os
 
-          # Hardcoded path to the aggregated CSV
           csv_file = "tests/target/site/jacoco-aggregate/jacoco.csv"
           summary_file = os.environ.get("GITHUB_STEP_SUMMARY")
 
@@ -165,21 +160,21 @@ jobs:
                   f.write(f"| **Line** | **{line_pct:.2f}%** |\n")
                   f.write(f"| **Branch** | **{branch_pct:.2f}%** |\n\n")
           '
+
       - name: Upload coverage to Codecov
         if: always() && matrix.os == 'ubuntu-latest' && matrix.java-version == '21'
         uses: codecov/codecov-action@v6
         with:
           token: ${{ secrets.CODECOV_TOKEN }}
           files: tests/target/site/jacoco-aggregate/jacoco.xml
           fail_ci_if_error: false
+
       - name: 🔗 Codecov Report Link
         if: always() && matrix.os == 'ubuntu-latest' && matrix.java-version == '21'
         run: |
-          # Use the PR head SHA if available, otherwise fallback to the push commit SHA
           COMMIT_SHA="${{ github.event.pull_request.head.sha || github.sha }}"
           REPO="${{ github.repository }}"
 
-          # Construct both URLs
           COMMIT_URL="https://app.codecov.io/github/$REPO/commit/$COMMIT_SHA"
           PROJECT_URL="https://app.codecov.io/github/$REPO"