feat(build): enhance JaCoCo reporting with coverage summary and enforce thresholds (#5352)

# Description of Changes

### What was changed
- Refactored Gradle task configuration to use `tasks.named` and
`configureEach` for better lazy configuration and compatibility.
- Centralized JaCoCo report handling by introducing a single
`jacocoReport` task reference.
- Added a post-processing step to the JaCoCo XML report to:
  - Parse coverage metrics (LINE, INSTRUCTION, BRANCH).
  - Calculate coverage ratios.
  - Print a formatted coverage summary table directly to the build logs.
- Enabled and aligned `jacocoTestCoverageVerification` rules with
defined minimum coverage thresholds.
- Ensured the `build` task depends on the JaCoCo report to always
generate coverage output.

### Why the change was made
- To improve visibility of test coverage results directly in CI and
local builds without manually opening the HTML report.
- To enforce consistent and explicit coverage thresholds for key
metrics.
- To modernize Gradle task configuration and avoid eager task
realization.

---

> Task :proprietary:jacocoTestReport

==== JaCoCo Coverage Summary ====
Metric      | Coverage | Covered/Total | Status | Target   
------------|----------|---------------|--------|----------
LINE        | 9.01%    | 759/8426      | FAIL   | >= 16.00%
INSTRUCTION | 8.41%    | 2741/32590    | FAIL   | >= 14.00%
BRANCH      | 6.04%    | 248/4103      | FAIL   | >= 9.00% 

---

> Task :common:jacocoTestReport

==== JaCoCo Coverage Summary ====
| Metric      | Coverage | Covered/Total | Status | Target   
|------------|----------|---------------|--------|----------
LINE        | 39.47%   | 2996/7591     | PASS   | >= 16.00%
INSTRUCTION | 41.05%   | 12868/31345   | PASS   | >= 14.00%
BRANCH      | 33.43%   | 1166/3488     | PASS   | >= 9.00% 

---

> Task :stirling-pdf:jacocoTestReport

==== JaCoCo Coverage Summary ====
Metric      | Coverage | Covered/Total | Status | Target   
------------|----------|---------------|--------|----------
LINE        | 13.63%   | 2554/18741    | FAIL   | >= 16.00%
INSTRUCTION | 14.59%   | 11459/78532   | PASS   | >= 14.00%
BRANCH      | 10.68%   | 868/8124      | PASS   | >= 9.00% 

---

## Checklist

### General

- [ ] I have read the [Contribution
Guidelines](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/CONTRIBUTING.md)
- [ ] I have read the [Stirling-PDF Developer
Guide](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/devGuide/DeveloperGuide.md)
(if applicable)
- [ ] I have read the [How to add new languages to
Stirling-PDF](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/devGuide/HowToAddNewLanguage.md)
(if applicable)
- [ ] I have performed a self-review of my own code
- [ ] My changes generate no new warnings

### Documentation

- [ ] I have updated relevant docs on [Stirling-PDF's doc
repo](https://github.com/Stirling-Tools/Stirling-Tools.github.io/blob/main/docs/)
(if functionality has heavily changed)
- [ ] I have read the section [Add New Translation
Tags](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/devGuide/HowToAddNewLanguage.md#add-new-translation-tags)
(for new translation tags only)

### Translations (if applicable)

- [ ] I ran
[`scripts/counter_translation.py`](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/docs/counter_translation.md)

### UI Changes (if applicable)

- [ ] Screenshots or videos demonstrating the UI changes are attached
(e.g., as comments or direct attachments in the PR)

### Testing (if applicable)

- [ ] I have tested my changes locally. Refer to the [Testing
Guide](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/devGuide/DeveloperGuide.md#6-testing)
for more details.

.github/workflows/build.yml

@@ -97,6 +97,7 @@ jobs:
         with:
           name: test-reports-jdk-${{ matrix.jdk-version }}-spring-security-${{ matrix.spring-security }}
           path: |
+            app/**/build/reports/jacoco/test
             app/**/build/reports/tests/
             app/**/build/test-results/
             app/**/build/reports/problems/
@@ -104,6 +105,17 @@ jobs:
           retention-days: 3
           if-no-files-found: warn
 
+      - name: Add coverage to PR with spring security ${{ matrix.spring-security }} and JDK ${{ matrix.jdk-version }}
+        id: jacoco
+        uses: madrapps/jacoco-report@50d3aff4548aa991e6753342d9ba291084e63848 # v1.7.2
+        with:
+          paths: |
+            ${{ github.workspace }}/**/build/reports/jacoco/test/jacocoTestReport.xml
+          token: ${{ secrets.GITHUB_TOKEN }}
+          min-coverage-overall: 10
+          min-coverage-changed-files: 0
+          comment-type: summary
+
   check-generateOpenApiDocs:
     if: needs.files-changed.outputs.openapi == 'true'
     needs: [files-changed]

build.gradle

@@ -14,6 +14,8 @@ plugins {
 import com.github.jk1.license.render.*
 import groovy.json.JsonOutput
 import groovy.json.JsonSlurper
+import groovy.xml.XmlSlurper
+import org.gradle.api.tasks.testing.Test
 
 ext {
     springBootVersion = "3.5.7"
@@ -183,30 +185,142 @@ subprojects {
         }
     }
 
-    compileJava {
+    tasks.named("compileJava", JavaCompile).configure {
-        options.compilerArgs << "-parameters"
+        options.compilerArgs.add("-parameters")
     }
 
-    test {
+    def jacocoReport = tasks.named("jacocoTestReport")
+
+    tasks.withType(Test).configureEach {
         useJUnitPlatform()
-        finalizedBy jacocoTestReport
+        finalizedBy(jacocoReport)
     }
 
-    jacocoTestReport {
+    jacocoReport.configure {
-        dependsOn test
+        dependsOn(tasks.named("test"))
         reports {
             xml.required.set(true)
             csv.required.set(false)
             html.required.set(true)
         }
+        doLast {
+            def xmlReport = reports.xml.outputLocation.get().asFile
+            if (!xmlReport.exists()) {
+                logger.lifecycle("Jacoco coverage report not found at ${xmlReport}")
+                return
+            }
+
+            def xmlContent = xmlReport.getText("UTF-8")
+            xmlContent = xmlContent.replaceFirst('(?s)<!DOCTYPE.*?>', '')
+            def report = new XmlSlurper(false, false).parseText(xmlContent)
+            def counters = report.counter.collectEntries { counter ->
+                def type = counter.@type.text()
+                def covered = counter.@covered.text() as BigDecimal
+                def missed = counter.@missed.text() as BigDecimal
+                [(type): [covered: covered, missed: missed]]
+            }
+
+            def thresholds = [
+                    LINE       : 0.16,
+                    INSTRUCTION: 0.14,
+                    BRANCH     : 0.09
+            ]
+
+            def types = ["LINE", "INSTRUCTION", "BRANCH"]
+            def headers = ["Metric", "Coverage", "Covered/Total", "Status", "Target"]
+
+            def rows = types.collect { String type ->
+                def data = counters[type]
+                if (!data) {
+                    return [type, "—", "—", "No data", ""]
+                }
+
+                def total = data.covered + data.missed
+                if (total == 0) {
+                    return [type, "—", "0/${total.toBigInteger()}", "No executions", ""]
+                }
+
+                def ratio = data.covered / total * 100
+                def coverageText = String.format(Locale.ROOT, "%.2f%%", ratio)
+                def coveredText = String.format(Locale.ROOT, "%d/%d",
+                        data.covered.toBigInteger(),
+                        total.toBigInteger())
+
+                def threshold = thresholds[type]
+                def thresholdPercent = threshold != null ? threshold * 100 : null
+                def targetText = thresholdPercent != null ?
+                        String.format(Locale.ROOT, ">= %.2f%%", thresholdPercent) : ""
+                def passed = thresholdPercent != null ? ratio >= thresholdPercent : null
+                def statusText = passed == null ? "" : (passed ? "PASS" : "FAIL")
+
+                return [type, coverageText, coveredText, statusText, targetText]
+            }
+
+            def columnIndexes = (0..<headers.size())
+            def columnWidths = columnIndexes.collect { idx ->
+                Math.max(headers[idx].length(), rows.collect { row ->
+                    row[idx] != null ? row[idx].toString().length() : 0
+                }.max() ?: 0)
+            }
+
+            def formatRow = { List<String> values ->
+                columnIndexes.collect { idx ->
+                    def value = values[idx] ?: ""
+                    value.padRight(columnWidths[idx])
+                }.join(" | ")
+            }
+
+            def separator = columnIndexes.collect { idx ->
+                ''.padRight(columnWidths[idx], '-')
+            }.join("-+-")
+
+            logger.lifecycle("")
+            logger.lifecycle("==== JaCoCo Coverage Summary ====")
+            logger.lifecycle(formatRow(headers))
+            logger.lifecycle(separator)
+            rows.each { row ->
+                logger.lifecycle(formatRow(row))
+            }
+            logger.lifecycle(separator)
+
+            def htmlReport = reports.html.outputLocation.get().asFile
+            logger.lifecycle("Detailed HTML report available at: ${htmlReport}")
+            if (rows.any { it[3] == "FAIL" }) {
+                logger.lifecycle("Some coverage targets were missed. Please review the detailed report above.")
+            } else if (rows.any { it[3] == "PASS" }) {
+                logger.lifecycle("Great job! All tracked coverage metrics meet their targets.")
+            }
+            logger.lifecycle("=================================\n")
+        }
+    }
+
+    tasks.named("build") {
+        dependsOn jacocoReport
     }
 
     jacocoTestCoverageVerification {
-        dependsOn jacocoTestReport
+        dependsOn jacocoReport
         violationRules {
             rule {
+                enabled = true
+                element = 'BUNDLE'
+                // Bytecode-Anweisungen abgedeckt
                 limit {
-                    minimum = 0.0
+                    counter = 'INSTRUCTION'
+                    value = 'COVEREDRATIO'
+                    minimum = 0.14
+                }
+                // wie viele Quellcode-Zeilen abgedeckt
+                limit {
+                    counter = 'LINE'
+                    value = 'COVEREDRATIO'
+                    minimum = 0.16
+                }
+                // Verzweigungen (if/else, switch) abgedeckt; misst Logik-Abdeckung
+                limit {
+                    counter = 'BRANCH'
+                    value = 'COVEREDRATIO'
+                    minimum = 0.09
                 }
             }
         }