Add Gradle 8.3 into test matrix

.github/workflows/ci.yml

@@ -14,6 +14,12 @@ jobs:
         os: [ ubuntu-latest, windows-latest ]
         # Always test on the latest version and some LTS.
         java: [ 17, 21, 24 ]
+        # Test on the minimum Gradle version and the latest.
+        gradle: [ 8.3, current ]
+        exclude:
+          # Gradle 8.3 doesn't support Java 24.
+          - gradle: 8.3
+            java: 24
     runs-on: ${{ matrix.os }}
     steps:
       - uses: actions/checkout@v4
@@ -22,7 +28,7 @@ jobs:
           distribution: 'zulu'
           java-version: ${{ matrix.java }}
       - uses: gradle/actions/setup-gradle@v4
-      - run: ./gradlew build
+      - run: ./gradlew build --info "-PtestGradleVersion=${{ matrix.gradle }}"
 
   publish-snapshot:
     needs: build

build.gradle.kts

@@ -111,6 +111,12 @@ val isCI = providers.environmentVariable("CI").isPresent
 tasks.withType<Test>().configureEach {
   useJUnitPlatform()
 
+  val testGradleVersion = providers.gradleProperty("testGradleVersion").orNull.let {
+    if (it == null || it == "current") GradleVersion.current().version else it
+  }
+  logger.info("Using test Gradle version: $testGradleVersion")
+  systemProperty("TEST_GRADLE_VERSION", testGradleVersion)
+
   maxParallelForks = Runtime.getRuntime().availableProcessors()
 
   if (isCI) {

src/main/groovy/com/github/jengelman/gradle/plugins/shadow/internal/RelocationUtil.groovy

@@ -12,7 +12,10 @@ class RelocationUtil {
                 JarFile jf = new JarFile(jar)
                 jf.entries().each { entry ->
                     if (entry.name.endsWith(".class") && entry.name != "module-info.class") {
-                        packages << entry.name[0..entry.name.lastIndexOf('/') - 1].replaceAll('/', '.')
+                        def i = entry.name.lastIndexOf('/')
+                        if (i != -1) {
+                            packages << entry.name.take(i).replaceAll('/', '.')
+                        }
                     }
                 }
                 jf.close()

src/test/groovy/com/github/jengelman/gradle/plugins/shadow/docs/executer/GradleBuildExecuter.groovy

@@ -54,7 +54,11 @@ include 'api', 'main'
 
         buildFile.text = replaceTokens(fullSnippet)
 
-        GradleRunner runner = GradleRunner.create().withProjectDir(tempDir).withPluginClasspath().forwardOutput()
+        GradleRunner runner = GradleRunner.create()
+            .withGradleVersion(PluginSpecification.TEST_GRADLE_VERSION)
+            .withProjectDir(tempDir)
+            .withPluginClasspath()
+            .forwardOutput()
 
         runner.withArguments(":main:build", "-m").build()
 

src/test/groovy/com/github/jengelman/gradle/plugins/shadow/util/PluginSpecification.groovy

@@ -18,6 +18,8 @@ abstract class PluginSpecification extends Specification {
 
     public static final String SHADOW_VERSION = System.getProperty("shadowVersion")
 
+    public static final String TEST_GRADLE_VERSION = System.getProperty("TEST_GRADLE_VERSION")
+
     AppendableMavenFileRepository repo
 
     def setup() {
@@ -55,6 +57,7 @@ abstract class PluginSpecification extends Specification {
 
     GradleRunner getRunner() {
         GradleRunner.create()
+                .withGradleVersion(TEST_GRADLE_VERSION)
                 .withProjectDir(dir.toFile())
                 .forwardOutput()
                 .withPluginClasspath()