build(oss-licenses): upgrade to Gradle 9.4 and enable full build cache support

oss-licenses-plugin/gradle.properties

@@ -8,3 +8,4 @@ systemProp.com.google.protobuf.use_unsafe_pre22_gencode=true
 
 org.gradle.configuration-cache=true
 org.gradle.caching=true
+org.gradle.jvmargs=-Xmx2048m -XX:MaxMetaspaceSize=1024m

oss-licenses-plugin/gradle/wrapper/gradle-wrapper.properties

@@ -1,6 +1,6 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-9.3.1-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-9.4.0-bin.zip
 networkTimeout=10000
 validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME

oss-licenses-plugin/src/main/groovy/com/google/android/gms/oss/licenses/plugin/ArtifactFiles.groovy

@@ -16,13 +16,24 @@
 
 package com.google.android.gms.oss.licenses.plugin
 
+import org.gradle.api.tasks.InputFile
+import org.gradle.api.tasks.Optional
+import org.gradle.api.tasks.PathSensitive
+import org.gradle.api.tasks.PathSensitivity
 import java.io.Serializable
 
 /**
  * Data class to hold the resolved physical files for a single dependency.
  */
 class ArtifactFiles implements Serializable {
+    @InputFile
+    @PathSensitive(PathSensitivity.NONE)
+    @Optional
     File pomFile
+
+    @InputFile
+    @PathSensitive(PathSensitivity.NONE)
+    @Optional
     File libraryFile
 
     ArtifactFiles(File pomFile, File libraryFile) {

oss-licenses-plugin/src/main/groovy/com/google/android/gms/oss/licenses/plugin/DependencyTask.groovy

@@ -21,8 +21,12 @@ import groovy.json.JsonBuilder
 import groovy.json.JsonGenerator
 import org.gradle.api.DefaultTask
 import org.gradle.api.file.RegularFileProperty
+import org.gradle.api.tasks.CacheableTask
 import org.gradle.api.tasks.InputFile
+import org.gradle.api.tasks.Optional
 import org.gradle.api.tasks.OutputFile
+import org.gradle.api.tasks.PathSensitive
+import org.gradle.api.tasks.PathSensitivity
 import org.gradle.api.tasks.TaskAction
 import org.slf4j.LoggerFactory
 
@@ -37,14 +41,16 @@ import static com.android.tools.build.libraries.metadata.Library.LibraryOneofCas
  * If the protobuf is not present (e.g. debug variants) it writes a single
  * dependency on the {@link DependencyUtil#ABSENT_ARTIFACT}.
  */
+@CacheableTask
 abstract class DependencyTask extends DefaultTask {
     private static final logger = LoggerFactory.getLogger(DependencyTask.class)
 
     @OutputFile
     abstract RegularFileProperty getDependenciesJson()
 
     @InputFile
-    @org.gradle.api.tasks.Optional
+    @PathSensitive(PathSensitivity.NONE)
+    @Optional
     abstract RegularFileProperty getLibraryDependenciesReport()
 
     @TaskAction

oss-licenses-plugin/src/main/groovy/com/google/android/gms/oss/licenses/plugin/LicensesTask.groovy

@@ -21,10 +21,14 @@ import groovy.xml.XmlSlurper
 import org.gradle.api.DefaultTask
 import org.gradle.api.file.DirectoryProperty
 import org.gradle.api.file.RegularFileProperty
+import org.gradle.api.tasks.CacheableTask
 import org.gradle.api.tasks.InputFile
 import org.gradle.api.tasks.Internal
+import org.gradle.api.tasks.Nested
 import org.gradle.api.tasks.OutputDirectory
 import org.gradle.api.tasks.OutputFile
+import org.gradle.api.tasks.PathSensitive
+import org.gradle.api.tasks.PathSensitivity
 import org.gradle.api.tasks.TaskAction
 import org.slf4j.LoggerFactory
 
@@ -38,6 +42,7 @@ import java.util.zip.ZipFile
  * mappings (POMs and Library artifacts) are provided as lazy input properties, 
  * making the task a pure function of its inputs.
  */
+@CacheableTask
 abstract class LicensesTask extends DefaultTask {
     private static final String UTF_8 = "UTF-8"
     private static final byte[] LINE_SEPARATOR = System
@@ -66,10 +71,11 @@ abstract class LicensesTask extends DefaultTask {
      * A map of GAV coordinates (group:name:version) to their resolved POM and Library files.
      * Populated by OssLicensesPlugin during configuration.
      */
-    @org.gradle.api.tasks.Input
+    @Nested
     abstract org.gradle.api.provider.MapProperty<String, ArtifactFiles> getArtifactFiles()
 
     @InputFile
+    @PathSensitive(PathSensitivity.NONE)
     abstract RegularFileProperty getDependenciesJson()
 
     @OutputDirectory

oss-licenses-plugin/src/test/java/com/google/android/gms/oss/licenses/plugin/EndToEndTest.kt

@@ -35,8 +35,12 @@ abstract class EndToEndTest(private val agpVersion: String, private val gradleVe
     private lateinit var projectDir: File
 
     private fun createRunner(vararg arguments: String): GradleRunner {
+        return createRunnerWithDir(projectDir, *arguments)
+    }
+
+    private fun createRunnerWithDir(dir: File, vararg arguments: String): GradleRunner {
         return GradleRunner.create()
-            .withProjectDir(projectDir)
+            .withProjectDir(dir)
             .withGradleVersion(gradleVersion)
             .forwardOutput()
             // Isolate TestKit per AGP version subclass to allow parallel execution
@@ -49,7 +53,11 @@ abstract class EndToEndTest(private val agpVersion: String, private val gradleVe
     @Before
     fun setup() {
         projectDir = tempDirectory.newFolder("basic")
-        File(projectDir, "build.gradle").writeText(
+        setupProject(projectDir)
+    }
+
+    private fun setupProject(dir: File) {
+        File(dir, "build.gradle").writeText(
             """
             plugins {
                 id("com.android.application") version "$agpVersion"
@@ -68,13 +76,13 @@ abstract class EndToEndTest(private val agpVersion: String, private val gradleVe
             }
         """.trimIndent()
         )
-        File(projectDir, "gradle.properties").writeText(
+        File(dir, "gradle.properties").writeText(
             """
             android.useAndroidX=true
             com.google.protobuf.use_unsafe_pre22_gencode=true
         """.trimIndent()
         )
-        File(projectDir, "settings.gradle").writeText(
+        File(dir, "settings.gradle").writeText(
             """
             pluginManagement {
                 repositories {
@@ -192,16 +200,72 @@ abstract class EndToEndTest(private val agpVersion: String, private val gradleVe
         // Gson 2.8.9 specifically uses the Apache 2.0 license URL.
         Assert.assertTrue(content.contains("apache.org/licenses/LICENSE-2.0"))
     }
+
+    @Test
+    fun testRelocatability() {
+        val cacheDir = tempDirectory.newFolder("cache")
+        val dir1 = tempDirectory.newFolder("dir1")
+        val dir2 = tempDirectory.newFolder("dir2")
+
+        // Helper to populate a directory with the test project
+        fun populate(dir: File) {
+            // ONLY copy the source files, NEVER the build outputs or local cache state
+            projectDir.listFiles()?.forEach { file ->
+                if (file.name != "build" && file.name != ".gradle") {
+                    file.copyRecursively(File(dir, file.name), overwrite = true)
+                }
+            }
+
+            // Update the settings.gradle to point to the correct repo path in the new location
+            File(dir, "settings.gradle").writeText(
+                """
+                pluginManagement {
+                    repositories {
+                        maven {
+                             url = uri("${System.getProperty("repo_path")}")
+                        }
+                        google()
+                        mavenCentral()
+                    }
+                }
+
+                buildCache {
+                    local {
+                        directory = '${cacheDir.absolutePath.replace("\\", "/")}'
+                    }
+                }
+                """.trimIndent()
+            )
+        }
+        populate(dir1)
+        populate(dir2)
+
+        // 1. Run in dir1 to prime the cache
+        val result1 = createRunnerWithDir(dir1, "releaseOssLicensesTask", "--build-cache").build()
+        Assert.assertEquals(TaskOutcome.SUCCESS, result1.task(":releaseOssLicensesTask")?.outcome)
+
+        // 2. Run in dir2 (different absolute path) and expect FROM-CACHE
+        val result2 = createRunnerWithDir(dir2, "releaseOssLicensesTask", "--build-cache").build()
+
+        Assert.assertEquals(
+            "LicensesTask should be relocatable",
+            TaskOutcome.FROM_CACHE,
+            result2.task(":releaseOssLicensesTask")?.outcome
+        )
+        Assert.assertEquals(
+            "DependencyTask should be relocatable",
+            TaskOutcome.FROM_CACHE,
+            result2.task(":releaseOssDependencyTask")?.outcome
+        )
+    }
 }
 
-class EndToEndTest_AGP74_G75 : EndToEndTest("7.4.2", "7.5")
-class EndToEndTest_AGP80_G80 : EndToEndTest("8.0.0", "8.0")
-class EndToEndTest_AGP82_G82 : EndToEndTest("8.2.0", "8.2")
-class EndToEndTest_AGP87_G89 : EndToEndTest("8.7.0", "8.9")
-class EndToEndTest_AGP810_G811 : EndToEndTest("8.10.0", "8.11.1")
-class EndToEndTest_AGP812_G814 : EndToEndTest("8.12.2", "8.14")
-class EndToEndTest_AGP90_G90 : EndToEndTest("9.0.0-alpha03", "9.0.0")
-class EndToEndTest_AGP91_G931 : EndToEndTest("9.1.0-alpha05", "9.3.1")
+class EndToEndTest_AGP74_G75 : EndToEndTest("7.4.2", "7.5.1")
+class EndToEndTest_AGP80_G80 : EndToEndTest("8.0.2", "8.0.2")
+class EndToEndTest_AGP87_G89 : EndToEndTest("8.7.3", "8.9")
+class EndToEndTest_AGP812_G814 : EndToEndTest("8.12.2", "8.14.1")
+class EndToEndTest_AGP_STABLE_90_G90 : EndToEndTest("9.0.1", "9.1.0")
+class EndToEndTest_AGP_ALPHA_92_G94 : EndToEndTest("9.2.0-alpha02", "9.4.0")
 
 private fun expectedDependenciesJson(builtInKotlinEnabled: Boolean, agpVersion: String) = """[
     {
@@ -382,7 +446,7 @@ private fun expectedDependenciesJson(builtInKotlinEnabled: Boolean, agpVersion:
     {
         "group": "org.jetbrains.kotlin",
         "name": "kotlin-stdlib",
-        "version": "${if (agpVersion.startsWith("9.1")) "2.2.10" else "2.2.0"}"""" else ""}
+        "version": "${if (agpVersion.startsWith("9"))"2.2.10" else "2.2.0"}"""" else ""}
     }
 ]"""