Introduce compatPatrouille.checkApiDependencies()

.github/workflows/publish-release.yaml

@@ -18,7 +18,6 @@ jobs:
       - uses: gradle/actions/setup-gradle@dbbdc275be76ac10734476cc723d82dfe7ec6eda #v3.4.2
       - run: |
           ./gradlew librarianPublishToMavenCentral
-          gh release create $GITHUB_REF_NAME --title $GITHUB_REF_NAME --verify-tag --notes-from-tag
         env:
           LIBRARIAN_SONATYPE_PASSWORD: ${{ secrets.OSSRH_PASSWORD }}
           LIBRARIAN_SONATYPE_USERNAME: ${{ secrets.OSSRH_USER }}

build.gradle.kts

@@ -4,6 +4,10 @@ plugins {
   alias(libs.plugins.kgp).apply(false)
   alias(libs.plugins.librarian).apply(false)
   alias(libs.plugins.compat.patrouille).apply(false)
+  alias(libs.plugins.gratatouille).apply(false)
+  alias(libs.plugins.ksp).apply(false)
 }
 
-Librarian.root(project)
+Librarian.root(project)
+
+

compat-patrouille-gradle-plugin/api/compat-patrouille-gradle-plugin.api

@@ -1,4 +1,5 @@
 public abstract interface class compat/patrouille/CompatPatrouilleExtension {
+	public abstract fun checkApiDependencies ()V
 	public abstract fun java (I)V
 	public abstract fun kotlin (Ljava/lang/String;)V
 }
@@ -25,5 +26,6 @@ public final class compat/patrouille/internal/Project_androidKt {
 
 public final class compat/patrouille/internal/Project_kotlinKt {
 	public static final fun getKotlinExtension (Lorg/gradle/api/Project;)Lorg/jetbrains/kotlin/gradle/dsl/KotlinProjectExtension;
+	public static final fun isKmp (Ljava/lang/Object;)Z
 }
 

compat-patrouille-gradle-plugin/build.gradle.kts

@@ -5,6 +5,7 @@ plugins {
   id("org.jetbrains.kotlin.jvm")
   id("java-gradle-plugin")
   id("com.gradleup.compat.patrouille")
+  id("com.gradleup.gratatouille")
 }
 
 Librarian.module(project)
@@ -13,6 +14,7 @@ dependencies {
   compileOnly(libs.gradle.api)
   compileOnly(libs.agp)
   compileOnly(libs.kgp)
+  gratatouille(project(":compat-patrouille-tasks"))
 }
 
 configurations.getByName("api").dependencies.removeIf {
@@ -33,3 +35,4 @@ gradlePlugin {
     }
   }
 }
+

compat-patrouille-gradle-plugin/src/main/kotlin/compat/patrouille/CompatPatrouilleExtension.kt

@@ -27,5 +27,13 @@ interface CompatPatrouilleExtension {
    * Examples: "1.9.0", "1.9.22", "2.0.21", "2.1.20",...
    */
   fun kotlin(version: String)
+
+  /**
+   * Registers a `compatPatrouilleCheckApiDependencies` task that walks all the api dependencies
+   * and checks that the metadata version in the `META-INF/${lib}.kotlin_module` file is compatible with
+   * the specified kotlin version.
+   * This is version n + 1 thanks to kotlinc n + 1 forward compatibility.
+   */
+  fun checkApiDependencies()
 }
 

compat-patrouille-gradle-plugin/src/main/kotlin/compat/patrouille/CompatPatrouillePlugin.kt

@@ -1,11 +1,20 @@
 package compat.patrouille
 
 import compat.patrouille.internal.CompatPatrouilleExtensionImpl
+import compat.patrouille.internal.isKmp
+import compat.patrouille.internal.kotlinExtensionOrNull
+import compat.patrouille.task.registerCheckApiDependenciesTask
 import org.gradle.api.Plugin
 import org.gradle.api.Project
+import org.jetbrains.kotlin.gradle.plugin.getKotlinPluginVersion
 
-class CompatPatrouillePlugin: Plugin<Project> {
+class CompatPatrouillePlugin : Plugin<Project> {
   override fun apply(target: Project) {
-    target.extensions.create(CompatPatrouilleExtension::class.java, "compatPatrouille", CompatPatrouilleExtensionImpl::class.java, target)
+    target.extensions.create(
+      CompatPatrouilleExtension::class.java,
+      "compatPatrouille",
+      CompatPatrouilleExtensionImpl::class.java,
+      target
+    )
   }
 }

compat-patrouille-gradle-plugin/src/main/kotlin/compat/patrouille/internal/CompatPatrouilleExtensionImpl.kt

@@ -3,14 +3,52 @@ package compat.patrouille.internal
 import compat.patrouille.CompatPatrouilleExtension
 import compat.patrouille.configureJavaCompatibility
 import compat.patrouille.configureKotlinCompatibility
+import compat.patrouille.task.registerCheckApiDependenciesTask
 import org.gradle.api.Project
+import org.jetbrains.kotlin.gradle.plugin.getKotlinPluginVersion
+
+internal abstract class CompatPatrouilleExtensionImpl(private val project: Project) : CompatPatrouilleExtension {
+  var kotlinVersion: String? = null
 
-internal abstract class CompatPatrouilleExtensionImpl(private val project: Project): CompatPatrouilleExtension {
   override fun java(version: Int) {
     project.configureJavaCompatibility(version)
   }
 
   override fun kotlin(version: String) {
+    val c = version.split(".")
+    require(c.size == 3) {
+      "Cannot parse Kotlin version $version. Expected format is X.Y.Z."
+    }
+    kotlinVersion = version
     project.configureKotlinCompatibility(version)
   }
+
+  override fun checkApiDependencies() {
+    val kotlin = project.extensions.findByName("kotlin")
+    val isKmp = if (kotlin != null) {
+      isKmp(kotlin)
+    } else {
+      false
+    }
+    val apiElementsConfigurationName = if (isKmp) {
+      "jvmApiElements"
+    } else {
+      "apiElements"
+    }
+    val configuration = project.configurations.create("compatPatrouilleCheck") {
+      it.isCanBeConsumed = false
+      it.isCanBeResolved = true
+      it.isVisible = false
+    }
+    configuration.extendsFrom(project.configurations.getByName(apiElementsConfigurationName))
+    val checkApiDependencies = project.registerCheckApiDependenciesTask(
+      taskName = "compatPatrouilleCheckApiDependencies",
+      compileClasspath = configuration,
+      kotlinVersion = project.provider { kotlinVersion ?: project.getKotlinPluginVersion() }
+    )
+
+    project.tasks.named("check").configure {
+      it.dependsOn(checkApiDependencies)
+    }
+  }
 }

compat-patrouille-gradle-plugin/src/main/kotlin/compat/patrouille/internal/project.kotlin.kt

@@ -1,8 +1,17 @@
 package compat.patrouille.internal
 
 import org.gradle.api.Project
+import org.jetbrains.kotlin.gradle.dsl.KotlinMultiplatformExtension
 import org.jetbrains.kotlin.gradle.dsl.KotlinProjectExtension
 
 internal val Project.kotlinExtensionOrNull: KotlinProjectExtension? get() = extensions.findByName("kotlin") as KotlinProjectExtension?
 
 val Project.kotlinExtension: KotlinProjectExtension get() = kotlinExtensionOrNull ?: error("no 'kotlin' extension found")
+
+/**
+ * This function is very simple but extracted to a separate file to avoid class loading issues
+ * if KGP is not in the classpath
+ */
+fun isKmp(extension: Any): Boolean {
+  return extension is KotlinMultiplatformExtension
+}

compat-patrouille-tasks/api/compat-patrouille-tasks.api

@@ -0,0 +1,10 @@
+public final class compat/patrouille/task/CheckApiDependenciesEntryPoint {
+	public static final field Companion Lcompat/patrouille/task/CheckApiDependenciesEntryPoint$Companion;
+	public fun <init> ()V
+	public static final fun run (Ljava/util/List;Ljava/lang/String;Ljava/io/File;)V
+}
+
+public final class compat/patrouille/task/CheckApiDependenciesEntryPoint$Companion {
+	public final fun run (Ljava/util/List;Ljava/lang/String;Ljava/io/File;)V
+}
+

compat-patrouille-tasks/build.gradle.kts

@@ -0,0 +1,25 @@
+import com.gradleup.librarian.gradle.Librarian
+
+plugins {
+  id("org.jetbrains.kotlin.jvm")
+  id("com.gradleup.compat.patrouille")
+  id("com.gradleup.gratatouille")
+  id("com.google.devtools.ksp")
+}
+
+Librarian.module(project)
+
+dependencies {
+  implementation(libs.gratatouille.runtime)
+  implementation(libs.kotlinx.metadata)
+}
+
+compatPatrouille {
+  java(11)
+}
+
+gratatouille {
+  codeGeneration {
+    classLoaderIsolation()
+  }
+}

compat-patrouille-tasks/src/main/kotlin/compat/patrouille/task/checkApiDependencies.kt

@@ -0,0 +1,60 @@
+package compat.patrouille.task
+
+import gratatouille.GClasspath
+import gratatouille.GOutputFile
+import gratatouille.GTask
+import kotlinx.metadata.jvm.JvmMetadataVersion
+import kotlinx.metadata.jvm.KotlinModuleMetadata
+import kotlinx.metadata.jvm.UnstableMetadataApi
+import java.io.File
+import java.util.zip.ZipInputStream
+
+@OptIn(UnstableMetadataApi::class)
+@GTask
+internal fun checkApiDependencies(
+  compileClasspath: GClasspath,
+  kotlinVersion: String,
+  output: GOutputFile
+) {
+  val c = kotlinVersion.split(".")
+  require(c.size == 3) {
+    "Cannot parse Kotlin version $kotlinVersion. Expected format is X.Y.Z."
+  }
+  var supportedMajor = c[0].toInt()
+  var supportedMinor = c[1].toInt()
+
+  if (supportedMajor == 1 && supportedMinor == 9) {
+    // 1.9 can read 2.0 metadata
+    supportedMajor = 2
+    supportedMinor = 0
+  } else {
+    // n + 1 forward compatibility in the general case
+    supportedMinor += 1
+  }
+
+  val supportedVersion = JvmMetadataVersion(supportedMajor, supportedMinor, 0)
+
+  compileClasspath.forEach { fileWithPath ->
+    fileWithPath.file.forEachModuleInfoFile { name, bytes ->
+      val metadata = KotlinModuleMetadata.read(bytes)
+      if (metadata.version > supportedVersion) {
+        error("${fileWithPath.file.path}:$name contains unsupported metadata ${metadata.version} (expected: $kotlinVersion)")
+      }
+    }
+  }
+
+  output.writeText("Nothing to see here, this file is just a marker that the task executed successfully.")
+}
+
+private fun File.forEachModuleInfoFile(block: (String, ByteArray) -> Unit) {
+  ZipInputStream(inputStream()).use { zis ->
+    var entry = zis.nextEntry
+    while (entry != null) {
+      if (entry.name.matches(Regex("META-INF/.*\\.kotlin_module"))) {
+        block(entry.name, zis.readBytes())
+      }
+      entry = zis.nextEntry
+    }
+  }
+}
+

gradle/libs.versions.toml

@@ -1,9 +1,16 @@
+[versions]
+gratatouille = "0.0.9"
+
 [libraries]
 gradle-api = "dev.gradleplugins:gradle-api:8.0"
 agp = "com.android.tools.build:gradle:8.2.0"
 kgp = "org.jetbrains.kotlin:kotlin-gradle-plugin:1.9.0"
+gratatouille-runtime = {  module = "com.gradleup.gratatouille:gratatouille-runtime", version.ref = "gratatouille" }
+kotlinx-metadata = "org.jetbrains.kotlinx:kotlinx-metadata-jvm:0.9.0"
 
 [plugins]
-kgp = { id = "org.jetbrains.kotlin.jvm", version = "2.1.20" }
+kgp = { id = "org.jetbrains.kotlin.jvm", version = "2.1.21" }
+ksp = { id = "com.google.devtools.ksp", version = "2.1.21-2.0.1" }
 librarian = { id = "com.gradleup.librarian", version = "0.0.8-SNAPSHOT-b703634bb1858f471503e23d2c23d7aeae9d6120" }
 compat-patrouille = { id = "com.gradleup.compat.patrouille", version = "0.0.0-SNAPSHOT-08185b86d960562682116f21e348d6a9bf0c63d6" }
+gratatouille = { id = "com.gradleup.gratatouille", version.ref = "gratatouille" }

settings.gradle.kts

@@ -8,4 +8,5 @@ pluginManagement {
   }
 }
 
-include(":compat-patrouille-gradle-plugin")
+include(":compat-patrouille-gradle-plugin")
+include(":compat-patrouille-tasks")

tests/build.gradle.kts

@@ -0,0 +1,5 @@
+plugins {
+  alias(libs.plugins.kgp).apply(false)
+  alias(libs.plugins.compat.patrouille).apply(false)
+}
+

tests/check-api-dependencies/build.gradle.kts

@@ -0,0 +1,15 @@
+plugins {
+  id("org.jetbrains.kotlin.jvm")
+  id("com.gradleup.compat.patrouille")
+}
+
+compatPatrouille {
+  java(11)
+  kotlin("1.9.0")
+  checkApiDependencies()
+}
+
+dependencies {
+//  api("org.jetbrains.kotlin:kotlin-stdlib:2.1.21")
+  api(libs.kotlinx.metadata)
+}

tests/check-api-dependencies/src/main/kotlin/hello.kt

@@ -0,0 +1 @@
+val hello = "world"

tests/gradle

@@ -0,0 +1 @@
+../gradle

tests/settings.gradle.kts

@@ -0,0 +1,8 @@
+pluginManagement {
+  listOf(repositories, dependencyResolutionManagement.repositories).forEach {
+    it.mavenCentral()
+  }
+}
+
+includeBuild("../")
+include(":check-api-dependencies")