Add maven publish plugin to Gradle projects.

Only adds the plugin and POM configuration enabling publishing to local repository, not yet configured for actual world publishing.

RELNOTES=N/A
PiperOrigin-RevId: 713019870

Author: danysantiago

buildSrc/build.gradle.kts

@@ -11,6 +11,7 @@ kotlin {
 dependencies {
     implementation(gradleApi())
     implementation(libs.kotlin.gradlePlugin)
+    implementation(libs.publishPlugin)
 }
 
 gradlePlugin {
@@ -20,4 +21,10 @@ gradlePlugin {
             implementationClass = "dagger.gradle.build.KotlinJvmConventionPlugin"
         }
     }
+    plugins {
+      register("publish") {
+        id = libs.plugins.dagger.publish.get().pluginId
+        implementationClass = "dagger.gradle.build.PublishConventionPlugin"
+      }
+    }
 }

buildSrc/src/main/kotlin/dagger/gradle/build/KotlinJvmConventionPlugin.kt

@@ -26,9 +26,9 @@ import org.gradle.jvm.toolchain.JavaLanguageVersion
 class KotlinJvmConventionPlugin : Plugin<Project> {
 
     override fun apply(project: Project) {
-        project.pluginManager.apply(KGP_JVM_ID)
+        project.pluginManager.apply(project.getPluginIdByName("kotlinJvm"))
 
-        project.plugins.withId(KGP_JVM_ID) {
+        project.plugins.withId(project.getPluginIdByName("kotlinJvm")) {
             val kotlinProject = project.extensions.getByName("kotlin") as KotlinJvmProjectExtension
             kotlinProject.explicitApi()
             kotlinProject.jvmToolchain {
@@ -41,8 +41,4 @@ class KotlinJvmConventionPlugin : Plugin<Project> {
             }
         }
     }
-
-    companion object {
-        private const val KGP_JVM_ID = "org.jetbrains.kotlin.jvm"
-    }
 }

buildSrc/src/main/kotlin/dagger/gradle/build/PublishConventionPlugin.kt

@@ -0,0 +1,73 @@
+/*
+ * Copyright (C) 2025 The Dagger Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package dagger.gradle.build
+
+import com.vanniktech.maven.publish.MavenPublishBaseExtension
+import com.vanniktech.maven.publish.SonatypeHost
+import org.gradle.api.Plugin
+import org.gradle.api.Project
+
+class PublishConventionPlugin : Plugin<Project> {
+    override fun apply(project: Project) {
+        project.pluginManager.apply(project.getPluginIdByName("publish"))
+
+        project.plugins.withId(project.getPluginIdByName("publish")) {
+            val publishExtension = project.extensions.getByName("mavenPublishing") as MavenPublishBaseExtension
+            publishExtension.apply {
+                coordinates(
+                    groupId = "com.google.dagger",
+                    artifactId = project.name,
+                    version = project.findProperty("PUBLISH_VERSION").toString()
+                )
+                publishToMavenCentral(SonatypeHost.CENTRAL_PORTAL)
+                pom {
+                    name.set(project.name.asPomName())
+                    description.set("A fast dependency injector for Android and Java.")
+                    url.set("https://github.com/google/dagger")
+                    scm {
+                        url.set("https://github.com/google/dagger/")
+                        connection.set("scm:git:git://github.com/google/dagger.git")
+                    }
+                    issueManagement {
+                        system.set("GitHub Issues")
+                        url.set("https://github.com/google/dagger/issues")
+                    }
+                    licenses {
+                        license {
+                            name.set("The Apache Software License, Version 2.0")
+                            url.set("https://www.apache.org/licenses/LICENSE-2.0.txt")
+                        }
+                    }
+                    organization {
+                        name.set("Google, Inc.")
+                        url.set("https://www.google.com")
+                    }
+                }
+            }
+        }
+    }
+
+    /**
+     * Converts the Gradle project name to a more appropriate name for the POM file.
+     *
+     * For example: 'dagger-compiler' to 'Dagger Compiler'
+     */
+    private fun String.asPomName(): String {
+        val parts = split("-").map { first().uppercaseChar() + drop(1) }
+        return parts.joinToString(separator = " ")
+    }
+}

buildSrc/src/main/kotlin/dagger/gradle/build/VersionCatalogs.kt

@@ -30,4 +30,13 @@ internal fun Project.getVersionByName(name: String): String {
     } else {
         error("Could not find a version for `$name`")
     }
+}
+
+internal fun Project.getPluginIdByName(name: String): String {
+    val plugin = versionCatalog.findPlugin(name)
+    return if (plugin.isPresent) {
+        plugin.get().map { it.pluginId }.get()
+    } else {
+        error("Could not find plugin id for `$name`")
+    }
 }

gradle-projects/dagger-runtime/build.gradle.kts

@@ -2,6 +2,7 @@ import dagger.gradle.build.daggerSources
 
 plugins {
     alias(libs.plugins.dagger.kotlinJvm)
+    alias(libs.plugins.dagger.publish)
 }
 
 daggerSources {

gradle.properties

@@ -15,4 +15,11 @@ org.gradle.caching=true
 org.gradle.configuration-cache=true
 
 # Kotlin code style for this project: "official" or "obsolete":
-kotlin.code.style=official
+kotlin.code.style=official
+
+# Don't include the stdlib as a dependency by default
+kotlin.stdlib.default.dependency=false
+
+# Publish version
+# TODO(danysantiago): Find a configurable location for the publishing version.
+PUBLISH_VERSION=LOCAL-SNAPSHOT

gradle/libs.versions.toml

@@ -5,6 +5,7 @@ junit = "4.13"
 jvmTarget = "1.8"
 kotlin = "2.0.21"
 kotlinTarget = "1.9"
+publish = "0.30.0"
 truth = "1.4.0"
 
 [libraries]
@@ -15,8 +16,11 @@ jspecify = { module = "org.jspecify:jspecify", version = "1.0.0" }
 junit = { module = "junit:junit", version.ref = "junit" }
 kotlin-gradlePlugin = { module = "org.jetbrains.kotlin:kotlin-gradle-plugin", version.ref = "kotlin" }
 kotlin-stdlib = { module = "org.jetbrains.kotlin:kotlin-stdlib", version.ref = "kotlin" }
+publishPlugin = { module = "com.vanniktech:gradle-maven-publish-plugin", version.ref = "publish" }
 truth = { module = "com.google.truth:truth", version.ref = "truth" }
 
 [plugins]
 dagger-kotlinJvm = { id = "dagger.gradle.build.jvm" }
-kotlinJvm = { id = "org.jetbrains.kotlin.jvm", version.ref = "kotlin" }
+dagger-publish = { id = "dagger.gradle.build.publish" }
+kotlinJvm = { id = "org.jetbrains.kotlin.jvm", version.ref = "kotlin" }
+publish = { id = "com.vanniktech.maven.publish", version.ref = "publish" }