Refactor Gradle tasks in Spring Framework build

This commit reorganizes tasks and scripts in the build to only apply
them where they're needed. We're considering here 3 "types" of projects
in our build:
* the root project, handling documentation, publishing, etc
* framework modules (a project that's published as a spring artifact)
* internal modules, such as the BOM, our coroutines support and our
integration-tests

With this change, we're strealining the project configuration for all
spring modules and only applying plugins when needed (typically our
kotlin support).

See gh-23282

Author: bclozel

Diff for: build.gradle

@@ -14,20 +14,13 @@ plugins {
 	id 'org.springframework.build.test-sources' apply false
 	id "io.spring.dependency-management" version "1.0.7.RELEASE" apply false
 	id "org.jetbrains.kotlin.jvm" version "1.3.41" apply false
-	id "org.jetbrains.dokka" version "0.9.18"
+	id "org.jetbrains.dokka" version "0.9.18" apply false
 	id "org.asciidoctor.convert" version "1.5.8"
 }
 
 ext {
-	linkHomepage = "https://spring.io/projects/spring-framework"
-	linkCi = "https://build.spring.io/browse/SPR"
-	linkIssue = "https://github.com/spring-projects/spring-framework/issues"
-	linkScmUrl = "https://github.com/spring-projects/spring-framework"
-	linkScmConnection = "scm:git:git://github.com/spring-projects/spring-framework.git"
-	linkScmDevConnection = "scm:git:ssh://git@github.com:spring-projects/spring-framework.git"
-
 	moduleProjects = subprojects.findAll {
-		(it.name != "spring-framework-bom") && (it.name != "spring-core-coroutines")
+		(it.name != "spring-framework-bom") && (it.name != "spring-core-coroutines") && (it.name != "integration-tests")
 	}
 
 	aspectjVersion       = "1.9.4"
@@ -51,7 +44,6 @@ ext {
 	tomcatVersion        = "9.0.22"
 	undertowVersion      = "2.0.23.Final"
 
-	gradleScriptDir = "${rootProject.projectDir}/gradle"
 	withoutJclOverSlf4j = {
 		exclude group: "org.slf4j", module: "jcl-over-slf4j"
 	}
@@ -61,13 +53,10 @@ configure(allprojects) { project ->
 	group = "org.springframework"
 
 	apply plugin: "java"
-	apply plugin: "kotlin"
 	apply plugin: "checkstyle"
 	apply plugin: 'org.springframework.build.compile'
-	apply plugin: 'org.springframework.build.optional-dependencies'
-	apply plugin: 'org.springframework.build.test-sources'
 	apply plugin: "io.spring.dependency-management"
-	apply from: "${gradleScriptDir}/ide.gradle"
+	apply from: "${rootDir}/gradle/ide.gradle"
 
 	dependencyManagement {
 		resolutionStrategy {
@@ -96,17 +85,19 @@ configure(allprojects) { project ->
 		}
 	}
 
-	compileKotlin {
-		kotlinOptions {
-			jvmTarget = "1.8"
-			freeCompilerArgs = ["-Xjsr305=strict"]
+	pluginManager.withPlugin("kotlin") {
+		apply plugin: "org.jetbrains.dokka"
+		compileKotlin {
+			kotlinOptions {
+				jvmTarget = "1.8"
+				freeCompilerArgs = ["-Xjsr305=strict"]
+			}
 		}
-	}
-
-	compileTestKotlin {
-		kotlinOptions {
-			jvmTarget = "1.8"
-			freeCompilerArgs = ["-Xjsr305=strict"]
+		compileTestKotlin {
+			kotlinOptions {
+				jvmTarget = "1.8"
+				freeCompilerArgs = ["-Xjsr305=strict"]
+			}
 		}
 	}
 
@@ -179,67 +170,18 @@ configure(allprojects) { project ->
 	] as String[]
 }
 
-configure(subprojects.findAll { (it.name != "spring-core-coroutines"
-		&& it.name != "spring-integration-tests") } ) { subproject ->
-	apply from: "${gradleScriptDir}/publish-maven.gradle"
-
-	jar {
-		manifest.attributes["Implementation-Title"] = subproject.name
-		manifest.attributes["Implementation-Version"] = subproject.version
-		manifest.attributes["Automatic-Module-Name"] = subproject.name.replace('-', '.')  // for Jigsaw
-		manifest.attributes["Created-By"] =
-				"${System.getProperty("java.version")} (${System.getProperty("java.specification.vendor")})"
-
-		from("${rootProject.projectDir}/src/docs/dist") {
-			include "license.txt"
-			include "notice.txt"
-			into "META-INF"
-			expand(copyright: new Date().format("yyyy"), version: project.version)
-		}
-	}
-
-	javadoc {
-		description = "Generates project-level javadoc for use in -javadoc jar"
-
-		options.encoding = "UTF-8"
-		options.memberLevel = org.gradle.external.javadoc.JavadocMemberLevel.PROTECTED
-		options.author = true
-		options.header = project.name
-		options.use = true
-		options.links(project.ext.javadocLinks)
-		options.addStringOption("Xdoclint:none", "-quiet")
-
-		// Suppress warnings due to cross-module @see and @link references.
-		// Note that global 'api' task does display all warnings.
-		logging.captureStandardError LogLevel.INFO
-		logging.captureStandardOutput LogLevel.INFO  // suppress "## warnings" message
-	}
-
-	task sourcesJar(type: Jar, dependsOn: classes) {
-		duplicatesStrategy = DuplicatesStrategy.EXCLUDE
-		classifier = "sources"
-		from sourceSets.main.allSource
-		// Don't include or exclude anything explicitly by default. See SPR-12085.
-	}
-
-	task javadocJar(type: Jar) {
-		classifier = "javadoc"
-		from javadoc
-	}
-
-	artifacts {
-		archives sourcesJar
-		archives javadocJar
-	}
+configure(moduleProjects) { project ->
+	apply from: "${rootDir}/gradle/spring-module.gradle"
 }
 
 configure(rootProject) {
 	description = "Spring Framework"
 
 	apply plugin: "groovy"
+	apply plugin: "kotlin"
 	apply plugin: "io.spring.nohttp"
 	apply plugin: 'org.springframework.build.api-diff'
-	apply from: "${gradleScriptDir}/docs.gradle"
+	apply from: "${rootDir}/gradle/docs.gradle"
 
 	nohttp {
 		source.exclude "**/test-output/**"
@@ -258,9 +200,6 @@ configure(rootProject) {
 		}
 	}
 
-	// Don't publish the default jar for the root project
-	configurations.archives.artifacts.clear()
-
 	dependencies {
 		asciidoctor("io.spring.asciidoctor:spring-asciidoctor-extensions:0.1.3.RELEASE")
 	}
@@ -270,6 +209,5 @@ configure(rootProject) {
 		archives schemaZip
 		archives distZip
 	}
-
 }