Fix Bintray upload of Gradle module metadata (#766)

__Motivation__

The recently introduced fix for Bintray plugin's Gradle module metadata issue is not working because the Bintray plugin copy task (`_bintrayRecordingCopy`) runs before the generation of the Gradle metadata (`generateMetadataFileForMavenJavaPublication`).

This was not detected locally because the Gradle metadata was preexisting in an unclean build when `bintrayUpload` was tested.

__Modifications__

- Use the workaround suggested in [1],
- Review application of `maven-publish` plugin as it now must be done before Bintray.

__Results__

Gradle module metadata files are uploaded to Bintray (hopefully 😅).

[1] bintray/gradle-bintray-plugin#229

servicetalk-bom-internal/build.gradle

@@ -16,7 +16,6 @@
 
 apply plugin: "servicetalk-core"
 apply plugin: "java-platform"
-apply plugin: "maven-publish"
 
 dependencies {
   constraints {

servicetalk-bom/build.gradle

@@ -16,7 +16,6 @@
 
 apply plugin: "servicetalk-core"
 apply plugin: "java-platform"
-apply plugin: "maven-publish"
 
 rootProject.subprojects.findAll { !it.name.contains("bom") && !it.name.contains("examples") }.each {
   dependencies.constraints.add("api", it)

servicetalk-gradle-plugin-internal/src/main/groovy/io/servicetalk/gradle/plugin/internal/ProjectUtils.groovy

@@ -134,7 +134,7 @@ final class ProjectUtils {
     configFile.exists() ? configFile : project.file("$project.projectDir/$path")
   }
 
-  private static void addQualityTask(Project project) {
+  static void addQualityTask(Project project) {
     project.configure(project) {
       project.task("quality") {
         description = "Run all quality analyzers for all source sets"

servicetalk-gradle-plugin-internal/src/main/groovy/io/servicetalk/gradle/plugin/internal/ServiceTalkCorePlugin.groovy

@@ -15,11 +15,15 @@
  */
 package io.servicetalk.gradle.plugin.internal
 
+import com.jfrog.bintray.gradle.tasks.BintrayUploadTask
 import org.gradle.api.GradleException
 import org.gradle.api.Plugin
 import org.gradle.api.Project
 import org.gradle.api.XmlProvider
 import org.gradle.api.plugins.quality.Checkstyle
+import org.gradle.api.publish.PublishingExtension
+import org.gradle.api.publish.maven.MavenPublication
+import org.gradle.api.publish.maven.internal.artifact.FileBasedMavenArtifact
 
 import static io.servicetalk.gradle.plugin.internal.ProjectUtils.addBuildContextExtensions
 import static io.servicetalk.gradle.plugin.internal.ProjectUtils.appendNodes
@@ -31,13 +35,14 @@ import static io.servicetalk.gradle.plugin.internal.Versions.CHECKSTYLE_VERSION
 import static io.servicetalk.gradle.plugin.internal.Versions.TARGET_VERSION
 
 class ServiceTalkCorePlugin implements Plugin<Project> {
-  void apply(Project project, boolean includeBintrayPlugin = true) {
+  void apply(Project project, boolean publishesArtifacts = true) {
     enforceUtf8FileSystem()
     addBuildContextExtensions project
     applyCheckstylePlugin project
     applyIdeaPlugin project
 
-    if (includeBintrayPlugin) {
+    if (publishesArtifacts) {
+      applyMavenPublishPlugin project
       applyBintrayPlugin project
     }
   }
@@ -123,6 +128,12 @@ class ServiceTalkCorePlugin implements Plugin<Project> {
     }
   }
 
+  private static void applyMavenPublishPlugin(Project project) {
+    project.configure(project) {
+      pluginManager.apply("maven-publish")
+    }
+  }
+
   private static void applyBintrayPlugin(Project project) {
     project.configure(project) {
       pluginManager.apply("com.jfrog.bintray")
@@ -147,15 +158,6 @@ class ServiceTalkCorePlugin implements Plugin<Project> {
           key = bintrayKey
           publications = ["mavenJava"]
 
-          // Temporary workaround for https://github.com/bintray/gradle-bintray-plugin/issues/229
-          def groupPath = project.group.replaceAll('\\.', '/')
-          filesSpec {
-            from "$buildDir/publications/mavenJava"
-            include "module.json"
-            into "$groupPath/$project.name/$project.version"
-            rename ".*", "$project.name-${project.version}.module"
-          }
-
           pkg {
             userOrg = "servicetalk"
             repo = "servicetalk"
@@ -166,6 +168,27 @@ class ServiceTalkCorePlugin implements Plugin<Project> {
           override = true
           publish = true
         }
+
+        // Temporary workaround for https://github.com/bintray/gradle-bintray-plugin/issues/229
+        PublishingExtension publishing = project.extensions.getByType(PublishingExtension)
+        project.tasks.withType(BintrayUploadTask) {
+          doFirst {
+            publishing.publications.withType(MavenPublication).each { publication ->
+              File moduleFile = project.buildDir.toPath()
+                  .resolve("publications/${publication.name}/module.json").toFile()
+
+              if (moduleFile.exists()) {
+                publication.artifact(new FileBasedMavenArtifact(moduleFile) {
+                  @Override
+                  protected String getDefaultExtension() {
+                    return "module"
+                  }
+                })
+              }
+            }
+          }
+        }
+
       }
     }
   }

servicetalk-gradle-plugin-internal/src/main/groovy/io/servicetalk/gradle/plugin/internal/ServiceTalkLibraryPlugin.groovy

@@ -51,7 +51,6 @@ final class ServiceTalkLibraryPlugin extends ServiceTalkCorePlugin {
   private static void applyJavaLibraryPlugin(Project project) {
     project.configure(project) {
       pluginManager.apply("java-library")
-      pluginManager.apply("maven-publish")
 
       sourceCompatibility = TARGET_VERSION
       targetCompatibility = TARGET_VERSION