Remove unnecessary logic for fixing generated POMs (#48721)

This commit eliminates some custom logic we have in place for post-hoc
cleanup of POM files generated by Gradle. There were to main issues this
logic was meant to address:

First, for dependencies marked as `transitive = false`, Gradle by
default creates a "wildcard" exclusion in the generated POM file. It
turns out that Ivy didn't handle these types of exclusions well, even
though they are perfectly valid and dealt with by Gradle and Maven as
expected. We've since confirmed that this issues is indeed resolved in
the most recent Ivy release (2.5.0-rc1) so going forward the suggestion
to folks consuming Elasticsearch dependencies with Ivy will be to use
this version.

Second, earlier versions of Gradle would incorrectly assign compile
dependencies to the "runtime" scope in the publish POM file. This could
cause issues if the dependencies were indeed needed at compile time
because their APIs were exposed. This has since been fixed and these
dependencies are correctly marked as "compile" scope in the POM.

Since these two issues have been resolved in their respective projects
we can eliminate this logic and all the supporting code, such as having
to create lots of "internal" configurations for tracking transitive
dependencies.

Author: mark-vieira

buildSrc/src/main/groovy/org/elasticsearch/gradle/BuildPlugin.groovy

@@ -22,7 +22,6 @@ import com.github.jengelman.gradle.plugins.shadow.ShadowBasePlugin
 import com.github.jengelman.gradle.plugins.shadow.ShadowExtension
 import com.github.jengelman.gradle.plugins.shadow.ShadowJavaPlugin
 import com.github.jengelman.gradle.plugins.shadow.tasks.ShadowJar
-import groovy.transform.CompileDynamic
 import groovy.transform.CompileStatic
 import org.apache.commons.io.IOUtils
 import org.elasticsearch.gradle.info.GlobalBuildInfoPlugin
@@ -41,13 +40,10 @@ import org.gradle.api.NamedDomainObjectContainer
 import org.gradle.api.Plugin
 import org.gradle.api.Project
 import org.gradle.api.Task
-import org.gradle.api.XmlProvider
 import org.gradle.api.artifacts.Configuration
 import org.gradle.api.artifacts.Dependency
 import org.gradle.api.artifacts.ModuleDependency
-import org.gradle.api.artifacts.ModuleVersionIdentifier
 import org.gradle.api.artifacts.ProjectDependency
-import org.gradle.api.artifacts.ResolvedArtifact
 import org.gradle.api.artifacts.dsl.RepositoryHandler
 import org.gradle.api.artifacts.repositories.IvyArtifactRepository
 import org.gradle.api.artifacts.repositories.IvyPatternRepositoryLayout
@@ -330,11 +326,6 @@ class BuildPlugin implements Plugin<Project> {
         return javaVersions.find { it.version == version }.javaHome.absolutePath
     }
 
-    /** Return the configuration name used for finding transitive deps of the given dependency. */
-    private static String transitiveDepConfigName(String groupId, String artifactId, String version) {
-        return "_transitive_${groupId}_${artifactId}_${version}"
-    }
-
     /**
      * Makes dependencies non-transitive.
      *
@@ -361,11 +352,6 @@ class BuildPlugin implements Plugin<Project> {
         }
         // fail on any conflicting dependency versions
         project.configurations.all({ Configuration configuration ->
-            if (configuration.name.startsWith('_transitive_')) {
-                // don't force transitive configurations to not conflict with themselves, since
-                // we just have them to find *what* transitive deps exist
-                return
-            }
             if (configuration.name.endsWith('Fixture')) {
                 // just a self contained test-fixture configuration, likely transitive and hellacious
                 return
@@ -380,14 +366,6 @@ class BuildPlugin implements Plugin<Project> {
             if (dep instanceof ModuleDependency && !(dep instanceof ProjectDependency)
                     && dep.group.startsWith('org.elasticsearch') == false) {
                 dep.transitive = false
-
-                // also create a configuration just for this dependency version, so that later
-                // we can determine which transitive dependencies it has
-                String depConfig = transitiveDepConfigName(dep.group, dep.name, dep.version)
-                if (project.configurations.findByName(depConfig) == null) {
-                    project.configurations.create(depConfig)
-                    project.dependencies.add(depConfig, "${dep.group}:${dep.name}:${dep.version}")
-                }
             }
         }
 
@@ -457,77 +435,6 @@ class BuildPlugin implements Plugin<Project> {
         }
     }
 
-    /**
-     * Returns a closure which can be used with a MavenPom for fixing problems with gradle generated poms.
-     *
-     * <ul>
-     *     <li>Remove transitive dependencies. We currently exclude all artifacts explicitly instead of using wildcards
-     *         as Ivy incorrectly translates POMs with * excludes to Ivy XML with * excludes which results in the main artifact
-     *         being excluded as well (see https://issues.apache.org/jira/browse/IVY-1531). Note that Gradle 2.14+ automatically
-     *         translates non-transitive dependencies to * excludes. We should revisit this when upgrading Gradle.</li>
-     *     <li>Set compile time deps back to compile from runtime (known issue with maven-publish plugin)</li>
-     * </ul>
-     */
-    @CompileDynamic
-    private static Closure fixupDependencies(Project project) {
-        return { XmlProvider xml ->
-            // first find if we have dependencies at all, and grab the node
-            NodeList depsNodes = xml.asNode().get('dependencies')
-            if (depsNodes.isEmpty()) {
-                return
-            }
-
-            // check each dependency for any transitive deps
-            for (Node depNode : depsNodes.get(0).children()) {
-                String groupId = depNode.get('groupId').get(0).text()
-                String artifactId = depNode.get('artifactId').get(0).text()
-                String version = depNode.get('version').get(0).text()
-
-                // fix deps incorrectly marked as runtime back to compile time deps
-                // see https://discuss.gradle.org/t/maven-publish-plugin-generated-pom-making-dependency-scope-runtime/7494/4
-                boolean isCompileDep = project.configurations.compile.allDependencies.find { dep ->
-                    dep.name == depNode.artifactId.text()
-                }
-                if (depNode.scope.text() == 'runtime' && isCompileDep) {
-                    depNode.scope*.value = 'compile'
-                }
-
-                // remove any exclusions added by gradle, they contain wildcards and systems like ivy have bugs with wildcards
-                // see https://github.com/elastic/elasticsearch/issues/24490
-                NodeList exclusionsNode = depNode.get('exclusions')
-                if (exclusionsNode.size() > 0) {
-                    depNode.remove(exclusionsNode.get(0))
-                }
-
-                // collect the transitive deps now that we know what this dependency is
-                String depConfig = transitiveDepConfigName(groupId, artifactId, version)
-                Configuration configuration = project.configurations.findByName(depConfig)
-                if (configuration == null) {
-                    continue // we did not make this dep non-transitive
-                }
-                Set<ResolvedArtifact> artifacts = configuration.resolvedConfiguration.resolvedArtifacts
-                if (artifacts.size() <= 1) {
-                    // this dep has no transitive deps (or the only artifact is itself)
-                    continue
-                }
-
-                // we now know we have something to exclude, so add exclusions for all artifacts except the main one
-                Node exclusions = depNode.appendNode('exclusions')
-                for (ResolvedArtifact artifact : artifacts) {
-                    ModuleVersionIdentifier moduleVersionIdentifier = artifact.moduleVersion.id;
-                    String depGroupId = moduleVersionIdentifier.group
-                    String depArtifactId = moduleVersionIdentifier.name
-                    // add exclusions for all artifacts except the main one
-                    if (depGroupId != groupId || depArtifactId != artifactId) {
-                        Node exclusion = exclusions.appendNode('exclusion')
-                        exclusion.appendNode('groupId', depGroupId)
-                        exclusion.appendNode('artifactId', depArtifactId)
-                    }
-                }
-            }
-        }
-    }
-
     /**Configuration generation of maven poms. */
     static void configurePomGeneration(Project project) {
         project.plugins.withType(MavenPublishPlugin).whenPluginAdded {
@@ -545,11 +452,6 @@ class BuildPlugin implements Plugin<Project> {
 
             PublishingExtension publishing = project.extensions.getByType(PublishingExtension)
 
-            project.extensions.getByType(PublishingExtension).publications.all { MavenPublication publication -> // we only deal with maven
-                // add exclusions to the pom directly, for each of the transitive deps of this project's deps
-                publication.pom.withXml(fixupDependencies(project))
-            }
-
             project.pluginManager.withPlugin('com.github.johnrengelman.shadow') {
                 MavenPublication publication = publishing.publications.maybeCreate('shadow', MavenPublication)
                 ShadowExtension shadow = project.extensions.getByType(ShadowExtension)