My Recent GitHub Activity
Loading...

Gradle API and Transitive Dependencies

15 April 2014

Recently, I have been working on porting the RAML Maven plugin to a Gradle plugin and ran into a limitation with Gradle and its API jars. An interesting difference between Gradle and Maven is that Gradle does not want you to rely on its API jars from a Maven repository (unlike Maven, whose API jars are all stored in the central Maven repository). Instead, the Gradle team has built in some special dependency handlers that in effect treat the required Gradle (and Groovy dependencies, if need be) as "provided" dependencies:

build.gradle
...
dependencies {
    gradleApi()						(1)
    localGroovy()					(2)
    compile 'commmons-lang:commons-lang:2.6'
}
...
1 Tells Gradle to include the gradle-core dependency and its required dependencies. Normally used for plugin development.
2 Tells Gradle to include the Groovy dependency used by Gradle, which at the time of writing is 1.8.6.

What this means is that when building your Gradle plugin, Gradle will use the jars that are part of the local Gradle installation to resolve these dependencies, thus ensuring that you get the right versions of jars used by the Gradle API based on the Gradle version. It will NOT resolve these dependencies against any external repository. This is a nice improvement over Maven, but it comes with one major limitation that can cause issues: there is no way to override and/or exclude any of the transitive dependencies brought in by the Gradle. This wouldn’t be that big of an issue, except for the fact the gradleApi() dependency has a bunch of transitive dependencies. Below is an example of what is include if both gradleApi() and localGroovy() are used:

~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/gradle-core-1.11.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/groovy-all-1.8.6.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/asm-all-5.0_BETA.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/ant-1.9.2.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/commons-collections-3.2.1.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/commons-io-1.4.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/commons-lang-2.6.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/ivy-2.2.0.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/logback-core-1.0.13.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/logback-classic-1.0.13.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/guava-jdk5-14.0.1.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/jcip-annotations-1.0.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/jul-to-slf4j-1.7.5.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/jarjar-1.3.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/javax.inject-1.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/bintray-client-java-impl-0.1.0.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/httpclient-4.2.2.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/slf4j-api-1.7.5.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/log4j-over-slf4j-1.7.5.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/jcl-over-slf4j-1.7.5.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/ant-launcher-1.9.2.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/jsch-0.1.46.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/joda-time-2.3.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/bintray-client-java-api-0.1.0.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/commons-logging-1.1.1.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/commons-beanutils-1.8.0.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/ezmorph-1.0.6.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/json-lib-2.3-jdk15.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/xml-resolver-1.2.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/http-builder-0.6.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/commons-codec-1.6.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/httpcore-4.2.2.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/jcifs-1.3.17.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/gradle-docs-1.11.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/gradle-base-services-groovy-1.11.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/gradle-base-services-1.11.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/gradle-resources-1.11.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/gradle-cli-1.11.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/gradle-native-1.11.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/jna-3.2.7.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/native-platform-0.7.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/jna-posix-1.0.3.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/jansi-1.2.1.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/native-platform-osx-i386-0.7.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/native-platform-osx-amd64-0.7.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/native-platform-linux-amd64-0.7.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/native-platform-linux-i386-0.7.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/native-platform-windows-amd64-0.7.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/native-platform-windows-i386-0.7.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/gradle-messaging-1.11.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/kryo-2.20.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/asm-4.0.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/reflectasm-1.07-shaded.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/minlog-1.2.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/objenesis-1.2.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/plugins/gradle-core-impl-1.11.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/plugins/jarjar-maven-settings-3.0.4.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/plugins/jarjar-maven-repository-metadata-3.0.4.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/plugins/jarjar-plexus-container-default-1.5.5.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/plugins/jarjar-maven-aether-provider-3.0.4.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/plugins/jarjar-wagon-provider-api-2.4.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/plugins/jarjar-plexus-cipher-1.7.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/plugins/jarjar-plexus-interpolation-1.14.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/plugins/jarjar-plexus-utils-2.0.6.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/plugins/jarjar-plexus-classworlds-2.4.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/plugins/jarjar-maven-plugin-api-3.0.4.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/plugins/jarjar-maven-model-builder-3.0.4.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/plugins/jarjar-plexus-sec-dispatcher-1.3.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/plugins/jarjar-plexus-component-annotations-1.5.5.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/plugins/jarjar-aether-connector-wagon-1.13.1.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/plugins/jarjar-maven-compat-3.0.4.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/plugins/jarjar-wagon-http-2.4.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/plugins/jarjar-aether-api-1.13.1.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/plugins/jarjar-maven-settings-builder-3.0.4.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/plugins/jarjar-aether-spi-1.13.1.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/plugins/jarjar-maven-core-3.0.4.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/plugins/jarjar-wagon-http-shared4-2.4.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/plugins/jarjar-aether-util-1.13.1.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/plugins/jarjar-maven-artifact-3.0.4.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/plugins/jarjar-maven-model-3.0.4.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/plugins/jarjar-aether-impl-1.13.1.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/plugins/maven-ant-tasks-2.1.3.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/plugins/nekohtml-1.9.14.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/plugins/xbean-reflect-3.4.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/plugins/xml-apis-1.3.04.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/plugins/xercesImpl-2.9.1.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/gradle-tooling-api-1.11.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/plugins/gradle-plugins-1.11.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/plugins/junit-4.11.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/plugins/testng-6.3.1.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/plugins/commons-cli-1.2.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/plugins/bsh-2.0b4.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/plugins/jcommander-1.12.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/plugins/snakeyaml-1.6.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/plugins/hamcrest-core-1.3.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/plugins/gradle-code-quality-1.11.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/plugins/gradle-jetty-1.11.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/plugins/jetty-6.1.25.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/plugins/jetty-util-6.1.25.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/plugins/servlet-api-2.5-20081211.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/plugins/jetty-plus-6.1.25.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/plugins/jsp-2.1-6.1.14.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/plugins/jetty-annotations-6.1.25.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/plugins/geronimo-annotation_1.0_spec-1.0.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/plugins/jetty-naming-6.1.25.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/plugins/core-3.1.1.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/plugins/jsp-api-2.1-6.1.14.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/plugins/gradle-antlr-1.11.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/plugins/ant-antlr-1.9.2.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/plugins/antlr-2.7.7.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/gradle-wrapper-1.11.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/plugins/gradle-osgi-1.11.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/plugins/bndlib-2.1.0.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/plugins/gradle-maven-1.11.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/plugins/pmaven-common-0.8-20100325.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/plugins/pmaven-groovy-0.8-20100325.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/plugins/plexus-component-annotations-1.5.2.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/plugins/gradle-ide-1.11.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/plugins/gradle-announce-1.11.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/plugins/gradle-scala-1.11.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/plugins/gradle-sonar-1.11.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/plugins/sonar-runner-2.0.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/plugins/sonar-batch-bootstrapper-2.9.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/plugins/gradle-signing-1.11.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/plugins/bcpg-jdk15-1.46.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/plugins/bcprov-jdk15-1.46.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/plugins/gradle-cpp-1.11.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/plugins/gradle-ear-1.11.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/plugins/gradle-javascript-1.11.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/plugins/rhino-1.7R3.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/plugins/gson-2.2.4.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/plugins/simple-4.1.21.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/plugins/gradle-build-comparison-1.11.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/plugins/gradle-diagnostics-1.11.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/plugins/gradle-reporting-1.11.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/plugins/jatl-0.2.2.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/plugins/gradle-publish-1.11.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/plugins/gradle-ivy-1.11.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/plugins/gradle-jacoco-1.11.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/plugins/gradle-build-init-1.11.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/plugins/gradle-language-jvm-1.11.jar
~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/plugins/gradle-language-base-1.11.jar

If you build a plugin and use it in another Gradle project, these dependencies do not appear to override and/or interfere with any dependencies of that project. Where this becomes an issues is with the "test" scope of the Gradle plugin project itself. I first noticed an issue when attempting to use the Groovy 2.0 version of Spock to write tests for my plugin. Each time I attempted to build the project (and therefore run the tests), Spock would complain that Groovy 1.8.6 was not compatible:

GroovyVersionException: The Spock compiler plugin cannot execute because Spock 0.7.0-groovy-2.0 is not compatible with Groovy 1.8.6. For more information, see http://versioninfo.spockframework.org
Spock location: file:~/.gradle/caches/artifacts-23/filestore/org.spockframework/spock-core/0.7-groovy-2.0/jar/4de0b428de0c14b6eb6375d8174f71848cbfc1d7/spock-core-0.7-groovy-2.0.jar
Groovy location: file:~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/groovy-all-1.8.6.jar

This seemed odd, as I was explicitly including version 2.2.1 of Groovy in my build.gradle script. After a little digging on the internets, I discovered that Gradle depends on Groovy 1.8.6 and by using the localGroovy() or gradleApi() dependencies, there is no way to replace/override this. Furthermore, its probably not a good idea to do so, as Gradle itself is partially written in Groovy. Luckily, Spock supports both Groovy 1.8.x and 2.x, so I simply changed my Spock dependency to be compatible with Groovy 1.8.6. I thought that I was out of the woods, but on my next attempt to run the tests, I ran into another issue. The tests failed, complaining about a missing method exception:

org.gradle.api.tasks.TaskExecutionException: Execution failed for task ':raml-generate'.
    at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.executeActions(ExecuteActionsTaskExecuter.java:69)
    at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.execute(ExecuteActionsTaskExecuter.java:46)
    at org.gradle.api.internal.tasks.execution.PostExecutionAnalysisTaskExecuter.execute(PostExecutionAnalysisTaskExecuter.java:35)
    at org.gradle.api.internal.tasks.execution.SkipUpToDateTaskExecuter.execute(SkipUpToDateTaskExecuter.java:64)
    at org.gradle.api.internal.tasks.execution.ValidatingTaskExecuter.execute(ValidatingTaskExecuter.java:58)
    at org.gradle.api.internal.tasks.execution.SkipEmptySourceFilesTaskExecuter.execute(SkipEmptySourceFilesTaskExecuter.java:42)
    at org.gradle.api.internal.tasks.execution.SkipTaskWithNoActionsExecuter.execute(SkipTaskWithNoActionsExecuter.java:52)
    at org.gradle.api.internal.tasks.execution.SkipOnlyIfTaskExecuter.execute(SkipOnlyIfTaskExecuter.java:53)
    at org.gradle.api.internal.tasks.execution.ExecuteAtMostOnceTaskExecuter.execute(ExecuteAtMostOnceTaskExecuter.java:43)
    at org.gradle.api.internal.AbstractTask.executeWithoutThrowingTaskFailure(AbstractTask.java:289)
    at org.gradle.api.internal.AbstractTask.execute(AbstractTask.java:284)
    at org.raml.jaxrs.codegen.gradle.CodeGeneratorTaskSpec.test the generation of JAX-RS annotated resources from a .raml file(CodeGeneratorTaskSpec.groovy:220)
Caused by: java.lang.NoSuchMethodError: org.yaml.snakeyaml.nodes.MappingNode.isMerged()Z
    at org.raml.parser.visitor.NodeVisitor.doVisitMappingNode(NodeVisitor.java:126)
    at org.raml.parser.visitor.NodeVisitor.visitDocument(NodeVisitor.java:209)
    at org.raml.parser.visitor.YamlValidationService.validate(YamlValidationService.java:64)
    at org.raml.parser.visitor.YamlValidationService.validate(YamlValidationService.java:95)
    at org.raml.parser.visitor.YamlValidationService.validate(YamlValidationService.java:76)
    at org.raml.jaxrs.codegen.core.Generator.run(Generator.java:110)
    at org.raml.jaxrs.codegen.gradle.CodeGeneratorTask.generate_closure1(CodeGeneratorTask.groovy:80)
    at groovy.lang.Closure.call(Closure.java:412)
    at groovy.lang.Closure.call(Closure.java:425)
    at org.raml.jaxrs.codegen.gradle.CodeGeneratorTask.generate(CodeGeneratorTask.groovy:79)
    at org.gradle.internal.reflect.JavaMethod.invoke(JavaMethod.java:63)
    at org.gradle.api.internal.project.taskfactory.AnnotationProcessingTaskFactory$StandardTaskAction.doExecute(AnnotationProcessingTaskFactory.java:219)
    at org.gradle.api.internal.project.taskfactory.AnnotationProcessingTaskFactory$StandardTaskAction.execute(AnnotationProcessingTaskFactory.java:212)
    at org.gradle.api.internal.project.taskfactory.AnnotationProcessingTaskFactory$StandardTaskAction.execute(AnnotationProcessingTaskFactory.java:201)
    at org.gradle.api.internal.AbstractTask$TaskActionWrapper.execute(AbstractTask.java:533)
    at org.gradle.api.internal.AbstractTask$TaskActionWrapper.execute(AbstractTask.java:516)
    at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.executeAction(ExecuteActionsTaskExecuter.java:80)
    at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.executeActions(ExecuteActionsTaskExecuter.java:61)
    ... 11 more

Well, that’s odd. The RAML libraries include org.yaml:snakeyaml:1.13 as a transitive dependency, which includes the proper version of MappingNode. Furthermore, I was able to test my plugin in a sample application and it works, so I figured something must be up with the "test" scope classpath in the Gradle plugin project. If we recall the list of dependencies above (which I got by printing out the contents of the configurations.testCompile configuration in my build.gradle script), you can see that there is a reference to the snakeyaml dependency:

~/.gradle/wrapper/dists/gradle-1.11-bin/4h5v8877arc3jhuqbm3osbr7o7/gradle-1.11/lib/plugins/snakeyaml-1.6.jar

Somehow, this dependency is winning out over the transitively included dependency from the RAML dependency, eventhough when printing out the resloved dependency tree via the Gradle dependencies task, it shows only version 1.13. Because there is no way (at least that I have found so far) to exclude the dependencies that are brought in by the Gradle API, this means that if you have a Gradle plugin project that uses any of the dependencies that are also used by the Gradle API, you are effectively stuck at the versions of those dependencies that match what Gradle currently depends on. I have brought this issue up on the Gradle forum and I noticed that a few other people have asked for a feature to allow for excluding dependencies from the Gradle API. I will keep you posted on this issue and if I get an answer and/or resolution.

comments powered by Disqus