gradle-2.0.md

Gradle 2.0

Gradle 2.0 is the next major Gradle release that offers the opportunity to make breaking changes to the public interface of Gradle. This document captures a laundry list of ideas to consider before shipping Gradle 2.0.

Note: for the change listed below, the old behaviour or feature to be removed should be deprecated in a Gradle 1.x release, probably no later than Gradle 1.8. Similarly for changes to behaviour.

Planned

The following stories are to be included in Gradle 2.0.

Remove all features deprecated as at Gradle 1.8

In the Gradle 2.0-rc-1 release, remove all features that are deprecated as at Gradle 1.8 or earlier:

• Search for usages of DeprecationLogger, @Deprecated, @deprecated and remove the associated feature.
• Review usages of DeprecationLogger.whileDisabled().

Remove Ivy types from the Gradle repository API

These types expose the implementation details of dependency management and force a certain implementation on Gradle. Removing these types from the API allows us to implement new features and remove some internal complexity.

• Remove methods from ArtifactRepositoryContainer and RepositoryHandler that accept an Ivy DependencyResolver as parameter.
• Remove methods from ArtifactRepositoryContainer that return DependencyResolver.
• Remove RepositoryHandler.mavenRepo().
• Change the MavenResolver implementation so that it no longer extends DependencyResolver.
• Change the FlatDirRepository implementation so that it no longer uses a DependencyResolver implementation.
• Remove Ivy version from the output of gradle -v.

Gradle Open API

Now that we have reasonable tooling support via the tooling API, remove the Open API.

• Implement a stub to fail with a reasonable error message when attempting to use Gradle from the Open API.
• Remove the remaining Open API classes and project.
• Add integration test coverage.

Remove the GradleLauncher API

The public API for launching Gradle is now the tooling API. The GradleBuild task can also be used.

• Replace internal usages of the static GradleLauncher methods.
• Remove the GradleLauncher type from the public API.
• Remove the public StartParameter constructor.
• Change StartParameter into an interface.

Misc API tidy-ups

• Remove unused IllegalOperationAtExecutionTimeException.
• Remove unused AntJavadoc.

Candidates

The following stories are candidates to be included in Gradle 2.0. They have not been scheduled yet:

Remove group and status from project

Alternatively, default the group to null.

Remove the Ant-task based Scala compiler

• Change the default for useAnt to false and deprecate the useAnt property.

Decouple publishing DSL from Maven Ant tasks

• Change the old publishing DSL to use the Maven 3 classes instead of Maven 2 classes. This affects:
  • MavenResolver.settings
  • MavenDeployer.repository and snapshotRepository.
  • MavenPom.dependencies.
• Remove MavenDeployer.addProtocolProviderJars().
• Change PublishFilter so that it accepts a PublishArtifact instead of an Artifact.

Copy tasks

There are serveral inconsitencies and confusing behaviours in the copy tasks and copy spec:

• Change copy tasks so that they no longer implement CopySpec. Instead, they should have a content property which is a CopySpec that contains the main content. Leave behind some methods which operate on the file tree as a whole, eg eachFile(), duplicatesStrategy, matching().
• Change the copy tasks so that into always refers to the root of the destination file tree, and that destinationDir (possibly with a better name) is instead used to specify the root of the destination file tree, for those tasks that produce a file tree on the file system.
• Change the Jar type so that there is a single metaInf copy spec which is a child of the main content, rather than creating a new copy spec each time metainf is referenced. Do the same for War.webInf.
• The CopySpec.with() method currently assumes that a root copy spec is supplied with all values specified, and no values are inherted by the attached copy spec. Instead, change CopySpec.with() so that values are inherited from the copy spec.
• Change the default duplicatesStrategy to fail or perhaps warn.
• Change the Ear type so that the generated descriptor takes precedence over a descriptor in the main content, similar to the manifest for Jar and the web XML for War.

Archive tasks + base plugin

• Move defaults for output directory to the tasks and remove from base plugin.
• Use ${task.name}.${task.extension} as the default archive name, so that the default does not conflict with the default for another archive task.

Test output directories

The current defaults for the outputs of tasks of type Test conflict with each other:

• Change the default result and report directory for the Test type to include the task's name, so that the default does not conflict with the default for another Test task.

Remove old dependency result graph

The old dependency result graph is expensive in terms of heap usage. We should remove it.

• Promote new dependency result graph to un-incubate it.
• Remove methods that use ResolvedDependency and UnresolvedDependency.
• Keep ResolvedArtifact and replace it later, as it is not terribly expensive to keep.

Remove API methods that are added by the DSL decoration

Some model types hand-code the DSL conventions in their API. We should remove these and let the DSL decoration take care of this, to simplify these types and to offer a more consistent DSL.

• Remove all methods that accept a Closure when an Action overload is available. Add missing overloads where appropriate.
• Remove all methods that accept a String or Object when a enum overload is available. Add missing overloads where appropriate.
• Remove CharSequence -> Enum conversion code in DefaultTaskLogging.
• Remove all set methods that contain no custom logic.

Remove tooling API support for some older versions

• Remove support from the consumer for providers earlier than 1.0-milestone-8:
  • Consumer fails with a decent error message instead of falling back to the methods on ConnectionVersion4.
  • Add integration test coverage.
• Remove support from the provider for consumers earlier than 1.2 (we can't tell the difference between clients from 1.0-milestone-8 and 1.1).
  • Change the implementation of methods on ConnectionVersion4 and InternalConnection to fail with a decent error message.
  • Model implementations no longer need to implement ProjectVersion3 or the protocol interfaces.
  • Add integration test coverage.
• Move UnsupportedBuildArgumentException and UnsupportedOperationConfigurationException up to org.gradle.tooling, to remove package cycle from the API.

Clean up DefaultTask hierarchy

• Inline ConventionTask and AbstractTask into DefaultTask.
• Remove Task.dependsOnTaskDidWork().
• Mix TaskInternal in during decoration and remove references to internal types.

Remove references to internal classes from API

• Remove Configurable from public API types.
• Remove PomFilterContainer.getActivePomFilters().
• Change StartParameter so that it no longer extends LoggingConfiguration.
• Move ConflictResolution from public API (it's only used internally).
• Move Module from public API (it's only used internally).
• Move Logging.ANT_IVY_2_SLF4J_LEVEL_MAPPER from public API.
• Move AntGroovydoc and AntScalaDoc from public API.
• Move BuildExceptionReporter, BuildResultLogger, TaskExecutionLogger and BuildLogger from public API.

Remove support for convention objects

Extension objects have been available for over 2 years and are now an established pattern.

• Migrate core plugins to use extensions.
• Remove Convention type.

Container API tidy-ups

• Remove the specialised subclasses of UnknownDomainObjectException and the overridden methods that exist simply to declare this from PluginContainer, ArtifactRepositoryContainer, ConfigurationContainer, TaskCollection.
• Remove the specialised methods such as whenTaskAdded() from PluginCollection, TaskCollection
• Remove the extends T upper bound on the type variable of DomainObjectCollection.withType().
• Remove the type varable from ReportContainer
• Remove unused constants from ArtifactRepositoryContainer
• Move ReportContainer.ImmutableViolationException to make top level.

Dependency API tidy-ups

• Remove equals() implementations from Dependency subclasses.
• Remove ExternalDependency.force. Use resolution strategy instead.
• Remove SelfResolvingDependency.resolve() methods. These should be internal and invoked only as part of resolution.
• Remove ClientModule and replace with consumer-side component meta-data rules.
• Remove ExternalModuleDependency.changing. Use component meta-data rules instead.

Misc API tidy-ups

• Rename IllegalDependencyNotation to add Exception to the end of its name.
• Remove ConventionProperty, replace it with documentation.
• Remove Settings.startParameter. Can use gradle.startParameter instead.
• Remove org.gradle.util from default imports.
• Remove AbstractOptions.

Remove sonar plugin

Promote the sonar-runner plugin and remove the sonar plugin.

Remove support for running Gradle on Java 5

Would still be able to compile for Java 5. Would need to improve cross-compilation support.

Remove usages of JNA and JNA-Posix

Replace all usages of JNA and JNA-Posix with native-platform. Currently, this means that console support and UNIX file permissions with JVMs earlier than Java 7 will not be supported on the following platforms:

• Linux-ia64
• Solaris-x86, -amd64, -sparc, -sparcv9
• FreeBSD-i386, -amd64

Decorate classes at load time instead of subclassing

Decorating classes at load time is generally a more reliable approach and offers a few new interesting use cases we can support. For example, by decorating classes at load time we can support expressions such as new MyDslType(), rather than requiring that Gradle control the instantiation of decorated objects.

Switching to decoration at load time should generally be transparent to most things, except for clients of ProjectBuilder that refer to types which are not loaded by Gradle, such as the classes under test.

Restructure plugin package heirarchy

buildNeeded and buildDependents

• Rename buildDependents to buildDownstream
• Rename buildNeeded to buildUpstream
• Add a new task buildStream which is equivalent to buildDownstream buildUpstream

build.gradle in a multiproject build

• A Gradle best pattern is to name the gradle file to be the same name as the subproject.
• In Gradle 2.0, let's support this out of the box, possibly as a preference to build.gradle, and maybe drop support for build.gradle in subprojects.

Why remind people about Maven?

Change from:

repositories {
    mavenCentral()
}

to:

repositories {
    central()
}