Previously, the optional configuration was added to the compile and
runtime classpaths of each source set and the the javadoc classpath
as well. This had a few disadvantages, the most notable of which is
that it meant that the configuration was ifrst resolved and then
the outcome of the resolution was added to the compile and runtime
classpaths. As a result, none of the attributes on the compile and
runtime classpaths were considered to influence variant selection.
This commit reworks the optional dependencies plugin so that the
compile and runtime classpaths of each source set are now configured
to extend from the optional configuration. This allows each
classpath configuration's attributes to influence the dependencies
that are selected from the optional configuration during resolution.
For example, when resolving the compile classpath, compile
dependencies (Usage.JAVA_API) will be selected and when resolving the
runtime classpath, runtime dependencies (Usage.JAVA_RUNTIME) will be
selected.
The above-described change means that runtime dependencies of an
optional dependencies will no longer leak into the compile classpath.
As a result of this, our Gradle plugin's test infrastructure has
been updated so that it no longer references runtime dependencies of
the Kotlin Gradle plugin at compile time.
Closes gh-27965
Previously, our conventions configured the source and target
compatibility on the project's JavaCompile tasks. This causes the
settings to be missed when importing the projects into Eclipse [1].
This commit updates the conventions to set the source and target
compatibility on the project-wide JavaPluginExtension. This allows
the Eclipse import to correctly detect and honour the settings.
Closes gh-26932
[1] https://github.com/eclipse/buildship/issues/978
Andy Wilkinson
izeye
dreis2211
Phillip Webb
Stephane Nicoll