How to make IntelliJ reference source code in another module?

Question

I have a typical project structure:

- root-dir (not a project)
 \- core-module (a gradle project)
 \- application (a gradle project)

Both core-module and application are imported into IntelliJ and kept on Auto Import. In application's build.gradle, core-module is referenced as:

compile('my-group-id:core-module:0.2.0-SNAPSHOT')

where 0.2.0-SNAPSHOT is the current version as declared in core-module's gradle.properties.

In application, when I try to view a class from core-module, I'm brought to the source code in core-module-0.2.0-SNAPSHOT-sources.jar, instead of the corresponding source code in the core-module module.

I know I can manually add core-module as a module dependency in application, but next time anything in application's build.gradle changes, auto import will overwrite that dependency.

Is there any way to make IntelliJ recognize automatically that I'm trying to view a class from another module and go there instead of the downloaded sources jar?

Furthermore, is there any way to make IntelliJ always prefer the core-module module over the dependency jar, not only for code viewing, but for building/running/debugging/etc.?

All the source files are in Kotlin, FWIW.

Answer 1

Use Gradle's composite build. Gradle has composite builds https://docs.gradle.org/4.4/userguide/composite_builds.html that allow one to 'include' a build directly, rather than from a repository.

IntelliJ also supports this functionality. This was added in 2016.3.

Here's a webcast:https://blog.jetbrains.com/idea/2017/03/webinar-recording-composite-builds-with-gradle/

In the Gradle tab, right-click on your application module. The menu will have a 'composite builds' option. On the dialog that appears, check the 'core-module' module and close.

Now, right-click on application module and do a 'refresh Gradle project'. I've found if I don't do this, the dependency doesn't get updated correctly.

To verify, look at the dependencies under the sourceSets. Instead of a version #, it will now look like a module dependency.

This provides many benefits. One is the navigation you were looking for. In addition, any changes made in core-module are immediately available, and used for the application.

Refactor a method in core-module that is used by application, and IntelliJ will refactor all usages.

Enjoy!