Fix #185 Removing test-scope dependencies before building dependency tree

[suztomo]

Problem

Fixes #185 , in which test-scope dependencies are unexpectedly excluded when

• a library itself only uses the dependency as test
• but another dependency actually uses the dependency (non-test)

(The issue has a diagram to illustrate the mechanism)

The root cause is that, when building the dependency tree of the project, test-scope dependencies hides the actually-used dependencies with "omitted for duplicate" mark.

Solution

With this pull request, when building a dependency tree, the plugin removes the direct, test-scope dependencies. This avoids marking the actually-used dependencies as "omitted for duplicate".

This modification is safe because the test-scope dependencies are not visible to library users in any way.

[suztomo]

@slawekjaranowski Would you help me by reviewing this change?

You might not have the context of #185 (2 years ago) and it's a bit complex problem. Unfortunately this issue came up in my organization recently; we released a library that excluded actually-used dependencies (googleapis/java-pubsub#1239). I want to contribute to fix it.

[slawekjaranowski]

I have merged #305 please resolve conflicts ... and check if new version of m-dependency-tree has the same issue.

[suztomo]

Yes, I will!

[suztomo]

In 2ced44c, I merged master branch and commented out my modification. I confirmed that the new version of maven-dependency-tree has the same problem: the test case for #185 it/flatten-dependency-all-both-test-and-transitive fails:

Running post-build script: /Users/suztomo/flatten-maven-plugin/target/it/flatten-dependency-all-both-test-and-transitive/verify.groovy
Assertion failed: 

assert 2 ==  flattenedProject.dependencies.dependency.size()
         |   |                |            |          |
         |   |                |            |          1
         |   |                |            org.codehaus.mojo.flatten.itscore3.2.1compileorg.codehaus.mojo.flatten.itsdepfalse
         |   |                org.codehaus.mojo.flatten.itscore3.2.1compileorg.codehaus.mojo.flatten.itsdepfalse
         |   4.0.0org.codehaus.mojo.flatten.itsflatten-dependency-all-both-test-and-transitive0.0.1-SNAPSHOTorg.codehaus.mojo.flatten.itscore3.2.1compileorg.codehaus.mojo.flatten.itsdepfalse
         false

	at org.codehaus.groovy.runtime.InvokerHelper.assertFailed(InvokerHelper.java:436)
	at org.codehaus.groovy.runtime.ScriptBytecodeAdapter.assertFailed(ScriptBytecodeAdapter.java:670)
	at Script1.run(Script1.groovy:35)

It fails because the flattened project does not have a actually-used dependency that was interfered by the direct test dependency.

Now, uncommenting my modification...

[suztomo]

@slawekjaranowski All tests passed. Would you review this pull request?

[slawekjaranowski]

looks ok, finally please squash to one commit

[suztomo]

I just squashed the commits into one and rebased origin/master. Waiting for the test results.

[suztomo]

Thank you!

[meltsufin]

@slawekjaranowski When can we expect a new release with this change included?

[suztomo]

It's been done as https://github.com/mojohaus/flatten-maven-plugin/releases/tag/flatten-maven-plugin-1.3.0