Recessive node attributes not set anymore in Xpp3DomUtils when dominant root node value is empty

[guylabs]

The change in 67ac243 causes different merging outcomes before and after the change. This has been discussed in 67ac243#r94996401.

A reproducer of the issue is shown in https://github.com/guylabs/plexus-utils-merge-xml-reproducer where the same configuration is executed on Maven 3.8.7 and on Maven 4.0.0-alpha3.

[guylabs]

@kwin were you able to have a look at the reproducer already?

[kwin]

Not yet. Can you simplify that into a unit test? The reproducer uses a lot of xpp3dom merging methods. It is still not clear to me which method calls the dominant element with an empty value and why…

[guylabs]

It's this part that has been removed:

67ac243#diff-8daf65446126b8abe5b619665bb0697d522273192ee8cb2bd74a371e3eb3b407L143-L148

It's not easy to simplify but the reproducer shows nicely the diff between the files and what is not working as expected.

[guylabs]

@kwin any update on this?

[c00ler]

@kwin @guylabs I wrote a simple reproducer test for this issue: https://github.com/c00ler/plexus-utils-merge-xml-reproducer/blob/main/src/test/java/com/github/avenderov/ReproducerTest.java. It shows that the issue is not in the plexus-utils. I run the test with the version before the change 3.4.2 and after the change 3.5.0, and in both cases test passes. The issue is happening in Maven 4 as it's not using Xpp3Dom class and corresponding utility methods anymore but has its own implementation that has a regression. I will create an issue in the maven issue tracker.

[c00ler]

The corresponding ticket in the maven issue tracker: https://issues.apache.org/jira/browse/MNG-7683

[gnodet]

Closing as the issue lies in the maven 4 code base.