[ARCHETYPE-552] Erroneous Inheritance Cycle Generated By Archetype Plugin

[jira-importer]

Scott MacDonald opened ARCHETYPE-552 and commented

When developing a multi module archetype with a root level aggregator pom which inherits from a sibling parent within the project,  the archetype generated project will incorrectly add the aggregator pom as a parent in the sibling parent pom file, causing an inheritance cycle in the generated project.

Attached is a zip file containing a minimal archetype project that demonstrates the behavior.

After running mvn install,   you can inspect target/test-classes/projects/it-basic/project/example-project/example-project-parent/pom.xml  and see that the generated project incorrectly adds the top-level aggregate pom  as a parent in the parent pom causing an inheritance cycle, even though such a parent designation is  not specified in the archetype resources.

 

The exact element that is incorrectly added to target/test-classes/projects/it-basic/project/example-project/example-project-parent/pom.xml is below..

    <parent>     <artifactId>example-project-aggregator</artifactId>     <groupId>com.foo</groupId>     <version>0.0.0</version>   </parent>

 

After the failure, removing the  incorrect parent pom element from the  target/test-classes/projects/it-basic/project/example-project/example-project-parent/pom.xml results in a working  maven project. 

 

 

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Affects: 3.0.1

Attachments:

• maven-archetype-parent-cycle-bug.zip (97.79 kB)

[jira-importer]

Scott MacDonald commented

Just ran into this exact  issue on maven 3.6.2 with the  bundled archetype plugin, and it also occurs  on latest 3.2.1 archetype  plugin.  Came here to log a bug and and submit a minimal reproducible case, but low and behold, somebody already did...me!! hah! over a year ago!!  Well that saves me little time (not as much as if I remembered I did that 2 hours ago...ha) .

 

Anyway, sure hope somebody can fix this cuz  using a sibling parent with an aggregator pom that inherits from it is a pretty nice pattern. Many people separate aggregation and inheritance this way. I've use this pattern on hundreds of projects and it work well.   I just can't generate working templated projects for them with the archetype plugin.  

A none ideal workaround is to break the inheritance from the aggregator to the parent, and then  specify  version in the aggregator, which isn't ideal  cuz DRY....and I also have call versions:set twice to change them (once on aggregator, once on parent).   Not a huge deal, but it would be wonderful if it archetype didn;t  erroneously add the inheritance  cycle in the first place.