Maven transitive dependencies with exclusion vs same transitive dependency without

I have this maven modules dependency hierarchy:

LibModel
+ Ext1
   - exclude(ext2)
LibApp
+ LibModel
+ Ext1 --- explicitly added without exclude this time
   + ext2

Other projects depends on LibModel and LibApp:

• One of them depends on LibApp, which pull LibModel and Ext1 which itself pull Ext2 => works fine
• And another one depends on LibModel and LibApp explicitly, and doesn't work :( I found out that Ext2 is not the in the dependency tree. If I remove the direct dependency to LibModel, Ext2 appears in the dependency tree. I understand that the project pulls Ext1 through LibModel thus with Ext2 excluded.

It really bothers me that depending on LibModel being explicitly listed as a dependency or otherwise being imported transitively through LibApp, the exclusion is applied on not. And I can't find information on that kind of dual import with and without exclusion.

=> is there a way to guaranty that if LibApp is a dependencies, Ext1 library is pulled full, disregarding LibModel being explicitly listed as a dependency?

Notes:

• I manage LibModel and LibApp but not Ext1/2
• For information, the Ext2 is a Spring lib which is required for the app to run. Compilation and even tests works find without it. I didn't look into it but I guess Ext2 contains some autoconfig required for deployed execution
• LibModel is a light weight lib containing only model classes and tooling, thus it should not import the whole applicative dependency tree but has classes that need to extend a class in Ext1. No way around it. So I added Ext1 as dependency of LibModel but with Ext2 excluded. Especially that LibApp has Ext1 dependency without Ext2 excluded

Not really. This is Maven dependency mediation. You can never guarantee certain transitive dependencies for a given library because other dependencies may override them.

Possible things to think about:

• Add a dependencyManagement entry for Ext1

• Add an explicit dependency on Ext1

• Avoid the exclusion. It is usually not a problem if LibModel has more dependencies than necessary at compile time if those dependencies are necessary at runtime.