m2e builds closed projects

[hohwille]

I am (trying to) using Eclipse with m2e in a large project (650 modules, 5 Mio LoC).
As it simply explodes when all modules are opened (almost infinite build loops and OOME), I closed most modules so only a few ones are opened that I am currently working on or affected by my refactorings.
I still observe long build times where Eclipse gets stalled and grayed out and observing the logs I see that m2e is updating and building many modules that are actually closed.

How is that actually possible?
Is there a severe bug in m2e or is that expected behaviour?

[mickaelistria]

I think it can be treated as a bug. Can you please try to create a very minimal case to reproduce this issue with detailed steps to reproduce, and share it in an issue report?

[hohwille]

Thanks for the quick response. I will try my best to do so.

BTW: It seems that m2e scales kind of exponential instead of linear with the number of modules/dependencies. I fully understand that the Maven model is extremely complex but it seems that if module A is build but depends on module B then B obviously needs to be build and in-sync before, now if later module C is build and also depends on A then m2e should detect that A was just rebuild. In general this seems to work but with more complexity added this stops working somehow and I see build cycles where m2e is busy building module A for longer time multiple-times in a row triggered by the same initial change. In this case I am quite sure that I am unable to provide a reproducer so I can just share the observation. I have observed that already in multiple bigger monolithic projects. If you want I can create a separate discussion for that but I am unsure if we really can make efficient progress on this problem. I also have a larger OSS project but in there it is working acceptable so it seems I only get this in contexts where I cannot share the source-code (and where developers have piled up crazy stuff for decades before I even join the project like having test-jar dependencies what I consider an anti-pattern as well as integrating every possible code-generator like mapstruct, JPA metamodel, lombok, openapi, jaxb, querydsl, etc. where I typically say that the need to generate code in the build typically indicates a flaw in your programming language or the design of your code on top of that). And for the record - even IntelliJ Ultimate is unable to work well in such project...

[laeubi]

@hohwille please see

• What is your favorite maven project that is NOT working with m2eclipse? #1064

It is almost impossible to guess what can be improved from "I am (trying to) using Eclipse with m2e in a large project (650 modules, 5 Mio LoC)"...

[mickaelistria]

Feel free to create a separate discussion; but also please try whenever you see such issue to describe clearly the case: have a reproducer and steps to reproduce. Some parts of m2e were tremendously "optimized" to make it usually linear (basically capacity to re-use content rather than rebuilding it), but some could be missing, and as the Maven model itself evolves, it can be that some of strategies in place to locate cached artifacts/models are not working as well as expected.
There can be many operations that can go quadratic (reslution, build, in editor or not...), we won't be able to find possible improvements easily without finer grain details and reproducers.