AnnotationProcessorFactoryLoader locks Jars which causes errors during a maven update with m2e 2.3.0

[RoiSoleil]

AnnotationProcessorFactoryLoader locks Jars which causes errors during a maven update with m2e 2.3.0

[rdicroce]

This has now been fixed (although we have no idea why the fix works) in Maven Resolver. See apache/maven-resolver#364. Now Resolver has to be released, and then Maven core has to update to the new Resolver release, and then Maven itself has to be released, and then m2e has to update to the new Maven release. No idea how long that will take but eventually this problem will go away.

[RoiSoleil]

This commit introduce the chnage in m2e : eclipse-m2e/m2e-core@eea96bf

@laeubi : What do you think about that ?

[laeubi]

@to-fr I think that this could cause issues seen with Maven 3.9.x where the update of snapshots failed.
@RoiSoleil thanks for bringing this up and for the analysis, I think this is mostly visible with windows then?

[RoiSoleil]

Yes i'm on Windows.

[to-fr]

Interesting. That would explain why I wasn't able to reproduce the issue with a standalone version of Maven 3.9.x on the commandline but why does the locking not occur with the Eclipse embedded maven runtime <3.9.x and m2e >2.3.0?

[laeubi]

I think as @RoiSoleil explained, the locking has occurred before but maven has not issued an error, now maven 3.9 uses file-locking it seem to having issues with that under windows as the file is permanently locked.

@RoiSoleil do you plan to propose a patch for this?

[RoiSoleil]

Not for now, i think it's a little too 'hard' for me.

[RoiSoleil]

Any thoughts ?

[laeubi]

@stephan-herrmann @iloveeclipse can you maybe look into this?!

[RoiSoleil]

@stephan-herrmann @iloveeclipse it would be nice to have a solution for the next release ;)

[stephan-herrmann]

Please don't hold your breath waiting for me to propose as solution. I'm not an expert for JDT/Apt issues.

[RoiSoleil]

To bypass the problem, i'm doing a copy of the JAR used in AnnotationProcessorFactoryLoader :

It's not a clean solution but it works for me ... Maybe it can helps.

[rdicroce]

I spent some time investigating this and wrote up my findings here.

The TL;DR is that ideally Maven Resolver needs to change how it stores snapshots on disk, so that the JAR files don't need to be replaced. Failing that, the "copy JARs to a temp dir and load from there" solution proposed by @RoiSoleil is probably the only thing Eclipse could do. Though it would make more sense to implement that logic in m2e than JDT, since this really is a Maven-specific problem.