Use Maven 4 as the runtime for m2eclipse

[laeubi]

Maven 4 will soon be released and should be able to execute Maven 3 projects as well. We should therefore upgrade m2e to use Maven 4 from now on.

For users that require Maven 3.9 line we can offer the latest 3.9.11 maven runtime as an additional install option like we already did for Maven 3.9.6

[github-actions]

Test Results

  330 files  +3    330 suites  +3   58m 44s ⏱️ - 18m 58s
  694 tests +2    371 ✅  - 303  16 💤 ±0  184 ❌ +183  123 🔥 +122 
2 082 runs  +6  1 113 ✅  - 913  48 💤 ±0  552 ❌ +551  369 🔥 +368 

For more details on these failures and errors, see this check.

Results for commit d2927b5. ± Comparison against base commit d18979f.

♻️ This comment has been updated with latest results.

[laeubi]

FYI @stbischof and @danthe1st as I know you are interested in Maven 4 support.

This at least already compiles ...

[stbischof]

Whooop whooop!!!!! Thank you a lot for your work

[laeubi]

All tests are passing... except some of the flapping ones.

So that's already promising, and as there is discussions about release Maven 4 soon (finally, really!) I think we then can quite easily upgrade here.

So next logical step would be to create a Maven 4 testcase to see if maven features actually work!

[laeubi]

We get a lot of deprecation warnings now but that is expected and we should fix those later on.
We maybe even just accept those for now to retain backward compatible for users that choose to use an older runtime.

One thing we need to check is if the new runtime is actually used for run the tests!

[laeubi]

It seems I was a bit to optimistic here, while the runtime itself compiles, due to we include the old ones as well these where picked up, if I enforce Maven 4 runtime the test fails (see previous commit) and if I enforce it to be used for compilation there are also compile error... so we need to check if

1. We can provide some "Compatibilty-Classes"
2. We can only support Maven 3 or Maven 4 ... what would be a bit unfortunate given not all plugins/extensions are yet compatible with maven 4 and it is unclear if Maven 4 is really completely compatible.

[akurtakov]

Wouldn't apache/maven#2380 supposed to help in this case?

[laeubi]

See also discussion here:

• The future evolution of m2eclipse #2065

[laeubi]

@HannesWell this is currently only a draft so may contain some changes that must be cleaned up before a final version. I now have made it to compile again with Maven4 but possibly retain backwards compatible with Maven 3.9.x ...

[laeubi]

Maven has added some backward compatibility support now so with next release some of the things might no longer be needed, still we have some issues where we extend maven classes that now uses JSR330 in maven 4 with constructor injections. I need to check how we can overcome this.

[laeubi]

Updated to Maven4-rc5 (currently 545 failing tests)

[laeubi]

With #2105 we are now down to 345 failing test... a lot seem about failing project configuration, some where we try to mutate now immutable objects.

[laeubi]

I added a null check and a catch for the unsupported operation, both seem to indicate some change in Maven 4 that we need to consider here. This should let some more test getting further (not that effective now 343 failing test...).

[laeubi]

We are currently hit by this bug:

• NullPointerException trying to clear project properties apache/maven#11552

(now 303 failing tests...)