m2e plugin sometimes "loses" resources - using snapshot 2.1.201.20230809-1423

[tarioch]

In some cases, the resources are deleted from the target folder and not copied over again.

e.g. one case I encounter is, if I do any change in the pom file, all my resources disappear until I touch any of the resources or java files.

This is the split up from the issues which are still existing in snapshot 2.1.201.20230809-1423

See #1302 for more details.

Reproduction: #1478

[tarioch]

@laeubi anything we can help on getting any progress on this?

[laeubi]

@tarioch It actually should have been improved by the last m2e eclipse release, but we can only try to make it less often as the underlying cause is here:

• [MSHARED-1285] use an up-to-date scanner instead the newscanner apache/maven-filtering#77

but it hasn't gotten much attention from the maven people yet (and I'm not a maven committer).

[laeubi]

Beside that, sponsoring is a good way to get specific issues fixed, so if this is crucial to your business and you likes to speed up the development of m2e in general a sponsoring would allow me to assign more time-slots to bug fixing or contact me for an individual contract for example fixing a specific issue, m2e is sadly manly drive by volunteers working on their (spare) free time so it often takes some time if no one can dedicate time or money.

[tarioch]

Thanks for your response. Unfortunately even with latest version it still is still very, very bad. Is there a fundamental change why this issue happens since 2022-12? I haven't seen it before.

[tarioch]

Did do some more testing, now used the plain eclipse java installation from eclipse and a very tiny project (empty pom file, one empty class and one dummy resource).

2022-12/m2e 2.1.2

Adding/removing a dependency to the pom.xml doesn't impact the resources, classes don't seem to get recompiled, resources are untouched

2023-03/m2e 2.2.1 (same behavior also in latest 2023-09)

Adding/removing a dependency to the pom.xml does seem to trigger a rebuild, afterwards the resource file is gone and the class file has a newer timestamp

Any idea what the big change in m2e 2.2 was that changed this behavior? From the release notes I saw that there was a change to execute plugins by default in incremental builds and I tried with the setting changed to ignore, but it's still the same behavior.

[lihomev587]

Did do some more testing, now used the plain eclipse java installation from eclipse and a very tiny project (empty pom file, one empty class and one dummy resource).

2022-12/m2e 2.1.2

Adding/removing a dependency to the pom.xml doesn't impact the resources, classes don't seem to get recompiled, resources are untouched

2023-03/m2e 2.2.1 (same behavior also in latest 2023-09)

Adding/removing a dependency to the pom.xml does seem to trigger a rebuild, afterwards the resource file is gone and the class file has a newer timestamp

Any idea what the big change in m2e 2.2 was that changed this behavior? From the release notes I saw that there was a change to execute plugins by default in incremental builds and I tried with the setting changed to ignore, but it's still the same behavior.

I've downgraded the version to 2.1.2, and it is as normal as you said.
just uninstall it, then use this url: "Eclipse IDE integration for Maven - https://download.eclipse.org/technology/m2e/releases/2.1.2" to install it.
I am using eclipse 2023-09 (4.29.0)

[mickaelistria]

@tarioch if you can create a minimal unit test (similar to what was done in #1478 ) that reproduces the issue, that would help. Then one could just bisect on the changes to find what has caused it and consider futher fixes more easily.

[laeubi]

Then one could just bisect on the changes to find what has caused it and consider futher fixes more easily.

I already analyzed that, the problem is that resource-mojo assumes that if a resource never gets deleted from the output without getting it as a "delta" what is not always true and m2e no longer perform such updates because it lead to infinite build cycles, I already proposed a fix but it got less interest and I'm currently not have time to push it forward:

• [MSHARED-1285] use an up-to-date scanner instead the newscanner apache/maven-filtering#77

so it does not really help to complain about m2e "not coping" because m2e does never has nor do copy anything...

[HannesWell]

If the maven-resources plugin cannot be fixed.
Maybe we could provide a connector in m2e that helps the plugin to do it right?

[laeubi]

If the maven-resources plugin cannot be fixed.

It can be fixed, see PR I just don't have had the time yet to look into the test failure what might just be a changed assumption.

I now also created

• Provide a new Resources API codehaus-plexus/plexus-build-api#76

to supply a more modern API for file changes.

[laeubi]

Maybe we could provide a connector in m2e that helps the plugin to do it right?

THis would require to disable the plugin completely and rewrite all its functionality from scratch...