[SUREFIRE-1654] Remove deprecated forkMode parameter

[SimonBaars]

The forkMode parameter has been deprecated in Surefire 2.14, and with the upcoming 3.0 release, it's finally time to remove the parameter once and for all.

Reviewer instructions

Removing the forkMode ended up being a quite comprehensive change. Throughout the refactoring/restructuring process, I ran the tests and integration tests often, to ensure equivalent behavior. I re-purposed most forkMode tests to test the forkCount parameter, removing a few that were per definition redundant.

Each commit should address a "sub-issue" I had to tackle to remove the forkMode. If the entire diff looks daunting, I can recommend reviewing commit-by-commit. Each commit should be a version that compiles on its own.

Here are a few more pointers for reviewing:

• Read this article about migrating forkMode to forkCount.
• Start with the first commit, where I remove the most important traces of the forkMode parameter, before moving on to the entire diff.
• I removed the migration guide from the docs. Is that okay or would we like to keep it up for now?
• I left some convenience methods for the different fork modes in the SurefireLauncher, let me know if you'd like me to unfold that.
• I avoided the term "fork mode" as much as possible, but still left some traces where it made sense.

What's next?

While working on this, I noticed a few codebase styling issues that I'd like to refactor. To keep the diff of this PR sensible, I decided it would be better to open a separate PR for that. So you can expect another PR incoming 😉

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[SimonBaars]

Hey, I'm aware of the integration test failures and will try to address them tomorrow.

[mthmulders]

Thanks for this thorough work, @SimonBaars! I also appreciate your "reviewers' guide".

I think the proposed changes introduce a few duplicate lines - nothing too serious in terms of damage caused, but let's make sure the code is left better than when we first found it.

We should make sure that the migration guide (how to get away from forkMode) ends up somewhere in the release announcements of Surefire 3.0.0 (and if there's a milestone release in between, maybe there as well).

Finally, I'd appreciate it if somebody else with knowledge about Surefire could review these changes, too.

[SimonBaars]

We should make sure that the migration guide (how to get away from forkMode) ends up somewhere in the release announcements of Surefire 3.0.0 (and if there's a milestone release in between, maybe there as well).

I don't know how to do this. Will you pull this?

[SimonBaars]

Hey, I resolved the failing tests (except for ubuntu-latest jdk-18-temurin, but that also fails onmaster). Can someone else do a review? Maybe @slawekjaranowski since you also chipped in on the other PR 😊

[SimonBaars]

@mthmulders We need another review for this PR, so ideally it won't lay dormant for too long. Do you know someone to include?

[mthmulders]

We should make sure that the migration guide (how to get away from forkMode) ends up somewhere in the release announcements of Surefire 3.0.0 (and if there's a milestone release in between, maybe there as well).

I don't know how to do this. Will you pull this?

In hindsight, it might be a better approach to keep the content in maven-surefire-plugin/src/site/apt/examples/fork-options-and-parallel-execution.apt.vm. We should update it - instead of

Although that parameter is still supported for backward compatibility, users are strongly encouraged to migrate their configuration and use <<<forkCount>>> and <<<reuseForks>>> instead.

We might want to go for something like

Starting with 3.0.0-M8, this parameter is no longer available. Users should have migrated their configuration to use <<<forkCount>>> and <<<reuseForks>>> instead.

[michael-o]

@SimonBaars Thank you for the massive work. I guess we owe you a pack of Amstel.

• Did you try a custom build against our Core ITs?
• Did you search our [https://github.com/apache/maven-sources/tree/submodules](Maven Sources] for this deprecated param, replace and see how it goes?

[slawekjaranowski]

@SimonBaars Thanks ... I will try to review and test in a few days

[slawekjaranowski]

First check:

• org.apache.maven.surefire.api.provider.SurefireProvider - forkMode in comments - to think, discover correct descriptions

• org.apache.maven.surefire.its.jiras.Surefire146ForkPerTestNoSetupIT - mentions test for forkMode=pertest - check if is still needed

• surefire-its/src/test/resources/surefire-146-forkPerTestNoSetup/pom.xml - forkMode=pertest in description

[slawekjaranowski]

Looks ok for me.

Local test ok, tested with it test and with Maven core-its

[michael-o]

If Slawek approves then I can I approve as well.

[slawekjaranowski]

Nobody knows - but every removed line of code can help for simplify, so be brave and go forward