Deprecate project; users should go to maven-executor instead

[cstamas]

Affected version

all

Bug description

The maven-executor replacement should be used that among other things offer smooth and transparent mvn3 and mvn4 support and same if not more functionality as maven-invoker and much more, like proper env isolation and so on.

[slachiewicz]

what is maven-executor ?

[cstamas]

https://github.com/apache/maven/tree/master/impl/maven-executor

Is already used to run ITs and supports Maven 3.9 and 4+

[cstamas]

So, today we have maven-invoker and maven-verifier (let's focus on "run maven programmatically" aspect ONLY). These two things:

• do pretty much same thing
• but, has totally different APIs, different approaches and "tailored" calls that must be updated once CLI gets new option (is time consuming to maintain)
• but only one can "fork", while other can "fork" and "embed"
• there are many overlapping and duplicated concerns, and heavy handed solutions just to invoke/run maven programmatically

Hence, maven-executor was done that:

• offers unified and simple API without need for changes when CLI changes https://github.com/apache/maven/tree/master/impl/maven-executor/src/main/java/org/apache/maven/api/cli
• provides both executors "forked" and "embedded" https://github.com/apache/maven/tree/master/impl/maven-executor/src/main/java/org/apache/maven/cling/executor
• is dependency-less

Maven Executor was made to support both, Maven 4+ and Maven 3.9 and is already used in Maven 4 ITs, where the (yet another confusing name class), the Verifier was rewritten fully, to use maven-executor. Basically maven-executor should be (nearly) a drop in replacement wherever "programmatic running of Maven happens" (with invoker case may require more, as invoker request basically "redoes" CLI).

[slachiewicz]

@slawekjaranowski some maintenance work to migrate/retire projects.

[cstamas]

Of course, maven-executor as initially adapted in Maven 4 ITs, so later own (when replacing maven-invoker and maven-verifier) they may be some use cases showing up that maven-executor does not have, so it may be not so "fully straightforward" drop in. Also, given maven-executor is really independent of Maven 4 (and dependency less), we could move it out from Maven 4 and make it standalone project?

@gnodet

[gnodet]

Of course, maven-executor as initially adapted in Maven 4 ITs, so later own (when replacing maven-invoker and maven-verifier) they may be some use cases showing up that maven-executor does not have, so it may be not so "fully straightforward" drop in. Also, given maven-executor is really independent of Maven 4 (and dependency less), we could move it out from Maven 4 and make it standalone project?

@gnodet

Yes, we could. I don't have a strong opinion. How does it relate to maven-invoker and the plugin ?

[cstamas]

Both, maven-invoker and maven-verifier "just" invoke Maven (with different APIs and different capabilities, like "only fork" or "fork" or "embed").

maven invoker:

• https://github.com/apache/maven-invoker
• relevant doco https://maven.apache.org/shared/maven-invoker/

maven-verifier:

• https://github.com/apache/maven-verifier
• https://maven.apache.org/shared/maven-verifier/getting-started.html

Both offer subtle different use cases, but for example the helper methods in verifier seems totally unrelated and can/should be made reusable instead.

My personal opinions:

• invoker redoes whole CLI for no reason, hence, if CLI gets new switch, requires release
• verifier does "too much", as those helper methods are for no good reason tied to verifier

But am open to other ideas as well.

Also,

• https://maven.apache.org/plugins/maven-invoker-plugin/ does all that verifier offers (unsure here)
• https://maven.apache.org/plugins/maven-verifier-plugin/ is dead, maven-verifier is used only programmatically to run mvn in ITs

[cstamas]

Also, related issue:
maveniverse/njord#199

Here, JD went for invoker only to execute mvn in ITs, all this setup should be MUCH SIMPLER IMO, but nothing helps right now.