Read Scala options from pom.xml

[carlosedp]

This PR adds POM parsing to fetch Scala compiler options defined in the scala-maven-plugin configuration.

The environment variable still have preference if passed.

[gsmet]

Thanks for this. Sorry, I completely missed this PR.

I can see why you would want that and I think we have a similar thing for Kotlin in core Quarkus.
I don't think this is the right approach though as we end up having something really tied to Maven in the extension implementation.

The Kotlin part is in two parts:

• Allow setting kotlinc compiler arguments in dev task/mojo quarkusio/quarkus#25346 - I think this could be implemented in this extension too. It's not ideal as you have to copy the args but it's still better than nothing and could be a workaround for now
• there is another part in DevMojo.setKotlinSpecificFlags(...) that is hardcoded and is not pluggable and that is actually doing what you want (I think)

So what I would recommend:

• implement the first approach in the extension to have a workaround for now
• and then the second approach would need some additional work in Quarkus core to make it pluggable (and the Kotlin part should be moved to the Kotlin extension too). If you want to pursue this, it's probably a good idea to ask @aloubyansky to ask for advice about the design.

HTH.

[carlosedp]

Thanks for the comment @gsmet ... I've revisited this and done a couple tests and found the compiler arguments set in scala-maven-plugin -> configuration -> args already applies to the dev mode:

Before:

❯ quarkus dev
[INFO] Scanning for projects...
[INFO]
[INFO] -----------------< org.acme:scala3-quarkus-quickstart >-----------------
[INFO] Building scala3-quarkus-quickstart 1.0.0-SNAPSHOT
[INFO]   from pom.xml
[INFO] --------------------------------[ jar ]---------------------------------
[INFO]
[INFO] --- quarkus:3.7.1:dev (default-cli) @ scala3-quarkus-quickstart ---
[INFO] Invoking scala:4.8.1:add-source (scala-compile-first) @ scala3-quarkus-quickstart
[INFO] Invoking scala:4.8.1:compile (scala-compile-first) @ scala3-quarkus-quickstart
[INFO] compiling 17 Scala sources to /Users/cdepaula/repos/scala/scala3-quarkus-quickstart/target/classes ...
[WARNING] /Users/cdepaula/repos/scala/scala3-quarkus-quickstart/src/main/scala/org/acme/GreetingResource.scala:5:13: unused import
[WARNING] one warning found
[INFO] done compiling
[INFO] compile in 8.0 s
[INFO] Invoking resources:3.3.1:resources (default-resources) @ scala3-quarkus-quickstart
...

After adding <arg>-Werror</arg> to pom.xml:

❯ quarkus dev
[INFO] Scanning for projects...
[INFO]
[INFO] -----------------< org.acme:scala3-quarkus-quickstart >-----------------
[INFO] Building scala3-quarkus-quickstart 1.0.0-SNAPSHOT
[INFO]   from pom.xml
[INFO] --------------------------------[ jar ]---------------------------------
[INFO]
[INFO] --- quarkus:3.7.1:dev (default-cli) @ scala3-quarkus-quickstart ---
[INFO] Invoking scala:4.8.1:add-source (scala-compile-first) @ scala3-quarkus-quickstart
[INFO] Invoking scala:4.8.1:compile (scala-compile-first) @ scala3-quarkus-quickstart
[INFO] compiling 17 Scala sources to /Users/cdepaula/repos/scala/scala3-quarkus-quickstart/target/classes ...
[ERROR] /Users/cdepaula/repos/scala/scala3-quarkus-quickstart/src/main/scala/org/acme/GreetingResource.scala:5:13: unused import
[ERROR] one error found
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time:  8.611 s
[INFO] Finished at: 2024-02-02T15:12:19-03:00
[INFO] ------------------------------------------------------------------------

So I understand the change in this PR and the suggestion you made is not needed. Right?