Add Error Prone

[vorburger]

How about adding https://errorprone.info/docs/installation to PicoCLI? Using (https://github.com/tbroyer/gradle-errorprone-plugin.)

It would have found the #2053 problem, and possibly others, and will prevent regressions of them, and future new bugs.

@remkop would a PR for this be a welcome contribution?

[remkop]

Hi @vorburger, yes that seems like a good idea!

One note of caution may be with the different Java versions.
When building picocli and creating releases, I use JDK 8.
Additionally, the GitHub Actions-based CI compiles and runs tests using various other JDK versions.
Both use cases would need to be supported.

There is a separate subproject for compiling/running on Java 6/7, we don't need to add ErrorProne to that.

If that is possible, then let's go for it!

[clebertsuconic]

I have a love / hate relationship with errorprone.

While it gets some issues eventually, it generates a lot of noise that unless you are willing to fix every single warning coming from errorprone those will get ignored as they become noise.

Picocli is not that huge, so it won't add much time to the build, but one issue I have with it in artemis is that it takes a good amount to time to process.

IMO though, picocli is very small. and I appreciate the fact it is small. I don't see much benefit from using errorprone.

[vorburger]

IMO though, picocli is very small. and I appreciate the fact it is small.

@clebertsuconic adding Error Prone to the PicoCLI build (only!) will keep the PicoCLI JAR and API as small as it is... 😺

When building picocli and creating releases, I use JDK 8. Additionally, the GitHub Actions-based CI compiles and runs tests using various other JDK versions. Both use cases would need to be supported.

@remkop I see! Because you use a Matrix Build it wouldn't "just work". Given https://errorprone.info/docs/installation stating "Please note that Error Prone must be run on JDK 11 or newer.", the best way maybe to simply have the gradle-errorprone-plugin run only on Java 11+ ... I've never done this with Gradle, but given how imperative Gradle is, and that it can bake Pizzas in addition to building software, presumably there is some way to make it so... does anyone reading this happen to know how to do that? Otherwise I'll look a bit more into it when I have some time.

[vorburger]

presumably there is some way to make it so

Asked on https://discuss.gradle.org/t/how-to-skip-disable-plugin-execution-based-on-java-version/47274

Will also update https://stackoverflow.com/a/77668885/421602 (which comes up when searching for this).

[vorburger]

WIP on main...vorburger:picocli:errorprone ...

... currently shows 2 errors, 100 warnings - I think at least for an initial version the simplest here is to hide the warnings and fix the 2 errors.