New Mill project in IDEA problems

[vayshya]

I created new Mill project by hand, with basic Spring Boot dependencies. And opened it in IDEA as BSP project. IDEA constantly can't see dependencies in editor and shows false errors in code. Invalidating cache and restarting every 10 minutes help. Is there anything that can be done to fix it?

[vaslabs]

@souvlakias let's have a look .

@vayshya this is with Java and/or kotlin? Could we have a sample repo or code to reproduce?

[vayshya]

Sure, here is repository where bugs are reproducible, I marked them with //FIXME comment. It's in Java.
https://github.com/vayshya/JdbiTest
To check it works you can launch IDEA configuration there, it starts Postgresql Docker image and opens URL in browser.
Also there is integrated test with Testcontainers.
The most strong bugs appearing when some settings in build.mill.yaml are wrong and fixed to right. Also there is no information what settings are wrong and if there is any error at all. I can't even see if file was downloaded nor click on dependency to go to file content. It makes configuring build very hard comparing to Maven.
By the way when I convert Maven projects to Mills they work perfectly. Only when I make new Mill project hell breaks loose in IDEA and there are no error messages to check what's wrong.

[souvlakias]

@vayshya thanks for the repo and your comments!
I see that it includes a mill.bat so I'm guessing you are on windows... Tbh, I haven't tried using IDEA with mill in windows so far, so not sure about potential issues and what causes them; on Linux the project seems fine at first glance.
I'll try to investigate on Windows when I get the chance.

Also about this FIXME note:

springBootPlatformVersion: 4.1.0 #FIXME Not works if bomMvnDeps added but still required. - org.springframework.boot:spring-boot-dependencies:4.1.0 needed to work.

This happens because the bomMvnDeps you added end up overriding the ones that SpringBootModule, so what you need is !append which translated to scala does override def bomMvnDeps = super.bomMvnDeps() ++ Seq(what_you_added)

-bomMvnDeps:
-  - org.springframework.boot:spring-boot-dependencies:4.1.0
+bomMvnDeps: !append
  - org.jdbi:jdbi3-bom:3.54.0

There an open issue about this need in #7345 (just linking for reference)

[vayshya]

I work both on Linux and Windows and configure my projects to work on both operating systems. I did not think about it yet but it's interesting question how to do it with Mill. I guess I need to put both scripts to project root. With Maven I download JDKs for corresponding OSes manually and Maven with Tomcat have OS independent Java build with both sh and bat scripts.

I will try to add mill.sh to project and edit in IDEA on Linux.

[lefou]

There is no need to have a mill.{sh,bat} script in the project. It's just convenient, but if you have it on your PATH, it's enough.

Older IDEA versions had a bug in their BSP support and failed if the script was missing, but that is fixed in recent versions.