Stupid question.. I haven't been doing Kotlin for...

# kotlin-toolchain

[James]

Stupid question..

I haven't been doing Kotlin for over a year.. And this is also the first time I'm using the Kotlin toolchain. I'm migrating one of my older project that I never released to maven central, hoping to making it easier to publish with the toolchain. Though, IntelliJ is showing me some issues:

Has anything changed with Kotlin, or have I configured the project incorrectly?

[James]

message has been deleted

[James]

Tests are passing, but IntelliJ is loading the project right anyways

[joffrey]

The kotlin-stdlib is automatically added to your classpath so you shouldn't have to add it. If the code is red in the IDE but green in the CLI, it's definitely a bug.

[James]

I'm invalidating caches and restarting

[joffrey]

One thing that I know was fixed recently (and might not be fixed in your IDEA version) is a bug that happens when you already have a .idea folder from a previous state of the project (e.g. if the project was originally in Gradle). I'd suggest to close the project, delete .idea and re-open, just to be sure. Also you can try the invalidate and restart, yes

[joffrey]

(@utikeev please correct me if I'm wrong here)

[James]

Invalidating the caches somehow made it worse

[James]

Deleting the .idea directory also did not help

[James]

Oh, even this broken now lol

[James]

stdlib is no longer resolved by the IDE now

[joffrey]

Really sorry to hear that. If there any chance you could share the project so we can try to reproduce?

[James]

Yep, I'll see about pushing a branch

[James]

Just need to sort out my signing keys (recently re-installed my Mac)

[joffrey]

No problem. And by the way, thank you so much for all the feedback here! It's very valuable. I'm always sad to hear when the onboarding experience is not smooth, but thanks to people like you who take the time to report this stuff, we can address some of the problems at least.

[James]

I have somehow not saved the passphrase to my signing keys in my password manager 🙂

[James]

Found it!

[joffrey]

Maybe that's a good thing we could automate (kotlin tool keygen that would upload the public key to common key servers as well), but I digress 😄

[joffrey]

(I mean we literally have kotlin tool generate-keystore already, but the shape of this command is a bit specific to Android stuff)

[James]

github.com/jamesbradlee/tools.logfmt/tree/kotlin-toolchain

git clone --depth 1 --single-branch --branch kotlin-toolchain [e-mail]:jamesbradlee/tools.logfmt.git

[James]

Pushed again with the kotlin wrapper binaries

[James]

> No problem. And by the way, thank you so much for all the feedback here! It's very valuable. I'm always sad to hear when the onboarding experience is not smooth, but thanks to people like you who take the time to report this stuff, we can address some of the problems at least.
When I was actively working with Kotlin projects I was already following this project back when it was still called Amper and waiting for it to be usable in enterprise environments. Pretty psyched to see it has come a lot further since then, with a website and everything. I noticed it again during some kotlin news.

[joffrey]

Thanks for sharing the project

[joffrey]

Everything is green for me in the IDE too laugh cry

[James]

Green as in, imports are ok?

[joffrey]

Yes

[joffrey]

message has been deleted

[James]

Gotta love non-deterministic/non-reproducible issues ¯\_(ツ)_/¯

[joffrey]

IntelliJ is a "beautiful" machine 😅 Powerful, yet full of mysteries

[James]

Ssshh you can't say that here! Friendly fire!

[joffrey]

Don't get me wrong, I would trade this IDE for nothing else 😄 But I have to acknowledge the quirks

[James]

message has been deleted

[James]

What JDK are you using? Maybe it's something wrong with how I've set it up?

[James]

message has been deleted

[joffrey]

I actually have no project-level JDK 🙂 Technially, the Kotlin Toolchain provisions JDKs at the module level, so there is no need for project JDK, but often IntelliJ complains about this because it was not really built for this situation, so it's probably for the best that you have a project-level JDK.

[joffrey]

Ok one thing that might help my colleague investigate. Do you by any chance have this Dump Workspace Entities to a File as Json action? (I'm not sure whether it's an internal thing or not)

[James]

message has been deleted

[joffrey]

And no other variant with the Dump Workspace Entities prefix I presume? Then maybe it's just an internal tool, sorry to have bothered you with this!

[James]

message has been deleted

[James]

❯ ./kotlin --version
Kotlin Toolchain version 0.12.0 (2039c53, 2026-08-25)

[James]

Kotlin Toolchain plugin: 262.10315.125

[joffrey]

Thanks, yeah I have all the same versions

[James]

Is there a log file for IntelliJ / the plugin anywhere?

[James]

message has been deleted

[joffrey]

There is a log file for IntelliJ as a whole, yes:

[joffrey]

I really think it's due some dangling state. It must either be in .idea (but you said you tried deleting it), or it might be in the IntelliJ's system directory. Maybe you can try deleting your project's folder there: <systemDir>/projects/tools.logfmt.<someHash>

[James]

I'm gonna just make a .bak of that one before I touch

[James]

Still no 😞

[James]

Building it still works though..

[joffrey]

Yeah it might just be the Kotlin plugin getting messed up dependencies for analysis of the files, but I'm just making random guesses now. If you go to the Project Structure like you did in your screenshot above, what do you get for the logfmt.main module in the Dependencies tab? (in your screenshot, you were on the Kotlin node)

[James]

message has been deleted

[joffrey]

Well, now _that_'s interesting

[joffrey]

so it somehow figured out your backup of the dir 😂 Maybe you can move it out of there?

[James]

Oh... I invalidated caches again

[James]

Now it works

[James]

Why it didn't work the first time I don't know

[James]

No nevermind

[James]

FUCK

[joffrey]

Wow, nice!

[joffrey]

Yeah I would be super eager to know the steps that led to the broken state

[James]

message has been deleted

[James]

Yeah I would be super eager to know the steps that led to the broken state

This is a fresh install from today 😢

[James]

I installed it via toolbox

[joffrey]

But you did open your project as a Gradle project, first, right?

[James]

message has been deleted

[James]

No, the first time I actually just created the project.yaml and module.yaml files manually before I even cloned the repo, just to test

[joffrey]

The red folders in the Sources tab are normal I believe. These are directories that are registered in case you add files there, so they will be picked up. I also have them red, but the rest of the code is fine

[joffrey]

Ok so, last thing, can you close the project, delete .idea, and move your .bak folder out of your IntelliJ system dir, and delete whatever other directory with your project name might have been created there?

[James]

Can I delete the whole dir? 🤔

[James]

message has been deleted

[joffrey]

I see no IntelliJ there, deleted already?

[James]

Wait.. Hold on..

[James]

/Users/t980781/Library/Caches/JetBrains

Do you think this is safe to delete?

[James]

I deleted it 🙂

[James]

Deleted .idea and the entire caches for jetbrains

[James]

Still doesn't work

[James]

Is this meant to have no classpath?

[joffrey]

Well you deleted the Library/Caches/JetBrains/Kotlin too I suppose 😄 Which contains the provisioned JDK, but the Kotlin Toolchain should re-provision it if you do kotlin build

[joffrey]

Or even just sync the project

[James]

Still empty

[joffrey]

Might be worth deleting this entry (in the SDKs table), and re-syncing the project

[James]

Which sync action?

[joffrey]

Sync Kotlin project

[James]

Found out, it has classpath now, but still no work

[joffrey]

Ok good (for the classpath), and bad for the red code

[joffrey]

I'm sorry I'm out of ideas. Maybe on Monday my all-knowing IDE-specifialist of a colleague @utikeev will be able to figure this out, or suggest more stuff, but in the meantime I'm at a loss

[joffrey]

I would normally say just nuke all your caches and data folders, but that apparently didn't work

[joffrey]

Ah actually there is more data cached for intellij

[joffrey]

In this Special files and folders view there is also a Config dir (not system):

[joffrey]

I'm not super familiar with all this, but the <configDir>/workspace directory seems to contain some data as well

[joffrey]

The problem is that it's hard to pinpoint stuff that you want to remove. I don't know if this contains important config for you

[joffrey]

(you can probably tell I don't know much about the IDE side of things 😅 )

[James]

Haha I don't blame you!

[James]

message has been deleted

[James]

IntelliJ is resolving dependencies now

[James]

Nope, still does not work

[James]

In fact, now it doesn't even recognize built-ins anymore, what

[James]

I'm just going to try uninstalling everything and re-install.

[James]

@joffrey It works now 🙂

[joffrey]

Oh great to hear!

[joffrey]

Sorry that you had to go through this trouble, but at least you have a working environment now

[James]

No problem! Thanks for all the help!

I really can't say what caused it not to work in the first place..

[James]

You know what? Could it be that my internet dropped out at a critical moment, and something that should have been installed didn't get installed?

[James]

I've had some hiccups with my internet today...

[joffrey]

On the IDE side I really don't know. On the CLI side, I guess we know it wasn't affected since it could build/test fine

[James]

Yea

[joffrey]

And for such a simple JVM project there is almost nothing to provision besides the JDK and the Kotlin compiler

[James]

Also, I don't know if its too late - but it would be VERY nice if the kotlin wrapper binary could be renamed to kotinw, because in IntelliJ there's no way to hide the kotlin wrapper binary, without also hiding any directory named kotlin (i.e. in projects that still uses Gradle).

[James]

Or at least kotlin.sh

[James]

I may have to bite the sour apple and use the kotlin wrapper, but at least I'd like to hide it from the file explorer 🙂

[joffrey]

Wow I have never used this IDEA feature 😅 I actually dislike anything that hides files, because I want to see everything 😄 But I get the point. I don't know if the name's going to change. One possible hope is that one day we might use a single file as a wrapper, and if we want to do that it's likely to have the name kotlin.cmd because cmd.exe on Windows can only run scripts named .bat or .cmd 🤷🏼 Or we might decide to go full powershell on Windows. Anyway, this is just random thoughts at the moment

[James]

It's broken again...

I checked out the main branch, which is a gradle project still, then back to the kotlin-toolchain branch, and now it's broken

[joffrey]

Ok so it does seem due to Gradle's latent state when trying to open as Kotlin Toolchain project

[joffrey]

Then it might very much be what my colleague is already aware of and trying to fix. But I'm surprised deleting .idea didn't solve the problem. I thought it did last time I checked

[James]

Yeah.. No it still doesn't work to delete the .idea directory

[klikh]

So, does it reproduce only for a Gradle project that was converted to Kotlin Toolchain? Or a newly created project is affected as well?

[James]

I'll try creating an entirely new project to see what happens, hold on though. I'm testing something else atm

[James]

Apart from logs, these are the only JetBrains related files related to the tools.logfmt project.

[James]

Deleting project related files did not solve anything.

[James]

So, creating a new project with spring boot seems to work

[James]

However.... The standard library no longer works, not even on the new spring boot project

[klikh]

Which version of IntelliJ IDEA and which version of the Kotlin Toolchain plugin do you use?

[James]

Kotlin Toolchain version 0.12.0 (2039c53, 2026-08-25)

IntelliJ IDEA 2026.2.2
Build #IU-262.10315.125, built on September 2, 2026
Source revision: 947f011dc3107
Licensed to Telenor Norge AS / James Bradlee
Subscription is active until March 8, 2027.
Runtime version: 25.0.4+1-b508.27 aarch64
VM: OpenJDK 64-Bit Server VM by JetBrains s.r.o.
Toolkit: sun.lwawt.macosx.LWCToolkit
macOS 26.6.2
Exception reporter ID: 0409262823efdad-9c42-4e67-b599-2a058129ca06
JCEF version: 144.0.15-262-b37
GC: G1 Young Generation, G1 Concurrent GC, G1 Old Generation
Memory: 2048MiB
Cores: 10
Metal Rendering is ON
Registry:
ide.experimental.ui=true
idea.ignore.disabled.plugins=true
trace.state.event.service.url=api.jetbrains.cloud/trace-status
Non-Bundled Plugins:
org.jetbrains.plugins.node-remote-interpreter (262.10315.135)
com.dprint.intellij.plugin (0.9.1)
com.nbadal.ktlint (0.30.5)
com.intellij.javaee (262.10315.131)
DuplicateLines (1.1.0)
org.jetbrains.kotlin-toolchain (262.10315.125)
Kotlin: 262.10315.125-IJ

[James]

org.jetbrains.plugins.node-remote-interpreter (262.10315.135)
com.intellij.javaee (262.10315.131)

So I did not install these?

[klikh]

Could you please share the idea.log file? (sorry if you already did: the thread got really big =)) )

[James]

Yep, hold on

[klikh]

So I did not install these?

They are not bundled, so I guess you did install them at some point. Maybe somewhen in the past. If you don’t need them, of course, feel free to disable/uninstall.

[James]

Hmm... No... They were pretty much there when I re-installed IntelliJ.. edit: they were also there the first time I installed IntelliJ, for that matter.

activating enterprise license maybe?

[James]

message has been deleted

[klikh]

Let’s try to disable them anyway, at least temporarily, just as a check, because the issue you’re experiencing is really strange, so it’s better to exclude all possible cases.

[James]

Yep

[James]

Or maybe not?

[James]

dprint I did install

[James]

Only the other two I did not

[klikh]

Yeah, anyway, let’s try to disable all of the custom plugins, except Kotlin Toolchain, and see what happens. I have some doubts about Ktlint suspicious

[James]

Nope, still doesn't work

[James]

So I disabled most of the plugins now, including bundled, I'll re-check

[James]

Yep, nope.. that did nothing

[James]

Let me do another re-install and run a diff on everything..

[James]

They are indeed bundled

[James]

I managed to click the wrong icon and stop the recording, anyway... this is after the re-install. I'm going to run a diff and compare the two idea.bak and idea2.bak

[klikh]

So, after the reinstallation everything started to work? The code seems to be green now?

[James]

Yes, after the re-install, everything works.

[James]

I have some findings in the diff, but I'm not done yet

[James]

I cannot for some reason reproduce it anymore either... what

[James]

Even with my extensions

[James]

Something killed it again now... WHAT

[James]

AH MY GHAD

[James]

I found the issue!

[James]

Settings -> Editor -> File Types -> Ignored Files and Folders

I had added kotlin and kotlin.bat to the ignored files, because I don't want to see them in my file explorer.

[James]

Please fix this 🙏

[joffrey]

But are you sure this feature is only cosmetic? This might be to tell intellij to ignore those files in all respects, but those are mandatory right now

[joffrey]

> controls which files the IDE's Virtual File System completely skips, hiding them from project views, code completion, and search results
So you're not hiding it for you, you're hiding it from the IDE's file system. We can't read this file if you do this, and as I mentioned earlier, the wrapper files are required right now for IDE support.
I think what we could improve is to properly notify when the wrappers are not found (short term), and longer term, maybe make it possible to use the global installation instead of the wrapper (if the version is moved to project.yaml), but in the meantime maybe you can just live with them in your root?

[utikeev]

Wow, that's indeed quite an unexpected aftermath of the understandable desire to hide the wrappers 😄 I'm sorry that you have to go through so many troubles!

As @joffrey rightfully mentioned, for now the wrappers are required for the proper support in the IDE being the only reasonable source of truth about the project version.
We do have an issue about lifting up this restriction and making wrappers truly optional: KTC-5156. This would also allow us to fallback to the global installation in the IDE more reliably than we can now (that's the reason it's not supported yet).

The code insight turned red because Kotlin standard library symbols have kotlin directory on its path (inside the JAR), so IntelliJ ignored everything under that 🙂

NB: the sync still discovers and launches the wrappers, even if they are excluded, because it doesn't access them through the VFS but just uses NIO as no IntelliJ features are required to operate with the wrappers. If the wrappers are missing on disk, we should produce better error messages and fixes, though, and maybe some explanation/links on why wrappers are needed.