Debugging support

[ZacSweers]

This is less of a feature request and more just sharing this in case anyone else is interested.

In general, I'd recommend writing up an example of debugging/testing story, perhaps a demo or contributing support to @tschuchortdev's https://github.com/tschuchortdev/kotlin-compile-testing project.

In the meantime, I've found success attaching the debugger manually from the Gradle invocation.

Example: ./gradlew :sample:build --no-daemon -Dorg.gradle.debug=true -Pkotlin.compiler.execution.strategy=in-process. Then connect via remote debugger in the IDE and you can hit your processor's breakpoints.

[ting-yuan]

If debugging without daemon is too slow (it has to start jvm everytime), ./gradlew -Dkotlin.daemon.jvm.options="-Xdebug,-Xrunjdwp:transport=dt_socket\,address=8765\,server=y\,suspend=n" ... and attach to the KotlinCompileDaemon process in the debugger might worth trying.

And thanks for the feedback! We'll investigate how to make debugging easier.

[ZacSweers]

@yigit recently contributed KSP testing support to kotlin-compile-testing here https://github.com/tschuchortdev/kotlin-compile-testing#kotlin-symbol-processing-api-support

[neetopia]

As you mentioned there is KSP support in kotlin-compile-testing now. Keep this issue for tracking related works like keep kotlin-compile-testing update to date with KSP or intaking more ideas.

[elect86]

attach to the KotlinCompileDaemon process in the debugger might worth trying.

How?

Because I cant get it working, this is my debug setup (pretty vanilla)

[ting-yuan]

Did you pass the following system property while running Gradle? So that KotlinCompileDaemon can be attached.

-Dkotlin.daemon.jvm.options="-Xdebug,-Xrunjdwp:transport=dt_socket\,address=5005\,server=y\,suspend=n"

I haven't tried to attach it in the way of the screenshot; Instead, I use [run] -> [Attach to Process...] in IntelliJ and the popup window prompts a list that contains the KotlinCompileDaemon process.

[elect86]

I'm not using those exactly, but the ones suggested by the remote configuration for jdk9+, that is

-agentlib:jdwp=transport=dt_socket,server=y,suspend=n,address=*:5005

First difference, I see that you have some backslashes in there.. are those mandatory?

Second, this is what happens on mine:

1. something uses jdk15, where both JavaCompile and KotlinCompile are set to use 1.8 both in processor and consume module

tasks {
    withType<JavaCompile> {
        sourceCompatibility = "1.8"
        targetCompatibility = "1.8"
    }
    withType<KotlinCompile> {
        kotlinOptions {
            jvmTarget = "1.8"
        }
    }
}

I have jdk11 default on PATH

elect@5800x:~$ java -version
openjdk version "11.0.11" 2021-04-20
OpenJDK Runtime Environment (build 11.0.11+9-Ubuntu-0ubuntu2)
OpenJDK 64-Bit Server VM (build 11.0.11+9-Ubuntu-0ubuntu2, mixed mode, sharing)

2. It stops in this Reference.class, I have no idea why

3. attaching on the daemon requires me to type in the admin pwd everytime

Here a gif to better illustrate my situation

Ps: without a daemon as Zac suggested works fine though (but as you said, it's too slow)

[ToxicMushroom]

My compilation completes before I can attach my intellij debugger ?
I tried
gradlew -Dkotlin.daemon.jvm.options="-agentlib:jdwp=transport=dt_socket,address=*:5005,server=y,suspend=n" clean assemble
output: https://gist.github.com/ToxicMushroom/eb19fac25e2acf9a5fd0dc554e5da408

I was able to get this to work last week on my laptop though so I am a bit confused what I'm doing different/wrong.

[ting-yuan]

@ToxicMushroom that's because suspend=n. The daemon should stick around for a while (IIRC 3 hours) and you can attach, and run gradlew again.

[DHosseiny]

Can you please explain it step by step? I didn't get it. I just ran the commands on this page but I do not know what to do next. @ZacSweers

[neetopia]

after running ksp task with JDWP, you should be able to attach a debugger via run -> attach to process

[zeroarst]

Sorry to dig the grave.

Can you help to confirm if these are the right step?

1. Run the command ./gardlew -Dkotlin.daemon.jvm.options="-Xdebug,-Xrunjdwp:transport=dt_socket\,address=5005\,server=y\,suspend=n".
2. Two ways to attach debug process to daemon:
   a. In Intellij, click Attach to Process..., and select KotlinCompileDaemon. For whatever reason, once it is attached, it runs into a break point and I cannot continue.
   

b. create a remove JVM debug configuration:

But I cannot attach it, only shows Error running 'ksp': Unable to open debugger port (localhost:5005): java.net.ConnectException "Connection refused: connect"

[neetopia]

Sorry to dig the grave.

Can you help to confirm if these are the right step?

1. Run the command ./gardlew -Dkotlin.daemon.jvm.options="-Xdebug,-Xrunjdwp:transport=dt_socket\,address=5005\,server=y\,suspend=n".
2. Two ways to attach debug process to daemon:
   a. In Intellij, click Attach to Process..., and select KotlinCompileDaemon. For whatever reason, once it is attached, it runs into a break point and I cannot continue.
   

b. create a remove JVM debug configuration:

But I cannot attach it, only shows Error running 'ksp': Unable to open debugger port (localhost:5005): java.net.ConnectException "Connection refused: connect"

Your screenshot looks more like general JDWP debugging issue to me. By searching the file you are stuck in I can get some existing issues like this one https://stackoverflow.com/questions/18992181/intellij-idea-breakpoints-stop-in-jars-instead-of-source-code-of-my-project

I would suggest looking into the JDWP set up part.

[carl10086]

The debugger did not stop at the breakpoint.

Commands:

1. ./gradlew --no-daemon -Dorg.gradle.debug=true -Dkotlin.daemon.jvm.options="-agentlib:jdwp=transport=dt_socket,server=y,suspend=n,address=*:5005" :dm-lib:clean :dm-lib:assemble`.
2. run attach the process

env:

• gradle : 7.5.1
• kotlin : 1.8.10
• ksp : 1.8.10-1.0.9
• java: openjdk version "17.0.4.1" 2022-08-12 LTS

[mikedawson]

I don't understand why this is "P3". Trying to develop without a working debugger is not fun.

It is possible using some combination of arguments (e.g. ./gradlew :module:taskName --no-daemon -Dorg.gradle.debug=true -Pkotlin.compiler.execution.strategy=in-process).

I think use of debugging needs to be supported and documented ASAP. This issue appears to have been open for three years.

[ZacSweers]

@mikedawson the approach I described in my OP plus the existence of compilation testing libraries means debugging works fine. You're not blocked, it's unclear what you're even asking for as I don't know what else they could do other than what I explained above.

I'm actually somewhat inclined to close this issue as I don't really feel it's an issue at this point, other than maybe just adding a debugging wiki explaining the above.

[mikedawson]

Hi @ZacSweers yes I am able to debug, which is good. My personal suggestion would be to put this in the documentation : either in the Quickstart section or the FAQ. I think anyone who is developing a non-trivial processor will likely need to use it. A debugging Wiki would also be helpful, but I think how to debug is essential info, and thus deserves to be included in the docs themselves.

What I mean by "support" - I mean to add it to the official docs / Wiki and to update those docs if/when the procedure changes.

[zption]

How to attach KotlinCompileDaemon? Does anybody know. I have tried many times and I still can not debug KSP. would anyone post the screenshot of detail steps ? Thanks。

[ting-yuan]

A page for how to debug has been added very recently. Specifically, this section shows how to pass necessary flags to KotlinCompileDaemon and how to find it.

[zption]

@ting-yuan hi, thanks for answering my question.
After executing the cmd ./gradlew :app:kspDebugKotlin --rerun-tasks -Dkotlin.daemon.jvm.options="-Xdebug,-Xrunjdwp:transport=dt_socket\,address=8765\,server=y\,suspend=n".
Then I click run -> Attach to process... and select KotlinCompileDaemon， and then Android studio show the error below:
"Error running 'localhost:'8765' CCannot run 'localhost:8765' on 'Pixel XL API33'"

[boris-faniuk-n26]

Looks like task named kspDebugKotlin doesn't exist for me. Where does it come from?