Feature request: "Run & Debug" feature without `launch.json` even without Maven or Gradle (CodeLens & automatic debug configurations)

[tats-u]

I don't know whether this issue should be here or in the debug adapter.

fwcd/kotlin-debug-adapter#62

Motivation

The Java extension of VS Code can run or debug (the main function of) .java files in the opened folder without launch.json.
This allows Java beginners to try their piece of code easily.

When you press F5 or click "Debug", you can start debugging without launch.json.

Description

Related: #17

Currently, Kotlin files can't be run without launch.json. No "Run | Debug" in the top of fun main.

Alternatives considered

launch.json: too complicated

[themkat]

That should already be available (ref: #92 ). My main guess is that it might not work on empty package names. Have you tried giving a package name? Looking for some output in the Kotlin-dropdown field in the Output menu might help. It is in the lower right corner where you find the terminal etc.:

[tats-u]

@themkat Just opened a folder without pom.xml or build.gradle(.kts).
I'll change the title later.

Did #92 make it possible to start debugging without launch.json?

[themkat]

Did #92 make it possible to start debugging without launch.json?

Yes. It gave you the Run/Debug code lenses like you see in the Java example you provided. Without any launch.json needing to be present.

When you mention it, the debug adapter isn't really working without Maven or Gradle. So even if you got the Run/Debug code lenses working, I guess you would not be able to run it. There is an open issue on this for the debug adapter: fwcd/kotlin-debug-adapter#62

[tats-u]

@themkat
Can you start debugging only with pressing F5 (not CodeLens action) in the main source file?
I can't prepare a project that can run in VS Code. I created one with IDEA with Kotlin + Gradle but didn't work with VS Code.
The Gradle extension didn't work well for me, either.

[tats-u]

https://github.com/ktorio/ktor-samples/tree/main/chat

I cloned and opened this directory but CodeLens around any of mains there.

Windows 11
Java: 17 (Temurin)
Kotlin / Maven: those bundled in IDEA 2023.1 Community
VS Code Java-related extension packs: Extension Packs for Java & Gradle Extension Pack

[themkat]

@themkat Can you start debugging only with pressing F5 (not CodeLens action) in the main source file? I can't prepare a project that can run in VS Code. I created one with IDEA with Kotlin + Gradle but didn't work with VS Code. The Gradle extension didn't work well for me, either.

No. That would off course require a launch.json. How else would it know what to run? Works perfectly that way with a launch.json though. I must have misunderstood you at first, because I thought it was about missing code lens.

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https://github.com/ktorio/ktor-samples/tree/main/chat

I cloned and opened this directory but CodeLens around any of mains there.

That project might sadly not work, even for some basic operations. The language server is not really good with the Kotlin multiplatform structures and stuff. The support for it, just fetching dependencies is very experimental. fwcd/kotlin-language-server#377

Tried building (to fetch dependencies), but the file is full of resolving issues. Not able to debug, but I get the run/debug-codelens in a weird place (above the comment):

The code lens works, but there seems to be other issues. Probably due to Kotlin multiplatform structures that the debug adapter is not used to looking for. Sadly I don't know enough about Kotlin multiplatform to find a fix. Might just be as simple as fixing some directory lookup here (in the debug adapter):
https://github.com/fwcd/kotlin-debug-adapter/blob/main/adapter/src/main/kotlin/org/javacs/ktda/classpath/ProjectClassesResolver.kt
(from what I can see, Multiplatform projects have directories like backend, js etc. inside of build/classes, instead of a more flat structure)

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For anyone not getting the Run/Debug code lens:
Make sure that the debug adapter is enabled in the VSCode Kotlin extension settings:

If it does not show up at once, restart your editor.

From a stupid Spring Boot project I just threw together:

Beyond these basics, I really don't know much about VSCode. Even if I have contributed to this extension, I NEVER use it beyond simple experiments. Emacs is the only true editor 😛