Hi, is it possible to get the source file of the c...

# kapt

[Timo Drick]

Hi, is it possible to get the source file of the code where an annotation is used inside of an annotation Processor?
So e.g. i do have the file main.kt and there is my annotation attached to the main function. Is it posiible to get the path and file name of that file inside of my Processor?

[yigit]

I don't think there is an api for that but you probably can via reflection.

We do something similar in room where we append element name to an error message if the element is from a .class file. (Otherwise, there is no location on the message)

https://cs.android.com/androidx/platform/frameworks/support/+/androidx-main:room/compiler-processing/src/main/java/androidx/room/compiler/processing/javac/JavacProcessingEnvMessager.kt;l=49

[Timo Drick]

@yigit thank you for this fast answer. I will look at it.
Yes i am able to get the file class (Not sure it is really called like that.) and from this name i know the file name of the source. But i do not get the path. It could be anywhere right?
But yes would be one solution to just search the source directory for the file.

[Timo Drick]

But i am writing a library that can be used from other projects. And i want to know the location of the file where my annotation is used. I need the exact path. For now the user has to provide this path by hand.

[yigit]

If it is a public library, i would say don't do it. At least if it is core functionality.
Maybe annotation processor is not what you want. Maybe this? https://projectlombok.org/
Also, with gradlew tasts etc, the file you find may not be the actual source file.

[Timo Drick]

I am working on an hot reload for compose for desktop and i have to observe file changes during runtime. So it will be only used during development.
I know that i can get the file name and line number by analyzing the stacktrace. But the path is missing.

[Timo Drick]

I mean observing source code file changes.

[Timo Drick]

So the program will hot reload itself when it detects that the source is changed.

[Timo Drick]

And also compiles itself 😄

[Timo Drick]

It is already working. But to use it you have to write some boilerplate code which i want to eliminate by generating this code with kapt.

[yigit]

Interesting project👍
Where do you use the annotation processor?
You may want to use a Gradle task to hook into the files.
Also, might be better to use ksp. It has a location api :https://github.com/google/ksp/blob/master/api/src/main/kotlin/com/google/devtools/ksp/symbol/Location.kt

[Timo Drick]

I do have a seperate module for the annotation processor for now. Because it is not compatible with compose.
I will have a look at ksp. Thank you for the hint.

[Timo Drick]

Looks interesting. I thought about writing a compiler plugin but looked a little bit too complicated to me. So maybe KSP is what i want 😄

[Timo Drick]

I was able to port my KAPT to KSP and now i do have all information i need and also the kotlin types are now easier to handle.
Thanks again @yigit
If anyone is interested on this project here is the source: https://gitlab.com/compose1/livecomposable

[yigit]

nice!

[yigit]

so this is hot reload on desktop?

[Timo Drick]

It is limited but yes. Hotreload for a @Composable function for Compose for Desktop

[Timo Drick]

I am preparing a demonstration video and fixing some issues. When i am finish i will post it on the compose-desktop channel.

[yigit]

yep and a blog post would be great!