Hi is it possible to get the source file of the code where a

Question

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 · Answer

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|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 · Answer

< 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 · Answer

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 · Answer

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 |https projectlombok org > Also with gradlew tasts etc the file you find may not be the actual source file

Timo Drick · Answer

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 · Answer

I mean observing source code file changes

Timo Drick · Answer

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

Timo Drick · Answer

And also compiles itself smile

Timo Drick · Answer

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 · Answer

Interesting project +1 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|https github com google ksp blob master api src main kotlin com google devtools ksp symbol Location kt>

Timo Drick · Answer

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 · Answer

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 smile

Timo Drick · Answer

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

yigit · Answer

nice

yigit · Answer

so this is hot reload on desktop

Timo Drick · Answer

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

Timo Drick · Answer

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

yigit · Answer

yep and a blog post would be great