i saw an answer to a question you provided on SO a

Question

< udalov> i saw an answer to a question you provided on SO and just wanted to get some more information It s about retaining parameter names on constructors

strelok · Answer

Was hoping you could shed some light on it for me

strelok · Answer

if you have a moment slightly smiling face

udalov · Answer

sure what are you interested in

strelok · Answer

Thanks for such quick reply slightly smiling face The question I saw your answer on is here <https stackoverflow com questions 36093019 does kotlin compiler always retain parameter names in bytecode> it was a while ago

strelok · Answer

but to boil down the issue I am noticing in IntelliJ that the parameter names are NOT retained

strelok · Answer

at some point the parameter names are lost on a data class constructor

udalov · Answer

how are you checking that

strelok · Answer

I m stepping through the spring data mongodb code

strelok · Answer

and i see params being named arg0 argXX

strelok · Answer

if I clean and re build parameter names come back

strelok · Answer

then at some point hard to pin point when exactly they re gone

udalov · Answer

where do you see that in the IntelliJ decompiler in the `javap` bytecode output in the Kotlin bytecode toolwindow in Kotlin reflection in Java reflection

strelok · Answer

as I am stepping through the java code of spring data mongo the code is looking at the constructor of a data class I am seeing it while stepping through in IntelliJ

strelok · Answer

spring data mongodb code is in Java the class that it s looking at is in Kotlin

udalov · Answer

OK so the StackOverflow link above is irrelevant here because it s only related to the parameters that are introspected via Kotlin reflection at runtime `KParameter name`

udalov · Answer

here you should pass the ` java parameters` command line argument to Kotlin

strelok · Answer

oh I will read the docs on that param but does it force preservation of param names

strelok · Answer

I was not aware of that option will try it and read the docs on it

udalov · Answer

there s no docs unfortunately yet only `kotlinc help` The ` java parameters` is basically equivalent to javac s ` parameters`

strelok · Answer

alright I will check it out thanks so much for your help I should be able to apply it in the kotlinOptions `build gradle` block as well right

udalov · Answer

yes

udalov · Answer

btw I found some docs here see `javaParameters` <https kotlinlang org docs reference using gradle html attributes specific for jvm>

strelok · Answer

haha I just found it too `Generate metadata for Java 1 8 reflection on method parameters` that s good enough docs for me

strelok · Answer

Just need to know when to look Thank you for pointing it out for me OGROMNOE SPASIBO