Can anyone tell me what does `Non-incremental compilation will be performed: NO_BUILD_HISTORY` mean ...

# compiler

[Matej Drobnič]

Can anyone tell me what does Non-incremental compilation will be performed: NO_BUILD_HISTORY mean in kotlin build report?

Occasionally build will take a long time (obviously non-incremental) and looking at the build report will produce above message. I have not cleaned the build folder or did anything similar (just normal run command while developing). How would I go about debugging what causes build history to get wiped?

[bashor]

cc @Andrey Uskov [JB]

[Andrey Uskov [JB]]

Hi. It usually happens if during previous compilation task was FROM-CACHE.
At the moment we consider existing approach with history files unoptimal and in 1.7 similar issues should not be reproduced any more.

[Matej Drobnič]

thanks for the answer

[Matej Drobnič]

I think it also might happen after a failed build

[Matej Drobnič]

is it expected that first build after a failed build (after maybe a syntax error) would be non-incremental?

[Matej Drobnič]

@Andrey Uskov [JB]

[Matej Drobnič]

@Andrey Uskov [JB] I can still reproduce this, even with config cache disabled. What can I do to help diagnose this issue?

[Andrey Uskov [JB]]

Hi. I'm sorry for missing the mention.
I'm afraid it is known issue of current implementation of incremental compilation. There are some cases when it fails to non-incremental mode (e.g. overflow of history file, dependency on non-kotlin module, rebuild, and others). These issues are known for current implementation.
The plan is to implement another approach which should be incremental in most cases. You could follow the top-level status in issue https://youtrack.jetbrains.com/issue/KT-42309. Our estimate that it should be in betta in 1.7.

[Matej Drobnič]

thanks