A modern programming language that makes developers happier.

kotlinlang

Screen Shot 2022-08-23 at 22.43.06 copy.png

hey folks; maven shop here,

&gt; Did K2 compilation went well?
yep. few minor fixes for type inference (+-10 lines), and having to bump up to 1.7.20-Beta due to <https://youtrack.jetbrains.com/issue/KT-52057/Unsupported-compile-time-value-STRINGCONCATENATION-and-GETFIELD-in-annotation-arguments|this bug> but was fine otherwise.

&gt; Have you noticed a difference in the build speed?
yep! our biggest module went from 44s to 20s on average so that’s great! overall, we see a ~25% improvement

&gt; Or what errors you encountered with, if they happened?
1. <https://youtrack.jetbrains.com/issue/KT-52057/Unsupported-compile-time-value-STRINGCONCATENATION-and-GETFIELD-in-annotation-arguments|aforementioned bug>
2. `value?.property` on a definitely non-null `value` was complaining, but am assuming it’s by design, so just fixed it
3. if both `kotlin-stdlib-jdk8` and `kotlin-stdlib-jre8` are somehow on path, the compiler complains about “confusing overloads”. excluding `-jre8` worked.

Cool, thank you for feedback
`value?.property` is nullable by design, yes. Existing behavior in K1 compiler is against specification (check <https://youtrack.jetbrains.com/issue/KT-46860|KT-46860> for more details)
Two different stdlibs is a build issue and it complains by design too: when someone reference class, then compiler chooses first class with that name found in classpath, but when someone reference function, compiler need to find all functions with that name in all dependencies because of overloads. I wonder how it worked for you with K1 compiler

I'm really curios about two modules in your project showed performance degradation. Can you please provide some details about those modules?

Is build can performed on Linux or MacOs?
If so could you please download <https://github.com/jvm-profiling-tools/async-profiler/releases|async-profiler>
Unpack it somewhere you like

```// Linux only, refer to async-profiler wiki for explanation
sysctl kernel.perf_event_paranoid=1
sysctl kernel.kptr_restrict=0```
<https://github.com/jvm-profiling-tools/async-profiler/wiki/Basic-Usage>

And then run kotlin compiler with additional argument of
`-Xprofile=&lt;async-profiler-dir-path&gt;/build/libasyncProfiler.so:event=cpu,interval=1ms,threads,start:&lt;output-dir-path&gt;`
Note: output-dir must exist beforehand
And then provide files `snapshot-*.collapsed` , it only contains JVM/Compiler stack-traces

apologies, was caught up with some other stuff..

<@U1PRSBLHJ> i’ve tried to get this working with maven (multi-module), but I keep getting a  `Profiler already started`

am only able to get this for individual modules (`-pl module`); as soon as it’s multi-module, or the module includes tests, this stops working..

any suggestions?

You could try to use `-Dmaven.test.skip=true`  to avoid compilation of tests
It is ok to collect it only for single module
Please collect it for that module, which is compiling significantly slower with K2

Also, does this build uses parallel building? If so, please disable it first