Vsevolod Tolstopyatov
qwwdfsad.bsky.social
Vsevolod Tolstopyatov
@qwwdfsad.bsky.social
Doing stuff in Kotlin @ JetBrains. API design, concurrency, performance,
Dima is a brilliant engineer, and the way he structures any discussion (be it internal or external) is always thoughtful and insightful. Every time I read his musings or talk to him, I learn something new or connect new dots
October 25, 2025 at 11:31 AM
New Kotlin Language Server goodies are out: github.com/Kotlin/kotli...!

A lot of work ahead, but it starts getting its shape 👀
Release v0.253.10629 · Kotlin/kotlin-lsp
🧪 Kotlin for VS Code Extension Includes the Kotlin Language Server bundled for use with Visual Studio Code. Download  |  SHA-256 Checksum 🗂️ Kotlin Language Server (Standalone ZIP) Standalone ver...
github.com
August 6, 2025 at 3:33 PM
Random quote of the day: income taxes 'required an element of understanding as to why they were needed on the part of the individuals subject to said taxes and this understanding was usually widely lacking'
July 1, 2025 at 8:24 PM
My *by far* the most favourite talk this year.

@Sellmair did an amazing job -- explaining dynamic classloading, DCEVM, continuous builds, Compose internals, anonymous classes naming policy, and more in a deeply technical yet engaging manner
The KotlinConf talks are available online 🎉

Check-out how Compose Hot Reload is implemented:

youtu.be/UebhKUdO2sQ?...
Implementing Compose Hot Reload | Sebastian Sellmair
YouTube video by Kotlin by JetBrains
youtu.be
June 20, 2025 at 2:34 PM
There is plenty of amazing stuff announced at KotlinConf.

But the thing I am most proud of is our release of Kotlin LSP along with VSC support: github.com/Kotlin/kotli...
Damn that was some action!
GitHub - Kotlin/kotlin-lsp: Kotlin Language Server and plugin for Visual Studio Code
Kotlin Language Server and plugin for Visual Studio Code - Kotlin/kotlin-lsp
github.com
May 23, 2025 at 7:34 AM
Futurama was definitely released ahead of its time
February 20, 2025 at 6:03 PM
If you want to participate in a naming battle, here's your chance!

I'd even say it might have an effect similar to deprecating String.capitalize(), but this time with a (hopefully) properly-named replacement
We're reworking one of the sharp edges of kotlinx.coroutines, the `withTimeout` function, which is useful, but has a few funky cancellation corners.

👉🏼 We need a name for the improved replacement function! What would you suggest as a name? (e.g. I'm a fan of `withTimeLimit`!)
February 20, 2025 at 5:43 PM
When dealing with concurrency problems, I leave comments with my findings even if they aren't really that meaningful (e.g. "don't do X, X leads to logical races" What races? Why?). I used to feel uneasy about that, but damn, every now and then, they save me hours of debugging
December 18, 2024 at 7:04 PM
Came up with this one when writing an internal blogpost about performance work
December 12, 2024 at 5:20 PM
An update to the posting: www.jetbrains.com/careers/jobs...

Now with Germany and Netherlands on the table!
December 12, 2024 at 2:07 PM
Kotlin libraries team is hiring: www.jetbrains.com/careers/jobs...

If you are eager to write something you are going to regret (if you are lucky, also be proud of) in 10 years, want to tinker with Kotlin and not afraid of dragons (also: performance, concurrency), drop me a line!
Kotlin Libraries Senior Software Developer (Kotlin) - Kotlin Libraries - Careers
www.jetbrains.com
December 9, 2024 at 9:32 AM
I have a weird quirk about benchmarks -- when I see the JMH score not in the 2-4 digits range, I have to change the output unit so the result would be in the range. Otherwise, I have *really* hard time interpreting/comparing the numbers and error margins.
Does anybody else have this at all?
November 26, 2024 at 3:45 PM
TIL there is a timezone named "Antarctica/Troll". And it delivers on its name, its daylight saving time transition is two hours.
November 25, 2024 at 5:15 PM
Uploading a PNG logo with a "transparent" background, which is, in fact, not, should be classified as a major crime
November 24, 2024 at 8:10 PM
The mystery of the day: `arrayOf(1, 2, 3)` is two times slower than `x1 = 1, x2 = 2, x3 = 3; arrayOf(x1, x2, x3)`

gist.github.com/qwwdfsad/b13...
ArrayAllocationBenchmark.kt
GitHub Gist: instantly share code, notes, and snippets.
gist.github.com
November 19, 2024 at 3:24 PM