Didn't they start with like C++, then zig, and now rust.

To me it's just not serious. They also had articles of "why we are doing zig and not rust".

It's an ambitious project, but I can't take it seriously when the tech stack is in constant flux.

Their origins are in C++, which is what SerenityOS has used. They've never done zig. They explored using Swift as a C++ successor language for the project[1], but seeing the platform support out of Apple was lacking, they gave up and made the bet on Rust[2].

The motivation to use a memory safe language as the alpha approaches sounds more of a longer term bet [3].

[1] https://ladybird.org/newsletter/2024-11-30/#swift-language-a...

[2] https://ladybird.org/posts/adopting-rust/

[3] https://ladybird.org/posts/changing-how-we-develop-ladybird/

They did start with C++. They experimented with Swift, then experimented with Rust, ultimately choosing Rust. I don't see how experimenting with things makes anything "not serious". If you don't question your primitives and just accept them "because that's how it has always been", you're not a very good engineer in my book. In any case, the tech stack is not in constant flux as you claim, it's still C++, with more and more parts moving / being started in Rust, with the eventual probability of Rust replacing C++ organically, I suppose. Seems like pretty sound strategy to me to slowly, but surely, adopt a memory-safe language.

I think they used swift instead of zig because Kling was using mac for development