An interesting tidbit is that large parts of the original Bun source code was a line-by-line port of esbuild from Go to Zig (mentioned here: https://bun.com/blog/bun-in-rust), tbh this lowered my respect for the project a bit (a line-by-line port simply isn't as interesting as original work), and it might also explain the subpar Zig code quality (a line-by-line port from Go to Zig simply won't result in idiomatic Zig). It also might explain why porting from Zig to Rust was done 'on a whim', the actual source code (and the idea of 'original work') never seemed to be all that important to the author (and I wouldn't be surprised if the project does more language-hopping in the future heh).

I read your link, written by Bun's author and totally get his thinking.

In the current world of cyber weaknesses everywhere, infrastructure must be solid and rust is a better choice than zig for something like bun.

In other words, bun is not a demo of zig programming that happens to do useful things. Bun does useful things, and must do them securely. That is its number one priority, language is secondary, inasmuch as it helps doing useful things securely.