I've been in this industry for a few decades at this point and I was around when this meme was started.

It was purely about maxing your compensation because changing jobs nets you more than promotions & raises.

I've never met an engineer in my life who truly earned a promotion every year and very few every two. Very few companies have org charts that even support that or have that many levels. This logic/advice only really applies at a few companies and people have adopted it no matter where they work. There's not enough growth/hiring at 95% of companies to even come close. The Peter Principle is also a real thing. Everyone's competence has a ceiling.

There's even an implicit understanding of this that people at smaller companies have inflated titles and you typically rank them down 1-2 levels when hiring/acquiring at larger companies.

Now I do agree that companies haven't been investing in their engineers, but that doesn't also mean this isn't a vicious cycle. Employers and employees are in a mexican standoff and things are only going to get worse until one side comes to its senses. Employers have all the leverage for it to not be them.

For the vast majority of companies the average tenure of an engineer sits between 18 and 30 months. They're also mostly hiring young engineers in their 20s. As an employer what is your upside to making such investments before they're at least mid-career? A lot of people seem to want the world and offer nothing in return for it.

The Bun author himself writes that the port is not idiomatic Rust:

    Do the rewrite that looks like we transpiled our Zig code to Rust. We can gradually refactor it to reduce unsafe usage and look more like idiomatic Rust after Bun v1.4 ships.

The original version of Bun was already a line-by-line (manual) port of esbuild from Go to Zig (also mentioned in this post), so the Zig code already wasn't "Zig-idiomatic" and apparently riddled with problems. That doesn't inspire much confidence in the LLM-translated Rust version tbh.

> "unidiomatic" rust means, 'don't use these parts of the language even though they're first-class citizens?'

that is indeed a roughly accurate definition of what "unidiomatic" means

It's mostly the same in any general purpose programming language though, parts of the language features are meant (or became seens as) tools to be used in very narrow cases, which people less familiar with the language tend to "overuse".

Eg. goto/jump, bare "except" statements in python, etc... In Rust, unsafe has its uses and is a first class language feature, but it certainly isn't idiomatic to use it to mimic access patterns from other languages (unless absolutely necessary).

It means "don't misuse parts of the language in ways that circumvent best practices" one of which is "keep unsafe regions as small and few as possible" not "never use unsafe"

Meh. The (a major?) goal of Rust is this sort of type safety flowing down to memory bugs. Not every possible access pattern was known at the beginning, and generally they developed a philosophy of keeping the "unsafe" memory access patterns extremely bounded and heavily inspected. I think that's a fair and admirable goal.