alt Hacker NewsNobody disputes that Rust is one of the programming languages that prevent several classes of frequent bugs, which is a valuable feature when compared with C/C++, even if that is a very low bar.
What many do not accept among the claims of the Rust fans is that rewriting a mature and very big codebase from another language into Rust is likely to reduce the number of bugs of that codebase.
For some buggier codebases, a rewrite in Rust or any other safer language may indeed help, but I agree with the opinion expressed by many other people that in most cases a rewrite from scratch is much more likely to have bugs, regardless in what programming language it is written.
If someone has the time to do it, a rewrite is useful in most cases, but it should be expected that it will take a lot of time after the completion of the project until it will have as few bugs as mature projects.
Replies
It's not a low bar when C/C++/D are basically the only languages in which you can write certain kinds of programs.
As other people have mentioned, the goal of uutils was not "let's reduce bugs in coreutils by rewriting it in Rust", it was "it's 2013 and here's a pre-1.0 language that looks neat and claims to be a credible replacement for C, let's test that hypothesis by porting coreutils, giving us an excuse to learn and play with a new language in the process". It seems worth emphasizing that its creation was neither ideologically motivated nor part of some nefarious GPL-erasure scheme, it was just some people hacking on a codebase for fun.
Whether or not it was wise for Canonical to attempt to then take that codebase and uplift it into Ubuntu is a different story altogether, but one that has no bearing on the motivations of the people behind the original port itself.
You can see an alternative approach with the authors of sudo-rs. Rather than porting all of userspace to Rust for fun, they identified a single component of a particularly security-critical nature (sudo), and then further justified their rewrite by removing legacy features, thereby producing an overall simpler tool with less surface area to attack in the first place. It was not "we're going to rewrite sudo in Rust so it has fewer bugs", it was "we're going to rewrite sudo with the goal of having fewer bugs, and as one subcomponent of that, we're going to use Rust". And of course sudo-rs has had fresh bugs of its own, as any rewrite will. But the mere existence of bugs does not invalidate their hypothesis, which is that a conscientious rewrite of a tool can result in fewer bugs overall.