> In other words, shouldn't the "rewrite it in Rust" folks have to prove that the cost of their proposed rewrite will be justified?
Agreed, they do. But that it hasn't been proven to make things better doesn't mean it will make things worse. It just means that we don't know enough to say. The right way to answer the "would this software have fewer bugs if it were rewritten in Rust?" question requires a detailed look at what bugs the software has empirically encountered.
A rewrite automatically makes things worse because you start with no code.
I figure it's one of the signs of programmer maturity, that you start to look askance at rewrites. So tempting, yet so rarely even finished let alone better.
In the case of Rust I don't believe this is 100% true given C ABI compatibility. You could start rewriting in such a way that it is integrated with the existing code and slowly, but surely tease the C out of the system.
It would for the longest time be a C program with a metastasizing wart of Rust hung off the side, impossible to get into, impossible to work with, debugging hell, compilation hell. The distros would weep.
Agreed, they do. But that it hasn't been proven to make things better doesn't mean it will make things worse. It just means that we don't know enough to say. The right way to answer the "would this software have fewer bugs if it were rewritten in Rust?" question requires a detailed look at what bugs the software has empirically encountered.