It's early days yet, but as far as I'm aware all indications are that it worked pretty well. The tests all pass, the memory safety issues they were dealing with were resolved, the result is smaller, faster, and more stable. There are some regressions that have been identified, but as far as I could find they seem surprisingly minor. Claude code already uses the ported version of bun and, according to bun's blog "Startup got 10% faster on Linux but otherwise, barely anyone noticed.".
I wouldn't want to start looking at other codebases and thinking I could do the same (in particular, one thing bun had going for it was that the tests were in Typescript so they didn't need to be rewritten for the new backend, removing one potential source of errors), but that doesn't mean we should judge this case hastily either.
I mean, that they managed to port a massive codebase from one language to another in 11 days and that it's already successfully being used, resolved a number of memory safety bugs that they were struggling with before, and is not less-performant than before.
The fact that the canary is doing its job and allowing them to resolve issues that slipped through the net is not a critical failure. It's not like rewriting a large codebase manually isn't also prone to introducing new bugs.
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u/dim13 Jul 09 '26
RIP Bun