os.Readdir() fetched 10.000 file names into a slice in 0.2s.
That's more than fine for most use cases and certainly doesn't look like "one of the stupidest, most broken interfaces I've ever seen".
Specially given that it's not the only way to iterate over files of a directory in Go. There's filepath.Walk() for one.
> The files are walked in lexical order, which makes the output deterministic but means that for very large directories Walk can be inefficient.
If it's fine for "most use cases," that's all well and good. Just implement the correct interface, which is fine for ALL use cases, and then implement this sugar on top of that.
Seems like they postponed incorporating fastwalk into the standard library because it would break API: https://godoc.org/golang.org/x/tools/internal/fastwalk
Perhaps until then one could use libraries that expose fastwalk:
I now built the exe and ran:
real 0m0.199s
user 0m0.000s
sys 0m0.014s
It is still a ton of time, about an order of magnitude more than optimal if the real/sys time split is to be believed.