The restrictedNamePattern was a basic regular expression. Replace it
with a minimal utility to do the same, without having to use regular
expressions (or the "lazyregexp" package).
Some quick benchmarking (not committed) show that the non-regex approach
is ~18x faster:
BenchmarkIsValidName_Regex_Valid-10 8516511 119.4 ns/op 0 B/op 0 allocs/op
BenchmarkIsValidName_Manual_Valid-10 172426240 6.964 ns/op 0 B/op 0 allocs/op
BenchmarkIsValidName_Regex_Invalid-10 34824540 34.22 ns/op 0 B/op 0 allocs/op
BenchmarkIsValidName_Manual_Invalid-10 550804021 2.173 ns/op 0 B/op 0 allocs/op
BenchmarkIsValidName_Regex_Parallel-10 69289900 17.30 ns/op 0 B/op 0 allocs/op
BenchmarkIsValidName_Manual_Parallel-10 1000000000 0.9296 ns/op 0 B/op 0 allocs/op
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
ab7018b590