Please try this instead https://play.golang.org/p/k7kmlXt15zF
See https://golang.org/pkg/time/#pkg-constants

I want not to accept hours, minutes neither seconds with an only digit. And it is parsed correctly for both minutes and seconds with the layout "15:04:05".

Ah, I undestand just now. Sorry.

I'm afraid there is no way to require 24-hour zero-padded hours with a time.Parse template.

/cc @rsc to confirm

@Virepri You can open a proposal if you want to discuss such a big change, but in general we try not to provide two different ways of doing very similar things in the standard library.

This might be better as an external package.

Change https://go.dev/cl/425044 mentions this issue: time: fix Parse to reject single digit hour in RFC3339

This might be better as an external package.

Seems a bit much to maintain and/or import an external package for such a minor feature?

Anyway, this is what I came up with for the time being:

// time.Parse() will accept numbers without a leading zero; there isn't any way
// to require it. https://github.com/golang/go/issues/29911
//
// The separators (- and :) should always be at the same location for the layout
// and date string.
func missingLeadingZero(d, l string) bool {
	for i, c := range []byte(l) {
		if c == '.' || c == 'Z' {
			return false
		}
		if (c < '0' || c > '9') && d[i] != c {
			return true
		}
	}
	return false
}