Please answer these questions before submitting your issue. Thanks!

What version of Go are you using (go version)?

go version go1.10.3 linux/amd64

Does this issue reproduce with the latest release?

Yes

What operating system and processor architecture are you using (go env)?

Ubuntu 18.04, amd64

What did you do?

Attempted to time.Parse the result of 'date --utc --rfc-3339=ns':

time.Parse(time.RFC3339Nano, "2018-06-18 10:19:31.800140702+00:00")

package main

import (
	"fmt"
	"os/exec"
	"strings"
	"time"
)

func main() {
	raw, err := exec.Command("date", "--utc", "--rfc-3339=ns").Output()
	if err != nil {
		panic(fmt.Sprintf("failed to run date: %v", err))
	}
	from_ubuntu := strings.TrimSpace(string(raw))
	t, err := time.Parse(time.RFC3339Nano, from_ubuntu)
	if err != nil {
		fmt.Printf("Unparsable: %q\n", string(from_ubuntu))
	} else {
		fmt.Printf("Parsed: %v\n", t)
	}
}

What did you expect to see?

Parsing to succeed

What did you see instead?

Failure, due to an old disagreement about the RFC: http://lists.gnu.org/archive/html/bug-coreutils/2006-05/msg00019.html

GNU coreutils team maintain whitespace is allowed, but the Go library requires the 'T' separator between the date and time components of the string representation.

Options to allow interoperability between GNU style and Go style RFC-3339 complient strings would be to either relax the Go parsing, or provide alternative predefined styles in the time package (time.RFC3339GNU and time.RFC3339NanoGNU, or time.GNU3339 and time.GNU3339Nano, or similar)