time: RFC3339Nano Z is invalid for offset according to RFC3339

[Aulilino]

the code: RFC3339Nano = "2006-01-02T15:04:05.999999999Z07:00"

go/src/time/format.go

Line 83 in 32e789f

RFC3339Nano = "2006-01-02T15:04:05.999999999Z07:00"

In the definition of RFC3339(https://www.ietf.org/rfc/rfc3339.txt), there is a clear explanation of character “Z”. It means no UTC offset when "Z" appeared.

      Z           A suffix which, when applied to a time, denotes a UTC
                  offset of 00:00; often spoken "Zulu" from the ICAO
                  phonetic alphabet representation of the letter "Z".

[seankhliao]

This is used to trigger different printing behaviour, from the docs:

Replacing the sign in the format with a Z triggers the ISO 8601 behavior of printing Z instead of an offset for the UTC zone.

I think this is working as intended?

[ianlancetaylor]

Please show us a small working code example that demonstrates the problem. Right now I don't see it. Thanks.

[Aulilino]

According to RFC3339, it means NO offset, when Z exists in the format.

The correct format should be "2006-01-02T15:04:05.999999999", "2006-01-02T15:04:05.999999999+07:00" or ""2006-01-02T15:04:05.999999999-07:00""

[seankhliao]

time.RFC3339Nano is a layout string, not a time

Some valid layouts are invalid time values for time.Parse, due to formats such as _ for space padding and Z for zone information.

[Aulilino]

Got it. Seems I got it wrong. Thanks.