time: UnixNano thinks year 1 comes after 1720

[vsekhar]

UnixNano gives inconsistent results. Specifically, it believes the year 1 comes after the year 1720.

package main

import (
	"fmt"
	"time"
)

func main() {
	t1 := time.Date(1, 1, 1, 0, 0, 0, 0, time.UTC)
	t2 := time.Date(1720, 12, 30, 0, 0, 0, 0, time.UTC)
	t3 := time.Date(1970, 1, 1, 0, 0, 0, 0, time.UTC)	
	
	fmt.Printf("%s: %d\n", t1, t1.UnixNano())
	fmt.Printf("%s: %d\n", t2, t2.UnixNano())
	fmt.Printf("%s: %d\n", t3, t3.UnixNano())
}

0001-01-01 00:00:00 +0000 UTC: -6795364578871345152
1720-12-30 00:00:00 +0000 UTC: -7857820800000000000
1970-01-01 00:00:00 +0000 UTC: 0

https://play.golang.org/p/XrtNdpfNFk1

[andybons]

@ianlancetaylor

[ALTree]

You can't call UnixNano on a date before the year 1678; this is clearly documented:

https://golang.org/pkg/time/#Time.UnixNano

UnixNano returns t as a Unix time, the number of nanoseconds elapsed since January 1, 1970 UTC. The result is undefined if the Unix time in nanoseconds cannot be represented by an int64 (a date before the year 1678 or [...] )

So your t1.UnixNano() call is not valid.

[vsekhar]

🤦 Thanks.