time: time.Parse unable to parse timestamps with unusual UTC offsets #26032

ALTree · 2018-06-24T11:34:14Z

$ gotip version
go version devel +d6a27e8edc Sat Jun 23 00:16:14 2018 +0000 linux/amd64

I dumped the time for each of the 425 timezones in my system's tz database in a file and tried to parse the timestamps. I got 17 errors, all caused by time.Parse inability to parse unusual offsets like +0545 (used in Asia/Kathmandu) or +13 (used in Pacific/Fakaofo).

Complete failures log:

Timezone:	 America/Scoresbysund
zdump time:	 Sun Jun 24 10:43:46 2018 +00
time.Parse:	 parsing time "Sun Jun 24 10:43:46 2018 +00": extra text: +00 

Timezone:	 Asia/Colombo
zdump time:	 Sun Jun 24 16:13:46 2018 +0530
time.Parse:	 parsing time "Sun Jun 24 16:13:46 2018 +0530": extra text: +0530 

Timezone:	 Asia/Kabul
zdump time:	 Sun Jun 24 15:13:46 2018 +0430
time.Parse:	 parsing time "Sun Jun 24 15:13:46 2018 +0430": extra text: +0430 

Timezone:	 Asia/Kathmandu
zdump time:	 Sun Jun 24 16:28:46 2018 +0545
time.Parse:	 parsing time "Sun Jun 24 16:28:46 2018 +0545": extra text: +0545 

Timezone:	 Asia/Tehran
zdump time:	 Sun Jun 24 15:13:46 2018 +0430
time.Parse:	 parsing time "Sun Jun 24 15:13:46 2018 +0430": extra text: +0430 

Timezone:	 Asia/Yangon
zdump time:	 Sun Jun 24 17:13:46 2018 +0630
time.Parse:	 parsing time "Sun Jun 24 17:13:46 2018 +0630": extra text: +0630 

Timezone:	 Atlantic/Azores
zdump time:	 Sun Jun 24 10:43:46 2018 +00
time.Parse:	 parsing time "Sun Jun 24 10:43:46 2018 +00": extra text: +00 

Timezone:	 Australia/Eucla
zdump time:	 Sun Jun 24 19:28:46 2018 +0845
time.Parse:	 parsing time "Sun Jun 24 19:28:46 2018 +0845": extra text: +0845 

Timezone:	 Australia/Lord_Howe
zdump time:	 Sun Jun 24 21:13:46 2018 +1030
time.Parse:	 parsing time "Sun Jun 24 21:13:46 2018 +1030": extra text: +1030 

Timezone:	 Indian/Cocos
zdump time:	 Sun Jun 24 17:13:46 2018 +0630
time.Parse:	 parsing time "Sun Jun 24 17:13:46 2018 +0630": extra text: +0630 

Timezone:	 Pacific/Apia
zdump time:	 Sun Jun 24 23:43:46 2018 +13
time.Parse:	 parsing time "Sun Jun 24 23:43:46 2018 +13": extra text: +13 

Timezone:	 Pacific/Chatham
zdump time:	 Sun Jun 24 23:28:46 2018 +1245
time.Parse:	 parsing time "Sun Jun 24 23:28:46 2018 +1245": extra text: +1245 

Timezone:	 Pacific/Enderbury
zdump time:	 Sun Jun 24 23:43:46 2018 +13
time.Parse:	 parsing time "Sun Jun 24 23:43:46 2018 +13": extra text: +13 

Timezone:	 Pacific/Fakaofo
zdump time:	 Sun Jun 24 23:43:46 2018 +13
time.Parse:	 parsing time "Sun Jun 24 23:43:46 2018 +13": extra text: +13 

Timezone:	 Pacific/Kiritimati
zdump time:	 Mon Jun 25 00:43:46 2018 +14
time.Parse:	 parsing time "Mon Jun 25 00:43:46 2018 +14": extra text: +14 

Timezone:	 Pacific/Marquesas
zdump time:	 Sun Jun 24 01:13:46 2018 -0930
time.Parse:	 parsing time "Sun Jun 24 01:13:46 2018 -0930": extra text: -0930 

Timezone:	 Pacific/Tongatapu
zdump time:	 Sun Jun 24 23:43:46 2018 +13
time.Parse:	 parsing time "Sun Jun 24 23:43:46 2018 +13": extra text: +13

https://gist.github.com/ALTree/de33561c1cc00ac46e2e9e6d6cca52fe

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gopherbot · 2018-06-24T12:19:37Z

Change https://golang.org/cl/120558 mentions this issue: time: accept UTC offsets +13,+14 in Parse, reject -13,-14

time.Parse currently rejects numeric timezones names with UTC offsets bigger than +12, but this is incorrect: there's a +13 timezone and a +14 timezone: $ zdump Pacific/Kiritimati Pacific/Kiritimati Mon Jun 25 02:15:03 2018 +14 For convenience, this cl changes the ranges of accepted offsets from -14..+12 to -23..+23 (zero still excluded), i.e. every possible offset that makes sense. We don't validate three-letter abbreviations for the timezones names, so there's no need to be too strict on numeric names. This change also fixes a bug in the parseTimeZone, that is currently unconditionally returning true (i.e. valid timezone), without checking the value returned by parseSignedOffset. This fixes 5 of 17 time.Parse() failures listed in Issue #26032. Updates #26032 Change-Id: I2f08ca9aa41ea4c6149ed35ed2dd8f23eeb42bff Reviewed-on: https://go-review.googlesource.com/120558 Reviewed-by: Rob Pike <r@golang.org>

gopherbot · 2018-08-22T09:14:10Z

Change https://golang.org/cl/130696 mentions this issue: time: allow +00 as numeric timezone name and GMT offset

A timezone with a zero offset from UTC and without a three-letter abbreviation will have a numeric name in timestamps: "+00". There are currently two of them: $ zdump Atlantic/Azores America/Scoresbysund Atlantic/Azores Wed Aug 22 09:01:05 2018 +00 America/Scoresbysund Wed Aug 22 09:01:05 2018 +00 These two timestamp are rejected by Parse, since it doesn't allow for zero offsets: parsing time "Wed Aug 22 09:01:05 2018 +00": extra text: +00 This change modifies Parse to accept a +00 offset in numeric timezone names. As side effect of this change, Parse also now accepts "GMT+00". It was explicitely disallowed (with a unit test ensuring it got rejected), but the restriction seems incorrect. DATE(1), for example, allows it: $ date --debug --date="2009-01-02 03:04:05 GMT+00" date: parsed date part: (Y-M-D) 2009-01-02 date: parsed time part: 03:04:05 date: parsed zone part: UTC+00 date: input timezone: parsed date/time string (+00) date: using specified time as starting value: '03:04:05' date: starting date/time: '(Y-M-D) 2009-01-02 03:04:05 TZ=+00' date: '(Y-M-D) 2009-01-02 03:04:05 TZ=+00' = 1230865445 epoch-seconds date: timezone: system default date: final: 1230865445.000000000 (epoch-seconds) date: final: (Y-M-D) 2009-01-02 03:04:05 (UTC) date: final: (Y-M-D) 2009-01-02 04:04:05 (UTC+01) Fri 2 Jan 04:04:05 CET 2009 This fixes 2 of 17 time.Parse() failures listed in Issue #26032. Updates #26032 Change-Id: I01cd067044371322b7bb1dae452fb3c758ed3cc2 Reviewed-on: https://go-review.googlesource.com/130696 Run-TryBot: Alberto Donizetti <alb.donizetti@gmail.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Ian Lance Taylor <iant@golang.org>

ALTree · 2018-08-26T12:24:20Z

+14 and +00 are now parsed correctly, down to 10 failures, all caused by non-integral UTC offsets:

$ gotip run parse_timezones.go 
Timezone:    Indian/Cocos
zdump time:  Sun Aug 5 18:25:10 2018 +0630
time.Parse:  parsing time "Sun Aug 5 18:25:10 2018 +0630" as "Mon Jan 2 15:04:05 2006 MST": cannot parse "+0630" as "MST" 

Timezone:    Asia/Kabul
zdump time:  Sun Aug 5 16:25:10 2018 +0430
time.Parse:  parsing time "Sun Aug 5 16:25:10 2018 +0430" as "Mon Jan 2 15:04:05 2006 MST": cannot parse "+0430" as "MST" 

Timezone:    Australia/Lord_Howe
zdump time:  Sun Aug 5 22:25:10 2018 +1030
time.Parse:  parsing time "Sun Aug 5 22:25:10 2018 +1030" as "Mon Jan 2 15:04:05 2006 MST": cannot parse "+1030" as "MST" 

Timezone:    Australia/Eucla
zdump time:  Sun Aug 5 20:40:10 2018 +0845
time.Parse:  parsing time "Sun Aug 5 20:40:10 2018 +0845" as "Mon Jan 2 15:04:05 2006 MST": cannot parse "+0845" as "MST" 

Timezone:    Asia/Kathmandu
zdump time:  Sun Aug 5 17:40:10 2018 +0545
time.Parse:  parsing time "Sun Aug 5 17:40:10 2018 +0545" as "Mon Jan 2 15:04:05 2006 MST": cannot parse "+0545" as "MST" 

Timezone:    Pacific/Chatham
zdump time:  Mon Aug 6 00:40:10 2018 +1245
time.Parse:  parsing time "Mon Aug 6 00:40:10 2018 +1245" as "Mon Jan 2 15:04:05 2006 MST": cannot parse "+1245" as "MST" 

Timezone:    Pacific/Marquesas
zdump time:  Sun Aug 5 02:25:10 2018 -0930
time.Parse:  parsing time "Sun Aug 5 02:25:10 2018 -0930" as "Mon Jan 2 15:04:05 2006 MST": cannot parse "-0930" as "MST" 

Timezone:    Asia/Colombo
zdump time:  Sun Aug 5 17:25:10 2018 +0530
time.Parse:  parsing time "Sun Aug 5 17:25:10 2018 +0530" as "Mon Jan 2 15:04:05 2006 MST": cannot parse "+0530" as "MST" 

Timezone:    Asia/Yangon
zdump time:  Sun Aug 5 18:25:10 2018 +0630
time.Parse:  parsing time "Sun Aug 5 18:25:10 2018 +0630" as "Mon Jan 2 15:04:05 2006 MST": cannot parse "+0630" as "MST" 

Timezone:    Asia/Tehran
zdump time:  Sun Aug 5 16:25:10 2018 +0430
time.Parse:  parsing time "Sun Aug 5 16:25:10 2018 +0430" as "Mon Jan 2 15:04:05 2006 MST": cannot parse "+0430" as "MST" 

Failures:    10

cstockton · 2019-08-22T15:44:40Z

I just ran into some timestamps formatted as 2019-08-22T10:41:59.006928+0000 - I know time parsing is complex but I believe the above is ISO8601 compliant. I believe the below should return the same times as date command, and definitely not have a parse failure:

Format	Cmd	Result
`2019-08-22T10:41:59.006928+0000`	`date`	`Thu Aug 22 03:41:59 MST 2019`
`2019-08-22T10:41:59.006928+0000`	`go`	`parsing time ""2019-08-22T10:41:59.006928+0000"" as ""2006-01-02T15:04:05Z07:00"": cannot parse "+0000"" as "Z07:00"`
`2019-08-22T10:41:59.006928+00:00`	`date`	`Thu Aug 22 03:41:59 MST 2019`
`2019-08-22T10:41:59.006928+00:00`	`go`	`2019-08-22 10:41:59.006928 +0000 +0000`
`2019-08-22T10:41:59.006928Z`	`date`	`Thu Aug 22 03:41:59 MST 2019`
`2019-08-22T10:41:59.006928Z`	`go`	`2019-08-22 10:41:59.006928 +0000 UTC`

Go 1.8-1.12.9 all have same result.

edit: sorry, I left out the fact it's parsing JSON. I could work around it easily if it was just a regular string. But there is never a clean way to fix JSON time parsing in without wrapping it in a custom type which makes working with the data structure unfortunate since you have to unwrap the type to do anything with it, or have a multiple step json.Unmarshal in the parent type which doesn't scale very well for nested occurrences. That said I think it may be worth fixing in json.Unmarshal even if it's a simple special case that accepts another set of 00 in place of a :.

ALTree · 2019-08-22T15:59:46Z

@cstockton It seems to be working (if you use the right parsing format):

package main

import (
	"fmt"
	"time"
)

func main() {
	tstamp := "2019-08-22T10:41:59.006928+0000"
	t, err := time.Parse("2006-01-02T15:04:05-0700", tstamp)
	if err != nil {
		panic(err)
	}
	fmt.Println(t.Format(time.UnixDate))
}

https://play.golang.org/p/RjhP0xB6AtX

what am I missing?

cstockton · 2019-08-22T16:13:10Z

I am using JSON Unmarshal.

With this CL Parse accepts all of `timedatectl list-timezones | xargs zdump` Fixes golang#26032

gopherbot · 2021-10-20T23:29:01Z

Change https://golang.org/cl/357450 mentions this issue: time: allow +0430,-0930 UTC offsets in Parse

With this CL Parse accepts all of `timedatectl list-timezones | xargs zdump` Fixes golang#26032

ALTree added the NeedsFix The path to resolution is known, but the work has not been done. label Jun 24, 2018

ALTree added this to the Go1.12 milestone Jun 24, 2018

ALTree self-assigned this Jun 24, 2018

ALTree modified the milestones: Go1.12, Go1.13 Nov 17, 2018

ALTree mentioned this issue May 1, 2019

time: Parse behaves inconsistently when parsing numerical timezones with an "MST" format string #30780

Open

ALTree modified the milestones: Go1.13, Go1.14 May 3, 2019

ianlancetaylor mentioned this issue May 31, 2019

time: regression in time.Parse from Go 1.11 to 1.12 #32358

Closed

rsc modified the milestones: Go1.14, Backlog Oct 9, 2019

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AlexanderYastrebov added a commit to AlexanderYastrebov/go that referenced this issue Oct 20, 2021

time: allow +0430,-0930 UTC offsets in Parse

b757d15

With this CL Parse accepts all of `timedatectl list-timezones | xargs zdump` Fixes golang#26032

AlexanderYastrebov mentioned this issue Oct 20, 2021

time: allow +0430,-0930 UTC offsets in Parse #49092

Closed

AlexanderYastrebov added a commit to AlexanderYastrebov/go that referenced this issue Oct 22, 2021

time: allow +0430,-0930 UTC offsets in Parse

6cee784

With this CL Parse accepts all of `timedatectl list-timezones | xargs zdump` Fixes golang#26032

AlexanderYastrebov added a commit to AlexanderYastrebov/go that referenced this issue Oct 22, 2021

time: allow +0430,-0930 UTC offsets in Parse

69b6d13

With this CL Parse accepts all of `timedatectl list-timezones | xargs zdump` Fixes golang#26032

ALTree removed their assignment Jun 23, 2022

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time: time.Parse unable to parse timestamps with unusual UTC offsets #26032

time: time.Parse unable to parse timestamps with unusual UTC offsets #26032

ALTree commented Jun 24, 2018 •

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gopherbot commented Oct 20, 2021

time: time.Parse unable to parse timestamps with unusual UTC offsets #26032

time: time.Parse unable to parse timestamps with unusual UTC offsets #26032

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