encoding/json: Marshalled time location inconsistent in GMT

[groob]

Please answer these questions before submitting your issue. Thanks!

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

1.7.3 (but tried tip as well)

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

GOARCH="amd64"
GOBIN=""
GOEXE=""
GOHOSTARCH="amd64"
GOHOSTOS="darwin"
GOOS="darwin"
GOPATH="/Users/victor/go"
GORACE=""
GOROOT="/usr/local/go"
GOTOOLDIR="/usr/local/go/pkg/tool/darwin_amd64"
CC="clang"
GOGCCFLAGS="-fPIC -m64 -pthread -fno-caret-diagnostics -Qunused-arguments -fmessage-length=0 -fdebug-prefix-map=/var/folders/02/k62z5c796fs5gm651jc610v80000gn/T/go-build475244754=/tmp/go-build -gno-record-gcc-switches -fno-common"
CXX="clang++"
CGO_ENABLED="1"

What did you do?

If possible, provide a recipe for reproducing the error.
A complete runnable program is good.
A link on play.golang.org is best.

https://play.golang.org/p/gFDhc-65Ft

What did you expect to see?

When using json.Marshal on a time value, I expected the a myTime.Location() to always be Local when the host timezone is set.

What did you see instead?

If my local time is set to GMT, I see UTC instead of Local.

using time.Parse() as shown in the example seems to work correctly, but when the value is marshaled to/from JSON the output is inconsistent between timezone.

[groob]

I tried time.Parse with RFC3339 time format, which makes the above clearer:

fmt.Println(time.Now().Format(time.RFC3339))
// Output in EST: 2016-11-12T11:12:37-05:00
// Output in PST: 2016-11-12T08:19:15-08:00
// Output in GMT: 2016-11-12T16:19:40Z

using time.Parse with 2016-11-12T16:19:40-00:00 prints Local correctly when in GMT.

[quentinmit]

This is a dupe of #17875; Local and UTC are the same if your timezone is GMT, so encoding/json is working as intended. We make no guarantees about which location object is attached to times, only that a time that is t.Equal is returned.