encoding/json: encode map key is of string kind, decode only of string type

[gopherbot]

by acmmlyc:

There's an asymmetry that's bugging me—I don't know if you care enough to have it
fixed, but it tripped me up, so it may be worth.

Encoding a map fails if v.Type().Key().Kind() != reflect.String, meaning the string type
*and* any synonym thereof (constructed with type X string) will work as a key.

Conversely, decoding fails if t := v.Type(); t.Key() != reflect.TypeOf(""),
forcing a string type rather than string kind.

Small demonstration here: http://play.golang.org/p/Jcl_elUQNx

Encode produces sensible JSON, but decode doesn't mutate the map.

Ideally it'd be consistent one way or another; by encoding rejecting anything not a
"string" type, or decoding accepting non-"string"-typed
string-kinds! If you think this is sensible, I'd be happy to try to hack a patch
together.

Cheers,

Arlen

[rsc]

Comment 1:

Labels changed: added priority-later, removed priority-triage.

Status changed to Accepted.

[rsc]

Comment 2:

Labels changed: added go1.1.

[rsc]

Comment 3:

Labels changed: added size-m.

[rsc]

Comment 4:

Labels changed: added suggested.

[davecheney]

Comment 5:

This issue was closed by revision a460012.

Status changed to Fixed.

[gopherbot]

Comment 6 by ar@len.me:

Thanks!