[PATCH FOLLOWUP STABLE] commitextras: make sure keys contains ascii letters, numbers, '_' and '-' only

[Martin von Zweigbergk]

On Fri, Jul 28, 2017 at 7:20 AM, Pulkit Goyal <7895pulkit at gmail.com> wrote:
> # HG changeset patch
> # User Pulkit Goyal <7895pulkit at gmail.com>
> # Date 1501207975 -19800
> #      Fri Jul 28 07:42:55 2017 +0530
> # Branch stable
> # Node ID 2545b963f05a731d51f632bdb0572a755e80eca5
> # Parent  850d2ec2cf6a266987a401752c909f95dd8c4c53
> commitextras: make sure keys contains ascii letters, numbers, '_' and '-' only

Why is that important? Are stored as is in the changeset data so they
can make it unparseable?