[PATCH 3 of 3 STABLE] devel-warn: issue a warning when writing bookmarks without holding the wlock

[Matt Mackall]

On Tue, 2015-08-11 at 17:06 -0700, Pierre-Yves David wrote:
> # HG changeset patch
> # User Laurent Charignon <lcharignon at fb.com>
> # Date 1438433019 25200
> #      Sat Aug 01 05:43:39 2015 -0700
> # Branch stable
> # Node ID bb267085bdd69fff0f5fa4091bbc223889d57c0b
> # Parent  3cfb0c92590589c9ccdef1884b6133d0d6303805
> devel-warn: issue a warning when writing bookmarks without holding the wlock
> 
> I saw an issue in an extension that we develop where we were writing bookmarks
> without holding the wlock. Another extension was taking a lock at the same time
> and wiped out the bookmarks we were about to write. This patch adds a
> devel-warning to urge people to fix their invalide code.

I've queued the first two for default. The last obviously doesn't belong
on stable, so I'll try to juggle it into the right place after I merge.
-- 
Mathematics is the supreme nostalgia of our time.