Help, how did Mozilla do this?

[Benjamin Smedberg]

On 4/10/2013 3:49 PM, Johnny P wrote:
> Ref: http://hg.mozilla.org/integration/gaia/graph
>
> In the picture below I found Mozilla's mercurial repository graph with 
> a situation that I thought was not possible. They have two commits 
> that have the same parent where one is a merge. I have wanted to do 
> this, but cannot find an answer on how to, can anyone help?
>
>     @ merge pull request from foo polish text
>     |\
>     | o bug 1 - add text ...
>     |/
>     o merge pull request from bar bug 2
>
> How did they get this to occur? Usually when you pull changes in that 
> add onto the head, if you attempt to merge you get "nothing to merge".
The "native" repository for gaia is the git repository, and what you are 
viewing here is an hg mirror of git. Git merge --no-ff will generate 
this kind of merge, and it is the default kind of merge performed by the 
github UI for pull requests.

I suspect that the git->hg conversion just kept the merge even though it 
isn't possible using native hg.

--BDS