Re: If merging that is really fast forwarding creates new commit

From: Liu Yubao <yubao.liu@gmail.com>
Date: Nov 7, 2006, 03:42 UTC
Message-ID: <4550008F.8030809@gmail.com>
In-Reply-To: <20061106133923.GB1151@robert.daprodeges.fqdn.th-h.de>

Rocco Rutte wrote:

Show 11 quoted lines

> Hi,
> 
> * Liu Yubao [06-11-06 21:00:07 +0800] wrote:
> 
>> Then, what bad *logical* problem will happen if a merging that is 
>> really a fast forwarding creates a new commit?
> 
> I don't know what you expect by "logical" nor if I get you right, but if 
> fast-forward merge a branch to another one, both branches now have 
> exactly the same hash. If you create a commit object for a fast-forward 
> merge, both tip hashes not identical anymore... which is bad.

Not so bad, you can know they point to same tree objects.

Fast forwarding style merge will blow away the *track* of your branch, and this track is useful, that is why reflog appears.

> 
> The identical hash important so that you really know they're identical 
> and for future reference like ancestry.

I guess you have mixed identical commits with identical trees. Trees is what we really need.

Fake commit doesn't mess the ancestry relation, you can refer to my previous mail replied to Andreas Ericsson in this topic.

> 
>   bye, Rocco