[darcs-devel] [issue772] bug in get_extra commuting patch

[zooko]

On Mar 31, 2008, at 9:38 AM, David Roundy wrote:
>
> This is a duplicate of issue27.  It's debatable whether this is a  
> bug in darcs
> or a bug in tailor.  Zooko would argue, I'm sure, that darcs  
> shouldn't give you
> the power to shoot yourself in the foot.

My argument is that patch ids should be unique, so that it is  
impossible for there to exist two different patches with the same  
patch id.  This is a property that monotone guaranteed, which git  
adopted, and which mercurial and bzr now offer as well.

It seems like it could be a useful property to rely upon.  It could  
theoretically be used by a future version of darcs to  
cryptographically verify the provenance of a repository, the way that  
monotone and the others already do.

The "garbage" that David referred to in his note would be a secure  
hash of the contents of the patch and the context of the patch, just  
as is done in the other revision control tools.

Hopefully it wouldn't need to be encoded into the long patch  
description itself, however, since that could collide with other uses  
of the long patch description.  Hopefully the patch hash information  
could be stored with the patch description in a separate field, just  
like monotone and the others do.

Regards,

Zooko