[PATCH] merge: give clearer error messages when there is nothing to merge

[Mads Kiilerich]

On 06/16/2010 04:20 PM, Dirkjan Ochtman wrote:
> On Wed, Jun 16, 2010 at 16:13, Matt Mackall<mpm at selenic.com>  wrote:
>> abort: dude, merging with an ancestor is a pointless no-op (think about
>> it)

Perhaps it would be helpful to give the hint that the revisions haven't 
diverged and that there thus is nothing to merge.

That might be a logical consequence of one being a descendant of the 
other, but for users not used to graph theory it might not be obvious.

>> or perhaps:
>>
>> abort: merging with ancestor has no effect
>
> I actually think the latter is an improvement.

Perhaps:
abort: can't merge with revision (it is already an ancestor)

The opposite message could be:
abort: can't merge with revision (it is already a descendant - use 'hg 
update' or check 'hg heads')

That way the comments gives the "you don't want this" advice, either 
because "you already got it" or "you can get it by updating".

/Mads