Re: [PATCH 2/2 - RFH/WIP] xdiff-merge: optionally show conflicts in "diff3 -m" style

[Linus Torvalds <torvalds@linux-foundation.org>]

On Thu, 28 Aug 2008, Junio C Hamano wrote:
> 
> Some poeple find it easier to be able to understand what is going on when
> they can view the common ancestor's version, which is used by "diff3 -m",
> which shows:
> 
>  <<<<<<<
>  postimage from one side;
>  |||||||
>  shared preimage;
>  =======
>  postimage of the other side; and
>  >>>>>>>
> 
> This is an initial step to bring that as an optional feature to git.
> Only "git merge-file" has been converted, with "--diff3" option.

If you have the common ancestor, why would you ever want this format, and 
not a nice conflict entry in the index?

Anyway, that's irrelevant for my real question, which is:

>  /*
> - * level == 0: mark all overlapping changes as conflict
> - * level == 1: mark overlapping changes as conflict only if not identical
> - * level == 2: analyze non-identical changes for minimal conflict set
> - * level == 3: analyze non-identical changes for minimal conflict set, but
> - *             treat hunks not containing any letter or number as conflicting
> + * "Level" parameter can be:
> + *
> + * (MINIMAL):
> + * Mark all overlapping changes as conflict
> + *
> + * (EAGER):
> + * Mark overlapping changes as conflict only if not identical
> + *
> + * (DIFF3):
> + * Same as EAGER but show the shared preimage in the output as well
> + *
> + * (ZEALOUS):
> + * Analyze non-identical changes for minimal conflict set
> + *
> + * (ZEALOUS_ALNUM):
> + * Analyze non-identical changes for minimal conflict set, but
> + * treat hunks not containing any letter or number as conflicting
>   *

Wouldn't it be much nicer to make this a bitflag, than an enumeration of 
different models?

In particular, why would it be wrong to want to be ZEALOUS (possibly 
_ALNUM) and still want DIFF3 output?

IOW, I don't think these are at all disjoint sets. In fact, I think DIFF3 
sounds not at all like a "level" to me, but like an output format thing, 
so it's in a totally different "address space".

Hmm?

		Linus