[darcs-users] unique features + exponential time issue

Stefan Monnier monnier at IRO.UMontreal.CA
Wed Oct 24 20:27:13 UTC 2007


>> All the other systems I tried use `diff3' when merging branches and this
>> doesn't make any more guesses or searches than darcs.  OTOH darcs's approach
>> can sometimes better resolve apparent conflicts.  Also the fact that it
>> doesn't rely on a *sequence* of patches makes it particularly good at
>> cherry-picking and keeping track of merge history.

> Note that the "inexact" version of 3-way is imprecise, in that it
> depends on few context lines around the patch. It therefore leads to

AFAIK diff3 has no "inexact version" of 3-way merge.

> So diff3 produces a conflict, although a clean (and correct) merge is
> very much achievable.

Yes, darcs may avoid conflicts.  That's good.  But what I objected to was
the claim that darcs was safer (i.e. correctly signals conflicts at places
where diff3 would have incorrectly "resolved" it).

> diff3 will happily pick wrong site for insertion, eg, when the place
> is ambiguous due to context. I can try producing an example, if you
> like : - ).

I've never heard od diff3 using "context".


        Stefan


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