Re: Wrong file diff for merge conflict

Linus Torvalds [off-list ref] writes:

So is it a bug? Nope. I can pretty much guarantee that it's not a bug....

Without the precise common ancestor version it is hard to tell, but using
the "one old version http://pastebin.ca/1483691" as a base and running
diff3 (or merge from RCS suite) yields identical results as ours, so in
that sense it is not a bug.

 - Tune the zealous merge a bit, and in particular try to avoid the cases 
   where this happens (as mentioned, in C code, it's often re-indentation 
   together with trivial lines that match after it).

   This is kind of what the "patience" diff algorithm tries to do: use 
   primarily non-trivial sequences as the anchors for similarity, and 
   ignore the trivial ones. We have a "--patience" switch to "git diff", 
   maybe we could tune the three-way merge somehow similarly.

Hmm. I have to think about this a bit.

 - Don't rely so heavily on just the traditional three-way merge result.

   This is what I personally do. The trivial 3-way merge result is 
   wondeful for the truly trivial merges, when it gives trivial results 
   that are easy to fix up. But let's face it, the traditional 3-way merge 
   result just sucks for anything more complicated. When you have an empty 
   side on one of the conflicts, is that because the other side added 
   everything, or is it because oen side removed it? Or is it, like in 
   this case, simply because trivially similar lines got the whole diff 
   confused about which parts didn't change at all?

   The good news is that git does have a few nice merge tools. One is 
   "git diff", which actually shows way more than the trivial three-way 
   end result, in that you can diff against either side, and by default it 
   does that fairly complex "diff against both sides" thing that is also 
   quite useful once you get used to it.

   Another is "gitk --merge [filename]" which is wonderful as a tool to 
   see what both sides actually did, to figure out what the intent of both 
   branches were when the three-way merge result is just noise.

Two other are "git log --merge -p" and "git checkout --conflicts=diff3".

The right answer is probably some combination of "all of the above". In 
the meantime, right now, only the last one is somethign git itself will 
help you with.