Re: help understanding git diff output

On Thu, Jan 27, 2011 at 6:05 PM, Junio C Hamano [off-list ref] wrote:

Eugene Sajine [off-list ref] writes:

quoted

I get empty diff when i execute:

$git diff branch1..branch2

and i also get empty diff when running

$git diff branch2..branch1

The thing is, "diff" is about comparing "two endpoints".

We still do support, as a backward compatibility measure, the A..B
notation to help people who learned "git diff" from ancient documents, and
we don't plan to deprecate the notation in any way, but don't be fooled by
the notation which usually means "the range from A to B".  In the context
of diff, it does not mean a range, as diff is about two "endpoints".

quoted

What i cannot wrap my mind around is why the command below with
symmetric difference range gives me non-empty diff

$git diff branch1...branch2

"git diff A...B" is a short-hand for "git diff $(git merge-base A B) B",
naming the fork point between branches A and B as one end, and B as the
other end, of the diff.  Again, diff is about two "endpoints", and the
notation does not mean a symmetric difference range.

Thanks a lot, Junio. I was looking at the wrong place in the
documentation. Skipped the part in diff doc explaining that range
notations are not exactly ranges for diff.

Thanks,
Eugene