Re: [PATCH 0/3] Un-pessimize "diff-index $commit -- $pathspec"

Junio C Hamano venit, vidit, dixit 29.08.2011 23:33:

"git diff A B -- $pathspec" to compare two tree-ishes knew how to apply
pathspec to avoid opening trees that fall outside the area of interest,
but "git diff A -- $pathspec" used unpack_trees() machinery that was meant
for full-tree merges, and ended up reading the whole tree only to discard
potentially major part of the work it does.

Seems my analysis wasn't that far off (though, admittedly, unspecific):

MG:

Well, we have to read the full tree before diffing. But I can't

...

I meant: The way "git diff" is now, it does that.

JC:

anything to do with it (iow, your "The way 'git diff' is now, it does
that" is not just incorrect---we don't read the full tree to begin
with---but irrelevant).

Anyways, as MR writes:

MR:

30s without patch and 0.3s with it. You rock ;)

I agree with all of that ;)

Michael