Re: [RFC] Enable 'check for copy and renames' (-C) also when path filtering

> "Marco Costalba" <mcostalba@gmail.com> writes:
>
> > It seems that -C option of git-diff-tree it works only if the whole
> > changeset is retrieved.
>
> Correct (sort of).  Pathspec works on the input side not on the
> output side.  It's been specified and worked that way from the
> beginning (check the list archive to see me arguing that it
> would be easier to use on the output side, and Linus vetoing
> because following a single file is not that interesting and the
> cost outweighs the benefit of that uninteresting case).
>
> Always feeding the whole tree is wasteful, but if we are
> interested in following a single file, we could do something
> like:
>
>  - follow that file and that file only from the recent to past;
>
>  - notice when that file disappears -- that is the point the
>    file was created.  it may have created from scratch, it may
>    have been renamed or copied.
>
>  - on that commit that creates the file, look at the whole tree
>    to see if we can find an origin.
>
>  - if we find that the file was created by renaming or copying
>    another, keep following that other file from that point on.
>