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

"Marco Costalba" <mcostalba@gmail.com> writes:

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.