Re: git grep doesn't follow symbolic link

On Sun, Jan 15, 2012 at 9:07 AM, Junio C Hamano [off-list ref] wrote:

Stop and think what "git diff --follow-symlinks v1.3.0 v1.7.0" should do
when these versions record a symbolic link, "from user perspective", if
the link points outside the tracked contents. Naturally, the users would
expect that the comparison is made between the contents of the file back
when v1.3.0 was tagged and the contents of the file (which may or may not
be the same path depending on the target of that symbolic link) back when
v1.7.0 was tagged.

But that is something that the user is *NOT* tracking with the system, and
hence something we cannot give the right answer. Your "--follow-symlinks"
option only encourages the *wrong* perception on the users' side, without
supporting what it appears to promise to the users. Why could it be an
improvement?

It's not wrong per se. It's an implication that users have to take
when they choose to use it. We may help make it clear that the
symlinks point to untracked files by putting some indication in the
diff.

When I do "git log -Sfoo -- '*.cxx'" I don't really care if bar.cxx is
a symlink. Neither does my compiler. It may be a symlink's target
change that makes "foo" appear. Git could help me detect that quickly
instead of sticking with tracked contents only.

Even if we decide --follow-symlinks=untracked is a bad idea,
--follow-symlinks=tracked (i.e. follow symlinks to tracked files only)
is still a good thing to support. And I suspect that's a more common
case as linking outside repository could is undeterministic.

The "=tracked" could be dropped if we have no other option value. I'm
thinking of --follow-symlinks=submodule, which is currently covered by
a separate option name.
-- 
Duy