Re: [PATCH] Add -r flag to show-diff for diff-cache/diff-tree like output.

[Junio C Hamano <junkio@cox.net>]

>>>>> "LT" == Linus Torvalds <torvalds@osdl.org> writes:

LT> Why not just make this the default? Who really cares about
LT> show-diff?

Me, to care enough about it to send patches in ;-).

LT> So why not just make "rational" the standard format, and then make 
LT> "diff-tree-helper" warn about unmerged ("U") files?

LT> As far as I can tell, that is really what _everybody_ wants.

I do not think of a good reason to forbid people from getting a
patch out of core GIT without going through the wrapper layer,
and the code is already there.  That said, I agree that scripts
usually do not use patch generating form.  I checked Cogito
before doing the patch to make sure it is not affected by this,
and my JIT core tools do not use it either.

I think making the diff-tree/cache compatible output default
would be fine.  The current diff-producing behaviour can be made
into an option (yes, I want to keep it).

LT> And calling "-r" "rational", when it means "recursive" for
LT> diff-tree and diff-cache doesn't sound rational to me.

Well, the truth is that -r does not stand for anything.  It just
is there to match useless -r to diff-cache (the change you made
to it to accept the same command line parameters -r (and
optionally -z) people would always give diff-tree.  You can call
it recursive if you want.

How about me doing the following and resubmitting?

 - Make this diff-tree/cache compatible output the default.

 - Take but ignore -r flag like diff-cache.

 - Add U warning to diff-tree-helper.

 - Add -p flag (patch) and have it cause the patch generating
   behaviour. 

Later I'll add -p flag to diff-cache and diff-tree, so the usage
of these three commands match.  That is:

    show-diff  -r (useless) -z           | diff-tree-helper -z
    diff-cache -r (useless) -z tree      | diff-tree-helper -z
    diff-tree  -r           -z tree tree | diff-tree-helper -z

    show-diff  -p [-r (useless)]
    diff-cache -p [-r (useless)]
    diff-tree  -p [-r]

With the GIT_EXTERNAL_DIFF envioronment variable, I suspect that
wrapper scripts do not have to use the diff-tree-helper but
directly use the -p form; but that will come later.  Thoughts?