Re: Two crazy proposals for changing git's diff commands

Linus Torvalds [off-list ref] writes:

In particular, I think the real culprit is the plain "git diff" with no 
arguments at all. Right now it ends up showing just a piece of the 
picture, and the piece it shows is incomplete enough to be irritating.

Not necessarily.  Your "during the merge" example is a good one,
and "so far it looks good and I do not want to see these diffs
while modifying things further -- update-index it!" workflow
benefits immensely from it.

Right now a plain "git diff" only shows the differences in the current 
tree against the index. I think that was just the wrong choice. I think 
almost everybody would actually prefer the default to be to show the 
difference against HEAD.

I somehow suspect this is welding training wheels to your
bicycle.

Teaching "git status" to take a "-p" flag (for "patch" - or -v for 
"verbose") might actually be a good thing. Then, instead of "git diff", 
you'd use "git status -p" and it would show you what the differences are 
in the index, and what they are in the tree, so you'd _really_ know what 
"git commit" in all its glory would do.

I think this may not be a bad idea.

What we could do is this:

	$ git status -v [--only | --include] [paths...]

When -v is given, it takes the same parameter as "git commit",
and changes its output format from the usual N x "# useful info lines"
to something like:

	---
        diff ...
        --- a/path
        +++ b/path
        @@ -N,M +L,K @@

that shows the commit preview.  At the same time we change "git
commit" commit log message reader to stop reading the input at
the first '---' line, just like we do for e-mailed patches.

Then:

 - If you want a commit preview _before_ initiating a commit,
   you can say:

	$ git status -v [whatever you planned to give git commit]

 - If you want a commit preview _while_ writing the commit log, you can
   say:

	$ git commit -v [whatever your parameters are]

   which internally would pass the -v and "$@" to git status
   that seeds the log message


 - If you want a commit preview after you made a commit, it is
   too late ;-).