Re: [PATCH] difftool: add support for an extended revision syntax

On  0, Jakub Narebski [off-list ref] wrote:

David Aguilar [off-list ref] writes:

quoted

This adds an extended revision syntax to git-difftool.
Users often ask "how do I compare a file against its
previous version" and the answer is typically a combination
of 'git log <file>' and 'git difftool <sha1> <sha1> <file>'.

[snip]

The extended revision syntax also expands revisions
that are suffixed with '!' as a convenient way to
see commit diffs.  Specifying only '!' is equivalent
to specifying 'HEAD!'.

This makes the following statements equivalent:

	$ git difftool !
	$ git difftool HEAD!
	$ git difftool HEAD~ HEAD

Errr... there already exists such syntax, and it is called HEAD^!

Yup, this patch was a mistake ;)

^! does exactly what I needed and difftool supports it since
git-diff does.

I'm still interested in the file~<n> idea [though maybe not
that exact syntax] and have been reading revision.c (as Junio
suggested) to see if it can be done in a good way.

I'm still not sure if it is a good idea since the types of
users who would want it are probably better off with tighter
integration between gitk and difftool as opposed to a
convenient command-line syntax (tho I do see how it would be
useful every now and then).  Ideally, we'd want to select two
commits in gitk and compare them.  I think qgit can do that,
but it doesn't yet know about difftool (since, of course,
difftool is not in master yet).

I noticed that my patches for "add tests to difftool" and "add
the -y shortcut for --no-prompt" were in git.git's pu branch
the other day but aren't there anymore.  Was that intentional?

(if git-difftool can accept a..b revision specification)... or not,
as git-rev-parse(1) states:

  r1^! includes commit r1 but excludes all of its parents.

So depending on how "r1 --not r1^" and "r1 --not r1^1 r1^2" is
interpreted by diff (which accpets points, not ranges) it might be, or
might be not what you wanted by introducying '!' / <rev>:!
specification...

-- 
Jakub Narebski
Poland
ShadeHawk on #git

-- 

	David