diff settings

How do I configure my local git so that diff always obeys a particular option, e.g. "-w", without needing to type it on the command line each time?

Thanks, Keith

On Sat, Jan 24, 2009 at 09:38:18AM -0800, Keith Cascio wrote:

AFAIK, there is not a way to do it in the general case (though there are specific config options for things like rename support). When I refactored the gitattributes diff=$foo code a few months back, I tried to keep in mind the possibility of a "diff options" field. But I never actually implemented anything, as I don't personally ever use diff options in such a way.

If you're interested, it would probably not be too hard to implement (see userdiff.[ch], and the external and textconv code in diff.c for a start).

-Peff

Keith Cascio (2009-01-24 09:38 -0800) wrote:

It seems that the answer is "no", but aliases are a work-around:

    git config --global alias.dff "diff -w"

Then "git dff" is your new "git diff -w". :-)

That feature is gonna come in handy. It doesn't 100% fulfill my needs here but I like it! Thanks, I did not know about alias.*

Mercurial has a "defaults.*" that does exactly what you want. That is, you can say

[defaults] diff = -w

and "hg diff" will automatically do "hg diff -w". Such a feature might be a nice addition to git.

--Ted

On Sun, 25 Jan 2009, Ted Pavlic wrote:

Thank you, that is very interesting. I just submitted a patch this morning that does exactly what you describe, but I called it "primer" instead of "defaults" because it seemed more explicit. Check it out.

                            -- Keith

I saw that. However, in Mercurial's case, the [defaults] section applies to all commands (including new ones introduced by extensions). That is, it looks like your patch adds a diff.primer, but Mercurial would add a primer.* that allows you to have a primer.diff, primer.commit, etc.

For example, wouldn't it be nice to have something like...

[defaults] diff = -w commit = -a

etc.? Right now the only way you can do that is with aliases (e.g., I have an alias from "ci" to "commit -a").

This task is pretty easy in Mercurial because Mercurial porcelains are implemented as modules that are all executed through the central "hg" command. This isn't the case with git.

(on a somewhat unrelated note, Mercurial does have a [diff] section that allows for, say, forcing the use of git diff and other things)

--Ted

(on the other hand, having a "[defaults]" section that only applies when commands are called via "git" might be nice. That way you can use the "git-CMD" when you want to use CMD without the "[defaults]"... perhaps?)

Hi,

On Thu, 29 Jan 2009, Ted Pavlic wrote:

Nope, the dash form is deprecated, and once y'all out there finally do not write it any more, we can start thinking about _not_ hardlinking the builtins to their dashed form anymore.

Believe it or not, we already have a distinction between what is called from scripts vs from humans: plumbing vs porcelain. So you can set the defaults for porcelain as much as you want, but please leave plumbing alone.

Ciao, Dscho

On Thu, 29 Jan 2009, Johannes Schindelin wrote:

May we consider "git diff" Porcelain and "git diff-{files,index,tree}" plumbing?

Quoting Keith Cascio <keith@CS.UCLA.EDU>:

Sure we may. To see the list of commands with categories, you can consult

http://www.kernel.org/pub/software/scm/git/docs/

Junio, I think you could have stated this a bit more clearly in your message

http://thread.gmane.org/gmane.comp.version-control.git/107069/focus=107165

to avoid confusion, especially when you know you are talking to somebody new to git.

As I already discussed, Mercurial has both "diff.primer" and "primer.diff" precisely because "diff" settings affects so many Hg commands.

In particular, in my .hgrc, I have:

[diff] git = 1

which causes all Mercurial commands that need to generate a diff to use gitdiff rather than truediff. However, if I *wanted* to apply a set of flags to a particular command, I could (using the equivalent "git" commands)...

[defaults] pull = --rebase commit = -a format-patch = -M

So I see a purpose for both *.defaults and defaults.*. Of course, aliases are also nice (IIRC, Mercurial doesn't have "aliases", but I could be wrong). Mercurial users are very happy with having both available. I imagine git people would be too.

--Ted

On Sat, 31 Jan 2009, Ted Pavlic wrote:

Yes I remember you did mention that.

I like it! I'm all for it. Perfect opportunity for future work. In fact, I think I already glanced at the part of the code that's the right place to make that stuff happen.

                                      -- Keith