Re: [PATCH 1/2] diff: add --word-diff option that generalizes --color-words

From: Junio C Hamano <gitster@pobox.com>
Date: Apr 5, 2010, 02:06 UTC
Message-ID: <7v39zay7or.fsf@alter.siamese.dyndns.org>
In-Reply-To: <a1e9ef6a4eb1d7930f69e9ac4b63dc3152ebc98c.1270388195.git.trast@student.ethz.ch>

Thomas Rast <trast@student.ethz.ch> writes:

Show 12 quoted lines

> This teaches the --color-words engine a more general interface that
> supports two new modes:
>
> * --word-diff=plain, inspired by the 'wdiff' utility (most similar to
>   'wdiff -n <old> <new>'): uses delimiters [-removed-] and {+added+}
>
> * --word-diff=porcelain, which generates an ad-hoc machine readable
>   format:
>   - each diff unit is prefixed by [-+ ] and terminated by newline as
>     in unified diff
>   - newlines in the input are output as a line consisting only of a
>     tilde '~'

Thanks.  This was a fun feature to look at.

I think it is a bug that "git show --word-diff" gives the colored format output when I have "color.ui" configuration.

Even though I may have "color.ui = auto" in the configuration, I am telling the command to do a --word-diff, not --color-words, from the command line, and that should override color.ui settings.

So I think a request for --word-diff that is not --word-diff=color should never use the --color-words _unless_ there is --color on the command line:

	git show --word-diff
	git show --word-diff=plain
	git show --word-diff=porcelain

All of the above may paint hunk headers and metainfo the usual way when I have "color.ui" set, but I do not want them to be painting the diff part like --color-words does. I am fine if "porcelain" did not to paint the metainfo, but I see this feature as three different output types of how word diff is presented, so in that sense, it probably is better to force scripts to explicitly ask for no-color, i.e.

	git show --no-color --word-diff=porcelain

if they want to read and interpret metainfo.

When the command line asks for color explicitly, then we should see the good old --color-words:

	git show --color-words
	git show --word-diff=color

I am not sure what the following two should do. One could argue that these default to --color-words; or --color should apply only to the coloring of metainfo but not the diff part:

        git show --color --word-diff
        git show --word-diff --color

I am slightly in favor of doing the same as --color-words, but people may have different opinions.

The following of course should show the plain word diff but the metainfo and friends colored:

        git show --word-diff=plain --color
        git show --color --word-diff=plain

It might be just the matter of defaulting --word-diff without "=<type>" not to "auto" but to "plain". I haven't looked at the code closely yet.