Re: [PATCH] log --format: teach %C(auto,black) to paint it black only on terminals

[Jeff King <peff@peff.net>]

On Mon, Dec 17, 2012 at 12:40:55AM -0800, Junio C Hamano wrote:

> +# %C(auto,...) should trump --color=always
> +#
> +# NEEDSWORK: --color=never should also be tested but we need to run a
> +# similar test under pseudo-terminal with test_terminal which is too
> +# much hassle for its worth.
> +
> +test_format advanced-colors-forced \
> +	'%C(auto,red yellow bold)foo%C(auto,reset)' --color=always <<'EOF'
> +commit 131a310eb913d107dd3c09a65d1651175898735d
> +foo
> +commit 86c75cfd708a0e5868dc876ed5b8bb66c80b4873
> +foo
> +EOF

Hmm. I would have expected this to output colors. In other words, for
"auto" to work just like the config-respecting colorization that is
built into git.

Yes, in this toy example, one could always just drop the "auto" when
using --color=always. But part of the point of this is that I could do:

  git config pretty.fake-oneline "%C(auto,yellow)%h%C(auto,reset) %s"

and have it behave like "--oneline", no matter what the user has in
their color.ui config or --color option on the command line.

I think the patch below (on top of yours) does the right thing by
copying the color option from the rev_info diff options into the
pretty-print context, which is the same place that the graph and
log-tree code look. That means you'll get consistent colorization
(either all or nothing) with:

  git log --graph -p --format='%C(auto,blue)%s%C(auto,reset)'

no matter what your setting of color.diff, color.ui, or --color on the
command line.

It also means that pretty-print defaults to "no colors, do not even
check stdout" when people initialize it to all-zeroes. That's probably a
good thing, as it means any callers of format_commit_message have to
consciously opt into allowing colorization in their format messages.

diff --git a/commit.h b/commit.h
index b6ad8f3..0f469e5 100644
--- a/commit.h
+++ b/commit.h
@@ -89,6 +89,7 @@ struct pretty_print_context {
 	char *notes_message;
 	struct reflog_walk_info *reflog_info;
 	const char *output_encoding;
+	int color;
 };
 
 struct userformat_want {
diff --git a/log-tree.c b/log-tree.c
index 4f86def..8876c73 100644
--- a/log-tree.c
+++ b/log-tree.c
@@ -671,6 +671,7 @@ void show_log(struct rev_info *opt)
 	ctx.preserve_subject = opt->preserve_subject;
 	ctx.reflog_info = opt->reflog_info;
 	ctx.fmt = opt->commit_format;
+	ctx.color = opt->diffopt.use_color;
 	pretty_print_commit(&ctx, commit, &msgbuf);
 
 	if (opt->add_signoff)
diff --git a/pretty.c b/pretty.c
index 9e51fec..e6a2886 100644
--- a/pretty.c
+++ b/pretty.c
@@ -967,7 +967,7 @@ static size_t format_commit_one(struct strbuf *sb, const char *placeholder,
 			if (!end)
 				return 0;
 			if (!memcmp(begin, "auto,", 5)) {
-				if (!want_color(-1))
+				if (!want_color(c->pretty_ctx->color))
 					return end - placeholder + 1;
 				begin += 5;
 			}