diff: reuse diff setup for --no-index case

When "--no-index" is in effect (or implied by the arguments), git-diff
jumps early to a special code path to perform that diff. This means we
miss out on some settings like enabling --ext-diff and --textconv by
default.

Let's jump to the no-index path _after_ we've done more setup on
rev.diffopt. Since some of the options don't affect us (e.g., items
related to the index), let's re-order the setup into two blocks (see the
in-code comments).

Note that we also need to stop re-initializing the diffopt struct in
diff_no_index(). This should not be necessary, as it will already have
been initialized by cmd_diff() (and there are no other callers). That in
turn lets us drop the "repository" argument from diff_no_index (which
never made much sense, since the whole point is that you don't need a
repository).

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 11 insertions, 9 deletions

diff --git a/builtin/diff.c b/builtin/diff.c
index f0393bba23..777ca87156 100644
--- a/builtin/diff.c
+++ b/builtin/diff.c
@@ -337,21 +337,23 @@ int cmd_diff(int argc, const char **argv, const char *prefix)
 		       "--no-index" : "[--no-index]");
 
 	}
-	if (no_index)
-		/* If this is a no-index diff, just run it and exit there. */
-		diff_no_index(the_repository, &rev, argc, argv);
-
-	/* Otherwise, we are doing the usual "git" diff */
-	rev.diffopt.skip_stat_unmatch = !!diff_auto_refresh_index;
 
-	/* Scale to real terminal size and respect statGraphWidth config */
+	/* Set up defaults that will apply to both no-index and regular diffs. */
 	rev.diffopt.stat_width = -1;
 	rev.diffopt.stat_graph_width = -1;
-
-	/* Default to let external and textconv be used */
 	rev.diffopt.flags.allow_external = 1;
 	rev.diffopt.flags.allow_textconv = 1;
 
+	/* If this is a no-index diff, just run it and exit there. */
+	if (no_index)
+		diff_no_index(&rev, argc, argv);
+
+	/*
+	 * Otherwise, we are doing the usual "git" diff; set up any
+	 * further defaults that apply to regular diffs.
+	 */
+	rev.diffopt.skip_stat_unmatch = !!diff_auto_refresh_index;
+
 	/*
 	 * Default to intent-to-add entries invisible in the
 	 * index. This makes them show up as new files in diff-files