diff: teach diff.relative to give default to --relative=<value>bp/diff-relative-config

Setting diff.relative configuration variable to true makes 'git diff'
behave as if '--relative=true' was passed on the command line.

Signed-off-by: Brandon Phillips <kelson@shysecurity.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 8 insertions, 0 deletions

diff --git a/diff.c b/diff.c
index 7bceba88d2..9e4ec1f8a7 100644
--- a/diff.c
+++ b/diff.c
@@ -223,6 +223,14 @@ int git_diff_ui_config(const char *var, const char *value, void *cb)
 		return 0;
 	}
 
+	if (!strcmp(var, "diff.relative")) {
+		if (git_config_bool(var, value))
+			DIFF_OPT_SET(&default_diff_options, RELATIVE_NAME);
+		else
+			DIFF_OPT_CLR(&default_diff_options, RELATIVE_NAME);
+		return 0;
+	}
+
 	if (git_color_config(var, value, cb) < 0)
 		return -1;