color: support "default" to restore fg/bg color

The name "default" can now be used in foreground or background colors,
and means to use the terminal's default color, discarding any
explicitly-set color without affecting the other attributes. On many
modern terminals, this is *not* the same as specifying "white" or
"black".

Although attributes could previously be cleared like "no-bold", there
had not been a similar mechanism available for colors, other than a full
"reset", which cannot currently be combined with other settings.

Note that this is *not* the same as the existing name "normal", which is
a no-op placeholder to permit setting the background without changing
the foreground. (i.e. what is currently called "normal" might have been
more descriptively named "inherit", "none", "pass" or similar).

Signed-off-by: Robert Estelle <robertestelle@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 12 insertions, 0 deletions

diff --git a/t/t4026-color.sh b/t/t4026-color.sh
index cc73161b46..d6907a66c3 100755
--- a/t/t4026-color.sh
+++ b/t/t4026-color.sh
@@ -96,6 +96,18 @@ test_expect_success '24-bit colors' '
 	color "#ff00ff black" "[38;2;255;0;255;40m"
 '
 
+test_expect_success '"default" foreground' '
+	color "default" "[39m"
+'
+
+test_expect_success '"normal default" to clear background' '
+	color "normal default" "[49m"
+'
+
+test_expect_success '"default" can be combined with attributes' '
+	color "default default no-reverse bold" "[1;27;39;49m"
+'
+
 test_expect_success '"normal" yields no color at all"' '
 	color "normal black" "[40m"
 '