git log: support "auto" decorations

This works kind of like "--color=auto" - add decorations for interactive
use, but do not change defaults when scripting or when piping the output
to anything but a terminal.

You can use either

[log]
decorate=auto

in the git config files, or the "--decorate=auto" command line option to
choose this behavior.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/builtin/log.c b/builtin/log.c
index 39e883635279ad21f3ddd7b224f484b9b04700b0..df6396c9c3d9f19b8e4d21a2873be3ebe0360944 100644 (file)
--- a/builtin/log.c
+++ b/builtin/log.c
@@ -63,6 +63,8 @@ static int parse_decoration_style(const char *var, const char *value)
                return DECORATE_FULL_REFS;
        else if (!strcmp(value, "short"))
                return DECORATE_SHORT_REFS;
+       else if (!strcmp(value, "auto"))
+               return (isatty(1) || pager_in_use()) ? DECORATE_SHORT_REFS : 0;
        return -1;
 }