[PATCH/RFC] "color.diff = true" is not "always" anymore.

[Junio C Hamano <gitster@pobox.com>]

Too many people got burned by setting color.diff and color.status to
true when they really should have set it to "auto".

This makes only "always" to do the unconditional colorization, and
change the meaning of "true" to the same as "auto": colorize only when
we are talking to a terminal.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
---

 * This is definitely a backward incompatible change, but I think it is
   only in a good way.  Are there people who have "color.* = true" and
   do mean it?  If we do this, they need to change their configuration
   and use "always", but I suspect there is no sane workflow that wants
   the color escape code in files (e.g. "git log >file") or pipes
   (e.g. "git diff | grep foo") by default, in which case this won't
   hurt anybody and would help countless normal people who were bitten
   by the mistaken meaning originally chosen for "true".

 color.c |   32 +++++++++++++++++++-------------
 1 files changed, 19 insertions(+), 13 deletions(-)

diff --git a/color.c b/color.c
index 124ba33..97cfbda 100644
--- a/color.c
+++ b/color.c
@@ -118,21 +118,27 @@ bad:
 
 int git_config_colorbool(const char *var, const char *value)
 {
-	if (!value)
-		return 1;
-	if (!strcasecmp(value, "auto")) {
-		if (isatty(1) || (pager_in_use && pager_use_color)) {
-			char *term = getenv("TERM");
-			if (term && strcmp(term, "dumb"))
-				return 1;
-		}
-		return 0;
+	if (value) {
+		if (!strcasecmp(value, "never"))
+			return 0;
+		if (!strcasecmp(value, "always"))
+			return 1;
+		if (!strcasecmp(value, "auto"))
+			goto auto_color;
 	}
-	if (!strcasecmp(value, "never"))
+
+	/* Missing or explicit false to turn off colorization */
+	if (!git_config_bool(var, value))
 		return 0;
-	if (!strcasecmp(value, "always"))
-		return 1;
-	return git_config_bool(var, value);
+
+	/* any normal truth value defaults to 'auto' */
+ auto_color:
+	if (isatty(1) || (pager_in_use && pager_use_color)) {
+		char *term = getenv("TERM");
+		if (term && strcmp(term, "dumb"))
+			return 1;
+	}
+	return 0;
 }
 
 static int color_vfprintf(FILE *fp, const char *color, const char *fmt,
-- 
1.5.3.6.2039.g0495