Merge branch 'bw/diff-metainfo-color' into maint

* bw/diff-metainfo-color:
  diff: fix coloring of extended diff headers

diff.c

@@ -1649,21 +1649,21 @@ static void builtin_diff(const char *name_a,
 	if (lbl[0][0] == '/') {
 		/* /dev/null */
 		strbuf_addf(&header, "%snew file mode %06o%s\n", set, two->mode, reset);
-		if (xfrm_msg && xfrm_msg[0])
-			strbuf_addf(&header, "%s%s%s\n", set, xfrm_msg, reset);
+		if (xfrm_msg)
+			strbuf_addstr(&header, xfrm_msg);
 	}
 	else if (lbl[1][0] == '/') {
 		strbuf_addf(&header, "%sdeleted file mode %06o%s\n", set, one->mode, reset);
-		if (xfrm_msg && xfrm_msg[0])
-			strbuf_addf(&header, "%s%s%s\n", set, xfrm_msg, reset);
+		if (xfrm_msg)
+			strbuf_addstr(&header, xfrm_msg);
 	}
 	else {
 		if (one->mode != two->mode) {
 			strbuf_addf(&header, "%sold mode %06o%s\n", set, one->mode, reset);
 			strbuf_addf(&header, "%snew mode %06o%s\n", set, two->mode, reset);
 		}
-		if (xfrm_msg && xfrm_msg[0])
-			strbuf_addf(&header, "%s%s%s\n", set, xfrm_msg, reset);
+		if (xfrm_msg)
+			strbuf_addstr(&header, xfrm_msg);
 
 		/*
 		 * we do not run diff between different kind
@@ -2319,30 +2319,36 @@ static void fill_metainfo(struct strbuf *msg,
 			  struct diff_filespec *one,
 			  struct diff_filespec *two,
 			  struct diff_options *o,
-			  struct diff_filepair *p)
+			  struct diff_filepair *p,
+			  int use_color)
 {
+	const char *set = diff_get_color(use_color, DIFF_METAINFO);
+	const char *reset = diff_get_color(use_color, DIFF_RESET);
+
 	strbuf_init(msg, PATH_MAX * 2 + 300);
 	switch (p->status) {
 	case DIFF_STATUS_COPIED:
-		strbuf_addf(msg, "similarity index %d%%", similarity_index(p));
-		strbuf_addstr(msg, "\ncopy from ");
+		strbuf_addf(msg, "%ssimilarity index %d%%",
+			    set, similarity_index(p));
+		strbuf_addf(msg, "%s\n%scopy from ", reset, set);
 		quote_c_style(name, msg, NULL, 0);
-		strbuf_addstr(msg, "\ncopy to ");
+		strbuf_addf(msg, "%s\n%scopy to ", reset, set);
 		quote_c_style(other, msg, NULL, 0);
-		strbuf_addch(msg, '\n');
+		strbuf_addf(msg, "%s\n", reset);
 		break;
 	case DIFF_STATUS_RENAMED:
-		strbuf_addf(msg, "similarity index %d%%", similarity_index(p));
-		strbuf_addstr(msg, "\nrename from ");
+		strbuf_addf(msg, "%ssimilarity index %d%%",
+			    set, similarity_index(p));
+		strbuf_addf(msg, "%s\n%srename from ", reset, set);
 		quote_c_style(name, msg, NULL, 0);
-		strbuf_addstr(msg, "\nrename to ");
+		strbuf_addf(msg, "%s\n%srename to ", reset, set);
 		quote_c_style(other, msg, NULL, 0);
-		strbuf_addch(msg, '\n');
+		strbuf_addf(msg, "%s\n", reset);
 		break;
 	case DIFF_STATUS_MODIFIED:
 		if (p->score) {
-			strbuf_addf(msg, "dissimilarity index %d%%\n",
-				    similarity_index(p));
+			strbuf_addf(msg, "%sdissimilarity index %d%%%s\n",
+				    set, similarity_index(p), reset);
 			break;
 		}
 		/* fallthru */
@@ -2359,15 +2365,13 @@ static void fill_metainfo(struct strbuf *msg,
 			    (!fill_mmfile(&mf, two) && diff_filespec_is_binary(two)))
 				abbrev = 40;
 		}
-		strbuf_addf(msg, "index %.*s..%.*s",
+		strbuf_addf(msg, "%sindex %.*s..%.*s", set,
 			    abbrev, sha1_to_hex(one->sha1),
 			    abbrev, sha1_to_hex(two->sha1));
 		if (one->mode == two->mode)
 			strbuf_addf(msg, " %06o", one->mode);
-		strbuf_addch(msg, '\n');
+		strbuf_addf(msg, "%s\n", reset);
 	}
-	if (msg->len)
-		strbuf_setlen(msg, msg->len - 1);
 }
 
 static void run_diff_cmd(const char *pgm,
@@ -2383,11 +2387,6 @@ static void run_diff_cmd(const char *pgm,
 	const char *xfrm_msg = NULL;
 	int complete_rewrite = (p->status == DIFF_STATUS_MODIFIED) && p->score;
 
-	if (msg) {
-		fill_metainfo(msg, name, other, one, two, o, p);
-		xfrm_msg = msg->len ? msg->buf : NULL;
-	}
-
 	if (!DIFF_OPT_TST(o, ALLOW_EXTERNAL))
 		pgm = NULL;
 	else {
@@ -2396,6 +2395,16 @@ static void run_diff_cmd(const char *pgm,
 			pgm = drv->external;
 	}
 
+	if (msg) {
+		/*
+		 * don't use colors when the header is intended for an
+		 * external diff driver
+		 */
+		fill_metainfo(msg, name, other, one, two, o, p,
+			      DIFF_OPT_TST(o, COLOR_DIFF) && !pgm);
+		xfrm_msg = msg->len ? msg->buf : NULL;
+	}
+
 	if (pgm) {
 		run_external_diff(pgm, name, other, one, two, xfrm_msg,
 				  complete_rewrite);