grep: print context hunk marks between files

Print a hunk mark before matches from a new file are shown, in addition
to the current behaviour of printing them if lines have been skipped.

The result is easier to read, as (presumably unrelated) matches from
different files are separated by a hunk mark.  GNU grep does the same.

Signed-off-by: Rene Scharfe <rene.scharfe@lsrfire.ath.cx>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 11 insertions, 0 deletions

diff --git a/builtin-grep.c b/builtin-grep.c
index 73fc922c49..48998af911 100644
--- a/builtin-grep.c
+++ b/builtin-grep.c
@@ -278,6 +278,17 @@ static int flush_grep(struct grep_opt *opt,
 		argc -= 2;
 	}
 
+	if (opt->pre_context || opt->post_context) {
+		/*
+		 * grep handles hunk marks between files, but we need to
+		 * do that ourselves between multiple calls.
+		 */
+		if (opt->show_hunk_mark)
+			write_or_die(1, "--\n", 3);
+		else
+			opt->show_hunk_mark = 1;
+	}
+
 	status = exec_grep(argc, argv);
 
 	if (kept_0) {