diff --color: color blank-at-eof

Since the coloring logic processed the patch output one line at a time, we
couldn't easily color code the new blank lines at the end of file.

Reuse the adds_blank_at_eof() function to find where the runs of such
blank lines start, keep track of the line number in the preimage while
processing the patch output one line at a time, and paint the new blank
lines that appear after that line to implement this.

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

1 files changed, 9 insertions, 0 deletions

diff --git a/t/t4019-diff-wserror.sh b/t/t4019-diff-wserror.sh
index 1517fff9c6..1e75f1a110 100755
--- a/t/t4019-diff-wserror.sh
+++ b/t/t4019-diff-wserror.sh
@@ -190,4 +190,13 @@ test_expect_success 'do not color trailing cr in context' '
 
 '
 
+test_expect_success 'color new trailing blank lines' '
+	{ echo a; echo b; echo; echo; } >x &&
+	git add x &&
+	{ echo a; echo; echo; echo; echo; } >x &&
+	git diff --color x >output &&
+	cnt=$(grep "${blue_grep}" output | wc -l) &&
+	test $cnt = 2
+'
+
 test_done