diff: fix "git show -C -C" output when renaming a binary file

A bug was introduced in 3e97c7c6af2901cec63bf35fcd43ae3472e24af8
(No diff -b/-w output for all-whitespace changes, Nov 19 2009)
that made the lines:

  diff --git a/bar b/sub/bar
  similarity index 100%
  rename from bar
  rename to sub/bar

disappear from "git show -C -C" output when file bar is a binary
file.

Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 37 insertions, 0 deletions

diff --git a/t/t4015-diff-whitespace.sh b/t/t4015-diff-whitespace.sh
index 90f3342..7e78851 100755
--- a/t/t4015-diff-whitespace.sh
+++ b/t/t4015-diff-whitespace.sh
@@ -396,6 +396,43 @@ test_expect_success 'whitespace-only changes not reported' '
 	test_cmp expect actual
 '
 
+cat <<EOF >expect
+diff --git a/x b/z
+similarity index NUM%
+rename from x
+rename to z
+index 380c32a..a97b785 100644
+EOF
+test_expect_success 'whitespace-only changes reported across renames' '
+	git reset --hard &&
+	for i in 1 2 3 4 5 6 7 8 9; do echo "$i$i$i$i$i$i"; done >x &&
+	git add x &&
+	git commit -m "base" &&
+	sed -e "5s/^/ /" x >z &&
+	git rm x &&
+	git add z &&
+	git diff -w -M --cached |
+	sed -e "/^similarity index /s/[0-9][0-9]*/NUM/" >actual &&
+	test_cmp expect actual
+'
+
+cat >expected <<\EOF
+diff --git a/empty b/void
+similarity index 100%
+rename from empty
+rename to void
+EOF
+
+test_expect_success 'rename empty' '
+	git reset --hard &&
+	>empty &&
+	git add empty &&
+	git commit -m empty &&
+	git mv empty void &&
+	git diff -w --cached -M >current &&
+	test_cmp expected current
+'
+
 test_expect_success 'combined diff with autocrlf conversion' '
 
 	git reset --hard &&