[PATCH v2] mv: prevent mismatched data when ignoring errors.

["brian m. carlson" <sandals@crustytoothpaste.net>]

We shrink the source and destination arrays, but not the modes or
submodule_gitfile arrays, resulting in potentially mismatched data.  Shrink
all the arrays at the same time to prevent this.  Add tests to ensure the
problem does not recur.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
---

I attempted to come up with a second patch that would refactor out the
four different arrays into one array of struct, as Jeff suggested, but
it became very ugly very quickly.  So this patch simply fixes the
problem and adds tests.

 builtin/mv.c  |  5 +++++
 t/t7001-mv.sh | 13 ++++++++++++-
 2 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/builtin/mv.c b/builtin/mv.c
index f99c91e..09bbc63 100644
--- a/builtin/mv.c
+++ b/builtin/mv.c
@@ -230,6 +230,11 @@ int cmd_mv(int argc, const char **argv, const char *prefix)
 					memmove(destination + i,
 						destination + i + 1,
 						(argc - i) * sizeof(char *));
+					memmove(modes + i, modes + i + 1,
+						(argc - i) * sizeof(enum update_mode));
+					memmove(submodule_gitfile + i,
+						submodule_gitfile + i + 1,
+						(argc - i) * sizeof(char *));
 					i--;
 				}
 			} else
diff --git a/t/t7001-mv.sh b/t/t7001-mv.sh
index e3c8c2c..215d43d 100755
--- a/t/t7001-mv.sh
+++ b/t/t7001-mv.sh
@@ -294,7 +294,8 @@ test_expect_success 'setup submodule' '
 	git submodule add ./. sub &&
 	echo content >file &&
 	git add file &&
-	git commit -m "added sub and file"
+	git commit -m "added sub and file" &&
+	git branch submodule
 '
 
 test_expect_success 'git mv cannot move a submodule in a file' '
@@ -463,4 +464,14 @@ test_expect_success 'checking out a commit before submodule moved needs manual u
 	! test -s actual
 '
 
+test_expect_success 'mv -k does not accidentally destroy submodules' '
+	git checkout submodule &&
+	mkdir dummy dest &&
+	git mv -k dummy sub dest &&
+	git status --porcelain >actual &&
+	grep "^R  sub -> dest/sub" actual &&
+	git reset --hard &&
+	git checkout .
+'
+
 test_done
-- 
1.9.0.1010.g6633b85.dirty