t6050: show that git cat-file --batch fails with replace objects

When --batch is passed to git cat-file, the sha1_object_info_extended()
function is used to get information about the objects passed to
git cat-file.

Unfortunately sha1_object_info_extended() doesn't take care of
object replacement properly, so it will often fail with a
message like this:

$ echo a3fb2e1845a1aaf129b7975048973414dc172173 | git cat-file --batch
a3fb2e1845a1aaf129b7975048973414dc172173 commit 231
fatal: object a3fb2e1845a1aaf129b7975048973414dc172173 change size!?

The goal of this patch is to show this breakage.

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

t/t6050-replace.sh

@@ -276,6 +276,11 @@ test_expect_success '-f option bypasses the type check' '
 	git replace -f HEAD^ $BLOB
 '
 
+test_expect_failure 'git cat-file --batch works on replace objects' '
+	git replace | grep $PARA3 &&
+	echo $PARA3 | git cat-file --batch
+'
+
 test_expect_success 'replace ref cleanup' '
 	test -n "$(git replace)" &&
 	git replace -d $(git replace) &&