t7700: demonstrate mishandling of objects in packs with a .keep file

Objects residing in pack files that have an associated .keep file are not
supposed to be repacked into new pack files, but they are.
Signed-off-by: NBrandon Casey <casey@nrlssc.navy.mil>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

t/t7700-repack.sh

+#!/bin/sh
+
+test_description='git repack works correctly'
+
+. ./test-lib.sh
+
+test_expect_failure 'objects in packs marked .keep are not repacked' '
+	echo content1 > file1 &&
+	echo content2 > file2 &&
+	git add . &&
+	git commit -m initial_commit &&
+	# Create two packs
+	# The first pack will contain all of the objects except one
+	git rev-list --objects --all | grep -v file2 |
+		git pack-objects pack > /dev/null &&
+	# The second pack will contain the excluded object
+	packsha1=$(git rev-list --objects --all | grep file2 |
+		git pack-objects pack) &&
+	touch -r pack-$packsha1.pack pack-$packsha1.keep &&
+	objsha1=$(git verify-pack -v pack-$packsha1.idx | head -n 1 |
+		sed -e "s/^\([0-9a-f]\{40\}\).*/\1/") &&
+	mv pack-* .git/objects/pack/ &&
+	git repack -A -d -l &&
+	git prune-packed &&
+	for p in .git/objects/pack/*.idx; do
+		idx=$(basename $p)
+		test "pack-$packsha1.idx" = "$idx" && continue
+		if git verify-pack -v $p | egrep "^$objsha1"; then
+			found_duplicate_object=1
+			echo "DUPLICATE OBJECT FOUND"
+			break
+		fi
+	done &&
+	test -z "$found_duplicate_object"
+'
+
+test_done
+