[PATCH 4/5] repack: turn on "ref paranoia" when doing a destructive repack

[Jeff King <peff@peff.net>]

If we are repacking with "-ad", we will drop any unreachable
objects. Likewise, using "-Ad --unpack-unreachable=<time>"
will drop any old, unreachable objects. In these cases, we
want to make sure the reachability we compute with "--all"
is complete. We can do this by passing GIT_REF_PARANOIA=1 in
the environment to pack-objects.

Note that "-Ad" is safe already, because it only loosens
unreachable objects. It is up to "git prune" to avoid
deleting them.

Signed-off-by: Jeff King <peff@peff.net>
---
 builtin/repack.c            | 8 ++++++--
 t/t5312-prune-corruption.sh | 2 +-
 2 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/builtin/repack.c b/builtin/repack.c
index 28fbc70..f2edeb0 100644
--- a/builtin/repack.c
+++ b/builtin/repack.c
@@ -228,13 +228,17 @@ int cmd_repack(int argc, const char **argv, const char *prefix)
 		get_non_kept_pack_filenames(&existing_packs);
 
 		if (existing_packs.nr && delete_redundant) {
-			if (unpack_unreachable)
+			if (unpack_unreachable) {
 				argv_array_pushf(&cmd.args,
 						"--unpack-unreachable=%s",
 						unpack_unreachable);
-			else if (pack_everything & LOOSEN_UNREACHABLE)
+				argv_array_push(&cmd.env_array, "GIT_REF_PARANOIA=1");
+			} else if (pack_everything & LOOSEN_UNREACHABLE) {
 				argv_array_push(&cmd.args,
 						"--unpack-unreachable");
+			} else {
+				argv_array_push(&cmd.env_array, "GIT_REF_PARANOIA=1");
+			}
 		}
 	} else {
 		argv_array_push(&cmd.args, "--unpacked");
diff --git a/t/t5312-prune-corruption.sh b/t/t5312-prune-corruption.sh
index cccab58..e3e9994 100755
--- a/t/t5312-prune-corruption.sh
+++ b/t/t5312-prune-corruption.sh
@@ -38,7 +38,7 @@ test_expect_success 'put bogus object into pack' '
 	verbose git cat-file -e $bogus
 '
 
-test_expect_failure 'destructive repack keeps packed object' '
+test_expect_success 'destructive repack keeps packed object' '
 	test_might_fail git repack -Ad --unpack-unreachable=now &&
 	verbose git cat-file -e $bogus &&
 	test_might_fail git repack -ad &&
-- 
2.3.3.520.g3cfbb5d