clone: run check_everything_connected

When we fetch from a remote, we do a revision walk to make
sure that what we received is connected to our existing
history. We do not do the same check for clone, which should
be able to check that we received an intact history graph.

The upside of this patch is that it will make clone more
resilient against propagating repository corruption. The
downside is that we will now traverse "rev-list --objects
--all" down to the roots, which may take some time (it is
especially noticeable for a "--local --bare" clone).

Note that we need to adjust t5710, which tries to make such
a bogus clone. Rather than checking after the fact that our
clone is bogus, we can simplify it to just make sure "git
clone" reports failure.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 26 insertions, 0 deletions

diff --git a/builtin/clone.c b/builtin/clone.c
index 7d48ef3b4e..eceaa74922 100644
--- a/builtin/clone.c
+++ b/builtin/clone.c
@@ -23,6 +23,7 @@
 #include "branch.h"
 #include "remote.h"
 #include "run-command.h"
+#include "connected.h"
 
 /*
  * Overall FIXMEs:
@@ -485,12 +486,37 @@ static void write_followtags(const struct ref *refs, const char *msg)
 	}
 }
 
+static int iterate_ref_map(void *cb_data, unsigned char sha1[20])
+{
+	struct ref **rm = cb_data;
+	struct ref *ref = *rm;
+
+	/*
+	 * Skip anything missing a peer_ref, which we are not
+	 * actually going to write a ref for.
+	 */
+	while (ref && !ref->peer_ref)
+		ref = ref->next;
+	/* Returning -1 notes "end of list" to the caller. */
+	if (!ref)
+		return -1;
+
+	hashcpy(sha1, ref->old_sha1);
+	*rm = ref->next;
+	return 0;
+}
+
 static void update_remote_refs(const struct ref *refs,
 			       const struct ref *mapped_refs,
 			       const struct ref *remote_head_points_at,
 			       const char *branch_top,
 			       const char *msg)
 {
+	const struct ref *rm = mapped_refs;
+
+	if (check_everything_connected(iterate_ref_map, 0, &rm))
+		die(_("remote did not send all necessary objects"));
+
 	if (refs) {
 		write_remote_refs(mapped_refs);
 		if (option_single_branch)