4 files changed, 106 insertions, 32 deletions

diff --git a/builtin/receive-pack.c b/builtin/receive-pack.c
index 760817dbd7..a5b5fc2ef6 100644
--- a/builtin/receive-pack.c
+++ b/builtin/receive-pack.c
@@ -731,43 +731,14 @@ static int delete_only(struct command *commands)
 	return 1;
 }
 
-static int add_refs_from_alternate(struct alternate_object_database *e, void *unused)
+static void add_one_alternate_ref(const struct ref *ref, void *unused)
 {
-	char *other;
-	size_t len;
-	struct remote *remote;
-	struct transport *transport;
-	const struct ref *extra;
-
-	e->name[-1] = '\0';
-	other = xstrdup(make_absolute_path(e->base));
-	e->name[-1] = '/';
-	len = strlen(other);
-
-	while (other[len-1] == '/')
-		other[--len] = '\0';
-	if (len < 8 || memcmp(other + len - 8, "/objects", 8))
-		return 0;
-	/* Is this a git repository with refs? */
-	memcpy(other + len - 8, "/refs", 6);
-	if (!is_directory(other))
-		return 0;
-	other[len - 8] = '\0';
-	remote = remote_get(other);
-	transport = transport_get(remote, other);
-	for (extra = transport_get_remote_refs(transport);
-	     extra;
-	     extra = extra->next) {
-		add_extra_ref(".have", extra->old_sha1, 0);
-	}
-	transport_disconnect(transport);
-	free(other);
-	return 0;
+	add_extra_ref(".have", ref->old_sha1, 0);
 }
 
 static void add_alternate_refs(void)
 {
-	foreach_alt_odb(add_refs_from_alternate, NULL);
+	foreach_alt_odb(refs_from_alternate_cb, add_one_alternate_ref);
 }
 
 int cmd_receive_pack(int argc, const char **argv, const char *prefix)
diff --git a/t/t5501-fetch-push-alternates.sh b/t/t5501-fetch-push-alternates.sh
new file mode 100755
index 0000000000..16a467654c
--- /dev/null
+++ b/t/t5501-fetch-push-alternates.sh
@@ -0,0 +1,66 @@
+#!/bin/sh
+
+test_description='fetch/push involving alternates'
+. ./test-lib.sh
+
+count_objects () {
+	loose=0 inpack=0
+	eval "$(
+		git count-objects -v |
+		sed -n -e 's/^count: \(.*\)/loose=\1/p' \
+		    -e 's/^in-pack: \(.*\)/inpack=\1/p'
+	)" &&
+	echo $(( $loose + $inpack ))
+}
+
+
+test_expect_success setup '
+	(
+		git init original &&
+		cd original &&
+		i=0 &&
+		while test $i -le 100
+		do
+			echo "$i" >count &&
+			git add count &&
+			git commit -m "$i" || exit
+			i=$(($i + 1))
+		done
+	) &&
+	(
+		git clone --reference=original "file:///$(pwd)/original" one &&
+		cd one &&
+		echo Z >count &&
+		git add count &&
+		git commit -m Z &&
+		count_objects >../one.count
+	) &&
+	A=$(pwd)/original/.git/objects &&
+	git init receiver &&
+	echo "$A" >receiver/.git/objects/info/alternates &&
+	git init fetcher &&
+	echo "$A" >fetcher/.git/objects/info/alternates
+'
+
+test_expect_success 'pushing into a repository with the same alternate' '
+	(
+		cd one &&
+		git push ../receiver master:refs/heads/it
+	) &&
+	(
+		cd receiver &&
+		count_objects >../receiver.count
+	) &&
+	test_cmp one.count receiver.count
+'
+
+test_expect_failure 'fetching from a repository with the same alternate' '
+	(
+		cd fetcher &&
+		git fetch ../one master:refs/heads/it &&
+		count_objects >../fetcher.count
+	) &&
+	test_cmp one.count fetcher.count
+'
+
+test_done
diff --git a/transport.c b/transport.c
index 0078660611..3dfbc6a79c 100644
--- a/transport.c
+++ b/transport.c
@@ -1189,3 +1189,37 @@ char *transport_anonymize_url(const char *url)
 literal_copy:
 	return xstrdup(url);
 }
+
+int refs_from_alternate_cb(struct alternate_object_database *e, void *cb)
+{
+	char *other;
+	size_t len;
+	struct remote *remote;
+	struct transport *transport;
+	const struct ref *extra;
+	alternate_ref_fn *ref_fn = cb;
+
+	e->name[-1] = '\0';
+	other = xstrdup(make_absolute_path(e->base));
+	e->name[-1] = '/';
+	len = strlen(other);
+
+	while (other[len-1] == '/')
+		other[--len] = '\0';
+	if (len < 8 || memcmp(other + len - 8, "/objects", 8))
+		return 0;
+	/* Is this a git repository with refs? */
+	memcpy(other + len - 8, "/refs", 6);
+	if (!is_directory(other))
+		return 0;
+	other[len - 8] = '\0';
+	remote = remote_get(other);
+	transport = transport_get(remote, other);
+	for (extra = transport_get_remote_refs(transport);
+	     extra;
+	     extra = extra->next)
+		ref_fn(extra, NULL);
+	transport_disconnect(transport);
+	free(other);
+	return 0;
+}
diff --git a/transport.h b/transport.h
index e803c0e7ba..efb1968869 100644
--- a/transport.h
+++ b/transport.h
@@ -166,4 +166,7 @@ int transport_refs_pushed(struct ref *ref);
 void transport_print_push_status(const char *dest, struct ref *refs,
 		  int verbose, int porcelain, int *nonfastforward);
 
+typedef void alternate_ref_fn(const struct ref *, void *);
+extern int refs_from_alternate_cb(struct alternate_object_database *e, void *cb);
+
 #endif