diff --git a/commit.h b/commit.h
index d912a9d4ac3fe36b2e69d48b1725f01bdf289b26..790e31bec85d9e2e8bdd8533b7d69af4c0f18ca4 100644
--- a/commit.h
+++ b/commit.h
@@ -198,6 +198,9 @@ extern struct commit_list *get_shallow_commits(struct object_array *heads,
 		int depth, int shallow_flag, int not_shallow_flag);
 extern void check_shallow_file_for_update(void);
 extern void set_alternate_shallow_file(const char *path);
+extern int write_shallow_commits(struct strbuf *out, int use_pack_protocol);
+extern void setup_alternate_shallow(struct lock_file *shallow_lock,
+				    const char **alternate_shallow_file);
 
 int is_descendant_of(struct commit *, struct commit_list *);
 int in_merge_bases(struct commit *, struct commit *);
diff --git a/fetch-pack.c b/fetch-pack.c
index 6684348c0ec9ea742eb98666b56a0bfcef316560..28195ed78b281204850de9c5bfeee03fa29efd79 100644
--- a/fetch-pack.c
+++ b/fetch-pack.c
@@ -184,36 +184,6 @@ static void consume_shallow_list(struct fetch_pack_args *args, int fd)
 	}
 }
 
-struct write_shallow_data {
-	struct strbuf *out;
-	int use_pack_protocol;
-	int count;
-};
-
-static int write_one_shallow(const struct commit_graft *graft, void *cb_data)
-{
-	struct write_shallow_data *data = cb_data;
-	const char *hex = sha1_to_hex(graft->sha1);
-	data->count++;
-	if (data->use_pack_protocol)
-		packet_buf_write(data->out, "shallow %s", hex);
-	else {
-		strbuf_addstr(data->out, hex);
-		strbuf_addch(data->out, '\n');
-	}
-	return 0;
-}
-
-static int write_shallow_commits(struct strbuf *out, int use_pack_protocol)
-{
-	struct write_shallow_data data;
-	data.out = out;
-	data.use_pack_protocol = use_pack_protocol;
-	data.count = 0;
-	for_each_commit_graft(write_one_shallow, &data);
-	return data.count;
-}
-
 static enum ack_type get_ack(int fd, unsigned char *result_sha1)
 {
 	int len;
@@ -795,27 +765,6 @@ static int cmp_ref_by_name(const void *a_, const void *b_)
 	return strcmp(a->name, b->name);
 }
 
-static void setup_alternate_shallow(void)
-{
-	struct strbuf sb = STRBUF_INIT;
-	int fd;
-
-	check_shallow_file_for_update();
-	fd = hold_lock_file_for_update(&shallow_lock, git_path("shallow"),
-				       LOCK_DIE_ON_ERROR);
-	if (write_shallow_commits(&sb, 0)) {
-		if (write_in_full(fd, sb.buf, sb.len) != sb.len)
-			die_errno("failed to write to %s", shallow_lock.filename);
-		alternate_shallow_file = shallow_lock.filename;
-	} else
-		/*
-		 * is_repository_shallow() sees empty string as "no
-		 * shallow file".
-		 */
-		alternate_shallow_file = "";
-	strbuf_release(&sb);
-}
-
 static struct ref *do_fetch_pack(struct fetch_pack_args *args,
 				 int fd[2],
 				 const struct ref *orig_ref,
@@ -896,7 +845,7 @@ static struct ref *do_fetch_pack(struct fetch_pack_args *args,
 	if (args->stateless_rpc)
 		packet_flush(fd[1]);
 	if (args->depth > 0)
-		setup_alternate_shallow();
+		setup_alternate_shallow(&shallow_lock, &alternate_shallow_file);
 	if (get_pack(args, fd, pack_lockfile))
 		die("git fetch-pack: fetch failed.");
 
diff --git a/shallow.c b/shallow.c
index 8a9c96d019a1b3df4942f370fe0d312467a36799..68dd10687b81d238ae9a5a99a61acf4e1396b668 100644
--- a/shallow.c
+++ b/shallow.c
@@ -1,6 +1,7 @@
 #include "cache.h"
 #include "commit.h"
 #include "tag.h"
+#include "pkt-line.h"
 
 static int is_shallow = -1;
 static struct stat shallow_stat;
@@ -141,3 +142,56 @@ void check_shallow_file_for_update(void)
 		   )
 		die("shallow file was changed during fetch");
 }
+
+struct write_shallow_data {
+	struct strbuf *out;
+	int use_pack_protocol;
+	int count;
+};
+
+static int write_one_shallow(const struct commit_graft *graft, void *cb_data)
+{
+	struct write_shallow_data *data = cb_data;
+	const char *hex = sha1_to_hex(graft->sha1);
+	data->count++;
+	if (data->use_pack_protocol)
+		packet_buf_write(data->out, "shallow %s", hex);
+	else {
+		strbuf_addstr(data->out, hex);
+		strbuf_addch(data->out, '\n');
+	}
+	return 0;
+}
+
+int write_shallow_commits(struct strbuf *out, int use_pack_protocol)
+{
+	struct write_shallow_data data;
+	data.out = out;
+	data.use_pack_protocol = use_pack_protocol;
+	data.count = 0;
+	for_each_commit_graft(write_one_shallow, &data);
+	return data.count;
+}
+
+void setup_alternate_shallow(struct lock_file *shallow_lock,
+			     const char **alternate_shallow_file)
+{
+	struct strbuf sb = STRBUF_INIT;
+	int fd;
+
+	check_shallow_file_for_update();
+	fd = hold_lock_file_for_update(shallow_lock, git_path("shallow"),
+				       LOCK_DIE_ON_ERROR);
+	if (write_shallow_commits(&sb, 0)) {
+		if (write_in_full(fd, sb.buf, sb.len) != sb.len)
+			die_errno("failed to write to %s",
+				  shallow_lock->filename);
+		*alternate_shallow_file = shallow_lock->filename;
+	} else
+		/*
+		 * is_repository_shallow() sees empty string as "no
+		 * shallow file".
+		 */
+		*alternate_shallow_file = "";
+	strbuf_release(&sb);
+}