receive-pack: fix "borrowing from alternate object store" implementation

In the alternate_object_database structure, ent->base[] is a buffer the
users can use to form pathnames to loose objects, and ent->name is a
pointer into that buffer (it points at one beyond ".git/objects/").  If
you get a call to add_refs_from_alternate() after somebody used the entry
(has_loose_object() has been called, for example), *ent->name would not be
NUL, and ent->base[] won't be the path to the object store.

This caller is expecting to read the path to the object store in ent->base[];
it needs to NUL terminate the buffer if it wants to.

Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/builtin-receive-pack.c b/builtin-receive-pack.c
index 45e3cd90fd476cdb0a32e5de27739b18e060e031..9f60f31c2bb7da7095de8d692d215c485ab5da0c 100644 (file)
--- a/builtin-receive-pack.c
+++ b/builtin-receive-pack.c
@@ -466,12 +466,17 @@ static int delete_only(struct command *cmd)
 
 static int add_refs_from_alternate(struct alternate_object_database *e, void *unused)
 {
-       char *other = xstrdup(make_absolute_path(e->base));
-       size_t len = strlen(other);
+       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))