[PATCH 4/4] push: receiver end advertises refs from alternate repositories
- From
Junio C Hamano <gitster@pobox.com>
- Date
- Sep 9, 2008, 08:27 UTC
- Message-ID
- <1220948830-3275-5-git-send-email-gitster@pobox.com>
- In-Reply-To
- <1220948830-3275-4-git-send-email-gitster@pobox.com>
Earlier, when pushing into a repository that borrows from alternate object stores, we followed the longstanding design decision not to trust refs in the alternate repository that houses the object store we are borrowing from. If your public repository is borrowing from Linus's public repository, you pushed into it long time ago, and now when you try to push your updated history that is in sync with more recent history from Linus, you will end up sending not just your own development, but also the changes you acquired through Linus's tree, even though the objects needed for the latter already exists at the receiving end. This is because the receiving end does not advertise that the objects only reachable from the borrowed repository (i.e. Linus's) are already available there.
This solves the issue by making the receiving end advertise refs from borrowed repositories. They are not sent with their true names but with a phoney name ".have" to make sure that the old senders will safely ignore them (otherwise, the old senders will misbehave, trying to push matching refs, and mirror push that deletes refs that only exist at the receiving end).
Signed-off-by: Junio C Hamano <gitster@pobox.com> --- builtin-receive-pack.c | 38 ++++++++++++++++++++++++++++++++++++++ cache.h | 2 ++ sha1_file.c | 10 ++++++++++ 3 files changed, 50 insertions(+), 0 deletions(-)
diff --git a/builtin-receive-pack.c b/builtin-receive-pack.c index 6d6027e..45e3cd9 100644 --- a/builtin-receive-pack.c +++ b/builtin-receive-pack.c @@ -6,6 +6,8 @@ #include "exec_cmd.h" #include "commit.h" #include "object.h" +#include "remote.h" +#include "transport.h" static const char receive_pack_usage[] = "git-receive-pack <git-dir>"; @@ -462,6 +464,40 @@ static int delete_only(struct command *cmd) return 1; } +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); + struct remote *remote; + struct transport *transport; + const struct ref *extra; + + 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; +} + +static void add_alternate_refs(void) +{ + foreach_alt_odb(add_refs_from_alternate, NULL); +} + int cmd_receive_pack(int argc, const char **argv, const char *prefix) { int i; @@ -497,7 +533,9 @@ int cmd_receive_pack(int argc, const char **argv, const char *prefix) else if (0 <= receive_unpack_limit) unpack_limit = receive_unpack_limit; + add_alternate_refs(); write_head_info(); + clear_extra_refs(); /* EOF */ packet_flush(1); diff --git a/cache.h b/cache.h index 98a7421..99af83a 100644 --- a/cache.h +++ b/cache.h @@ -641,6 +641,8 @@ extern struct alternate_object_database { } *alt_odb_list; extern void prepare_alt_odb(void); extern void add_to_alternates_file(const char *reference); +typedef int alt_odb_fn(struct alternate_object_database *, void *); +extern void foreach_alt_odb(alt_odb_fn, void*); struct pack_window { struct pack_window *next; diff --git a/sha1_file.c b/sha1_file.c index ae550e8..12be17b 100644 --- a/sha1_file.c +++ b/sha1_file.c @@ -393,6 +393,16 @@ void add_to_alternates_file(const char *reference) link_alt_odb_entries(alt, alt + strlen(alt), '\n', NULL, 0); } +void foreach_alt_odb(alt_odb_fn fn, void *cb) +{ + struct alternate_object_database *ent; + + prepare_alt_odb(); + for (ent = alt_odb_list; ent; ent = ent->next) + if (fn(ent, cb)) + return; +} + void prepare_alt_odb(void) { const char *alt;
-- 1.6.0.1.415.g7bb82