[RFC PATCH v2 3/4] transport: list refs before fetch if necessary
- From
- Jonathan Tan <jonathantanmy@google.com>
- Date
- Sep 27, 2018, 19:24 UTC
- Message-ID
- <33b22cf96ee27053a6de22fdfb48f58cc8012644.1538075680.git.jonathantanmy@google.com>
- In-Reply-To
- <cover.1538075680.git.jonathantanmy@google.com>
The built-in bundle transport and the transport helper interface do not work when transport_fetch_refs() is called immediately after transport creation. This will be needed in a subsequent patch, so fix this.
Evidence: fetch_refs_from_bundle() relies on data->header being initialized in get_refs_from_bundle(), and fetch() in transport-helper.c relies on either data->fetch or data->import being set by get_helper(), but neither transport_helper_init() nor fetch() calls get_helper().
Up until the introduction of the partial clone feature, this has not been a problem, because transport_fetch_refs() is always called after transport_get_remote_refs(). With the introduction of the partial clone feature, which involves calling transport_fetch_refs() (to fetch objects by their OIDs) without transport_get_remote_refs(), this is still not a problem, but only coincidentally - we do not support partially cloning a bundle, and as for cloning using a transport-helper-using protocol, it so happens that before transport_fetch_refs() is called, fetch_refs() in fetch-object.c calls transport_set_option(), which means that the aforementioned get_helper() is invoked through set_helper_option() in transport-helper.c.
This could be fixed by fixing the transports themselves, but it doesn't seem like a good idea to me to open up previously untested code paths; also, there may be transport helpers in the wild that assume that "list" is always called before "fetch". Instead, fix this by having transport_fetch_refs() call transport_get_remote_refs() to ensure that the latter is always called at least once, unless the transport explicitly states that it supports fetching without listing refs.
Signed-off-by: Jonathan Tan <jonathantanmy@google.com> --- transport-helper.c | 1 + transport-internal.h | 6 ++++++ transport.c | 12 ++++++++++++ 3 files changed, 19 insertions(+)
diff --git a/transport-helper.c b/transport-helper.c index 143ca008c8..7213fa0d32 100644 --- a/transport-helper.c +++ b/transport-helper.c @@ -1105,6 +1105,7 @@ static struct ref *get_refs_list(struct transport *transport, int for_push, } static struct transport_vtable vtable = { + 0, set_helper_option, get_refs_list, fetch, diff --git a/transport-internal.h b/transport-internal.h index 1cde6258a7..004bee5e36 100644 --- a/transport-internal.h +++ b/transport-internal.h @@ -6,6 +6,12 @@ struct transport; struct argv_array; struct transport_vtable { + /** + * This transport supports the fetch() function being called + * without get_refs_list() first being called. + */ + unsigned fetch_without_list : 1; + /** * Returns 0 if successful, positive if the option is not * recognized or is inapplicable, and negative if the option diff --git a/transport.c b/transport.c index 4329cca8e5..ea72fff6a6 100644 --- a/transport.c +++ b/transport.c @@ -733,6 +733,7 @@ static int disconnect_git(struct transport *transport) } static struct transport_vtable taken_over_vtable = { + 1, NULL, get_refs_via_connect, fetch_refs_via_pack, @@ -882,6 +883,7 @@ void transport_check_allowed(const char *type) } static struct transport_vtable bundle_vtable = { + 0, NULL, get_refs_from_bundle, fetch_refs_from_bundle, @@ -891,6 +893,7 @@ static struct transport_vtable bundle_vtable = { }; static struct transport_vtable builtin_smart_vtable = { + 1, NULL, get_refs_via_connect, fetch_refs_via_pack, @@ -1254,6 +1257,15 @@ int transport_fetch_refs(struct transport *transport, struct ref *refs) struct ref **heads = NULL; struct ref *rm; + if (!transport->vtable->fetch_without_list) + /* + * Some transports (e.g. the built-in bundle transport and the + * transport helper interface) do not work when fetching is + * done immediately after transport creation. List the remote + * refs anyway (if not already listed) as a workaround. + */ + transport_get_remote_refs(transport, NULL); + for (rm = refs; rm; rm = rm->next) { nr_refs++; if (rm->peer_ref &&
-- 2.19.0.605.g01d371f741-goog