[RFCv2 01/12] Allow late reporting of fetched hashes

From: Daniel Barkalow <barkalow@xxxxxxxxxxxx>

Some future transports (in particular, foreign VCS importers) will
only report the hashes of new commits when the objects are also
available. In preparation, allow fetch_refs() to modify the refs it
gets (in particular, the remote side's sha1), and treat the null sha1,
when reported by get_ref_list(), as different from any value,
including itself (which, when local, indicates that the local version
doesn't exist yet).

Signed-off-by: Daniel Barkalow <barkalow@xxxxxxxxxxxx>
Signed-off-by: Johan Herland <johan@xxxxxxxxxxx>
---
 builtin-clone.c |    6 ++++--
 transport.c     |   17 +++++++++--------
 transport.h     |    4 ++--
 3 files changed, 15 insertions(+), 12 deletions(-)

diff --git a/builtin-clone.c b/builtin-clone.c
index 32dea74..f281756 100644
--- a/builtin-clone.c
+++ b/builtin-clone.c
@@ -509,8 +509,10 @@ int cmd_clone(int argc, const char **argv, const char 
*prefix)
                                             option_upload_pack);
 
                refs = transport_get_remote_refs(transport);
-               if(refs)
-                       transport_fetch_refs(transport, refs);
+               if (refs) {
+                       struct ref *ref_cpy = copy_ref_list(refs);
+                       transport_fetch_refs(transport, ref_cpy);
+               }
        }
 
        if (refs) {
diff --git a/transport.c b/transport.c
index 8a42e76..349ccae 100644
--- a/transport.c
+++ b/transport.c
@@ -207,7 +207,7 @@ static struct ref *get_refs_via_rsync(struct transport 
*transport, int for_push)
 }
 
 static int fetch_objs_via_rsync(struct transport *transport,
-                               int nr_objs, const struct ref **to_fetch)
+                               int nr_objs, struct ref **to_fetch)
 {
        struct strbuf buf = STRBUF_INIT;
        struct child_process rsync;
@@ -356,7 +356,7 @@ static int rsync_transport_push(struct transport *transport,
 
 #ifndef NO_CURL /* http fetch is the only user */
 static int fetch_objs_via_walker(struct transport *transport,
-                                int nr_objs, const struct ref **to_fetch)
+                                int nr_objs, struct ref **to_fetch)
 {
        char *dest = xstrdup(transport->url);
        struct walker *walker = transport->data;
@@ -500,7 +500,7 @@ static struct ref *get_refs_via_curl(struct transport 
*transport, int for_push)
 }
 
 static int fetch_objs_via_curl(struct transport *transport,
-                                int nr_objs, const struct ref **to_fetch)
+                                int nr_objs, struct ref **to_fetch)
 {
        if (!transport->data)
                transport->data = get_http_walker(transport->url,
@@ -540,7 +540,7 @@ static struct ref *get_refs_from_bundle(struct transport 
*transport, int for_pus
 }
 
 static int fetch_refs_from_bundle(struct transport *transport,
-                              int nr_heads, const struct ref **to_fetch)
+                              int nr_heads, struct ref **to_fetch)
 {
        struct bundle_transport_data *data = transport->data;
        return unbundle(&data->header, data->fd);
@@ -618,7 +618,7 @@ static struct ref *get_refs_via_connect(struct transport 
*transport, int for_pus
 }
 
 static int fetch_refs_via_pack(struct transport *transport,
-                              int nr_heads, const struct ref **to_fetch)
+                              int nr_heads, struct ref **to_fetch)
 {
        struct git_transport_data *data = transport->data;
        char **heads = xmalloc(nr_heads * sizeof(*heads));
@@ -1032,15 +1032,16 @@ const struct ref *transport_get_remote_refs(struct 
transport *transport)
        return transport->remote_refs;
 }
 
-int transport_fetch_refs(struct transport *transport, const struct ref *refs)
+int transport_fetch_refs(struct transport *transport, struct ref *refs)
 {
        int rc;
        int nr_heads = 0, nr_alloc = 0;
-       const struct ref **heads = NULL;
-       const struct ref *rm;
+       struct ref **heads = NULL;
+       struct ref *rm;
 
        for (rm = refs; rm; rm = rm->next) {
                if (rm->peer_ref &&
+                   !is_null_sha1(rm->old_sha1) &&
                    !hashcmp(rm->peer_ref->old_sha1, rm->old_sha1))
                        continue;
                ALLOC_GROW(heads, nr_heads + 1, nr_alloc);
diff --git a/transport.h b/transport.h
index 51b5397..3cb0abc 100644
--- a/transport.h
+++ b/transport.h
@@ -19,7 +19,7 @@ struct transport {
                          const char *value);
 
        struct ref *(*get_refs_list)(struct transport *transport, int for_push);
-       int (*fetch)(struct transport *transport, int refs_nr, const struct ref 
**refs);
+       int (*fetch)(struct transport *transport, int refs_nr, struct ref 
**refs);
        int (*push_refs)(struct transport *transport, struct ref *refs, int 
flags);
        int (*push)(struct transport *connection, int refspec_nr, const char 
**refspec, int flags);
 
@@ -72,7 +72,7 @@ int transport_push(struct transport *connection,
 
 const struct ref *transport_get_remote_refs(struct transport *transport);
 
-int transport_fetch_refs(struct transport *transport, const struct ref *refs);
+int transport_fetch_refs(struct transport *transport, struct ref *refs);
 void transport_unlock_pack(struct transport *transport);
 int transport_disconnect(struct transport *transport);
 char *transport_anonymize_url(const char *url);
-- 
1.6.4.rc3.138.ga6b98.dirty

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