Merge branch 'jt/fetch-pack-error-reporting'

"git fetch-pack" was not prepared to accept ERR packet that the
upload-pack can send with a human-readable error message.  It
showed the packet contents with ERR prefix, so there was no data
loss, but it was redundant to say "ERR" in an error message.

* jt/fetch-pack-error-reporting:
fetch-pack: show clearer error message upon ERR

diff --combined fetch-pack.c
index 42969353d675af777ea1e34e4740ad1842802f0f,986b1efebca1853ff98ce71153dfd546d8778a23..c5e686706100fc5f6b3a3ede30b0c6ce6a8645d6
--- 1/fetch-pack.c
--- 2/fetch-pack.c
+++ b/fetch-pack.c
@@@ -35,7 -35,6 +35,7 @@@ static const char *alternate_shallow_fi
  #define COMMON_REF    (1U << 2)
  #define SEEN          (1U << 3)
  #define POPPED                (1U << 4)
 +#define ALTERNATE     (1U << 5)
  
  static int marked;
  
@@@ -68,41 -67,6 +68,41 @@@ static inline void print_verbose(const 
        fputc('\n', stderr);
  }
  
 +struct alternate_object_cache {
 +      struct object **items;
 +      size_t nr, alloc;
 +};
 +
 +static void cache_one_alternate(const char *refname,
 +                              const struct object_id *oid,
 +                              void *vcache)
 +{
 +      struct alternate_object_cache *cache = vcache;
 +      struct object *obj = parse_object(oid->hash);
 +
 +      if (!obj || (obj->flags & ALTERNATE))
 +              return;
 +
 +      obj->flags |= ALTERNATE;
 +      ALLOC_GROW(cache->items, cache->nr + 1, cache->alloc);
 +      cache->items[cache->nr++] = obj;
 +}
 +
 +static void for_each_cached_alternate(void (*cb)(struct object *))
 +{
 +      static int initialized;
 +      static struct alternate_object_cache cache;
 +      size_t i;
 +
 +      if (!initialized) {
 +              for_each_alternate_ref(cache_one_alternate, &cache);
 +              initialized = 1;
 +      }
 +
 +      for (i = 0; i < cache.nr; i++)
 +              cb(cache.items[i]);
 +}
 +
  static void rev_list_push(struct commit *commit, int mark)
  {
        if (!(commit->object.flags & mark)) {
@@@ -276,6 -240,8 +276,8 @@@ static enum ack_type get_ack(int fd, un
                        return ACK;
                }
        }
+       if (skip_prefix(line, "ERR ", &arg))
+               die(_("remote error: %s"), arg);
        die(_("git fetch-pack: expected ACK/NAK, got '%s'"), line);
  }
  
@@@ -289,9 -255,9 +291,9 @@@ static void send_request(struct fetch_p
                write_or_die(fd, buf->buf, buf->len);
  }
  
 -static void insert_one_alternate_ref(const struct ref *ref, void *unused)
 +static void insert_one_alternate_object(struct object *obj)
  {
 -      rev_list_insert_ref(NULL, ref->old_oid.hash);
 +      rev_list_insert_ref(NULL, obj->oid.hash);
  }
  
  #define INITIAL_FLUSH 16
@@@ -334,7 -300,7 +336,7 @@@ static int find_common(struct fetch_pac
        marked = 1;
  
        for_each_ref(rev_list_insert_ref_oid, NULL);
 -      for_each_alternate_ref(insert_one_alternate_ref, NULL);
 +      for_each_cached_alternate(insert_one_alternate_object);
  
        fetching = 0;
        for ( ; refs ; refs = refs->next) {
@@@ -657,9 -623,9 +659,9 @@@ static void filter_refs(struct fetch_pa
        *refs = newlist;
  }
  
 -static void mark_alternate_complete(const struct ref *ref, void *unused)
 +static void mark_alternate_complete(struct object *obj)
  {
 -      mark_complete(ref->old_oid.hash);
 +      mark_complete(obj->oid.hash);
  }
  
  static int everything_local(struct fetch_pack_args *args,
@@@ -695,7 -661,7 +697,7 @@@
  
        if (!args->deepen) {
                for_each_ref(mark_complete_oid, NULL);
 -              for_each_alternate_ref(mark_alternate_complete, NULL);
 +              for_each_cached_alternate(mark_alternate_complete);
                commit_list_sort_by_date(&complete);
                if (cutoff)
                        mark_recent_complete_commits(args, cutoff);
@@@ -1015,7 -981,7 +1017,7 @@@ static void update_shallow(struct fetch
                           struct ref **sought, int nr_sought,
                           struct shallow_info *si)
  {
 -      struct sha1_array ref = SHA1_ARRAY_INIT;
 +      struct oid_array ref = OID_ARRAY_INIT;
        int *status;
        int i;
  
@@@ -1038,18 -1004,18 +1040,18 @@@
                 * shallow points that exist in the pack (iow in repo
                 * after get_pack() and reprepare_packed_git())
                 */
 -              struct sha1_array extra = SHA1_ARRAY_INIT;
 -              unsigned char (*sha1)[20] = si->shallow->sha1;
 +              struct oid_array extra = OID_ARRAY_INIT;
 +              struct object_id *oid = si->shallow->oid;
                for (i = 0; i < si->shallow->nr; i++)
 -                      if (has_sha1_file(sha1[i]))
 -                              sha1_array_append(&extra, sha1[i]);
 +                      if (has_object_file(&oid[i]))
 +                              oid_array_append(&extra, &oid[i]);
                if (extra.nr) {
                        setup_alternate_shallow(&shallow_lock,
                                                &alternate_shallow_file,
                                                &extra);
                        commit_lock_file(&shallow_lock);
                }
 -              sha1_array_clear(&extra);
 +              oid_array_clear(&extra);
                return;
        }
  
@@@ -1060,7 -1026,7 +1062,7 @@@
        if (!si->nr_ours && !si->nr_theirs)
                return;
        for (i = 0; i < nr_sought; i++)
 -              sha1_array_append(&ref, sought[i]->old_oid.hash);
 +              oid_array_append(&ref, &sought[i]->old_oid);
        si->ref = &ref;
  
        if (args->update_shallow) {
@@@ -1070,23 -1036,23 +1072,23 @@@
                 * shallow roots that are actually reachable from new
                 * refs.
                 */
 -              struct sha1_array extra = SHA1_ARRAY_INIT;
 -              unsigned char (*sha1)[20] = si->shallow->sha1;
 +              struct oid_array extra = OID_ARRAY_INIT;
 +              struct object_id *oid = si->shallow->oid;
                assign_shallow_commits_to_refs(si, NULL, NULL);
                if (!si->nr_ours && !si->nr_theirs) {
 -                      sha1_array_clear(&ref);
 +                      oid_array_clear(&ref);
                        return;
                }
                for (i = 0; i < si->nr_ours; i++)
 -                      sha1_array_append(&extra, sha1[si->ours[i]]);
 +                      oid_array_append(&extra, &oid[si->ours[i]]);
                for (i = 0; i < si->nr_theirs; i++)
 -                      sha1_array_append(&extra, sha1[si->theirs[i]]);
 +                      oid_array_append(&extra, &oid[si->theirs[i]]);
                setup_alternate_shallow(&shallow_lock,
                                        &alternate_shallow_file,
                                        &extra);
                commit_lock_file(&shallow_lock);
 -              sha1_array_clear(&extra);
 -              sha1_array_clear(&ref);
 +              oid_array_clear(&extra);
 +              oid_array_clear(&ref);
                return;
        }
  
@@@ -1102,7 -1068,7 +1104,7 @@@
                                sought[i]->status = REF_STATUS_REJECT_SHALLOW;
        }
        free(status);
 -      sha1_array_clear(&ref);
 +      oid_array_clear(&ref);
  }
  
  struct ref *fetch_pack(struct fetch_pack_args *args,
@@@ -1110,7 -1076,7 +1112,7 @@@
                       const struct ref *ref,
                       const char *dest,
                       struct ref **sought, int nr_sought,
 -                     struct sha1_array *shallow,
 +                     struct oid_array *shallow,
                       char **pack_lockfile)
  {
        struct ref *ref_cpy;