packaging: Add contrib installation
[platform/upstream/git.git] / fetch-pack.c
index b8a58fa..876f90c 100644 (file)
@@ -1,9 +1,12 @@
 #include "cache.h"
+#include "repository.h"
+#include "config.h"
+#include "lockfile.h"
 #include "refs.h"
 #include "pkt-line.h"
 #include "commit.h"
 #include "tag.h"
-#include "exec_cmd.h"
+#include "exec-cmd.h"
 #include "pack.h"
 #include "sideband.h"
 #include "fetch-pack.h"
 #include "connect.h"
 #include "transport.h"
 #include "version.h"
-#include "prio-queue.h"
-#include "sha1-array.h"
+#include "oid-array.h"
+#include "oidset.h"
+#include "packfile.h"
+#include "object-store.h"
+#include "connected.h"
+#include "fetch-negotiator.h"
+#include "fsck.h"
+#include "shallow.h"
 
 static int transfer_unpack_limit = -1;
 static int fetch_unpack_limit = -1;
 static int unpack_limit = 100;
 static int prefer_ofs_delta = 1;
 static int no_done;
+static int deepen_since_ok;
+static int deepen_not_ok;
 static int fetch_fsck_objects = -1;
 static int transfer_fsck_objects = -1;
 static int agent_supported;
-static struct lock_file shallow_lock;
+static int server_supports_filtering;
+static int advertise_sid;
+static struct shallow_lock shallow_lock;
 static const char *alternate_shallow_file;
+static struct strbuf fsck_msg_types = STRBUF_INIT;
+static struct string_list uri_protocols = STRING_LIST_INIT_DUP;
 
 /* Remember to update object flag allocation in object.h */
 #define COMPLETE       (1U << 0)
-#define COMMON         (1U << 1)
-#define COMMON_REF     (1U << 2)
-#define SEEN           (1U << 3)
-#define POPPED         (1U << 4)
-
-static int marked;
+#define ALTERNATE      (1U << 1)
 
 /*
  * After sending this many "have"s if we do not get any new ACK , we
@@ -41,122 +51,106 @@ static int marked;
  */
 #define MAX_IN_VAIN 256
 
-static struct prio_queue rev_list = { compare_commits_by_commit_date };
-static int non_common_revs, multi_ack, use_sideband, allow_tip_sha1_in_want;
+static int multi_ack, use_sideband;
+/* Allow specifying sha1 if it is a ref tip. */
+#define ALLOW_TIP_SHA1 01
+/* Allow request of a sha1 if it is reachable from a ref (possibly hidden ref). */
+#define ALLOW_REACHABLE_SHA1   02
+static unsigned int allow_unadvertised_object_request;
 
-static void rev_list_push(struct commit *commit, int mark)
+__attribute__((format (printf, 2, 3)))
+static inline void print_verbose(const struct fetch_pack_args *args,
+                                const char *fmt, ...)
 {
-       if (!(commit->object.flags & mark)) {
-               commit->object.flags |= mark;
-
-               if (parse_commit(commit))
-                       return;
+       va_list params;
 
-               prio_queue_put(&rev_list, commit);
+       if (!args->verbose)
+               return;
 
-               if (!(commit->object.flags & COMMON))
-                       non_common_revs++;
-       }
+       va_start(params, fmt);
+       vfprintf(stderr, fmt, params);
+       va_end(params);
+       fputc('\n', stderr);
 }
 
-static int rev_list_insert_ref(const char *refname, const unsigned char *sha1, int flag, void *cb_data)
+struct alternate_object_cache {
+       struct object **items;
+       size_t nr, alloc;
+};
+
+static void cache_one_alternate(const struct object_id *oid,
+                               void *vcache)
 {
-       struct object *o = deref_tag(parse_object(sha1), refname, 0);
+       struct alternate_object_cache *cache = vcache;
+       struct object *obj = parse_object(the_repository, oid);
 
-       if (o && o->type == OBJ_COMMIT)
-               rev_list_push((struct commit *)o, SEEN);
+       if (!obj || (obj->flags & ALTERNATE))
+               return;
 
-       return 0;
+       obj->flags |= ALTERNATE;
+       ALLOC_GROW(cache->items, cache->nr + 1, cache->alloc);
+       cache->items[cache->nr++] = obj;
 }
 
-static int clear_marks(const char *refname, const unsigned char *sha1, int flag, void *cb_data)
+static void for_each_cached_alternate(struct fetch_negotiator *negotiator,
+                                     void (*cb)(struct fetch_negotiator *,
+                                                struct object *))
 {
-       struct object *o = deref_tag(parse_object(sha1), refname, 0);
+       static int initialized;
+       static struct alternate_object_cache cache;
+       size_t i;
 
-       if (o && o->type == OBJ_COMMIT)
-               clear_commit_marks((struct commit *)o,
-                                  COMMON | COMMON_REF | SEEN | POPPED);
-       return 0;
-}
+       if (!initialized) {
+               for_each_alternate_ref(cache_one_alternate, &cache);
+               initialized = 1;
+       }
 
-/*
-   This function marks a rev and its ancestors as common.
-   In some cases, it is desirable to mark only the ancestors (for example
-   when only the server does not yet know that they are common).
-*/
+       for (i = 0; i < cache.nr; i++)
+               cb(negotiator, cache.items[i]);
+}
 
-static void mark_common(struct commit *commit,
-               int ancestors_only, int dont_parse)
+static struct commit *deref_without_lazy_fetch(const struct object_id *oid,
+                                              int mark_tags_complete)
 {
-       if (commit != NULL && !(commit->object.flags & COMMON)) {
-               struct object *o = (struct object *)commit;
-
-               if (!ancestors_only)
-                       o->flags |= COMMON;
-
-               if (!(o->flags & SEEN))
-                       rev_list_push(commit, SEEN);
-               else {
-                       struct commit_list *parents;
-
-                       if (!ancestors_only && !(o->flags & POPPED))
-                               non_common_revs--;
-                       if (!o->parsed && !dont_parse)
-                               if (parse_commit(commit))
-                                       return;
-
-                       for (parents = commit->parents;
-                                       parents;
-                                       parents = parents->next)
-                               mark_common(parents->item, 0, dont_parse);
+       enum object_type type;
+       struct object_info info = { .typep = &type };
+
+       while (1) {
+               if (oid_object_info_extended(the_repository, oid, &info,
+                                            OBJECT_INFO_SKIP_FETCH_OBJECT | OBJECT_INFO_QUICK))
+                       return NULL;
+               if (type == OBJ_TAG) {
+                       struct tag *tag = (struct tag *)
+                               parse_object(the_repository, oid);
+
+                       if (!tag->tagged)
+                               return NULL;
+                       if (mark_tags_complete)
+                               tag->object.flags |= COMPLETE;
+                       oid = &tag->tagged->oid;
+               } else {
+                       break;
                }
        }
+       if (type == OBJ_COMMIT)
+               return (struct commit *) parse_object(the_repository, oid);
+       return NULL;
 }
 
-/*
-  Get the next rev to send, ignoring the common.
-*/
-
-static const unsigned char *get_rev(void)
+static int rev_list_insert_ref(struct fetch_negotiator *negotiator,
+                              const struct object_id *oid)
 {
-       struct commit *commit = NULL;
-
-       while (commit == NULL) {
-               unsigned int mark;
-               struct commit_list *parents;
-
-               if (rev_list.nr == 0 || non_common_revs == 0)
-                       return NULL;
+       struct commit *c = deref_without_lazy_fetch(oid, 0);
 
-               commit = prio_queue_get(&rev_list);
-               parse_commit(commit);
-               parents = commit->parents;
-
-               commit->object.flags |= POPPED;
-               if (!(commit->object.flags & COMMON))
-                       non_common_revs--;
-
-               if (commit->object.flags & COMMON) {
-                       /* do not send "have", and ignore ancestors */
-                       commit = NULL;
-                       mark = COMMON | SEEN;
-               } else if (commit->object.flags & COMMON_REF)
-                       /* send "have", and ignore ancestors */
-                       mark = COMMON | SEEN;
-               else
-                       /* send "have", also for its ancestors */
-                       mark = SEEN;
-
-               while (parents) {
-                       if (!(parents->item->object.flags & SEEN))
-                               rev_list_push(parents->item, mark);
-                       if (mark & COMMON)
-                               mark_common(parents->item, 1, 0);
-                       parents = parents->next;
-               }
-       }
+       if (c)
+               negotiator->add_tip(negotiator, c);
+       return 0;
+}
 
-       return commit->object.sha1;
+static int rev_list_insert_ref_oid(const char *refname, const struct object_id *oid,
+                                  int flag, void *cb_data)
+{
+       return rev_list_insert_ref(cb_data, oid);
 }
 
 enum ack_type {
@@ -167,50 +161,54 @@ enum ack_type {
        ACK_ready
 };
 
-static void consume_shallow_list(struct fetch_pack_args *args, int fd)
+static void consume_shallow_list(struct fetch_pack_args *args,
+                                struct packet_reader *reader)
 {
-       if (args->stateless_rpc && args->depth > 0) {
+       if (args->stateless_rpc && args->deepen) {
                /* If we sent a depth we will get back "duplicate"
                 * shallow and unshallow commands every time there
                 * is a block of have lines exchanged.
                 */
-               char *line;
-               while ((line = packet_read_line(fd, NULL))) {
-                       if (starts_with(line, "shallow "))
+               while (packet_reader_read(reader) == PACKET_READ_NORMAL) {
+                       if (starts_with(reader->line, "shallow "))
                                continue;
-                       if (starts_with(line, "unshallow "))
+                       if (starts_with(reader->line, "unshallow "))
                                continue;
-                       die("git fetch-pack: expected shallow list");
+                       die(_("git fetch-pack: expected shallow list"));
                }
+               if (reader->status != PACKET_READ_FLUSH)
+                       die(_("git fetch-pack: expected a flush packet after shallow list"));
        }
 }
 
-static enum ack_type get_ack(int fd, unsigned char *result_sha1)
+static enum ack_type get_ack(struct packet_reader *reader,
+                            struct object_id *result_oid)
 {
        int len;
-       char *line = packet_read_line(fd, &len);
        const char *arg;
 
-       if (!len)
-               die("git fetch-pack: expected ACK/NAK, got EOF");
-       if (!strcmp(line, "NAK"))
+       if (packet_reader_read(reader) != PACKET_READ_NORMAL)
+               die(_("git fetch-pack: expected ACK/NAK, got a flush packet"));
+       len = reader->pktlen;
+
+       if (!strcmp(reader->line, "NAK"))
                return NAK;
-       if (skip_prefix(line, "ACK ", &arg)) {
-               if (!get_sha1_hex(arg, result_sha1)) {
-                       arg += 40;
-                       len -= arg - line;
+       if (skip_prefix(reader->line, "ACK ", &arg)) {
+               const char *p;
+               if (!parse_oid_hex(arg, result_oid, &p)) {
+                       len -= p - reader->line;
                        if (len < 1)
                                return ACK;
-                       if (strstr(arg, "continue"))
+                       if (strstr(p, "continue"))
                                return ACK_continue;
-                       if (strstr(arg, "common"))
+                       if (strstr(p, "common"))
                                return ACK_common;
-                       if (strstr(arg, "ready"))
+                       if (strstr(p, "ready"))
                                return ACK_ready;
                        return ACK;
                }
        }
-       die("git fetch_pack: expected ACK/NAK, got '%s'", line);
+       die(_("git fetch-pack: expected ACK/NAK, got '%s'"), reader->line);
 }
 
 static void send_request(struct fetch_pack_args *args,
@@ -219,55 +217,81 @@ static void send_request(struct fetch_pack_args *args,
        if (args->stateless_rpc) {
                send_sideband(fd, -1, buf->buf, buf->len, LARGE_PACKET_MAX);
                packet_flush(fd);
-       } else
-               write_or_die(fd, buf->buf, buf->len);
+       } else {
+               if (write_in_full(fd, buf->buf, buf->len) < 0)
+                       die_errno(_("unable to write to remote"));
+       }
 }
 
-static void insert_one_alternate_ref(const struct ref *ref, void *unused)
+static void insert_one_alternate_object(struct fetch_negotiator *negotiator,
+                                       struct object *obj)
 {
-       rev_list_insert_ref(NULL, ref->old_sha1, 0, NULL);
+       rev_list_insert_ref(negotiator, &obj->oid);
 }
 
 #define INITIAL_FLUSH 16
 #define PIPESAFE_FLUSH 32
-#define LARGE_FLUSH 1024
+#define LARGE_FLUSH 16384
 
-static int next_flush(struct fetch_pack_args *args, int count)
+static int next_flush(int stateless_rpc, int count)
 {
-       int flush_limit = args->stateless_rpc ? LARGE_FLUSH : PIPESAFE_FLUSH;
-
-       if (count < flush_limit)
-               count <<= 1;
-       else
-               count += flush_limit;
+       if (stateless_rpc) {
+               if (count < LARGE_FLUSH)
+                       count <<= 1;
+               else
+                       count = count * 11 / 10;
+       } else {
+               if (count < PIPESAFE_FLUSH)
+                       count <<= 1;
+               else
+                       count += PIPESAFE_FLUSH;
+       }
        return count;
 }
 
-static int find_common(struct fetch_pack_args *args,
-                      int fd[2], unsigned char *result_sha1,
+static void mark_tips(struct fetch_negotiator *negotiator,
+                     const struct oid_array *negotiation_tips)
+{
+       int i;
+
+       if (!negotiation_tips) {
+               for_each_rawref(rev_list_insert_ref_oid, negotiator);
+               return;
+       }
+
+       for (i = 0; i < negotiation_tips->nr; i++)
+               rev_list_insert_ref(negotiator, &negotiation_tips->oid[i]);
+       return;
+}
+
+static int find_common(struct fetch_negotiator *negotiator,
+                      struct fetch_pack_args *args,
+                      int fd[2], struct object_id *result_oid,
                       struct ref *refs)
 {
        int fetching;
        int count = 0, flushes = 0, flush_at = INITIAL_FLUSH, retval;
-       const unsigned char *sha1;
+       const struct object_id *oid;
        unsigned in_vain = 0;
        int got_continue = 0;
        int got_ready = 0;
        struct strbuf req_buf = STRBUF_INIT;
        size_t state_len = 0;
+       struct packet_reader reader;
 
        if (args->stateless_rpc && multi_ack == 1)
-               die("--stateless-rpc requires multi_ack_detailed");
-       if (marked)
-               for_each_ref(clear_marks, NULL);
-       marked = 1;
+               die(_("--stateless-rpc requires multi_ack_detailed"));
+
+       packet_reader_init(&reader, fd[0], NULL, 0,
+                          PACKET_READ_CHOMP_NEWLINE |
+                          PACKET_READ_DIE_ON_ERR_PACKET);
 
-       for_each_ref(rev_list_insert_ref, NULL);
-       for_each_alternate_ref(insert_one_alternate_ref, NULL);
+       mark_tips(negotiator, args->negotiation_tips);
+       for_each_cached_alternate(negotiator, insert_one_alternate_object);
 
        fetching = 0;
        for ( ; refs ; refs = refs->next) {
-               unsigned char *remote = refs->old_sha1;
+               struct object_id *remote = &refs->old_oid;
                const char *remote_hex;
                struct object *o;
 
@@ -281,12 +305,12 @@ static int find_common(struct fetch_pack_args *args,
                 * interested in the case we *know* the object is
                 * reachable and we have already scanned it.
                 */
-               if (((o = lookup_object(remote)) != NULL) &&
+               if (((o = lookup_object(the_repository, remote)) != NULL) &&
                                (o->flags & COMPLETE)) {
                        continue;
                }
 
-               remote_hex = sha1_to_hex(remote);
+               remote_hex = oid_to_hex(remote);
                if (!fetching) {
                        struct strbuf c = STRBUF_INIT;
                        if (multi_ack == 2)     strbuf_addstr(&c, " multi_ack_detailed");
@@ -294,12 +318,19 @@ static int find_common(struct fetch_pack_args *args,
                        if (no_done)            strbuf_addstr(&c, " no-done");
                        if (use_sideband == 2)  strbuf_addstr(&c, " side-band-64k");
                        if (use_sideband == 1)  strbuf_addstr(&c, " side-band");
+                       if (args->deepen_relative) strbuf_addstr(&c, " deepen-relative");
                        if (args->use_thin_pack) strbuf_addstr(&c, " thin-pack");
                        if (args->no_progress)   strbuf_addstr(&c, " no-progress");
                        if (args->include_tag)   strbuf_addstr(&c, " include-tag");
                        if (prefer_ofs_delta)   strbuf_addstr(&c, " ofs-delta");
+                       if (deepen_since_ok)    strbuf_addstr(&c, " deepen-since");
+                       if (deepen_not_ok)      strbuf_addstr(&c, " deepen-not");
                        if (agent_supported)    strbuf_addf(&c, " agent=%s",
                                                            git_user_agent_sanitized());
+                       if (advertise_sid)
+                               strbuf_addf(&c, " session-id=%s", trace2_session_id());
+                       if (args->filter_options.choice)
+                               strbuf_addstr(&c, " filter");
                        packet_buf_write(&req_buf, "want %s%s\n", remote_hex, c.buf);
                        strbuf_release(&c);
                } else
@@ -313,39 +344,54 @@ static int find_common(struct fetch_pack_args *args,
                return 1;
        }
 
-       if (is_repository_shallow())
+       if (is_repository_shallow(the_repository))
                write_shallow_commits(&req_buf, 1, NULL);
        if (args->depth > 0)
                packet_buf_write(&req_buf, "deepen %d", args->depth);
+       if (args->deepen_since) {
+               timestamp_t max_age = approxidate(args->deepen_since);
+               packet_buf_write(&req_buf, "deepen-since %"PRItime, max_age);
+       }
+       if (args->deepen_not) {
+               int i;
+               for (i = 0; i < args->deepen_not->nr; i++) {
+                       struct string_list_item *s = args->deepen_not->items + i;
+                       packet_buf_write(&req_buf, "deepen-not %s", s->string);
+               }
+       }
+       if (server_supports_filtering && args->filter_options.choice) {
+               const char *spec =
+                       expand_list_objects_filter_spec(&args->filter_options);
+               packet_buf_write(&req_buf, "filter %s", spec);
+       }
        packet_buf_flush(&req_buf);
        state_len = req_buf.len;
 
-       if (args->depth > 0) {
-               char *line;
+       if (args->deepen) {
                const char *arg;
-               unsigned char sha1[20];
+               struct object_id oid;
 
                send_request(args, fd[1], &req_buf);
-               while ((line = packet_read_line(fd[0], NULL))) {
-                       if (skip_prefix(line, "shallow ", &arg)) {
-                               if (get_sha1_hex(arg, sha1))
-                                       die("invalid shallow line: %s", line);
-                               register_shallow(sha1);
+               while (packet_reader_read(&reader) == PACKET_READ_NORMAL) {
+                       if (skip_prefix(reader.line, "shallow ", &arg)) {
+                               if (get_oid_hex(arg, &oid))
+                                       die(_("invalid shallow line: %s"), reader.line);
+                               register_shallow(the_repository, &oid);
                                continue;
                        }
-                       if (skip_prefix(line, "unshallow ", &arg)) {
-                               if (get_sha1_hex(arg, sha1))
-                                       die("invalid unshallow line: %s", line);
-                               if (!lookup_object(sha1))
-                                       die("object not found: %s", line);
+                       if (skip_prefix(reader.line, "unshallow ", &arg)) {
+                               if (get_oid_hex(arg, &oid))
+                                       die(_("invalid unshallow line: %s"), reader.line);
+                               if (!lookup_object(the_repository, &oid))
+                                       die(_("object not found: %s"), reader.line);
                                /* make sure that it is parsed as shallow */
-                               if (!parse_object(sha1))
-                                       die("error in object: %s", line);
-                               if (unregister_shallow(sha1))
-                                       die("no shallow found: %s", line);
+                               if (!parse_object(the_repository, &oid))
+                                       die(_("error in object: %s"), reader.line);
+                               if (unregister_shallow(&oid))
+                                       die(_("no shallow found: %s"), reader.line);
                                continue;
                        }
-                       die("expected shallow/unshallow, got %s", line);
+                       die(_("expected shallow/unshallow, got %s"), reader.line);
                }
        } else if (!args->stateless_rpc)
                send_request(args, fd[1], &req_buf);
@@ -358,12 +404,12 @@ static int find_common(struct fetch_pack_args *args,
                state_len = 0;
        }
 
+       trace2_region_enter("fetch-pack", "negotiation_v0_v1", the_repository);
        flushes = 0;
        retval = -1;
-       while ((sha1 = get_rev())) {
-               packet_buf_write(&req_buf, "have %s\n", sha1_to_hex(sha1));
-               if (args->verbose)
-                       fprintf(stderr, "have %s\n", sha1_to_hex(sha1));
+       while ((oid = negotiator->next(negotiator))) {
+               packet_buf_write(&req_buf, "have %s\n", oid_to_hex(oid));
+               print_verbose(args, "have %s", oid_to_hex(oid));
                in_vain++;
                if (flush_at <= ++count) {
                        int ack;
@@ -372,7 +418,7 @@ static int find_common(struct fetch_pack_args *args,
                        send_request(args, fd[1], &req_buf);
                        strbuf_setlen(&req_buf, state_len);
                        flushes++;
-                       flush_at = next_flush(args, count);
+                       flush_at = next_flush(args->stateless_rpc, count);
 
                        /*
                         * We keep one window "ahead" of the other side, and
@@ -381,12 +427,12 @@ static int find_common(struct fetch_pack_args *args,
                        if (!args->stateless_rpc && count == INITIAL_FLUSH)
                                continue;
 
-                       consume_shallow_list(args, fd[0]);
+                       consume_shallow_list(args, &reader);
                        do {
-                               ack = get_ack(fd[0], result_sha1);
-                               if (args->verbose && ack)
-                                       fprintf(stderr, "got ack %d %s\n", ack,
-                                                       sha1_to_hex(result_sha1));
+                               ack = get_ack(&reader, result_oid);
+                               if (ack)
+                                       print_verbose(args, _("got %s %d %s"), "ack",
+                                                     ack, oid_to_hex(result_oid));
                                switch (ack) {
                                case ACK:
                                        flushes = 0;
@@ -397,47 +443,56 @@ static int find_common(struct fetch_pack_args *args,
                                case ACK_ready:
                                case ACK_continue: {
                                        struct commit *commit =
-                                               lookup_commit(result_sha1);
+                                               lookup_commit(the_repository,
+                                                             result_oid);
+                                       int was_common;
+
                                        if (!commit)
-                                               die("invalid commit %s", sha1_to_hex(result_sha1));
+                                               die(_("invalid commit %s"), oid_to_hex(result_oid));
+                                       was_common = negotiator->ack(negotiator, commit);
                                        if (args->stateless_rpc
                                         && ack == ACK_common
-                                        && !(commit->object.flags & COMMON)) {
+                                        && !was_common) {
                                                /* We need to replay the have for this object
                                                 * on the next RPC request so the peer knows
                                                 * it is in common with us.
                                                 */
-                                               const char *hex = sha1_to_hex(result_sha1);
+                                               const char *hex = oid_to_hex(result_oid);
                                                packet_buf_write(&req_buf, "have %s\n", hex);
                                                state_len = req_buf.len;
-                                       }
-                                       mark_common(commit, 0, 1);
+                                               /*
+                                                * Reset in_vain because an ack
+                                                * for this commit has not been
+                                                * seen.
+                                                */
+                                               in_vain = 0;
+                                       } else if (!args->stateless_rpc
+                                                  || ack != ACK_common)
+                                               in_vain = 0;
                                        retval = 0;
-                                       in_vain = 0;
                                        got_continue = 1;
-                                       if (ack == ACK_ready) {
-                                               clear_prio_queue(&rev_list);
+                                       if (ack == ACK_ready)
                                                got_ready = 1;
-                                       }
                                        break;
                                        }
                                }
                        } while (ack);
                        flushes--;
                        if (got_continue && MAX_IN_VAIN < in_vain) {
-                               if (args->verbose)
-                                       fprintf(stderr, "giving up\n");
+                               print_verbose(args, _("giving up"));
                                break; /* give up */
                        }
+                       if (got_ready)
+                               break;
                }
        }
 done:
+       trace2_region_leave("fetch-pack", "negotiation_v0_v1", the_repository);
        if (!got_ready || !no_done) {
                packet_buf_write(&req_buf, "done\n");
                send_request(args, fd[1], &req_buf);
        }
-       if (args->verbose)
-               fprintf(stderr, "done\n");
+       print_verbose(args, _("done"));
        if (retval != 0) {
                multi_ack = 0;
                flushes++;
@@ -445,13 +500,12 @@ done:
        strbuf_release(&req_buf);
 
        if (!got_ready || !no_done)
-               consume_shallow_list(args, fd[0]);
+               consume_shallow_list(args, &reader);
        while (flushes || multi_ack) {
-               int ack = get_ack(fd[0], result_sha1);
+               int ack = get_ack(&reader, result_oid);
                if (ack) {
-                       if (args->verbose)
-                               fprintf(stderr, "got ack (%d) %s\n", ack,
-                                       sha1_to_hex(result_sha1));
+                       print_verbose(args, _("got %s (%d) %s"), "ack",
+                                     ack, oid_to_hex(result_oid));
                        if (ack == ACK)
                                return 0;
                        multi_ack = 1;
@@ -465,46 +519,61 @@ done:
 
 static struct commit_list *complete;
 
-static int mark_complete(const char *refname, const unsigned char *sha1, int flag, void *cb_data)
+static int mark_complete(const struct object_id *oid)
 {
-       struct object *o = parse_object(sha1);
-
-       while (o && o->type == OBJ_TAG) {
-               struct tag *t = (struct tag *) o;
-               if (!t->tagged)
-                       break; /* broken repository */
-               o->flags |= COMPLETE;
-               o = parse_object(t->tagged->sha1);
-       }
-       if (o && o->type == OBJ_COMMIT) {
-               struct commit *commit = (struct commit *)o;
-               if (!(commit->object.flags & COMPLETE)) {
-                       commit->object.flags |= COMPLETE;
-                       commit_list_insert(commit, &complete);
-               }
+       struct commit *commit = deref_without_lazy_fetch(oid, 1);
+
+       if (commit && !(commit->object.flags & COMPLETE)) {
+               commit->object.flags |= COMPLETE;
+               commit_list_insert(commit, &complete);
        }
        return 0;
 }
 
+static int mark_complete_oid(const char *refname, const struct object_id *oid,
+                            int flag, void *cb_data)
+{
+       return mark_complete(oid);
+}
+
 static void mark_recent_complete_commits(struct fetch_pack_args *args,
-                                        unsigned long cutoff)
+                                        timestamp_t cutoff)
 {
        while (complete && cutoff <= complete->item->date) {
-               if (args->verbose)
-                       fprintf(stderr, "Marking %s as complete\n",
-                               sha1_to_hex(complete->item->object.sha1));
+               print_verbose(args, _("Marking %s as complete"),
+                             oid_to_hex(&complete->item->object.oid));
                pop_most_recent_commit(&complete, COMPLETE);
        }
 }
 
+static void add_refs_to_oidset(struct oidset *oids, struct ref *refs)
+{
+       for (; refs; refs = refs->next)
+               oidset_insert(oids, &refs->old_oid);
+}
+
+static int is_unmatched_ref(const struct ref *ref)
+{
+       struct object_id oid;
+       const char *p;
+       return  ref->match_status == REF_NOT_MATCHED &&
+               !parse_oid_hex(ref->name, &oid, &p) &&
+               *p == '\0' &&
+               oideq(&oid, &ref->old_oid);
+}
+
 static void filter_refs(struct fetch_pack_args *args,
                        struct ref **refs,
                        struct ref **sought, int nr_sought)
 {
        struct ref *newlist = NULL;
        struct ref **newtail = &newlist;
+       struct ref *unmatched = NULL;
        struct ref *ref, *next;
+       struct oidset tip_oids = OIDSET_INIT;
        int i;
+       int strict = !(allow_unadvertised_object_request &
+                      (ALLOW_TIP_SHA1 | ALLOW_REACHABLE_SHA1));
 
        i = 0;
        for (ref = *refs; ref; ref = next) {
@@ -512,78 +581,116 @@ static void filter_refs(struct fetch_pack_args *args,
                next = ref->next;
 
                if (starts_with(ref->name, "refs/") &&
-                   check_refname_format(ref->name, 0))
-                       ; /* trash */
-               else {
+                   check_refname_format(ref->name, 0)) {
+                       /*
+                        * trash or a peeled value; do not even add it to
+                        * unmatched list
+                        */
+                       free_one_ref(ref);
+                       continue;
+               } else {
                        while (i < nr_sought) {
                                int cmp = strcmp(ref->name, sought[i]->name);
                                if (cmp < 0)
                                        break; /* definitely do not have it */
                                else if (cmp == 0) {
                                        keep = 1; /* definitely have it */
-                                       sought[i]->matched = 1;
+                                       sought[i]->match_status = REF_MATCHED;
                                }
                                i++;
                        }
-               }
 
-               if (!keep && args->fetch_all &&
-                   (!args->depth || !starts_with(ref->name, "refs/tags/")))
-                       keep = 1;
+                       if (!keep && args->fetch_all &&
+                           (!args->deepen || !starts_with(ref->name, "refs/tags/")))
+                               keep = 1;
+               }
 
                if (keep) {
                        *newtail = ref;
                        ref->next = NULL;
                        newtail = &ref->next;
                } else {
-                       free(ref);
+                       ref->next = unmatched;
+                       unmatched = ref;
                }
        }
 
-       /* Append unmatched requests to the list */
-       if (allow_tip_sha1_in_want) {
+       if (strict) {
                for (i = 0; i < nr_sought; i++) {
                        ref = sought[i];
-                       if (ref->matched)
-                               continue;
-                       if (get_sha1_hex(ref->name, ref->old_sha1))
+                       if (!is_unmatched_ref(ref))
                                continue;
 
-                       ref->matched = 1;
-                       *newtail = ref;
-                       ref->next = NULL;
-                       newtail = &ref->next;
+                       add_refs_to_oidset(&tip_oids, unmatched);
+                       add_refs_to_oidset(&tip_oids, newlist);
+                       break;
                }
        }
+
+       /* Append unmatched requests to the list */
+       for (i = 0; i < nr_sought; i++) {
+               ref = sought[i];
+               if (!is_unmatched_ref(ref))
+                       continue;
+
+               if (!strict || oidset_contains(&tip_oids, &ref->old_oid)) {
+                       ref->match_status = REF_MATCHED;
+                       *newtail = copy_ref(ref);
+                       newtail = &(*newtail)->next;
+               } else {
+                       ref->match_status = REF_UNADVERTISED_NOT_ALLOWED;
+               }
+       }
+
+       oidset_clear(&tip_oids);
+       free_refs(unmatched);
+
        *refs = newlist;
 }
 
-static void mark_alternate_complete(const struct ref *ref, void *unused)
+static void mark_alternate_complete(struct fetch_negotiator *unused,
+                                   struct object *obj)
 {
-       mark_complete(NULL, ref->old_sha1, 0, NULL);
+       mark_complete(&obj->oid);
 }
 
-static int everything_local(struct fetch_pack_args *args,
-                           struct ref **refs,
-                           struct ref **sought, int nr_sought)
+struct loose_object_iter {
+       struct oidset *loose_object_set;
+       struct ref *refs;
+};
+
+/*
+ * Mark recent commits available locally and reachable from a local ref as
+ * COMPLETE.
+ *
+ * The cutoff time for recency is determined by this heuristic: it is the
+ * earliest commit time of the objects in refs that are commits and that we know
+ * the commit time of.
+ */
+static void mark_complete_and_common_ref(struct fetch_negotiator *negotiator,
+                                        struct fetch_pack_args *args,
+                                        struct ref **refs)
 {
        struct ref *ref;
-       int retval;
-       unsigned long cutoff = 0;
+       int old_save_commit_buffer = save_commit_buffer;
+       timestamp_t cutoff = 0;
 
        save_commit_buffer = 0;
 
+       trace2_region_enter("fetch-pack", "parse_remote_refs_and_find_cutoff", NULL);
        for (ref = *refs; ref; ref = ref->next) {
                struct object *o;
 
-               if (!has_sha1_file(ref->old_sha1))
+               if (!has_object_file_with_flags(&ref->old_oid,
+                                               OBJECT_INFO_QUICK |
+                                                       OBJECT_INFO_SKIP_FETCH_OBJECT))
                        continue;
-
-               o = parse_object(ref->old_sha1);
+               o = parse_object(the_repository, &ref->old_oid);
                if (!o)
                        continue;
 
-               /* We already have it -- which may mean that we were
+               /*
+                * We already have it -- which may mean that we were
                 * in sync with the other side at some time after
                 * that (it is OK if we guess wrong here).
                 */
@@ -593,80 +700,117 @@ static int everything_local(struct fetch_pack_args *args,
                                cutoff = commit->date;
                }
        }
+       trace2_region_leave("fetch-pack", "parse_remote_refs_and_find_cutoff", NULL);
 
-       if (!args->depth) {
-               for_each_ref(mark_complete, NULL);
-               for_each_alternate_ref(mark_alternate_complete, NULL);
+       /*
+        * This block marks all local refs as COMPLETE, and then recursively marks all
+        * parents of those refs as COMPLETE.
+        */
+       trace2_region_enter("fetch-pack", "mark_complete_local_refs", NULL);
+       if (!args->deepen) {
+               for_each_rawref(mark_complete_oid, NULL);
+               for_each_cached_alternate(NULL, mark_alternate_complete);
                commit_list_sort_by_date(&complete);
                if (cutoff)
                        mark_recent_complete_commits(args, cutoff);
        }
+       trace2_region_leave("fetch-pack", "mark_complete_local_refs", NULL);
 
        /*
         * Mark all complete remote refs as common refs.
         * Don't mark them common yet; the server has to be told so first.
         */
+       trace2_region_enter("fetch-pack", "mark_common_remote_refs", NULL);
        for (ref = *refs; ref; ref = ref->next) {
-               struct object *o = deref_tag(lookup_object(ref->old_sha1),
-                                            NULL, 0);
+               struct commit *c = deref_without_lazy_fetch(&ref->old_oid, 0);
 
-               if (!o || o->type != OBJ_COMMIT || !(o->flags & COMPLETE))
+               if (!c || !(c->object.flags & COMPLETE))
                        continue;
 
-               if (!(o->flags & SEEN)) {
-                       rev_list_push((struct commit *)o, COMMON_REF | SEEN);
-
-                       mark_common((struct commit *)o, 1, 1);
-               }
+               negotiator->known_common(negotiator, c);
        }
+       trace2_region_leave("fetch-pack", "mark_common_remote_refs", NULL);
 
-       filter_refs(args, refs, sought, nr_sought);
+       save_commit_buffer = old_save_commit_buffer;
+}
+
+/*
+ * Returns 1 if every object pointed to by the given remote refs is available
+ * locally and reachable from a local ref, and 0 otherwise.
+ */
+static int everything_local(struct fetch_pack_args *args,
+                           struct ref **refs)
+{
+       struct ref *ref;
+       int retval;
 
        for (retval = 1, ref = *refs; ref ; ref = ref->next) {
-               const unsigned char *remote = ref->old_sha1;
-               unsigned char local[20];
+               const struct object_id *remote = &ref->old_oid;
                struct object *o;
 
-               o = lookup_object(remote);
+               o = lookup_object(the_repository, remote);
                if (!o || !(o->flags & COMPLETE)) {
                        retval = 0;
-                       if (!args->verbose)
-                               continue;
-                       fprintf(stderr,
-                               "want %s (%s)\n", sha1_to_hex(remote),
-                               ref->name);
+                       print_verbose(args, "want %s (%s)", oid_to_hex(remote),
+                                     ref->name);
                        continue;
                }
-
-               hashcpy(ref->new_sha1, local);
-               if (!args->verbose)
-                       continue;
-               fprintf(stderr,
-                       "already have %s (%s)\n", sha1_to_hex(remote),
-                       ref->name);
+               print_verbose(args, _("already have %s (%s)"), oid_to_hex(remote),
+                             ref->name);
        }
+
        return retval;
 }
 
 static int sideband_demux(int in, int out, void *data)
 {
        int *xd = data;
+       int ret;
 
-       int ret = recv_sideband("fetch-pack", xd[0], out);
+       ret = recv_sideband("fetch-pack", xd[0], out);
        close(out);
        return ret;
 }
 
+static void write_promisor_file(const char *keep_name,
+                               struct ref **sought, int nr_sought)
+{
+       struct strbuf promisor_name = STRBUF_INIT;
+       int suffix_stripped;
+       FILE *output;
+       int i;
+
+       strbuf_addstr(&promisor_name, keep_name);
+       suffix_stripped = strbuf_strip_suffix(&promisor_name, ".keep");
+       if (!suffix_stripped)
+               BUG("name of pack lockfile should end with .keep (was '%s')",
+                   keep_name);
+       strbuf_addstr(&promisor_name, ".promisor");
+
+       output = xfopen(promisor_name.buf, "w");
+       for (i = 0; i < nr_sought; i++)
+               fprintf(output, "%s %s\n", oid_to_hex(&sought[i]->old_oid),
+                       sought[i]->name);
+       fclose(output);
+
+       strbuf_release(&promisor_name);
+}
+
+/*
+ * Pass 1 as "only_packfile" if the pack received is the only pack in this
+ * fetch request (that is, if there were no packfile URIs provided).
+ */
 static int get_pack(struct fetch_pack_args *args,
-                   int xd[2], char **pack_lockfile)
+                   int xd[2], struct string_list *pack_lockfiles,
+                   int only_packfile,
+                   struct ref **sought, int nr_sought)
 {
        struct async demux;
-       const char *argv[22];
-       char keep_arg[256];
-       char hdr_arg[256];
-       const char **av, *cmd_name;
        int do_keep = args->keep_pack;
-       struct child_process cmd;
+       const char *cmd_name;
+       struct pack_header header;
+       int pass_header = 0;
+       struct child_process cmd = CHILD_PROCESS_INIT;
        int ret;
 
        memset(&demux, 0, sizeof(demux));
@@ -678,25 +822,18 @@ static int get_pack(struct fetch_pack_args *args,
                demux.proc = sideband_demux;
                demux.data = xd;
                demux.out = -1;
+               demux.isolate_sigpipe = 1;
                if (start_async(&demux))
-                       die("fetch-pack: unable to fork off sideband"
-                           " demultiplexer");
+                       die(_("fetch-pack: unable to fork off sideband demultiplexer"));
        }
        else
                demux.out = xd[0];
 
-       memset(&cmd, 0, sizeof(cmd));
-       cmd.argv = argv;
-       av = argv;
-       *hdr_arg = 0;
        if (!args->keep_pack && unpack_limit) {
-               struct pack_header header;
 
                if (read_pack_header(demux.out, &header))
-                       die("protocol error: bad pack header");
-               snprintf(hdr_arg, sizeof(hdr_arg),
-                        "--pack_header=%"PRIu32",%"PRIu32,
-                        ntohl(header.hdr_version), ntohl(header.hdr_entries));
+                       die(_("protocol error: bad pack header"));
+               pass_header = 1;
                if (ntohl(header.hdr_entries) < unpack_limit)
                        do_keep = 0;
                else
@@ -704,51 +841,86 @@ static int get_pack(struct fetch_pack_args *args,
        }
 
        if (alternate_shallow_file) {
-               *av++ = "--shallow-file";
-               *av++ = alternate_shallow_file;
+               strvec_push(&cmd.args, "--shallow-file");
+               strvec_push(&cmd.args, alternate_shallow_file);
        }
 
-       if (do_keep) {
-               if (pack_lockfile)
+       if (do_keep || args->from_promisor) {
+               if (pack_lockfiles)
                        cmd.out = -1;
-               *av++ = cmd_name = "index-pack";
-               *av++ = "--stdin";
+               cmd_name = "index-pack";
+               strvec_push(&cmd.args, cmd_name);
+               strvec_push(&cmd.args, "--stdin");
                if (!args->quiet && !args->no_progress)
-                       *av++ = "-v";
+                       strvec_push(&cmd.args, "-v");
                if (args->use_thin_pack)
-                       *av++ = "--fix-thin";
-               if (args->lock_pack || unpack_limit) {
-                       int s = sprintf(keep_arg,
-                                       "--keep=fetch-pack %"PRIuMAX " on ", (uintmax_t) getpid());
-                       if (gethostname(keep_arg + s, sizeof(keep_arg) - s))
-                               strcpy(keep_arg + s, "localhost");
-                       *av++ = keep_arg;
+                       strvec_push(&cmd.args, "--fix-thin");
+               if (do_keep && (args->lock_pack || unpack_limit)) {
+                       char hostname[HOST_NAME_MAX + 1];
+                       if (xgethostname(hostname, sizeof(hostname)))
+                               xsnprintf(hostname, sizeof(hostname), "localhost");
+                       strvec_pushf(&cmd.args,
+                                    "--keep=fetch-pack %"PRIuMAX " on %s",
+                                    (uintmax_t)getpid(), hostname);
                }
-               if (args->check_self_contained_and_connected)
-                       *av++ = "--check-self-contained-and-connected";
+               if (only_packfile && args->check_self_contained_and_connected)
+                       strvec_push(&cmd.args, "--check-self-contained-and-connected");
+               else
+                       /*
+                        * We cannot perform any connectivity checks because
+                        * not all packs have been downloaded; let the caller
+                        * have this responsibility.
+                        */
+                       args->check_self_contained_and_connected = 0;
+
+               if (args->from_promisor)
+                       /*
+                        * write_promisor_file() may be called afterwards but
+                        * we still need index-pack to know that this is a
+                        * promisor pack. For example, if transfer.fsckobjects
+                        * is true, index-pack needs to know that .gitmodules
+                        * is a promisor object (so that it won't complain if
+                        * it is missing).
+                        */
+                       strvec_push(&cmd.args, "--promisor");
        }
        else {
-               *av++ = cmd_name = "unpack-objects";
+               cmd_name = "unpack-objects";
+               strvec_push(&cmd.args, cmd_name);
                if (args->quiet || args->no_progress)
-                       *av++ = "-q";
+                       strvec_push(&cmd.args, "-q");
                args->check_self_contained_and_connected = 0;
        }
-       if (*hdr_arg)
-               *av++ = hdr_arg;
+
+       if (pass_header)
+               strvec_pushf(&cmd.args, "--pack_header=%"PRIu32",%"PRIu32,
+                            ntohl(header.hdr_version),
+                                ntohl(header.hdr_entries));
        if (fetch_fsck_objects >= 0
            ? fetch_fsck_objects
            : transfer_fsck_objects >= 0
            ? transfer_fsck_objects
-           : 0)
-               *av++ = "--strict";
-       *av++ = NULL;
+           : 0) {
+               if (args->from_promisor || !only_packfile)
+                       /*
+                        * We cannot use --strict in index-pack because it
+                        * checks both broken objects and links, but we only
+                        * want to check for broken objects.
+                        */
+                       strvec_push(&cmd.args, "--fsck-objects");
+               else
+                       strvec_pushf(&cmd.args, "--strict%s",
+                                    fsck_msg_types.buf);
+       }
 
        cmd.in = demux.out;
        cmd.git_cmd = 1;
        if (start_command(&cmd))
-               die("fetch-pack: unable to fork off %s", cmd_name);
-       if (do_keep && pack_lockfile) {
-               *pack_lockfile = index_pack_lockfile(cmd.out);
+               die(_("fetch-pack: unable to fork off %s"), cmd_name);
+       if (do_keep && pack_lockfiles) {
+               char *pack_lockfile = index_pack_lockfile(cmd.out);
+               if (pack_lockfile)
+                       string_list_append_nodup(pack_lockfiles, pack_lockfile);
                close(cmd.out);
        }
 
@@ -762,9 +934,17 @@ static int get_pack(struct fetch_pack_args *args,
                        args->check_self_contained_and_connected &&
                        ret == 0;
        else
-               die("%s failed", cmd_name);
+               die(_("%s failed"), cmd_name);
        if (use_sideband && finish_async(&demux))
-               die("error in sideband demultiplexer");
+               die(_("error in sideband demultiplexer"));
+
+       /*
+        * Now that index-pack has succeeded, write the promisor file using the
+        * obtained .keep filename if necessary
+        */
+       if (do_keep && pack_lockfiles && pack_lockfiles->nr && args->from_promisor)
+               write_promisor_file(pack_lockfiles->items[0].string, sought, nr_sought);
+
        return 0;
 }
 
@@ -780,131 +960,785 @@ static struct ref *do_fetch_pack(struct fetch_pack_args *args,
                                 const struct ref *orig_ref,
                                 struct ref **sought, int nr_sought,
                                 struct shallow_info *si,
-                                char **pack_lockfile)
+                                struct string_list *pack_lockfiles)
 {
+       struct repository *r = the_repository;
        struct ref *ref = copy_ref_list(orig_ref);
-       unsigned char sha1[20];
+       struct object_id oid;
        const char *agent_feature;
        int agent_len;
+       struct fetch_negotiator negotiator_alloc;
+       struct fetch_negotiator *negotiator;
+
+       negotiator = &negotiator_alloc;
+       fetch_negotiator_init(r, negotiator);
 
        sort_ref_list(&ref, ref_compare_name);
-       qsort(sought, nr_sought, sizeof(*sought), cmp_ref_by_name);
+       QSORT(sought, nr_sought, cmp_ref_by_name);
 
-       if (is_repository_shallow() && !server_supports("shallow"))
-               die("Server does not support shallow clients");
+       if ((agent_feature = server_feature_value("agent", &agent_len))) {
+               agent_supported = 1;
+               if (agent_len)
+                       print_verbose(args, _("Server version is %.*s"),
+                                     agent_len, agent_feature);
+       }
+
+       if (!server_supports("session-id"))
+               advertise_sid = 0;
+
+       if (server_supports("shallow"))
+               print_verbose(args, _("Server supports %s"), "shallow");
+       else if (args->depth > 0 || is_repository_shallow(r))
+               die(_("Server does not support shallow clients"));
+       if (args->depth > 0 || args->deepen_since || args->deepen_not)
+               args->deepen = 1;
        if (server_supports("multi_ack_detailed")) {
-               if (args->verbose)
-                       fprintf(stderr, "Server supports multi_ack_detailed\n");
+               print_verbose(args, _("Server supports %s"), "multi_ack_detailed");
                multi_ack = 2;
                if (server_supports("no-done")) {
-                       if (args->verbose)
-                               fprintf(stderr, "Server supports no-done\n");
+                       print_verbose(args, _("Server supports %s"), "no-done");
                        if (args->stateless_rpc)
                                no_done = 1;
                }
        }
        else if (server_supports("multi_ack")) {
-               if (args->verbose)
-                       fprintf(stderr, "Server supports multi_ack\n");
+               print_verbose(args, _("Server supports %s"), "multi_ack");
                multi_ack = 1;
        }
        if (server_supports("side-band-64k")) {
-               if (args->verbose)
-                       fprintf(stderr, "Server supports side-band-64k\n");
+               print_verbose(args, _("Server supports %s"), "side-band-64k");
                use_sideband = 2;
        }
        else if (server_supports("side-band")) {
-               if (args->verbose)
-                       fprintf(stderr, "Server supports side-band\n");
+               print_verbose(args, _("Server supports %s"), "side-band");
                use_sideband = 1;
        }
        if (server_supports("allow-tip-sha1-in-want")) {
-               if (args->verbose)
-                       fprintf(stderr, "Server supports allow-tip-sha1-in-want\n");
-               allow_tip_sha1_in_want = 1;
+               print_verbose(args, _("Server supports %s"), "allow-tip-sha1-in-want");
+               allow_unadvertised_object_request |= ALLOW_TIP_SHA1;
+       }
+       if (server_supports("allow-reachable-sha1-in-want")) {
+               print_verbose(args, _("Server supports %s"), "allow-reachable-sha1-in-want");
+               allow_unadvertised_object_request |= ALLOW_REACHABLE_SHA1;
        }
-       if (!server_supports("thin-pack"))
+       if (server_supports("thin-pack"))
+               print_verbose(args, _("Server supports %s"), "thin-pack");
+       else
                args->use_thin_pack = 0;
-       if (!server_supports("no-progress"))
+       if (server_supports("no-progress"))
+               print_verbose(args, _("Server supports %s"), "no-progress");
+       else
                args->no_progress = 0;
-       if (!server_supports("include-tag"))
+       if (server_supports("include-tag"))
+               print_verbose(args, _("Server supports %s"), "include-tag");
+       else
                args->include_tag = 0;
-       if (server_supports("ofs-delta")) {
-               if (args->verbose)
-                       fprintf(stderr, "Server supports ofs-delta\n");
-       } else
+       if (server_supports("ofs-delta"))
+               print_verbose(args, _("Server supports %s"), "ofs-delta");
+       else
                prefer_ofs_delta = 0;
 
-       if ((agent_feature = server_feature_value("agent", &agent_len))) {
-               agent_supported = 1;
-               if (args->verbose && agent_len)
-                       fprintf(stderr, "Server version is %.*s\n",
-                               agent_len, agent_feature);
+       if (server_supports("filter")) {
+               server_supports_filtering = 1;
+               print_verbose(args, _("Server supports %s"), "filter");
+       } else if (args->filter_options.choice) {
+               warning("filtering not recognized by server, ignoring");
        }
 
-       if (everything_local(args, &ref, sought, nr_sought)) {
+       if (server_supports("deepen-since")) {
+               print_verbose(args, _("Server supports %s"), "deepen-since");
+               deepen_since_ok = 1;
+       } else if (args->deepen_since)
+               die(_("Server does not support --shallow-since"));
+       if (server_supports("deepen-not")) {
+               print_verbose(args, _("Server supports %s"), "deepen-not");
+               deepen_not_ok = 1;
+       } else if (args->deepen_not)
+               die(_("Server does not support --shallow-exclude"));
+       if (server_supports("deepen-relative"))
+               print_verbose(args, _("Server supports %s"), "deepen-relative");
+       else if (args->deepen_relative)
+               die(_("Server does not support --deepen"));
+       if (!server_supports_hash(the_hash_algo->name, NULL))
+               die(_("Server does not support this repository's object format"));
+
+       mark_complete_and_common_ref(negotiator, args, &ref);
+       filter_refs(args, &ref, sought, nr_sought);
+       if (everything_local(args, &ref)) {
                packet_flush(fd[1]);
                goto all_done;
        }
-       if (find_common(args, fd, sha1, ref) < 0)
+       if (find_common(negotiator, args, fd, &oid, ref) < 0)
                if (!args->keep_pack)
                        /* When cloning, it is not unusual to have
                         * no common commit.
                         */
-                       warning("no common commits");
+                       warning(_("no common commits"));
 
        if (args->stateless_rpc)
                packet_flush(fd[1]);
-       if (args->depth > 0)
+       if (args->deepen)
                setup_alternate_shallow(&shallow_lock, &alternate_shallow_file,
                                        NULL);
        else if (si->nr_ours || si->nr_theirs)
                alternate_shallow_file = setup_temporary_shallow(si->shallow);
        else
                alternate_shallow_file = NULL;
-       if (get_pack(args, fd, pack_lockfile))
-               die("git fetch-pack: fetch failed.");
+       if (get_pack(args, fd, pack_lockfiles, 1, sought, nr_sought))
+               die(_("git fetch-pack: fetch failed."));
 
  all_done:
+       if (negotiator)
+               negotiator->release(negotiator);
        return ref;
 }
 
-static int fetch_pack_config(const char *var, const char *value, void *cb)
+static void add_shallow_requests(struct strbuf *req_buf,
+                                const struct fetch_pack_args *args)
 {
-       if (strcmp(var, "fetch.unpacklimit") == 0) {
-               fetch_unpack_limit = git_config_int(var, value);
-               return 0;
+       if (is_repository_shallow(the_repository))
+               write_shallow_commits(req_buf, 1, NULL);
+       if (args->depth > 0)
+               packet_buf_write(req_buf, "deepen %d", args->depth);
+       if (args->deepen_since) {
+               timestamp_t max_age = approxidate(args->deepen_since);
+               packet_buf_write(req_buf, "deepen-since %"PRItime, max_age);
+       }
+       if (args->deepen_not) {
+               int i;
+               for (i = 0; i < args->deepen_not->nr; i++) {
+                       struct string_list_item *s = args->deepen_not->items + i;
+                       packet_buf_write(req_buf, "deepen-not %s", s->string);
+               }
        }
+       if (args->deepen_relative)
+               packet_buf_write(req_buf, "deepen-relative\n");
+}
 
-       if (strcmp(var, "transfer.unpacklimit") == 0) {
-               transfer_unpack_limit = git_config_int(var, value);
-               return 0;
+static void add_wants(const struct ref *wants, struct strbuf *req_buf)
+{
+       int use_ref_in_want = server_supports_feature("fetch", "ref-in-want", 0);
+
+       for ( ; wants ; wants = wants->next) {
+               const struct object_id *remote = &wants->old_oid;
+               struct object *o;
+
+               /*
+                * If that object is complete (i.e. it is an ancestor of a
+                * local ref), we tell them we have it but do not have to
+                * tell them about its ancestors, which they already know
+                * about.
+                *
+                * We use lookup_object here because we are only
+                * interested in the case we *know* the object is
+                * reachable and we have already scanned it.
+                */
+               if (((o = lookup_object(the_repository, remote)) != NULL) &&
+                   (o->flags & COMPLETE)) {
+                       continue;
+               }
+
+               if (!use_ref_in_want || wants->exact_oid)
+                       packet_buf_write(req_buf, "want %s\n", oid_to_hex(remote));
+               else
+                       packet_buf_write(req_buf, "want-ref %s\n", wants->name);
+       }
+}
+
+static void add_common(struct strbuf *req_buf, struct oidset *common)
+{
+       struct oidset_iter iter;
+       const struct object_id *oid;
+       oidset_iter_init(common, &iter);
+
+       while ((oid = oidset_iter_next(&iter))) {
+               packet_buf_write(req_buf, "have %s\n", oid_to_hex(oid));
        }
+}
 
-       if (strcmp(var, "repack.usedeltabaseoffset") == 0) {
-               prefer_ofs_delta = git_config_bool(var, value);
-               return 0;
+static int add_haves(struct fetch_negotiator *negotiator,
+                    int seen_ack,
+                    struct strbuf *req_buf,
+                    int *haves_to_send, int *in_vain)
+{
+       int ret = 0;
+       int haves_added = 0;
+       const struct object_id *oid;
+
+       while ((oid = negotiator->next(negotiator))) {
+               packet_buf_write(req_buf, "have %s\n", oid_to_hex(oid));
+               if (++haves_added >= *haves_to_send)
+                       break;
+       }
+
+       *in_vain += haves_added;
+       if (!haves_added || (seen_ack && *in_vain >= MAX_IN_VAIN)) {
+               /* Send Done */
+               packet_buf_write(req_buf, "done\n");
+               ret = 1;
+       }
+
+       /* Increase haves to send on next round */
+       *haves_to_send = next_flush(1, *haves_to_send);
+
+       return ret;
+}
+
+static int send_fetch_request(struct fetch_negotiator *negotiator, int fd_out,
+                             struct fetch_pack_args *args,
+                             const struct ref *wants, struct oidset *common,
+                             int *haves_to_send, int *in_vain,
+                             int sideband_all, int seen_ack)
+{
+       int ret = 0;
+       const char *hash_name;
+       struct strbuf req_buf = STRBUF_INIT;
+
+       if (server_supports_v2("fetch", 1))
+               packet_buf_write(&req_buf, "command=fetch");
+       if (server_supports_v2("agent", 0))
+               packet_buf_write(&req_buf, "agent=%s", git_user_agent_sanitized());
+       if (advertise_sid && server_supports_v2("session-id", 0))
+               packet_buf_write(&req_buf, "session-id=%s", trace2_session_id());
+       if (args->server_options && args->server_options->nr &&
+           server_supports_v2("server-option", 1)) {
+               int i;
+               for (i = 0; i < args->server_options->nr; i++)
+                       packet_buf_write(&req_buf, "server-option=%s",
+                                        args->server_options->items[i].string);
+       }
+
+       if (server_feature_v2("object-format", &hash_name)) {
+               int hash_algo = hash_algo_by_name(hash_name);
+               if (hash_algo_by_ptr(the_hash_algo) != hash_algo)
+                       die(_("mismatched algorithms: client %s; server %s"),
+                           the_hash_algo->name, hash_name);
+               packet_write_fmt(fd_out, "object-format=%s", the_hash_algo->name);
+       } else if (hash_algo_by_ptr(the_hash_algo) != GIT_HASH_SHA1) {
+               die(_("the server does not support algorithm '%s'"),
+                   the_hash_algo->name);
+       }
+
+       packet_buf_delim(&req_buf);
+       if (args->use_thin_pack)
+               packet_buf_write(&req_buf, "thin-pack");
+       if (args->no_progress)
+               packet_buf_write(&req_buf, "no-progress");
+       if (args->include_tag)
+               packet_buf_write(&req_buf, "include-tag");
+       if (prefer_ofs_delta)
+               packet_buf_write(&req_buf, "ofs-delta");
+       if (sideband_all)
+               packet_buf_write(&req_buf, "sideband-all");
+
+       /* Add shallow-info and deepen request */
+       if (server_supports_feature("fetch", "shallow", 0))
+               add_shallow_requests(&req_buf, args);
+       else if (is_repository_shallow(the_repository) || args->deepen)
+               die(_("Server does not support shallow requests"));
+
+       /* Add filter */
+       if (server_supports_feature("fetch", "filter", 0) &&
+           args->filter_options.choice) {
+               const char *spec =
+                       expand_list_objects_filter_spec(&args->filter_options);
+               print_verbose(args, _("Server supports filter"));
+               packet_buf_write(&req_buf, "filter %s", spec);
+       } else if (args->filter_options.choice) {
+               warning("filtering not recognized by server, ignoring");
+       }
+
+       if (server_supports_feature("fetch", "packfile-uris", 0)) {
+               int i;
+               struct strbuf to_send = STRBUF_INIT;
+
+               for (i = 0; i < uri_protocols.nr; i++) {
+                       const char *s = uri_protocols.items[i].string;
+
+                       if (!strcmp(s, "https") || !strcmp(s, "http")) {
+                               if (to_send.len)
+                                       strbuf_addch(&to_send, ',');
+                               strbuf_addstr(&to_send, s);
+                       }
+               }
+               if (to_send.len) {
+                       packet_buf_write(&req_buf, "packfile-uris %s",
+                                        to_send.buf);
+                       strbuf_release(&to_send);
+               }
+       }
+
+       /* add wants */
+       add_wants(wants, &req_buf);
+
+       /* Add all of the common commits we've found in previous rounds */
+       add_common(&req_buf, common);
+
+       /* Add initial haves */
+       ret = add_haves(negotiator, seen_ack, &req_buf,
+                       haves_to_send, in_vain);
+
+       /* Send request */
+       packet_buf_flush(&req_buf);
+       if (write_in_full(fd_out, req_buf.buf, req_buf.len) < 0)
+               die_errno(_("unable to write request to remote"));
+
+       strbuf_release(&req_buf);
+       return ret;
+}
+
+/*
+ * Processes a section header in a server's response and checks if it matches
+ * `section`.  If the value of `peek` is 1, the header line will be peeked (and
+ * not consumed); if 0, the line will be consumed and the function will die if
+ * the section header doesn't match what was expected.
+ */
+static int process_section_header(struct packet_reader *reader,
+                                 const char *section, int peek)
+{
+       int ret;
+
+       if (packet_reader_peek(reader) != PACKET_READ_NORMAL)
+               die(_("error reading section header '%s'"), section);
+
+       ret = !strcmp(reader->line, section);
+
+       if (!peek) {
+               if (!ret)
+                       die(_("expected '%s', received '%s'"),
+                           section, reader->line);
+               packet_reader_read(reader);
+       }
+
+       return ret;
+}
+
+enum common_found {
+       /*
+        * No commit was found to be possessed by both the client and the
+        * server, and "ready" was not received.
+        */
+       NO_COMMON_FOUND,
+
+       /*
+        * At least one commit was found to be possessed by both the client and
+        * the server, and "ready" was not received.
+        */
+       COMMON_FOUND,
+
+       /*
+        * "ready" was received, indicating that the server is ready to send
+        * the packfile without any further negotiation.
+        */
+       READY
+};
+
+static enum common_found process_acks(struct fetch_negotiator *negotiator,
+                                     struct packet_reader *reader,
+                                     struct oidset *common)
+{
+       /* received */
+       int received_ready = 0;
+       int received_ack = 0;
+
+       process_section_header(reader, "acknowledgments", 0);
+       while (packet_reader_read(reader) == PACKET_READ_NORMAL) {
+               const char *arg;
+
+               if (!strcmp(reader->line, "NAK"))
+                       continue;
+
+               if (skip_prefix(reader->line, "ACK ", &arg)) {
+                       struct object_id oid;
+                       received_ack = 1;
+                       if (!get_oid_hex(arg, &oid)) {
+                               struct commit *commit;
+                               oidset_insert(common, &oid);
+                               commit = lookup_commit(the_repository, &oid);
+                               if (negotiator)
+                                       negotiator->ack(negotiator, commit);
+                       }
+                       continue;
+               }
+
+               if (!strcmp(reader->line, "ready")) {
+                       received_ready = 1;
+                       continue;
+               }
+
+               die(_("unexpected acknowledgment line: '%s'"), reader->line);
+       }
+
+       if (reader->status != PACKET_READ_FLUSH &&
+           reader->status != PACKET_READ_DELIM)
+               die(_("error processing acks: %d"), reader->status);
+
+       /*
+        * If an "acknowledgments" section is sent, a packfile is sent if and
+        * only if "ready" was sent in this section. The other sections
+        * ("shallow-info" and "wanted-refs") are sent only if a packfile is
+        * sent. Therefore, a DELIM is expected if "ready" is sent, and a FLUSH
+        * otherwise.
+        */
+       if (received_ready && reader->status != PACKET_READ_DELIM)
+               die(_("expected packfile to be sent after 'ready'"));
+       if (!received_ready && reader->status != PACKET_READ_FLUSH)
+               die(_("expected no other sections to be sent after no 'ready'"));
+
+       return received_ready ? READY :
+               (received_ack ? COMMON_FOUND : NO_COMMON_FOUND);
+}
+
+static void receive_shallow_info(struct fetch_pack_args *args,
+                                struct packet_reader *reader,
+                                struct oid_array *shallows,
+                                struct shallow_info *si)
+{
+       int unshallow_received = 0;
+
+       process_section_header(reader, "shallow-info", 0);
+       while (packet_reader_read(reader) == PACKET_READ_NORMAL) {
+               const char *arg;
+               struct object_id oid;
+
+               if (skip_prefix(reader->line, "shallow ", &arg)) {
+                       if (get_oid_hex(arg, &oid))
+                               die(_("invalid shallow line: %s"), reader->line);
+                       oid_array_append(shallows, &oid);
+                       continue;
+               }
+               if (skip_prefix(reader->line, "unshallow ", &arg)) {
+                       if (get_oid_hex(arg, &oid))
+                               die(_("invalid unshallow line: %s"), reader->line);
+                       if (!lookup_object(the_repository, &oid))
+                               die(_("object not found: %s"), reader->line);
+                       /* make sure that it is parsed as shallow */
+                       if (!parse_object(the_repository, &oid))
+                               die(_("error in object: %s"), reader->line);
+                       if (unregister_shallow(&oid))
+                               die(_("no shallow found: %s"), reader->line);
+                       unshallow_received = 1;
+                       continue;
+               }
+               die(_("expected shallow/unshallow, got %s"), reader->line);
+       }
+
+       if (reader->status != PACKET_READ_FLUSH &&
+           reader->status != PACKET_READ_DELIM)
+               die(_("error processing shallow info: %d"), reader->status);
+
+       if (args->deepen || unshallow_received) {
+               /*
+                * Treat these as shallow lines caused by our depth settings.
+                * In v0, these lines cannot cause refs to be rejected; do the
+                * same.
+                */
+               int i;
+
+               for (i = 0; i < shallows->nr; i++)
+                       register_shallow(the_repository, &shallows->oid[i]);
+               setup_alternate_shallow(&shallow_lock, &alternate_shallow_file,
+                                       NULL);
+               args->deepen = 1;
+       } else if (shallows->nr) {
+               /*
+                * Treat these as shallow lines caused by the remote being
+                * shallow. In v0, remote refs that reach these objects are
+                * rejected (unless --update-shallow is set); do the same.
+                */
+               prepare_shallow_info(si, shallows);
+               if (si->nr_ours || si->nr_theirs)
+                       alternate_shallow_file =
+                               setup_temporary_shallow(si->shallow);
+               else
+                       alternate_shallow_file = NULL;
+       } else {
+               alternate_shallow_file = NULL;
+       }
+}
+
+static int cmp_name_ref(const void *name, const void *ref)
+{
+       return strcmp(name, (*(struct ref **)ref)->name);
+}
+
+static void receive_wanted_refs(struct packet_reader *reader,
+                               struct ref **sought, int nr_sought)
+{
+       process_section_header(reader, "wanted-refs", 0);
+       while (packet_reader_read(reader) == PACKET_READ_NORMAL) {
+               struct object_id oid;
+               const char *end;
+               struct ref **found;
+
+               if (parse_oid_hex(reader->line, &oid, &end) || *end++ != ' ')
+                       die(_("expected wanted-ref, got '%s'"), reader->line);
+
+               found = bsearch(end, sought, nr_sought, sizeof(*sought),
+                               cmp_name_ref);
+               if (!found)
+                       die(_("unexpected wanted-ref: '%s'"), reader->line);
+               oidcpy(&(*found)->old_oid, &oid);
+       }
+
+       if (reader->status != PACKET_READ_DELIM)
+               die(_("error processing wanted refs: %d"), reader->status);
+}
+
+static void receive_packfile_uris(struct packet_reader *reader,
+                                 struct string_list *uris)
+{
+       process_section_header(reader, "packfile-uris", 0);
+       while (packet_reader_read(reader) == PACKET_READ_NORMAL) {
+               if (reader->pktlen < the_hash_algo->hexsz ||
+                   reader->line[the_hash_algo->hexsz] != ' ')
+                       die("expected '<hash> <uri>', got: %s\n", reader->line);
+
+               string_list_append(uris, reader->line);
+       }
+       if (reader->status != PACKET_READ_DELIM)
+               die("expected DELIM");
+}
+
+enum fetch_state {
+       FETCH_CHECK_LOCAL = 0,
+       FETCH_SEND_REQUEST,
+       FETCH_PROCESS_ACKS,
+       FETCH_GET_PACK,
+       FETCH_DONE,
+};
+
+static void do_check_stateless_delimiter(const struct fetch_pack_args *args,
+                                        struct packet_reader *reader)
+{
+       check_stateless_delimiter(args->stateless_rpc, reader,
+                                 _("git fetch-pack: expected response end packet"));
+}
+
+static struct ref *do_fetch_pack_v2(struct fetch_pack_args *args,
+                                   int fd[2],
+                                   const struct ref *orig_ref,
+                                   struct ref **sought, int nr_sought,
+                                   struct oid_array *shallows,
+                                   struct shallow_info *si,
+                                   struct string_list *pack_lockfiles)
+{
+       struct repository *r = the_repository;
+       struct ref *ref = copy_ref_list(orig_ref);
+       enum fetch_state state = FETCH_CHECK_LOCAL;
+       struct oidset common = OIDSET_INIT;
+       struct packet_reader reader;
+       int in_vain = 0, negotiation_started = 0;
+       int haves_to_send = INITIAL_FLUSH;
+       struct fetch_negotiator negotiator_alloc;
+       struct fetch_negotiator *negotiator;
+       int seen_ack = 0;
+       struct string_list packfile_uris = STRING_LIST_INIT_DUP;
+       int i;
+
+       negotiator = &negotiator_alloc;
+       fetch_negotiator_init(r, negotiator);
+
+       packet_reader_init(&reader, fd[0], NULL, 0,
+                          PACKET_READ_CHOMP_NEWLINE |
+                          PACKET_READ_DIE_ON_ERR_PACKET);
+       if (git_env_bool("GIT_TEST_SIDEBAND_ALL", 1) &&
+           server_supports_feature("fetch", "sideband-all", 0)) {
+               reader.use_sideband = 1;
+               reader.me = "fetch-pack";
        }
 
-       if (!strcmp(var, "fetch.fsckobjects")) {
-               fetch_fsck_objects = git_config_bool(var, value);
+       while (state != FETCH_DONE) {
+               switch (state) {
+               case FETCH_CHECK_LOCAL:
+                       sort_ref_list(&ref, ref_compare_name);
+                       QSORT(sought, nr_sought, cmp_ref_by_name);
+
+                       /* v2 supports these by default */
+                       allow_unadvertised_object_request |= ALLOW_REACHABLE_SHA1;
+                       use_sideband = 2;
+                       if (args->depth > 0 || args->deepen_since || args->deepen_not)
+                               args->deepen = 1;
+
+                       /* Filter 'ref' by 'sought' and those that aren't local */
+                       mark_complete_and_common_ref(negotiator, args, &ref);
+                       filter_refs(args, &ref, sought, nr_sought);
+                       if (everything_local(args, &ref))
+                               state = FETCH_DONE;
+                       else
+                               state = FETCH_SEND_REQUEST;
+
+                       mark_tips(negotiator, args->negotiation_tips);
+                       for_each_cached_alternate(negotiator,
+                                                 insert_one_alternate_object);
+                       break;
+               case FETCH_SEND_REQUEST:
+                       if (!negotiation_started) {
+                               negotiation_started = 1;
+                               trace2_region_enter("fetch-pack",
+                                                   "negotiation_v2",
+                                                   the_repository);
+                       }
+                       if (send_fetch_request(negotiator, fd[1], args, ref,
+                                              &common,
+                                              &haves_to_send, &in_vain,
+                                              reader.use_sideband,
+                                              seen_ack))
+                               state = FETCH_GET_PACK;
+                       else
+                               state = FETCH_PROCESS_ACKS;
+                       break;
+               case FETCH_PROCESS_ACKS:
+                       /* Process ACKs/NAKs */
+                       switch (process_acks(negotiator, &reader, &common)) {
+                       case READY:
+                               /*
+                                * Don't check for response delimiter; get_pack() will
+                                * read the rest of this response.
+                                */
+                               state = FETCH_GET_PACK;
+                               break;
+                       case COMMON_FOUND:
+                               in_vain = 0;
+                               seen_ack = 1;
+                               /* fallthrough */
+                       case NO_COMMON_FOUND:
+                               do_check_stateless_delimiter(args, &reader);
+                               state = FETCH_SEND_REQUEST;
+                               break;
+                       }
+                       break;
+               case FETCH_GET_PACK:
+                       trace2_region_leave("fetch-pack",
+                                           "negotiation_v2",
+                                           the_repository);
+                       /* Check for shallow-info section */
+                       if (process_section_header(&reader, "shallow-info", 1))
+                               receive_shallow_info(args, &reader, shallows, si);
+
+                       if (process_section_header(&reader, "wanted-refs", 1))
+                               receive_wanted_refs(&reader, sought, nr_sought);
+
+                       /* get the pack(s) */
+                       if (process_section_header(&reader, "packfile-uris", 1))
+                               receive_packfile_uris(&reader, &packfile_uris);
+                       process_section_header(&reader, "packfile", 0);
+                       if (get_pack(args, fd, pack_lockfiles,
+                                    !packfile_uris.nr, sought, nr_sought))
+                               die(_("git fetch-pack: fetch failed."));
+                       do_check_stateless_delimiter(args, &reader);
+
+                       state = FETCH_DONE;
+                       break;
+               case FETCH_DONE:
+                       continue;
+               }
+       }
+
+       for (i = 0; i < packfile_uris.nr; i++) {
+               struct child_process cmd = CHILD_PROCESS_INIT;
+               char packname[GIT_MAX_HEXSZ + 1];
+               const char *uri = packfile_uris.items[i].string +
+                       the_hash_algo->hexsz + 1;
+
+               strvec_push(&cmd.args, "http-fetch");
+               strvec_pushf(&cmd.args, "--packfile=%.*s",
+                            (int) the_hash_algo->hexsz,
+                            packfile_uris.items[i].string);
+               strvec_push(&cmd.args, uri);
+               cmd.git_cmd = 1;
+               cmd.no_stdin = 1;
+               cmd.out = -1;
+               if (start_command(&cmd))
+                       die("fetch-pack: unable to spawn http-fetch");
+
+               if (read_in_full(cmd.out, packname, 5) < 0 ||
+                   memcmp(packname, "keep\t", 5))
+                       die("fetch-pack: expected keep then TAB at start of http-fetch output");
+
+               if (read_in_full(cmd.out, packname,
+                                the_hash_algo->hexsz + 1) < 0 ||
+                   packname[the_hash_algo->hexsz] != '\n')
+                       die("fetch-pack: expected hash then LF at end of http-fetch output");
+
+               packname[the_hash_algo->hexsz] = '\0';
+
+               close(cmd.out);
+
+               if (finish_command(&cmd))
+                       die("fetch-pack: unable to finish http-fetch");
+
+               if (memcmp(packfile_uris.items[i].string, packname,
+                          the_hash_algo->hexsz))
+                       die("fetch-pack: pack downloaded from %s does not match expected hash %.*s",
+                           uri, (int) the_hash_algo->hexsz,
+                           packfile_uris.items[i].string);
+
+               string_list_append_nodup(pack_lockfiles,
+                                        xstrfmt("%s/pack/pack-%s.keep",
+                                                get_object_directory(),
+                                                packname));
+       }
+       string_list_clear(&packfile_uris, 0);
+
+       if (negotiator)
+               negotiator->release(negotiator);
+
+       oidset_clear(&common);
+       return ref;
+}
+
+static int fetch_pack_config_cb(const char *var, const char *value, void *cb)
+{
+       if (strcmp(var, "fetch.fsck.skiplist") == 0) {
+               const char *path;
+
+               if (git_config_pathname(&path, var, value))
+                       return 1;
+               strbuf_addf(&fsck_msg_types, "%cskiplist=%s",
+                       fsck_msg_types.len ? ',' : '=', path);
+               free((char *)path);
                return 0;
        }
 
-       if (!strcmp(var, "transfer.fsckobjects")) {
-               transfer_fsck_objects = git_config_bool(var, value);
+       if (skip_prefix(var, "fetch.fsck.", &var)) {
+               if (is_valid_msg_type(var, value))
+                       strbuf_addf(&fsck_msg_types, "%c%s=%s",
+                               fsck_msg_types.len ? ',' : '=', var, value);
+               else
+                       warning("Skipping unknown msg id '%s'", var);
                return 0;
        }
 
        return git_default_config(var, value, cb);
 }
 
+static void fetch_pack_config(void)
+{
+       git_config_get_int("fetch.unpacklimit", &fetch_unpack_limit);
+       git_config_get_int("transfer.unpacklimit", &transfer_unpack_limit);
+       git_config_get_bool("repack.usedeltabaseoffset", &prefer_ofs_delta);
+       git_config_get_bool("fetch.fsckobjects", &fetch_fsck_objects);
+       git_config_get_bool("transfer.fsckobjects", &transfer_fsck_objects);
+       git_config_get_bool("transfer.advertisesid", &advertise_sid);
+       if (!uri_protocols.nr) {
+               char *str;
+
+               if (!git_config_get_string("fetch.uriprotocols", &str) && str) {
+                       string_list_split(&uri_protocols, str, ',', -1);
+                       free(str);
+               }
+       }
+
+       git_config(fetch_pack_config_cb, NULL);
+}
+
 static void fetch_pack_setup(void)
 {
        static int did_setup;
        if (did_setup)
                return;
-       git_config(fetch_pack_config, NULL);
+       fetch_pack_config();
        if (0 <= transfer_unpack_limit)
                unpack_limit = transfer_unpack_limit;
        else if (0 <= fetch_unpack_limit)
@@ -937,16 +1771,17 @@ static void update_shallow(struct fetch_pack_args *args,
                           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;
 
-       if (args->depth > 0 && alternate_shallow_file) {
+       if (args->deepen && alternate_shallow_file) {
                if (*alternate_shallow_file == '\0') { /* --unshallow */
-                       unlink_or_warn(git_path("shallow"));
-                       rollback_lock_file(&shallow_lock);
+                       unlink_or_warn(git_path_shallow(the_repository));
+                       rollback_shallow_file(the_repository, &shallow_lock);
                } else
-                       commit_lock_file(&shallow_lock);
+                       commit_shallow_file(the_repository, &shallow_lock);
+               alternate_shallow_file = NULL;
                return;
        }
 
@@ -960,18 +1795,19 @@ static void update_shallow(struct fetch_pack_args *args,
                 * 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);
+                       commit_shallow_file(the_repository, &shallow_lock);
+                       alternate_shallow_file = NULL;
                }
-               sha1_array_clear(&extra);
+               oid_array_clear(&extra);
                return;
        }
 
@@ -982,7 +1818,7 @@ static void update_shallow(struct fetch_pack_args *args,
        if (!si->nr_ours && !si->nr_theirs)
                return;
        for (i = 0; i < nr_sought; i++)
-               sha1_array_append(&ref, sought[i]->old_sha1);
+               oid_array_append(&ref, &sought[i]->old_oid);
        si->ref = &ref;
 
        if (args->update_shallow) {
@@ -992,23 +1828,24 @@ static void update_shallow(struct fetch_pack_args *args,
                 * 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);
+               commit_shallow_file(the_repository, &shallow_lock);
+               oid_array_clear(&extra);
+               oid_array_clear(&ref);
+               alternate_shallow_file = NULL;
                return;
        }
 
@@ -1024,33 +1861,97 @@ static void update_shallow(struct fetch_pack_args *args,
                                sought[i]->status = REF_STATUS_REJECT_SHALLOW;
        }
        free(status);
-       sha1_array_clear(&ref);
+       oid_array_clear(&ref);
+}
+
+static int iterate_ref_map(void *cb_data, struct object_id *oid)
+{
+       struct ref **rm = cb_data;
+       struct ref *ref = *rm;
+
+       if (!ref)
+               return -1; /* end of the list */
+       *rm = ref->next;
+       oidcpy(oid, &ref->old_oid);
+       return 0;
 }
 
 struct ref *fetch_pack(struct fetch_pack_args *args,
-                      int fd[], struct child_process *conn,
+                      int fd[],
                       const struct ref *ref,
-                      const char *dest,
                       struct ref **sought, int nr_sought,
-                      struct sha1_array *shallow,
-                      char **pack_lockfile)
+                      struct oid_array *shallow,
+                      struct string_list *pack_lockfiles,
+                      enum protocol_version version)
 {
        struct ref *ref_cpy;
        struct shallow_info si;
+       struct oid_array shallows_scratch = OID_ARRAY_INIT;
 
        fetch_pack_setup();
        if (nr_sought)
                nr_sought = remove_duplicates_in_refs(sought, nr_sought);
 
-       if (!ref) {
+       if (version != protocol_v2 && !ref) {
                packet_flush(fd[1]);
-               die("no matching remote head");
+               die(_("no matching remote head"));
+       }
+       if (version == protocol_v2) {
+               if (shallow->nr)
+                       BUG("Protocol V2 does not provide shallows at this point in the fetch");
+               memset(&si, 0, sizeof(si));
+               ref_cpy = do_fetch_pack_v2(args, fd, ref, sought, nr_sought,
+                                          &shallows_scratch, &si,
+                                          pack_lockfiles);
+       } else {
+               prepare_shallow_info(&si, shallow);
+               ref_cpy = do_fetch_pack(args, fd, ref, sought, nr_sought,
+                                       &si, pack_lockfiles);
+       }
+       reprepare_packed_git(the_repository);
+
+       if (!args->cloning && args->deepen) {
+               struct check_connected_options opt = CHECK_CONNECTED_INIT;
+               struct ref *iterator = ref_cpy;
+               opt.shallow_file = alternate_shallow_file;
+               if (args->deepen)
+                       opt.is_deepening_fetch = 1;
+               if (check_connected(iterate_ref_map, &iterator, &opt)) {
+                       error(_("remote did not send all necessary objects"));
+                       free_refs(ref_cpy);
+                       ref_cpy = NULL;
+                       rollback_shallow_file(the_repository, &shallow_lock);
+                       goto cleanup;
+               }
+               args->connectivity_checked = 1;
        }
-       prepare_shallow_info(&si, shallow);
-       ref_cpy = do_fetch_pack(args, fd, ref, sought, nr_sought,
-                               &si, pack_lockfile);
-       reprepare_packed_git();
+
        update_shallow(args, sought, nr_sought, &si);
+cleanup:
        clear_shallow_info(&si);
+       oid_array_clear(&shallows_scratch);
        return ref_cpy;
 }
+
+int report_unmatched_refs(struct ref **sought, int nr_sought)
+{
+       int i, ret = 0;
+
+       for (i = 0; i < nr_sought; i++) {
+               if (!sought[i])
+                       continue;
+               switch (sought[i]->match_status) {
+               case REF_MATCHED:
+                       continue;
+               case REF_NOT_MATCHED:
+                       error(_("no such remote ref %s"), sought[i]->name);
+                       break;
+               case REF_UNADVERTISED_NOT_ALLOWED:
+                       error(_("Server does not allow request for unadvertised object %s"),
+                             sought[i]->name);
+                       break;
+               }
+               ret = 1;
+       }
+       return ret;
+}