pack-objects: use reachability bitmap index when generating non-stdout pack
[gitweb.git] / remote.c
index dca3442abacfdc45561df0483f031e7ee7c06259..a326e4e2516e2129e7a08bfc149786402ec160fb 100644 (file)
--- a/remote.c
+++ b/remote.c
@@ -8,6 +8,7 @@
 #include "tag.h"
 #include "string-list.h"
 #include "mergesort.h"
+#include "argv-array.h"
 
 enum map_direction { FROM_SRC, FROM_DST };
 
@@ -54,9 +55,6 @@ static const char *pushremote_name;
 static struct rewrites rewrites;
 static struct rewrites rewrites_push;
 
-#define BUF_SIZE (2048)
-static char buffer[BUF_SIZE];
-
 static int valid_remote(const struct remote *remote)
 {
        return (!!remote->url) || (!!remote->foreign_vcs);
@@ -65,7 +63,6 @@ static int valid_remote(const struct remote *remote)
 static const char *alias_url(const char *url, struct rewrites *r)
 {
        int i, j;
-       char *ret;
        struct counted_string *longest;
        int longest_i;
 
@@ -86,11 +83,7 @@ static const char *alias_url(const char *url, struct rewrites *r)
        if (!longest)
                return url;
 
-       ret = xmalloc(r->rewrite[longest_i]->baselen +
-                    (strlen(url) - longest->len) + 1);
-       strcpy(ret, r->rewrite[longest_i]->base);
-       strcpy(ret + r->rewrite[longest_i]->baselen, url + longest->len);
-       return ret;
+       return xstrfmt("%s%s", r->rewrite[longest_i]->base, url + longest->len);
 }
 
 static void add_push_refspec(struct remote *remote, const char *ref)
@@ -248,199 +241,165 @@ static void add_instead_of(struct rewrite *rewrite, const char *instead_of)
        rewrite->instead_of_nr++;
 }
 
+static const char *skip_spaces(const char *s)
+{
+       while (isspace(*s))
+               s++;
+       return s;
+}
+
 static void read_remotes_file(struct remote *remote)
 {
+       struct strbuf buf = STRBUF_INIT;
        FILE *f = fopen(git_path("remotes/%s", remote->name), "r");
 
        if (!f)
                return;
        remote->origin = REMOTE_REMOTES;
-       while (fgets(buffer, BUF_SIZE, f)) {
-               int value_list;
-               char *s, *p;
-
-               if (starts_with(buffer, "URL:")) {
-                       value_list = 0;
-                       s = buffer + 4;
-               } else if (starts_with(buffer, "Push:")) {
-                       value_list = 1;
-                       s = buffer + 5;
-               } else if (starts_with(buffer, "Pull:")) {
-                       value_list = 2;
-                       s = buffer + 5;
-               } else
-                       continue;
-
-               while (isspace(*s))
-                       s++;
-               if (!*s)
-                       continue;
+       while (strbuf_getline(&buf, f) != EOF) {
+               const char *v;
 
-               p = s + strlen(s);
-               while (isspace(p[-1]))
-                       *--p = 0;
+               strbuf_rtrim(&buf);
 
-               switch (value_list) {
-               case 0:
-                       add_url_alias(remote, xstrdup(s));
-                       break;
-               case 1:
-                       add_push_refspec(remote, xstrdup(s));
-                       break;
-               case 2:
-                       add_fetch_refspec(remote, xstrdup(s));
-                       break;
-               }
+               if (skip_prefix(buf.buf, "URL:", &v))
+                       add_url_alias(remote, xstrdup(skip_spaces(v)));
+               else if (skip_prefix(buf.buf, "Push:", &v))
+                       add_push_refspec(remote, xstrdup(skip_spaces(v)));
+               else if (skip_prefix(buf.buf, "Pull:", &v))
+                       add_fetch_refspec(remote, xstrdup(skip_spaces(v)));
        }
+       strbuf_release(&buf);
        fclose(f);
 }
 
 static void read_branches_file(struct remote *remote)
 {
        char *frag;
-       struct strbuf branch = STRBUF_INIT;
-       int n = 1000;
-       FILE *f = fopen(git_path("branches/%.*s", n, remote->name), "r");
-       char *s, *p;
-       int len;
+       struct strbuf buf = STRBUF_INIT;
+       FILE *f = fopen(git_path("branches/%s", remote->name), "r");
 
        if (!f)
                return;
-       s = fgets(buffer, BUF_SIZE, f);
+
+       strbuf_getline_lf(&buf, f);
        fclose(f);
-       if (!s)
-               return;
-       while (isspace(*s))
-               s++;
-       if (!*s)
+       strbuf_trim(&buf);
+       if (!buf.len) {
+               strbuf_release(&buf);
                return;
+       }
+
        remote->origin = REMOTE_BRANCHES;
-       p = s + strlen(s);
-       while (isspace(p[-1]))
-               *--p = 0;
-       len = p - s;
-       p = xmalloc(len + 1);
-       strcpy(p, s);
 
        /*
         * The branches file would have URL and optionally
         * #branch specified.  The "master" (or specified) branch is
-        * fetched and stored in the local branch of the same name.
+        * fetched and stored in the local branch matching the
+        * remote name.
         */
-       frag = strchr(p, '#');
-       if (frag) {
+       frag = strchr(buf.buf, '#');
+       if (frag)
                *(frag++) = '\0';
-               strbuf_addf(&branch, "refs/heads/%s", frag);
-       } else
-               strbuf_addstr(&branch, "refs/heads/master");
+       else
+               frag = "master";
+
+       add_url_alias(remote, strbuf_detach(&buf, NULL));
+       add_fetch_refspec(remote, xstrfmt("refs/heads/%s:refs/heads/%s",
+                                         frag, remote->name));
 
-       strbuf_addf(&branch, ":refs/heads/%s", remote->name);
-       add_url_alias(remote, p);
-       add_fetch_refspec(remote, strbuf_detach(&branch, NULL));
        /*
         * Cogito compatible push: push current HEAD to remote #branch
         * (master if missing)
         */
-       strbuf_init(&branch, 0);
-       strbuf_addstr(&branch, "HEAD");
-       if (frag)
-               strbuf_addf(&branch, ":refs/heads/%s", frag);
-       else
-               strbuf_addstr(&branch, ":refs/heads/master");
-       add_push_refspec(remote, strbuf_detach(&branch, NULL));
+       add_push_refspec(remote, xstrfmt("HEAD:refs/heads/%s", frag));
        remote->fetch_tags = 1; /* always auto-follow */
 }
 
 static int handle_config(const char *key, const char *value, void *cb)
 {
        const char *name;
+       int namelen;
        const char *subkey;
        struct remote *remote;
        struct branch *branch;
-       if (starts_with(key, "branch.")) {
-               name = key + 7;
-               subkey = strrchr(name, '.');
-               if (!subkey)
+       if (parse_config_key(key, "branch", &name, &namelen, &subkey) >= 0) {
+               if (!name)
                        return 0;
-               branch = make_branch(name, subkey - name);
-               if (!strcmp(subkey, ".remote")) {
+               branch = make_branch(name, namelen);
+               if (!strcmp(subkey, "remote")) {
                        return git_config_string(&branch->remote_name, key, value);
-               } else if (!strcmp(subkey, ".pushremote")) {
+               } else if (!strcmp(subkey, "pushremote")) {
                        return git_config_string(&branch->pushremote_name, key, value);
-               } else if (!strcmp(subkey, ".merge")) {
+               } else if (!strcmp(subkey, "merge")) {
                        if (!value)
                                return config_error_nonbool(key);
                        add_merge(branch, xstrdup(value));
                }
                return 0;
        }
-       if (starts_with(key, "url.")) {
+       if (parse_config_key(key, "url", &name, &namelen, &subkey) >= 0) {
                struct rewrite *rewrite;
-               name = key + 4;
-               subkey = strrchr(name, '.');
-               if (!subkey)
+               if (!name)
                        return 0;
-               if (!strcmp(subkey, ".insteadof")) {
-                       rewrite = make_rewrite(&rewrites, name, subkey - name);
+               if (!strcmp(subkey, "insteadof")) {
+                       rewrite = make_rewrite(&rewrites, name, namelen);
                        if (!value)
                                return config_error_nonbool(key);
                        add_instead_of(rewrite, xstrdup(value));
-               } else if (!strcmp(subkey, ".pushinsteadof")) {
-                       rewrite = make_rewrite(&rewrites_push, name, subkey - name);
+               } else if (!strcmp(subkey, "pushinsteadof")) {
+                       rewrite = make_rewrite(&rewrites_push, name, namelen);
                        if (!value)
                                return config_error_nonbool(key);
                        add_instead_of(rewrite, xstrdup(value));
                }
        }
 
-       if (!starts_with(key,  "remote."))
+       if (parse_config_key(key, "remote", &name, &namelen, &subkey) < 0)
                return 0;
-       name = key + 7;
 
        /* Handle remote.* variables */
-       if (!strcmp(name, "pushdefault"))
+       if (!name && !strcmp(subkey, "pushdefault"))
                return git_config_string(&pushremote_name, key, value);
 
+       if (!name)
+               return 0;
        /* Handle remote.<name>.* variables */
        if (*name == '/') {
                warning("Config remote shorthand cannot begin with '/': %s",
                        name);
                return 0;
        }
-       subkey = strrchr(name, '.');
-       if (!subkey)
-               return 0;
-       remote = make_remote(name, subkey - name);
+       remote = make_remote(name, namelen);
        remote->origin = REMOTE_CONFIG;
-       if (!strcmp(subkey, ".mirror"))
+       if (!strcmp(subkey, "mirror"))
                remote->mirror = git_config_bool(key, value);
-       else if (!strcmp(subkey, ".skipdefaultupdate"))
+       else if (!strcmp(subkey, "skipdefaultupdate"))
                remote->skip_default_update = git_config_bool(key, value);
-       else if (!strcmp(subkey, ".skipfetchall"))
+       else if (!strcmp(subkey, "skipfetchall"))
                remote->skip_default_update = git_config_bool(key, value);
-       else if (!strcmp(subkey, ".prune"))
+       else if (!strcmp(subkey, "prune"))
                remote->prune = git_config_bool(key, value);
-       else if (!strcmp(subkey, ".url")) {
+       else if (!strcmp(subkey, "url")) {
                const char *v;
                if (git_config_string(&v, key, value))
                        return -1;
                add_url(remote, v);
-       } else if (!strcmp(subkey, ".pushurl")) {
+       } else if (!strcmp(subkey, "pushurl")) {
                const char *v;
                if (git_config_string(&v, key, value))
                        return -1;
                add_pushurl(remote, v);
-       } else if (!strcmp(subkey, ".push")) {
+       } else if (!strcmp(subkey, "push")) {
                const char *v;
                if (git_config_string(&v, key, value))
                        return -1;
                add_push_refspec(remote, v);
-       } else if (!strcmp(subkey, ".fetch")) {
+       } else if (!strcmp(subkey, "fetch")) {
                const char *v;
                if (git_config_string(&v, key, value))
                        return -1;
                add_fetch_refspec(remote, v);
-       } else if (!strcmp(subkey, ".receivepack")) {
+       } else if (!strcmp(subkey, "receivepack")) {
                const char *v;
                if (git_config_string(&v, key, value))
                        return -1;
@@ -448,7 +407,7 @@ static int handle_config(const char *key, const char *value, void *cb)
                        remote->receivepack = v;
                else
                        error("more than one receivepack given, using the first");
-       } else if (!strcmp(subkey, ".uploadpack")) {
+       } else if (!strcmp(subkey, "uploadpack")) {
                const char *v;
                if (git_config_string(&v, key, value))
                        return -1;
@@ -456,15 +415,18 @@ static int handle_config(const char *key, const char *value, void *cb)
                        remote->uploadpack = v;
                else
                        error("more than one uploadpack given, using the first");
-       } else if (!strcmp(subkey, ".tagopt")) {
+       } else if (!strcmp(subkey, "tagopt")) {
                if (!strcmp(value, "--no-tags"))
                        remote->fetch_tags = -1;
                else if (!strcmp(value, "--tags"))
                        remote->fetch_tags = 2;
-       } else if (!strcmp(subkey, ".proxy")) {
+       } else if (!strcmp(subkey, "proxy")) {
                return git_config_string((const char **)&remote->http_proxy,
                                         key, value);
-       } else if (!strcmp(subkey, ".vcs")) {
+       } else if (!strcmp(subkey, "proxyauthmethod")) {
+               return git_config_string((const char **)&remote->http_proxy_authmethod,
+                                        key, value);
+       } else if (!strcmp(subkey, "vcs")) {
                return git_config_string(&remote->foreign_vcs, key, value);
        }
        return 0;
@@ -492,8 +454,7 @@ static void alias_all_urls(void)
 static void read_config(void)
 {
        static int loaded;
-       unsigned char sha1[20];
-       const char *head_ref;
+       struct object_id oid;
        int flag;
 
        if (loaded)
@@ -501,10 +462,12 @@ static void read_config(void)
        loaded = 1;
 
        current_branch = NULL;
-       head_ref = resolve_ref_unsafe("HEAD", 0, sha1, &flag);
-       if (head_ref && (flag & REF_ISSYMREF) &&
-           skip_prefix(head_ref, "refs/heads/", &head_ref)) {
-               current_branch = make_branch(head_ref, 0);
+       if (startup_info->have_repository) {
+               const char *head_ref = resolve_ref_unsafe("HEAD", 0, oid.hash, &flag);
+               if (head_ref && (flag & REF_ISSYMREF) &&
+                   skip_prefix(head_ref, "refs/heads/", &head_ref)) {
+                       current_branch = make_branch(head_ref, 0);
+               }
        }
        git_config(handle_config, NULL);
        alias_all_urls();
@@ -580,12 +543,12 @@ static struct refspec *parse_refspec_internal(int nr_refspec, const char **refsp
                flags = REFNAME_ALLOW_ONELEVEL | (is_glob ? REFNAME_REFSPEC_PATTERN : 0);
 
                if (fetch) {
-                       unsigned char unused[40];
+                       struct object_id unused;
 
                        /* LHS */
                        if (!*rs[i].src)
                                ; /* empty is ok; it means "HEAD" */
-                       else if (llen == 40 && !get_sha1_hex(rs[i].src, unused))
+                       else if (llen == GIT_SHA1_HEXSZ && !get_oid_hex(rs[i].src, &unused))
                                rs[i].exact_sha1 = 1; /* ok */
                        else if (!check_refname_format(rs[i].src, flags))
                                ; /* valid looking ref is ok */
@@ -751,18 +714,9 @@ struct remote *pushremote_get(const char *name)
        return remote_get_1(name, pushremote_for_branch);
 }
 
-int remote_is_configured(const char *name)
+int remote_is_configured(struct remote *remote)
 {
-       struct remotes_hash_key lookup;
-       struct hashmap_entry lookup_entry;
-       read_config();
-
-       init_remotes_hash();
-       lookup.str = name;
-       lookup.len = strlen(name);
-       hashmap_entry_init(&lookup_entry, memhash(name, lookup.len));
-
-       return hashmap_get(&remotes_hash, &lookup_entry, &lookup) != NULL;
+       return remote && remote->origin;
 }
 
 int for_each_remote(each_remote_fn fn, void *priv)
@@ -964,7 +918,7 @@ static struct ref *alloc_ref_with_prefix(const char *prefix, size_t prefixlen,
                const char *name)
 {
        size_t len = strlen(name);
-       struct ref *ref = xcalloc(1, sizeof(struct ref) + prefixlen + len + 1);
+       struct ref *ref = xcalloc(1, st_add4(sizeof(*ref), prefixlen, len, 1));
        memcpy(ref->name, prefix, prefixlen);
        memcpy(ref->name + prefixlen, name, len);
        return ref;
@@ -981,9 +935,9 @@ struct ref *copy_ref(const struct ref *ref)
        size_t len;
        if (!ref)
                return NULL;
-       len = strlen(ref->name);
-       cpy = xmalloc(sizeof(struct ref) + len + 1);
-       memcpy(cpy, ref, sizeof(struct ref) + len + 1);
+       len = st_add3(sizeof(struct ref), strlen(ref->name), 1);
+       cpy = xmalloc(len);
+       memcpy(cpy, ref, len);
        cpy->next = NULL;
        cpy->symref = xstrdup_or_null(ref->symref);
        cpy->remote_status = xstrdup_or_null(ref->remote_status);
@@ -1111,14 +1065,14 @@ static void tail_link_ref(struct ref *ref, struct ref ***tail)
 static struct ref *alloc_delete_ref(void)
 {
        struct ref *ref = alloc_ref("(delete)");
-       hashclr(ref->new_sha1);
+       oidclr(&ref->new_oid);
        return ref;
 }
 
 static int try_explicit_object_name(const char *name,
                                    struct ref **match)
 {
-       unsigned char sha1[20];
+       struct object_id oid;
 
        if (!*name) {
                if (match)
@@ -1126,12 +1080,12 @@ static int try_explicit_object_name(const char *name,
                return 0;
        }
 
-       if (get_sha1(name, sha1))
+       if (get_sha1(name, oid.hash))
                return -1;
 
        if (match) {
                *match = alloc_ref(name);
-               hashcpy((*match)->new_sha1, sha1);
+               oidcpy(&(*match)->new_oid, &oid);
        }
        return 0;
 }
@@ -1146,10 +1100,10 @@ static struct ref *make_linked_ref(const char *name, struct ref ***tail)
 static char *guess_ref(const char *name, struct ref *peer)
 {
        struct strbuf buf = STRBUF_INIT;
-       unsigned char sha1[20];
+       struct object_id oid;
 
        const char *r = resolve_ref_unsafe(peer->name, RESOLVE_REF_READING,
-                                          sha1, NULL);
+                                          oid.hash, NULL);
        if (!r)
                return NULL;
 
@@ -1207,12 +1161,12 @@ static int match_explicit(struct ref *src, struct ref *dst,
                return -1;
 
        if (!dst_value) {
-               unsigned char sha1[20];
+               struct object_id oid;
                int flag;
 
                dst_value = resolve_ref_unsafe(matched_src->name,
                                               RESOLVE_REF_READING,
-                                              sha1, &flag);
+                                              oid.hash, &flag);
                if (!dst_value ||
                    ((flag & REF_ISSYMREF) &&
                     !starts_with(dst_value, "refs/heads/")))
@@ -1226,7 +1180,7 @@ static int match_explicit(struct ref *src, struct ref *dst,
        case 0:
                if (starts_with(dst_value, "refs/"))
                        matched_dst = make_linked_ref(dst_value, dst_tail);
-               else if (is_null_sha1(matched_src->new_sha1))
+               else if (is_null_oid(&matched_src->new_oid))
                        error("unable to delete '%s': remote ref does not exist",
                              dst_value);
                else if ((dst_guess = guess_ref(dst_value, matched_src)))
@@ -1328,13 +1282,13 @@ struct tips {
        int nr, alloc;
 };
 
-static void add_to_tips(struct tips *tips, const unsigned char *sha1)
+static void add_to_tips(struct tips *tips, const struct object_id *oid)
 {
        struct commit *commit;
 
-       if (is_null_sha1(sha1))
+       if (is_null_oid(oid))
                return;
-       commit = lookup_commit_reference_gently(sha1, 1);
+       commit = lookup_commit_reference_gently(oid->hash, 1);
        if (!commit || (commit->object.flags & TMP_MARK))
                return;
        commit->object.flags |= TMP_MARK;
@@ -1357,10 +1311,10 @@ static void add_missing_tags(struct ref *src, struct ref **dst, struct ref ***ds
        memset(&sent_tips, 0, sizeof(sent_tips));
        for (ref = *dst; ref; ref = ref->next) {
                if (ref->peer_ref &&
-                   !is_null_sha1(ref->peer_ref->new_sha1))
-                       add_to_tips(&sent_tips, ref->peer_ref->new_sha1);
+                   !is_null_oid(&ref->peer_ref->new_oid))
+                       add_to_tips(&sent_tips, &ref->peer_ref->new_oid);
                else
-                       add_to_tips(&sent_tips, ref->old_sha1);
+                       add_to_tips(&sent_tips, &ref->old_oid);
                if (starts_with(ref->name, "refs/tags/"))
                        string_list_append(&dst_tag, ref->name);
        }
@@ -1374,7 +1328,7 @@ static void add_missing_tags(struct ref *src, struct ref **dst, struct ref ***ds
                        continue; /* not a tag */
                if (string_list_has_string(&dst_tag, ref->name))
                        continue; /* they already have it */
-               if (sha1_object_info(ref->new_sha1, NULL) != OBJ_TAG)
+               if (sha1_object_info(ref->new_oid.hash, NULL) != OBJ_TAG)
                        continue; /* be conservative */
                item = string_list_append(&src_tag, ref->name);
                item->util = ref;
@@ -1394,9 +1348,9 @@ static void add_missing_tags(struct ref *src, struct ref **dst, struct ref ***ds
                        struct ref *dst_ref;
                        struct commit *commit;
 
-                       if (is_null_sha1(ref->new_sha1))
+                       if (is_null_oid(&ref->new_oid))
                                continue;
-                       commit = lookup_commit_reference_gently(ref->new_sha1, 1);
+                       commit = lookup_commit_reference_gently(ref->new_oid.hash, 1);
                        if (!commit)
                                /* not pushing a commit, which is not an error */
                                continue;
@@ -1410,7 +1364,7 @@ static void add_missing_tags(struct ref *src, struct ref **dst, struct ref ***ds
 
                        /* Add it in */
                        dst_ref = make_linked_ref(ref->name, dst_tail);
-                       hashcpy(dst_ref->new_sha1, ref->new_sha1);
+                       oidcpy(&dst_ref->new_oid, &ref->new_oid);
                        dst_ref->peer_ref = copy_ref(ref);
                }
        }
@@ -1517,7 +1471,7 @@ int match_push_refs(struct ref *src, struct ref **dst,
 
                        /* Create a new one and link it */
                        dst_peer = make_linked_ref(dst_name, &dst_tail);
-                       hashcpy(dst_peer->new_sha1, ref->new_sha1);
+                       oidcpy(&dst_peer->new_oid, &ref->new_oid);
                        string_list_insert(&dst_ref_index,
                                dst_peer->name)->util = dst_peer;
                }
@@ -1569,23 +1523,20 @@ void set_ref_status_for_push(struct ref *remote_refs, int send_mirror,
                int reject_reason = 0;
 
                if (ref->peer_ref)
-                       hashcpy(ref->new_sha1, ref->peer_ref->new_sha1);
+                       oidcpy(&ref->new_oid, &ref->peer_ref->new_oid);
                else if (!send_mirror)
                        continue;
 
-               ref->deletion = is_null_sha1(ref->new_sha1);
+               ref->deletion = is_null_oid(&ref->new_oid);
                if (!ref->deletion &&
-                       !hashcmp(ref->old_sha1, ref->new_sha1)) {
+                       !oidcmp(&ref->old_oid, &ref->new_oid)) {
                        ref->status = REF_STATUS_UPTODATE;
                        continue;
                }
 
                /*
-                * Bypass the usual "must fast-forward" check but
-                * replace it with a weaker "the old value must be
-                * this value we observed".  If the remote ref has
-                * moved and is now different from what we expect,
-                * reject any push.
+                * If the remote ref has moved and is now different
+                * from what we expect, reject any push.
                 *
                 * It also is an error if the user told us to check
                 * with the remote-tracking branch to find the value
@@ -1594,12 +1545,16 @@ void set_ref_status_for_push(struct ref *remote_refs, int send_mirror,
                 */
                if (ref->expect_old_sha1) {
                        if (ref->expect_old_no_trackback ||
-                           hashcmp(ref->old_sha1, ref->old_sha1_expect))
+                           oidcmp(&ref->old_oid, &ref->old_oid_expect))
                                reject_reason = REF_STATUS_REJECT_STALE;
+                       else
+                               /* If the ref isn't stale then force the update. */
+                               force_ref_update = 1;
                }
 
                /*
-                * The usual "must fast-forward" rules.
+                * If the update isn't already rejected then check
+                * the usual "must fast-forward" rules.
                 *
                 * Decide whether an individual refspec A:B can be
                 * pushed.  The push will succeed if any of the
@@ -1618,15 +1573,15 @@ void set_ref_status_for_push(struct ref *remote_refs, int send_mirror,
                 *     passing the --force argument
                 */
 
-               else if (!ref->deletion && !is_null_sha1(ref->old_sha1)) {
+               if (!reject_reason && !ref->deletion && !is_null_oid(&ref->old_oid)) {
                        if (starts_with(ref->name, "refs/tags/"))
                                reject_reason = REF_STATUS_REJECT_ALREADY_EXISTS;
-                       else if (!has_sha1_file(ref->old_sha1))
+                       else if (!has_object_file(&ref->old_oid))
                                reject_reason = REF_STATUS_REJECT_FETCH_FIRST;
-                       else if (!lookup_commit_reference_gently(ref->old_sha1, 1) ||
-                                !lookup_commit_reference_gently(ref->new_sha1, 1))
+                       else if (!lookup_commit_reference_gently(ref->old_oid.hash, 1) ||
+                                !lookup_commit_reference_gently(ref->new_oid.hash, 1))
                                reject_reason = REF_STATUS_REJECT_NEEDS_FORCE;
-                       else if (!ref_newer(ref->new_sha1, ref->old_sha1))
+                       else if (!ref_newer(&ref->new_oid, &ref->old_oid))
                                reject_reason = REF_STATUS_REJECT_NONFASTFORWARD;
                }
 
@@ -1645,7 +1600,7 @@ static void set_merge(struct branch *ret)
 {
        struct remote *remote;
        char *ref;
-       unsigned char sha1[20];
+       struct object_id oid;
        int i;
 
        if (!ret)
@@ -1671,7 +1626,7 @@ static void set_merge(struct branch *ret)
                    strcmp(ret->remote_name, "."))
                        continue;
                if (dwim_ref(ret->merge_name[i], strlen(ret->merge_name[i]),
-                            sha1, &ref) == 1)
+                            oid.hash, &ref) == 1)
                        ret->merge[i]->dst = ref;
                else
                        ret->merge[i]->dst = xstrdup(ret->merge_name[i]);
@@ -1705,19 +1660,136 @@ int branch_merge_matches(struct branch *branch,
        return refname_match(branch->merge[i]->src, refname);
 }
 
-const char *branch_get_upstream(struct branch *branch)
+__attribute__((format (printf,2,3)))
+static const char *error_buf(struct strbuf *err, const char *fmt, ...)
 {
-       if (!branch || !branch->merge || !branch->merge[0])
-               return NULL;
+       if (err) {
+               va_list ap;
+               va_start(ap, fmt);
+               strbuf_vaddf(err, fmt, ap);
+               va_end(ap);
+       }
+       return NULL;
+}
+
+const char *branch_get_upstream(struct branch *branch, struct strbuf *err)
+{
+       if (!branch)
+               return error_buf(err, _("HEAD does not point to a branch"));
+
+       if (!branch->merge || !branch->merge[0]) {
+               /*
+                * no merge config; is it because the user didn't define any,
+                * or because it is not a real branch, and get_branch
+                * auto-vivified it?
+                */
+               if (!ref_exists(branch->refname))
+                       return error_buf(err, _("no such branch: '%s'"),
+                                        branch->name);
+               return error_buf(err,
+                                _("no upstream configured for branch '%s'"),
+                                branch->name);
+       }
+
+       if (!branch->merge[0]->dst)
+               return error_buf(err,
+                                _("upstream branch '%s' not stored as a remote-tracking branch"),
+                                branch->merge[0]->src);
+
        return branch->merge[0]->dst;
 }
 
+static const char *tracking_for_push_dest(struct remote *remote,
+                                         const char *refname,
+                                         struct strbuf *err)
+{
+       char *ret;
+
+       ret = apply_refspecs(remote->fetch, remote->fetch_refspec_nr, refname);
+       if (!ret)
+               return error_buf(err,
+                                _("push destination '%s' on remote '%s' has no local tracking branch"),
+                                refname, remote->name);
+       return ret;
+}
+
+static const char *branch_get_push_1(struct branch *branch, struct strbuf *err)
+{
+       struct remote *remote;
+
+       if (!branch)
+               return error_buf(err, _("HEAD does not point to a branch"));
+
+       remote = remote_get(pushremote_for_branch(branch, NULL));
+       if (!remote)
+               return error_buf(err,
+                                _("branch '%s' has no remote for pushing"),
+                                branch->name);
+
+       if (remote->push_refspec_nr) {
+               char *dst;
+               const char *ret;
+
+               dst = apply_refspecs(remote->push, remote->push_refspec_nr,
+                                    branch->refname);
+               if (!dst)
+                       return error_buf(err,
+                                        _("push refspecs for '%s' do not include '%s'"),
+                                        remote->name, branch->name);
+
+               ret = tracking_for_push_dest(remote, dst, err);
+               free(dst);
+               return ret;
+       }
+
+       if (remote->mirror)
+               return tracking_for_push_dest(remote, branch->refname, err);
+
+       switch (push_default) {
+       case PUSH_DEFAULT_NOTHING:
+               return error_buf(err, _("push has no destination (push.default is 'nothing')"));
+
+       case PUSH_DEFAULT_MATCHING:
+       case PUSH_DEFAULT_CURRENT:
+               return tracking_for_push_dest(remote, branch->refname, err);
+
+       case PUSH_DEFAULT_UPSTREAM:
+               return branch_get_upstream(branch, err);
+
+       case PUSH_DEFAULT_UNSPECIFIED:
+       case PUSH_DEFAULT_SIMPLE:
+               {
+                       const char *up, *cur;
+
+                       up = branch_get_upstream(branch, err);
+                       if (!up)
+                               return NULL;
+                       cur = tracking_for_push_dest(remote, branch->refname, err);
+                       if (!cur)
+                               return NULL;
+                       if (strcmp(cur, up))
+                               return error_buf(err,
+                                                _("cannot resolve 'simple' push to a single destination"));
+                       return cur;
+               }
+       }
+
+       die("BUG: unhandled push situation");
+}
+
+const char *branch_get_push(struct branch *branch, struct strbuf *err)
+{
+       if (!branch->push_tracking_ref)
+               branch->push_tracking_ref = branch_get_push_1(branch, err);
+       return branch->push_tracking_ref;
+}
+
 static int ignore_symref_update(const char *refname)
 {
-       unsigned char sha1[20];
+       struct object_id oid;
        int flag;
 
-       if (!resolve_ref_unsafe(refname, 0, sha1, &flag))
+       if (!resolve_ref_unsafe(refname, 0, oid.hash, &flag))
                return 0; /* non-existing refs are OK */
        return (flag & REF_ISSYMREF);
 }
@@ -1808,7 +1880,7 @@ int get_fetch_map(const struct ref *remote_refs,
 
                if (refspec->exact_sha1) {
                        ref_map = alloc_ref(name);
-                       get_sha1_hex(name, ref_map->old_sha1);
+                       get_oid_hex(name, &ref_map->old_oid);
                } else {
                        ref_map = get_remote_ref(remote_refs, name);
                }
@@ -1849,7 +1921,7 @@ int resolve_remote_symref(struct ref *ref, struct ref *list)
                return 0;
        for (; list; list = list->next)
                if (!strcmp(ref->symref, list->name)) {
-                       hashcpy(ref->old_sha1, list->old_sha1);
+                       oidcpy(&ref->old_oid, &list->old_oid);
                        return 0;
                }
        return 1;
@@ -1858,14 +1930,12 @@ int resolve_remote_symref(struct ref *ref, struct ref *list)
 static void unmark_and_free(struct commit_list *list, unsigned int mark)
 {
        while (list) {
-               struct commit_list *temp = list;
-               temp->item->object.flags &= ~mark;
-               list = temp->next;
-               free(temp);
+               struct commit *commit = pop_commit(&list);
+               commit->object.flags &= ~mark;
        }
 }
 
-int ref_newer(const unsigned char *new_sha1, const unsigned char *old_sha1)
+int ref_newer(const struct object_id *new_oid, const struct object_id *old_oid)
 {
        struct object *o;
        struct commit *old, *new;
@@ -1876,12 +1946,12 @@ int ref_newer(const unsigned char *new_sha1, const unsigned char *old_sha1)
         * Both new and old must be commit-ish and new is descendant of
         * old.  Otherwise we require --force.
         */
-       o = deref_tag(parse_object(old_sha1), NULL, 0);
+       o = deref_tag(parse_object(old_oid->hash), NULL, 0);
        if (!o || o->type != OBJ_COMMIT)
                return 0;
        old = (struct commit *) o;
 
-       o = deref_tag(parse_object(new_sha1), NULL, 0);
+       o = deref_tag(parse_object(new_oid->hash), NULL, 0);
        if (!o || o->type != OBJ_COMMIT)
                return 0;
        new = (struct commit *) o;
@@ -1906,58 +1976,58 @@ int ref_newer(const unsigned char *new_sha1, const unsigned char *old_sha1)
 
 /*
  * Compare a branch with its upstream, and save their differences (number
- * of commits) in *num_ours and *num_theirs.
+ * of commits) in *num_ours and *num_theirs. The name of the upstream branch
+ * (or NULL if no upstream is defined) is returned via *upstream_name, if it
+ * is not itself NULL.
  *
- * Return 0 if branch has no upstream (no base), -1 if upstream is missing
- * (with "gone" base), otherwise 1 (with base).
+ * Returns -1 if num_ours and num_theirs could not be filled in (e.g., no
+ * upstream defined, or ref does not exist), 0 otherwise.
  */
-int stat_tracking_info(struct branch *branch, int *num_ours, int *num_theirs)
+int stat_tracking_info(struct branch *branch, int *num_ours, int *num_theirs,
+                      const char **upstream_name)
 {
-       unsigned char sha1[20];
+       struct object_id oid;
        struct commit *ours, *theirs;
-       char symmetric[84];
        struct rev_info revs;
-       const char *rev_argv[10], *base;
-       int rev_argc;
+       const char *base;
+       struct argv_array argv = ARGV_ARRAY_INIT;
 
        /* Cannot stat unless we are marked to build on top of somebody else. */
-       base = branch_get_upstream(branch);
+       base = branch_get_upstream(branch, NULL);
+       if (upstream_name)
+               *upstream_name = base;
        if (!base)
-               return 0;
+               return -1;
 
        /* Cannot stat if what we used to build on no longer exists */
-       if (read_ref(base, sha1))
+       if (read_ref(base, oid.hash))
                return -1;
-       theirs = lookup_commit_reference(sha1);
+       theirs = lookup_commit_reference(oid.hash);
        if (!theirs)
                return -1;
 
-       if (read_ref(branch->refname, sha1))
+       if (read_ref(branch->refname, oid.hash))
                return -1;
-       ours = lookup_commit_reference(sha1);
+       ours = lookup_commit_reference(oid.hash);
        if (!ours)
                return -1;
 
        /* are we the same? */
        if (theirs == ours) {
                *num_theirs = *num_ours = 0;
-               return 1;
+               return 0;
        }
 
        /* Run "rev-list --left-right ours...theirs" internally... */
-       rev_argc = 0;
-       rev_argv[rev_argc++] = NULL;
-       rev_argv[rev_argc++] = "--left-right";
-       rev_argv[rev_argc++] = symmetric;
-       rev_argv[rev_argc++] = "--";
-       rev_argv[rev_argc] = NULL;
-
-       strcpy(symmetric, sha1_to_hex(ours->object.sha1));
-       strcpy(symmetric + 40, "...");
-       strcpy(symmetric + 43, sha1_to_hex(theirs->object.sha1));
+       argv_array_push(&argv, ""); /* ignored */
+       argv_array_push(&argv, "--left-right");
+       argv_array_pushf(&argv, "%s...%s",
+                        oid_to_hex(&ours->object.oid),
+                        oid_to_hex(&theirs->object.oid));
+       argv_array_push(&argv, "--");
 
        init_revisions(&revs, NULL);
-       setup_revisions(rev_argc, rev_argv, &revs, NULL);
+       setup_revisions(argv.argc, argv.argv, &revs, NULL);
        if (prepare_revision_walk(&revs))
                die("revision walk setup failed");
 
@@ -1977,7 +2047,9 @@ int stat_tracking_info(struct branch *branch, int *num_ours, int *num_theirs)
        /* clear object flags smudged by the above traversal */
        clear_commit_marks(ours, ALL_REV_FLAGS);
        clear_commit_marks(theirs, ALL_REV_FLAGS);
-       return 1;
+
+       argv_array_clear(&argv);
+       return 0;
 }
 
 /*
@@ -1986,23 +2058,17 @@ int stat_tracking_info(struct branch *branch, int *num_ours, int *num_theirs)
 int format_tracking_info(struct branch *branch, struct strbuf *sb)
 {
        int ours, theirs;
+       const char *full_base;
        char *base;
        int upstream_is_gone = 0;
 
-       switch (stat_tracking_info(branch, &ours, &theirs)) {
-       case 0:
-               /* no base */
-               return 0;
-       case -1:
-               /* with "gone" base */
+       if (stat_tracking_info(branch, &ours, &theirs, &full_base) < 0) {
+               if (!full_base)
+                       return 0;
                upstream_is_gone = 1;
-               break;
-       default:
-               /* with base */
-               break;
        }
 
-       base = shorten_unambiguous_ref(branch->merge[0]->dst, 0);
+       base = shorten_unambiguous_ref(full_base, 0);
        if (upstream_is_gone) {
                strbuf_addf(sb,
                        _("Your branch is based on '%s', but the upstream is gone.\n"),
@@ -2042,7 +2108,7 @@ int format_tracking_info(struct branch *branch, struct strbuf *sb)
                           "Your branch and '%s' have diverged,\n"
                               "and have %d and %d different commits each, "
                               "respectively.\n",
-                          theirs),
+                          ours + theirs),
                        base, ours, theirs);
                if (advice_status_hints)
                        strbuf_addf(sb,
@@ -2052,20 +2118,18 @@ int format_tracking_info(struct branch *branch, struct strbuf *sb)
        return 1;
 }
 
-static int one_local_ref(const char *refname, const unsigned char *sha1, int flag, void *cb_data)
+static int one_local_ref(const char *refname, const struct object_id *oid,
+                        int flag, void *cb_data)
 {
        struct ref ***local_tail = cb_data;
        struct ref *ref;
-       int len;
 
        /* we already know it starts with refs/ to get here */
        if (check_refname_format(refname + 5, 0))
                return 0;
 
-       len = strlen(refname) + 1;
-       ref = xcalloc(1, sizeof(*ref) + len);
-       hashcpy(ref->new_sha1, sha1);
-       memcpy(ref->name, refname, len);
+       ref = alloc_ref(refname);
+       oidcpy(&ref->new_oid, oid);
        **local_tail = ref;
        *local_tail = &ref->next;
        return 0;
@@ -2074,6 +2138,7 @@ static int one_local_ref(const char *refname, const unsigned char *sha1, int fla
 struct ref *get_local_heads(void)
 {
        struct ref *local_refs = NULL, **local_tail = &local_refs;
+
        for_each_ref(one_local_ref, &local_tail);
        return local_refs;
 }
@@ -2100,7 +2165,7 @@ struct ref *guess_remote_head(const struct ref *head,
        /* If refs/heads/master could be right, it is. */
        if (!all) {
                r = find_ref_by_name(refs, "refs/heads/master");
-               if (r && !hashcmp(r->old_sha1, head->old_sha1))
+               if (r && !oidcmp(&r->old_oid, &head->old_oid))
                        return copy_ref(r);
        }
 
@@ -2108,7 +2173,7 @@ struct ref *guess_remote_head(const struct ref *head,
        for (r = refs; r; r = r->next) {
                if (r != head &&
                    starts_with(r->name, "refs/heads/") &&
-                   !hashcmp(r->old_sha1, head->old_sha1)) {
+                   !oidcmp(&r->old_oid, &head->old_oid)) {
                        *tail = copy_ref(r);
                        tail = &((*tail)->next);
                        if (!all)
@@ -2126,8 +2191,8 @@ struct stale_heads_info {
        int ref_count;
 };
 
-static int get_stale_heads_cb(const char *refname,
-       const unsigned char *sha1, int flags, void *cb_data)
+static int get_stale_heads_cb(const char *refname, const struct object_id *oid,
+                             int flags, void *cb_data)
 {
        struct stale_heads_info *info = cb_data;
        struct string_list matches = STRING_LIST_INIT_DUP;
@@ -2156,7 +2221,7 @@ static int get_stale_heads_cb(const char *refname,
 
        if (stale) {
                struct ref *ref = make_linked_ref(refname, &info->stale_refs_tail);
-               hashcpy(ref->new_sha1, sha1);
+               oidcpy(&ref->new_oid, oid);
        }
 
 clean_exit:
@@ -2169,6 +2234,7 @@ struct ref *get_stale_heads(struct refspec *refs, int ref_count, struct ref *fet
        struct ref *ref, *stale_refs = NULL;
        struct string_list ref_names = STRING_LIST_INIT_NODUP;
        struct stale_heads_info info;
+
        info.ref_names = &ref_names;
        info.stale_refs_tail = &stale_refs;
        info.refs = refs;
@@ -2250,14 +2316,14 @@ int is_empty_cas(const struct push_cas_option *cas)
  * If we cannot do so, return negative to signal an error.
  */
 static int remote_tracking(struct remote *remote, const char *refname,
-                          unsigned char sha1[20])
+                          struct object_id *oid)
 {
        char *dst;
 
        dst = apply_refspecs(remote->fetch, remote->fetch_refspec_nr, refname);
        if (!dst)
                return -1; /* no tracking ref for refname at remote */
-       if (read_ref(dst, sha1))
+       if (read_ref(dst, oid->hash))
                return -1; /* we know what the tracking ref is but we cannot read it */
        return 0;
 }
@@ -2275,8 +2341,8 @@ static void apply_cas(struct push_cas_option *cas,
                        continue;
                ref->expect_old_sha1 = 1;
                if (!entry->use_tracking)
-                       hashcpy(ref->old_sha1_expect, cas->entry[i].expect);
-               else if (remote_tracking(remote, ref->name, ref->old_sha1_expect))
+                       hashcpy(ref->old_oid_expect.hash, cas->entry[i].expect);
+               else if (remote_tracking(remote, ref->name, &ref->old_oid_expect))
                        ref->expect_old_no_trackback = 1;
                return;
        }
@@ -2286,7 +2352,7 @@ static void apply_cas(struct push_cas_option *cas,
                return;
 
        ref->expect_old_sha1 = 1;
-       if (remote_tracking(remote, ref->name, ref->old_sha1_expect))
+       if (remote_tracking(remote, ref->name, &ref->old_oid_expect))
                ref->expect_old_no_trackback = 1;
 }