Imported Upstream version 2.21.1
[platform/upstream/git.git] / commit.c
index 4ff8077..a5333c7 100644 (file)
--- a/commit.c
+++ b/commit.c
@@ -1,16 +1,24 @@
 #include "cache.h"
 #include "tag.h"
 #include "commit.h"
+#include "commit-graph.h"
+#include "repository.h"
+#include "object-store.h"
 #include "pkt-line.h"
 #include "utf8.h"
 #include "diff.h"
 #include "revision.h"
 #include "notes.h"
+#include "alloc.h"
 #include "gpg-interface.h"
 #include "mergesort.h"
 #include "commit-slab.h"
 #include "prio-queue.h"
 #include "sha1-lookup.h"
+#include "wt-status.h"
+#include "advice.h"
+#include "refs.h"
+#include "commit-reach.h"
 
 static struct commit_extra_header *read_commit_extra_header_lines(const char *buf, size_t len, const char **);
 
@@ -18,72 +26,58 @@ int save_commit_buffer = 1;
 
 const char *commit_type = "commit";
 
-static struct commit *check_commit(struct object *obj,
-                                  const unsigned char *sha1,
-                                  int quiet)
+struct commit *lookup_commit_reference_gently(struct repository *r,
+               const struct object_id *oid, int quiet)
 {
-       if (obj->type != OBJ_COMMIT) {
-               if (!quiet)
-                       error("Object %s is a %s, not a commit",
-                             sha1_to_hex(sha1), typename(obj->type));
-               return NULL;
-       }
-       return (struct commit *) obj;
-}
-
-struct commit *lookup_commit_reference_gently(const unsigned char *sha1,
-                                             int quiet)
-{
-       struct object *obj = deref_tag(parse_object(sha1), NULL, 0);
+       struct object *obj = deref_tag(r,
+                                      parse_object(r, oid),
+                                      NULL, 0);
 
        if (!obj)
                return NULL;
-       return check_commit(obj, sha1, quiet);
+       return object_as_type(r, obj, OBJ_COMMIT, quiet);
 }
 
-struct commit *lookup_commit_reference(const unsigned char *sha1)
+struct commit *lookup_commit_reference(struct repository *r, const struct object_id *oid)
 {
-       return lookup_commit_reference_gently(sha1, 0);
+       return lookup_commit_reference_gently(r, oid, 0);
 }
 
-struct commit *lookup_commit_or_die(const unsigned char *sha1, const char *ref_name)
+struct commit *lookup_commit_or_die(const struct object_id *oid, const char *ref_name)
 {
-       struct commit *c = lookup_commit_reference(sha1);
+       struct commit *c = lookup_commit_reference(the_repository, oid);
        if (!c)
                die(_("could not parse %s"), ref_name);
-       if (hashcmp(sha1, c->object.sha1)) {
+       if (!oideq(oid, &c->object.oid)) {
                warning(_("%s %s is not a commit!"),
-                       ref_name, sha1_to_hex(sha1));
+                       ref_name, oid_to_hex(oid));
        }
        return c;
 }
 
-struct commit *lookup_commit(const unsigned char *sha1)
+struct commit *lookup_commit(struct repository *r, const struct object_id *oid)
 {
-       struct object *obj = lookup_object(sha1);
-       if (!obj) {
-               struct commit *c = alloc_commit_node();
-               return create_object(sha1, OBJ_COMMIT, c);
-       }
-       if (!obj->type)
-               obj->type = OBJ_COMMIT;
-       return check_commit(obj, sha1, 0);
+       struct object *obj = lookup_object(r, oid->hash);
+       if (!obj)
+               return create_object(r, oid->hash,
+                                    alloc_commit_node(r));
+       return object_as_type(r, obj, OBJ_COMMIT, 0);
 }
 
 struct commit *lookup_commit_reference_by_name(const char *name)
 {
-       unsigned char sha1[20];
+       struct object_id oid;
        struct commit *commit;
 
-       if (get_sha1_committish(name, sha1))
+       if (get_oid_committish(name, &oid))
                return NULL;
-       commit = lookup_commit_reference(sha1);
+       commit = lookup_commit_reference(the_repository, &oid);
        if (parse_commit(commit))
                return NULL;
        return commit;
 }
 
-static unsigned long parse_commit_date(const char *buf, const char *tail)
+static timestamp_t parse_commit_date(const char *buf, const char *tail)
 {
        const char *dateptr;
 
@@ -106,93 +100,110 @@ static unsigned long parse_commit_date(const char *buf, const char *tail)
                /* nada */;
        if (buf >= tail)
                return 0;
-       /* dateptr < buf && buf[-1] == '\n', so strtoul will stop at buf-1 */
-       return strtoul(dateptr, NULL, 10);
+       /* dateptr < buf && buf[-1] == '\n', so parsing will stop at buf-1 */
+       return parse_timestamp(dateptr, NULL, 10);
 }
 
-static struct commit_graft **commit_graft;
-static int commit_graft_alloc, commit_graft_nr;
-
 static const unsigned char *commit_graft_sha1_access(size_t index, void *table)
 {
        struct commit_graft **commit_graft_table = table;
-       return commit_graft_table[index]->sha1;
+       return commit_graft_table[index]->oid.hash;
 }
 
-static int commit_graft_pos(const unsigned char *sha1)
+static int commit_graft_pos(struct repository *r, const unsigned char *sha1)
 {
-       return sha1_pos(sha1, commit_graft, commit_graft_nr,
+       return sha1_pos(sha1, r->parsed_objects->grafts,
+                       r->parsed_objects->grafts_nr,
                        commit_graft_sha1_access);
 }
 
-int register_commit_graft(struct commit_graft *graft, int ignore_dups)
+int register_commit_graft(struct repository *r, struct commit_graft *graft,
+                         int ignore_dups)
 {
-       int pos = commit_graft_pos(graft->sha1);
+       int pos = commit_graft_pos(r, graft->oid.hash);
 
        if (0 <= pos) {
                if (ignore_dups)
                        free(graft);
                else {
-                       free(commit_graft[pos]);
-                       commit_graft[pos] = graft;
+                       free(r->parsed_objects->grafts[pos]);
+                       r->parsed_objects->grafts[pos] = graft;
                }
                return 1;
        }
        pos = -pos - 1;
-       ALLOC_GROW(commit_graft, commit_graft_nr + 1, commit_graft_alloc);
-       commit_graft_nr++;
-       if (pos < commit_graft_nr)
-               memmove(commit_graft + pos + 1,
-                       commit_graft + pos,
-                       (commit_graft_nr - pos - 1) *
-                       sizeof(*commit_graft));
-       commit_graft[pos] = graft;
+       ALLOC_GROW(r->parsed_objects->grafts,
+                  r->parsed_objects->grafts_nr + 1,
+                  r->parsed_objects->grafts_alloc);
+       r->parsed_objects->grafts_nr++;
+       if (pos < r->parsed_objects->grafts_nr)
+               memmove(r->parsed_objects->grafts + pos + 1,
+                       r->parsed_objects->grafts + pos,
+                       (r->parsed_objects->grafts_nr - pos - 1) *
+                       sizeof(*r->parsed_objects->grafts));
+       r->parsed_objects->grafts[pos] = graft;
        return 0;
 }
 
-struct commit_graft *read_graft_line(char *buf, int len)
+struct commit_graft *read_graft_line(struct strbuf *line)
 {
        /* The format is just "Commit Parent1 Parent2 ...\n" */
-       int i;
+       int i, phase;
+       const char *tail = NULL;
        struct commit_graft *graft = NULL;
+       struct object_id dummy_oid, *oid;
 
-       while (len && isspace(buf[len-1]))
-               buf[--len] = '\0';
-       if (buf[0] == '#' || buf[0] == '\0')
+       strbuf_rtrim(line);
+       if (!line->len || line->buf[0] == '#')
                return NULL;
-       if ((len + 1) % 41)
-               goto bad_graft_data;
-       i = (len + 1) / 41 - 1;
-       graft = xmalloc(sizeof(*graft) + 20 * i);
-       graft->nr_parent = i;
-       if (get_sha1_hex(buf, graft->sha1))
-               goto bad_graft_data;
-       for (i = 40; i < len; i += 41) {
-               if (buf[i] != ' ')
-                       goto bad_graft_data;
-               if (get_sha1_hex(buf + i + 1, graft->parent[i/41]))
+       /*
+        * phase 0 verifies line, counts hashes in line and allocates graft
+        * phase 1 fills graft
+        */
+       for (phase = 0; phase < 2; phase++) {
+               oid = graft ? &graft->oid : &dummy_oid;
+               if (parse_oid_hex(line->buf, oid, &tail))
                        goto bad_graft_data;
+               for (i = 0; *tail != '\0'; i++) {
+                       oid = graft ? &graft->parent[i] : &dummy_oid;
+                       if (!isspace(*tail++) || parse_oid_hex(tail, oid, &tail))
+                               goto bad_graft_data;
+               }
+               if (!graft) {
+                       graft = xmalloc(st_add(sizeof(*graft),
+                                              st_mult(sizeof(struct object_id), i)));
+                       graft->nr_parent = i;
+               }
        }
        return graft;
 
 bad_graft_data:
-       error("bad graft data: %s", buf);
-       free(graft);
+       error("bad graft data: %s", line->buf);
+       assert(!graft);
        return NULL;
 }
 
-static int read_graft_file(const char *graft_file)
+static int read_graft_file(struct repository *r, const char *graft_file)
 {
-       FILE *fp = fopen(graft_file, "r");
+       FILE *fp = fopen_or_warn(graft_file, "r");
        struct strbuf buf = STRBUF_INIT;
        if (!fp)
                return -1;
+       if (advice_graft_file_deprecated)
+               advise(_("Support for <GIT_DIR>/info/grafts is deprecated\n"
+                        "and will be removed in a future Git version.\n"
+                        "\n"
+                        "Please use \"git replace --convert-graft-file\"\n"
+                        "to convert the grafts into replace refs.\n"
+                        "\n"
+                        "Turn this message off by running\n"
+                        "\"git config advice.graftFileDeprecated false\""));
        while (!strbuf_getwholeline(&buf, fp, '\n')) {
                /* The format is just "Commit Parent1 Parent2 ...\n" */
-               struct commit_graft *graft = read_graft_line(buf.buf, buf.len);
+               struct commit_graft *graft = read_graft_line(&buf);
                if (!graft)
                        continue;
-               if (register_commit_graft(graft, 1))
+               if (register_commit_graft(r, graft, 1))
                        error("duplicate graft data: %s", buf.buf);
        }
        fclose(fp);
@@ -200,48 +211,50 @@ static int read_graft_file(const char *graft_file)
        return 0;
 }
 
-static void prepare_commit_graft(void)
+void prepare_commit_graft(struct repository *r)
 {
-       static int commit_graft_prepared;
        char *graft_file;
 
-       if (commit_graft_prepared)
+       if (r->parsed_objects->commit_graft_prepared)
                return;
-       graft_file = get_graft_file();
-       read_graft_file(graft_file);
+       if (!startup_info->have_repository)
+               return;
+
+       graft_file = get_graft_file(r);
+       read_graft_file(r, graft_file);
        /* make sure shallows are read */
-       is_repository_shallow();
-       commit_graft_prepared = 1;
+       is_repository_shallow(r);
+       r->parsed_objects->commit_graft_prepared = 1;
 }
 
-struct commit_graft *lookup_commit_graft(const unsigned char *sha1)
+struct commit_graft *lookup_commit_graft(struct repository *r, const struct object_id *oid)
 {
        int pos;
-       prepare_commit_graft();
-       pos = commit_graft_pos(sha1);
+       prepare_commit_graft(r);
+       pos = commit_graft_pos(r, oid->hash);
        if (pos < 0)
                return NULL;
-       return commit_graft[pos];
+       return r->parsed_objects->grafts[pos];
 }
 
 int for_each_commit_graft(each_commit_graft_fn fn, void *cb_data)
 {
        int i, ret;
-       for (i = ret = 0; i < commit_graft_nr && !ret; i++)
-               ret = fn(commit_graft[i], cb_data);
+       for (i = ret = 0; i < the_repository->parsed_objects->grafts_nr && !ret; i++)
+               ret = fn(the_repository->parsed_objects->grafts[i], cb_data);
        return ret;
 }
 
-int unregister_shallow(const unsigned char *sha1)
+int unregister_shallow(const struct object_id *oid)
 {
-       int pos = commit_graft_pos(sha1);
+       int pos = commit_graft_pos(the_repository, oid->hash);
        if (pos < 0)
                return -1;
-       if (pos + 1 < commit_graft_nr)
-               memmove(commit_graft + pos, commit_graft + pos + 1,
-                               sizeof(struct commit_graft *)
-                               * (commit_graft_nr - pos - 1));
-       commit_graft_nr--;
+       if (pos + 1 < the_repository->parsed_objects->grafts_nr)
+               MOVE_ARRAY(the_repository->parsed_objects->grafts + pos,
+                          the_repository->parsed_objects->grafts + pos + 1,
+                          the_repository->parsed_objects->grafts_nr - pos - 1);
+       the_repository->parsed_objects->grafts_nr--;
        return 0;
 }
 
@@ -250,62 +263,120 @@ struct commit_buffer {
        unsigned long size;
 };
 define_commit_slab(buffer_slab, struct commit_buffer);
-static struct buffer_slab buffer_slab = COMMIT_SLAB_INIT(1, buffer_slab);
 
-void set_commit_buffer(struct commit *commit, void *buffer, unsigned long size)
+struct buffer_slab *allocate_commit_buffer_slab(void)
 {
-       struct commit_buffer *v = buffer_slab_at(&buffer_slab, commit);
+       struct buffer_slab *bs = xmalloc(sizeof(*bs));
+       init_buffer_slab(bs);
+       return bs;
+}
+
+void free_commit_buffer_slab(struct buffer_slab *bs)
+{
+       clear_buffer_slab(bs);
+       free(bs);
+}
+
+void set_commit_buffer(struct repository *r, struct commit *commit, void *buffer, unsigned long size)
+{
+       struct commit_buffer *v = buffer_slab_at(
+               r->parsed_objects->buffer_slab, commit);
        v->buffer = buffer;
        v->size = size;
 }
 
-const void *get_cached_commit_buffer(const struct commit *commit, unsigned long *sizep)
+const void *get_cached_commit_buffer(struct repository *r, const struct commit *commit, unsigned long *sizep)
 {
-       struct commit_buffer *v = buffer_slab_at(&buffer_slab, commit);
+       struct commit_buffer *v = buffer_slab_peek(
+               r->parsed_objects->buffer_slab, commit);
+       if (!v) {
+               if (sizep)
+                       *sizep = 0;
+               return NULL;
+       }
        if (sizep)
                *sizep = v->size;
        return v->buffer;
 }
 
-const void *get_commit_buffer(const struct commit *commit, unsigned long *sizep)
+const void *repo_get_commit_buffer(struct repository *r,
+                                  const struct commit *commit,
+                                  unsigned long *sizep)
 {
-       const void *ret = get_cached_commit_buffer(commit, sizep);
+       const void *ret = get_cached_commit_buffer(r, commit, sizep);
        if (!ret) {
                enum object_type type;
                unsigned long size;
-               ret = read_sha1_file(commit->object.sha1, &type, &size);
+               ret = repo_read_object_file(r, &commit->object.oid, &type, &size);
                if (!ret)
                        die("cannot read commit object %s",
-                           sha1_to_hex(commit->object.sha1));
+                           oid_to_hex(&commit->object.oid));
                if (type != OBJ_COMMIT)
                        die("expected commit for %s, got %s",
-                           sha1_to_hex(commit->object.sha1), typename(type));
+                           oid_to_hex(&commit->object.oid), type_name(type));
                if (sizep)
                        *sizep = size;
        }
        return ret;
 }
 
-void unuse_commit_buffer(const struct commit *commit, const void *buffer)
+void repo_unuse_commit_buffer(struct repository *r,
+                             const struct commit *commit,
+                             const void *buffer)
 {
-       struct commit_buffer *v = buffer_slab_at(&buffer_slab, commit);
-       if (v->buffer != buffer)
+       struct commit_buffer *v = buffer_slab_peek(
+               r->parsed_objects->buffer_slab, commit);
+       if (!(v && v->buffer == buffer))
                free((void *)buffer);
 }
 
-void free_commit_buffer(struct commit *commit)
+void free_commit_buffer(struct parsed_object_pool *pool, struct commit *commit)
 {
-       struct commit_buffer *v = buffer_slab_at(&buffer_slab, commit);
-       free(v->buffer);
-       v->buffer = NULL;
-       v->size = 0;
+       struct commit_buffer *v = buffer_slab_peek(
+               pool->buffer_slab, commit);
+       if (v) {
+               FREE_AND_NULL(v->buffer);
+               v->size = 0;
+       }
+}
+
+struct tree *get_commit_tree(const struct commit *commit)
+{
+       if (commit->maybe_tree || !commit->object.parsed)
+               return commit->maybe_tree;
+
+       if (commit->graph_pos == COMMIT_NOT_FROM_GRAPH)
+               BUG("commit has NULL tree, but was not loaded from commit-graph");
+
+       return get_commit_tree_in_graph(the_repository, commit);
+}
+
+struct object_id *get_commit_tree_oid(const struct commit *commit)
+{
+       return &get_commit_tree(commit)->object.oid;
+}
+
+void release_commit_memory(struct parsed_object_pool *pool, struct commit *c)
+{
+       c->maybe_tree = NULL;
+       c->index = 0;
+       free_commit_buffer(pool, c);
+       free_commit_list(c->parents);
+
+       c->object.parsed = 0;
 }
 
 const void *detach_commit_buffer(struct commit *commit, unsigned long *sizep)
 {
-       struct commit_buffer *v = buffer_slab_at(&buffer_slab, commit);
+       struct commit_buffer *v = buffer_slab_peek(
+               the_repository->parsed_objects->buffer_slab, commit);
        void *ret;
 
+       if (!v) {
+               if (sizep)
+                       *sizep = 0;
+               return NULL;
+       }
        ret = v->buffer;
        if (sizep)
                *sizep = v->size;
@@ -315,43 +386,46 @@ const void *detach_commit_buffer(struct commit *commit, unsigned long *sizep)
        return ret;
 }
 
-int parse_commit_buffer(struct commit *item, const void *buffer, unsigned long size)
+int parse_commit_buffer(struct repository *r, struct commit *item, const void *buffer, unsigned long size, int check_graph)
 {
        const char *tail = buffer;
        const char *bufptr = buffer;
-       unsigned char parent[20];
+       struct object_id parent;
        struct commit_list **pptr;
        struct commit_graft *graft;
+       const int tree_entry_len = the_hash_algo->hexsz + 5;
+       const int parent_entry_len = the_hash_algo->hexsz + 7;
 
        if (item->object.parsed)
                return 0;
        item->object.parsed = 1;
        tail += size;
-       if (tail <= bufptr + 46 || memcmp(bufptr, "tree ", 5) || bufptr[45] != '\n')
-               return error("bogus commit object %s", sha1_to_hex(item->object.sha1));
-       if (get_sha1_hex(bufptr + 5, parent) < 0)
+       if (tail <= bufptr + tree_entry_len + 1 || memcmp(bufptr, "tree ", 5) ||
+                       bufptr[tree_entry_len] != '\n')
+               return error("bogus commit object %s", oid_to_hex(&item->object.oid));
+       if (get_oid_hex(bufptr + 5, &parent) < 0)
                return error("bad tree pointer in commit %s",
-                            sha1_to_hex(item->object.sha1));
-       item->tree = lookup_tree(parent);
-       bufptr += 46; /* "tree " + "hex sha1" + "\n" */
+                            oid_to_hex(&item->object.oid));
+       item->maybe_tree = lookup_tree(r, &parent);
+       bufptr += tree_entry_len + 1; /* "tree " + "hex sha1" + "\n" */
        pptr = &item->parents;
 
-       graft = lookup_commit_graft(item->object.sha1);
-       while (bufptr + 48 < tail && !memcmp(bufptr, "parent ", 7)) {
+       graft = lookup_commit_graft(r, &item->object.oid);
+       while (bufptr + parent_entry_len < tail && !memcmp(bufptr, "parent ", 7)) {
                struct commit *new_parent;
 
-               if (tail <= bufptr + 48 ||
-                   get_sha1_hex(bufptr + 7, parent) ||
-                   bufptr[47] != '\n')
-                       return error("bad parents in commit %s", sha1_to_hex(item->object.sha1));
-               bufptr += 48;
+               if (tail <= bufptr + parent_entry_len + 1 ||
+                   get_oid_hex(bufptr + 7, &parent) ||
+                   bufptr[parent_entry_len] != '\n')
+                       return error("bad parents in commit %s", oid_to_hex(&item->object.oid));
+               bufptr += parent_entry_len + 1;
                /*
                 * The clone is shallow if nr_parent < 0, and we must
                 * not traverse its real parents even when we unhide them.
                 */
                if (graft && (graft->nr_parent < 0 || grafts_replace_parents))
                        continue;
-               new_parent = lookup_commit(parent);
+               new_parent = lookup_commit(r, &parent);
                if (new_parent)
                        pptr = &commit_list_insert(new_parent, pptr)->next;
        }
@@ -359,7 +433,8 @@ int parse_commit_buffer(struct commit *item, const void *buffer, unsigned long s
                int i;
                struct commit *new_parent;
                for (i = 0; i < graft->nr_parent; i++) {
-                       new_parent = lookup_commit(graft->parent[i]);
+                       new_parent = lookup_commit(r,
+                                                  &graft->parent[i]);
                        if (!new_parent)
                                continue;
                        pptr = &commit_list_insert(new_parent, pptr)->next;
@@ -367,10 +442,16 @@ int parse_commit_buffer(struct commit *item, const void *buffer, unsigned long s
        }
        item->date = parse_commit_date(bufptr, tail);
 
+       if (check_graph)
+               load_commit_graph_info(the_repository, item);
+
        return 0;
 }
 
-int parse_commit(struct commit *item)
+int repo_parse_commit_internal(struct repository *r,
+                              struct commit *item,
+                              int quiet_on_missing,
+                              int use_commit_graph)
 {
        enum object_type type;
        void *buffer;
@@ -381,29 +462,39 @@ int parse_commit(struct commit *item)
                return -1;
        if (item->object.parsed)
                return 0;
-       buffer = read_sha1_file(item->object.sha1, &type, &size);
+       if (use_commit_graph && parse_commit_in_graph(r, item))
+               return 0;
+       buffer = repo_read_object_file(r, &item->object.oid, &type, &size);
        if (!buffer)
-               return error("Could not read %s",
-                            sha1_to_hex(item->object.sha1));
+               return quiet_on_missing ? -1 :
+                       error("Could not read %s",
+                            oid_to_hex(&item->object.oid));
        if (type != OBJ_COMMIT) {
                free(buffer);
                return error("Object %s not a commit",
-                            sha1_to_hex(item->object.sha1));
+                            oid_to_hex(&item->object.oid));
        }
-       ret = parse_commit_buffer(item, buffer, size);
+
+       ret = parse_commit_buffer(r, item, buffer, size, 0);
        if (save_commit_buffer && !ret) {
-               set_commit_buffer(item, buffer, size);
+               set_commit_buffer(r, item, buffer, size);
                return 0;
        }
        free(buffer);
        return ret;
 }
 
+int repo_parse_commit_gently(struct repository *r,
+                            struct commit *item, int quiet_on_missing)
+{
+       return repo_parse_commit_internal(r, item, quiet_on_missing, 1);
+}
+
 void parse_commit_or_die(struct commit *item)
 {
        if (parse_commit(item))
                die("unable to parse commit %s",
-                   item ? sha1_to_hex(item->object.sha1) : "(null)");
+                   item ? oid_to_hex(&item->object.oid) : "(null)");
 }
 
 int find_commit_subject(const char *commit_buffer, const char **subject)
@@ -414,9 +505,8 @@ int find_commit_subject(const char *commit_buffer, const char **subject)
        while (*p && (*p != '\n' || p[1] != '\n'))
                p++;
        if (*p) {
-               p += 2;
-               for (eol = p; *eol && *eol != '\n'; eol++)
-                       ; /* do nothing */
+               p = skip_blank_lines(p + 2);
+               eol = strchrnul(p, '\n');
        } else
                eol = p;
 
@@ -447,12 +537,7 @@ struct commit_list *copy_commit_list(struct commit_list *list)
        struct commit_list *head = NULL;
        struct commit_list **pp = &head;
        while (list) {
-               struct commit_list *new;
-               new = xmalloc(sizeof(struct commit_list));
-               new->item = list->item;
-               new->next = NULL;
-               *pp = new;
-               pp = &new->next;
+               pp = commit_list_append(list->item, pp);
                list = list->next;
        }
        return head;
@@ -460,11 +545,8 @@ struct commit_list *copy_commit_list(struct commit_list *list)
 
 void free_commit_list(struct commit_list *list)
 {
-       while (list) {
-               struct commit_list *temp = list;
-               list = temp->next;
-               free(temp);
-       }
+       while (list)
+               pop_commit(&list);
 }
 
 struct commit_list * commit_list_insert_by_date(struct commit *item, struct commit_list **list)
@@ -482,8 +564,8 @@ struct commit_list * commit_list_insert_by_date(struct commit *item, struct comm
 
 static int commit_list_compare_by_date(const void *a, const void *b)
 {
-       unsigned long a_date = ((const struct commit_list *)a)->item->date;
-       unsigned long b_date = ((const struct commit_list *)b)->item->date;
+       timestamp_t a_date = ((const struct commit_list *)a)->item->date;
+       timestamp_t b_date = ((const struct commit_list *)b)->item->date;
        if (a_date < b_date)
                return 1;
        if (a_date > b_date)
@@ -510,12 +592,8 @@ void commit_list_sort_by_date(struct commit_list **list)
 struct commit *pop_most_recent_commit(struct commit_list **list,
                                      unsigned int mark)
 {
-       struct commit *ret = (*list)->item;
+       struct commit *ret = pop_commit(list);
        struct commit_list *parents = ret->parents;
-       struct commit_list *old = *list;
-
-       *list = (*list)->next;
-       free(old);
 
        while (parents) {
                struct commit *commit = parents->item;
@@ -555,7 +633,7 @@ void clear_commit_marks_many(int nr, struct commit **commit, unsigned int mark)
        struct commit_list *list = NULL;
 
        while (nr--) {
-               commit_list_insert(*commit, &list);
+               clear_commit_marks_1(&list, *commit, mark);
                commit++;
        }
        while (list)
@@ -567,20 +645,6 @@ void clear_commit_marks(struct commit *commit, unsigned int mark)
        clear_commit_marks_many(1, &commit, mark);
 }
 
-void clear_commit_marks_for_object_array(struct object_array *a, unsigned mark)
-{
-       struct object *object;
-       struct commit *commit;
-       unsigned int i;
-
-       for (i = 0; i < a->nr; i++) {
-               object = a->objects[i].item;
-               commit = lookup_commit_reference_gently(object->sha1, 1);
-               if (commit)
-                       clear_commit_marks(commit, mark);
-       }
-}
-
 struct commit *pop_commit(struct commit_list **stack)
 {
        struct commit_list *top = *stack;
@@ -600,34 +664,26 @@ struct commit *pop_commit(struct commit_list **stack)
 /* count number of children that have not been emitted */
 define_commit_slab(indegree_slab, int);
 
-/* record author-date for each commit object */
-define_commit_slab(author_date_slab, unsigned long);
+define_commit_slab(author_date_slab, timestamp_t);
 
-static void record_author_date(struct author_date_slab *author_date,
-                              struct commit *commit)
+void record_author_date(struct author_date_slab *author_date,
+                       struct commit *commit)
 {
-       const char *buf, *line_end, *ident_line;
        const char *buffer = get_commit_buffer(commit, NULL);
        struct ident_split ident;
+       const char *ident_line;
+       size_t ident_len;
        char *date_end;
-       unsigned long date;
-
-       for (buf = buffer; buf; buf = line_end + 1) {
-               line_end = strchrnul(buf, '\n');
-               ident_line = skip_prefix(buf, "author ");
-               if (!ident_line) {
-                       if (!line_end[0] || line_end[1] == '\n')
-                               return; /* end of header */
-                       continue;
-               }
-               if (split_ident_line(&ident,
-                                    ident_line, line_end - ident_line) ||
-                   !ident.date_begin || !ident.date_end)
-                       goto fail_exit; /* malformed "author" line */
-               break;
-       }
+       timestamp_t date;
 
-       date = strtoul(ident.date_begin, &date_end, 10);
+       ident_line = find_commit_header(buffer, "author", &ident_len);
+       if (!ident_line)
+               goto fail_exit; /* no author line */
+       if (split_ident_line(&ident, ident_line, ident_len) ||
+           !ident.date_begin || !ident.date_end)
+               goto fail_exit; /* malformed "author" line */
+
+       date = parse_timestamp(ident.date_begin, &date_end, 10);
        if (date_end != ident.date_end)
                goto fail_exit; /* malformed date */
        *(author_date_slab_at(author_date, commit)) = date;
@@ -636,13 +692,13 @@ fail_exit:
        unuse_commit_buffer(commit, buffer);
 }
 
-static int compare_commits_by_author_date(const void *a_, const void *b_,
-                                         void *cb_data)
+int compare_commits_by_author_date(const void *a_, const void *b_,
+                                  void *cb_data)
 {
        const struct commit *a = a_, *b = b_;
        struct author_date_slab *author_date = cb_data;
-       unsigned long a_date = *(author_date_slab_at(author_date, a));
-       unsigned long b_date = *(author_date_slab_at(author_date, b));
+       timestamp_t a_date = *(author_date_slab_at(author_date, a));
+       timestamp_t b_date = *(author_date_slab_at(author_date, b));
 
        /* newer commits with larger date first */
        if (a_date < b_date)
@@ -652,6 +708,24 @@ static int compare_commits_by_author_date(const void *a_, const void *b_,
        return 0;
 }
 
+int compare_commits_by_gen_then_commit_date(const void *a_, const void *b_, void *unused)
+{
+       const struct commit *a = a_, *b = b_;
+
+       /* newer commits first */
+       if (a->generation < b->generation)
+               return 1;
+       else if (a->generation > b->generation)
+               return -1;
+
+       /* use date as a heuristic when generations are equal */
+       if (a->date < b->date)
+               return 1;
+       else if (a->date > b->date)
+               return -1;
+       return 0;
+}
+
 int compare_commits_by_commit_date(const void *a_, const void *b_, void *unused)
 {
        const struct commit *a = a_, *b = b_;
@@ -777,331 +851,86 @@ void sort_in_topological_order(struct commit_list **list, enum rev_sort_order so
                clear_author_date_slab(&author_date);
 }
 
-/* merge-base stuff */
-
-/* Remember to update object flag allocation in object.h */
-#define PARENT1                (1u<<16)
-#define PARENT2                (1u<<17)
-#define STALE          (1u<<18)
-#define RESULT         (1u<<19)
-
-static const unsigned all_flags = (PARENT1 | PARENT2 | STALE | RESULT);
-
-static struct commit *interesting(struct commit_list *list)
-{
-       while (list) {
-               struct commit *commit = list->item;
-               list = list->next;
-               if (commit->object.flags & STALE)
-                       continue;
-               return commit;
-       }
-       return NULL;
-}
+struct rev_collect {
+       struct commit **commit;
+       int nr;
+       int alloc;
+       unsigned int initial : 1;
+};
 
-/* all input commits in one and twos[] must have been parsed! */
-static struct commit_list *paint_down_to_common(struct commit *one, int n, struct commit **twos)
+static void add_one_commit(struct object_id *oid, struct rev_collect *revs)
 {
-       struct commit_list *list = NULL;
-       struct commit_list *result = NULL;
-       int i;
+       struct commit *commit;
 
-       one->object.flags |= PARENT1;
-       commit_list_insert_by_date(one, &list);
-       if (!n)
-               return list;
-       for (i = 0; i < n; i++) {
-               twos[i]->object.flags |= PARENT2;
-               commit_list_insert_by_date(twos[i], &list);
-       }
+       if (is_null_oid(oid))
+               return;
 
-       while (interesting(list)) {
-               struct commit *commit;
-               struct commit_list *parents;
-               struct commit_list *next;
-               int flags;
-
-               commit = list->item;
-               next = list->next;
-               free(list);
-               list = next;
-
-               flags = commit->object.flags & (PARENT1 | PARENT2 | STALE);
-               if (flags == (PARENT1 | PARENT2)) {
-                       if (!(commit->object.flags & RESULT)) {
-                               commit->object.flags |= RESULT;
-                               commit_list_insert_by_date(commit, &result);
-                       }
-                       /* Mark parents of a found merge stale */
-                       flags |= STALE;
-               }
-               parents = commit->parents;
-               while (parents) {
-                       struct commit *p = parents->item;
-                       parents = parents->next;
-                       if ((p->object.flags & flags) == flags)
-                               continue;
-                       if (parse_commit(p))
-                               return NULL;
-                       p->object.flags |= flags;
-                       commit_list_insert_by_date(p, &list);
-               }
-       }
+       commit = lookup_commit(the_repository, oid);
+       if (!commit ||
+           (commit->object.flags & TMP_MARK) ||
+           parse_commit(commit))
+               return;
 
-       free_commit_list(list);
-       return result;
+       ALLOC_GROW(revs->commit, revs->nr + 1, revs->alloc);
+       revs->commit[revs->nr++] = commit;
+       commit->object.flags |= TMP_MARK;
 }
 
-static struct commit_list *merge_bases_many(struct commit *one, int n, struct commit **twos)
+static int collect_one_reflog_ent(struct object_id *ooid, struct object_id *noid,
+                                 const char *ident, timestamp_t timestamp,
+                                 int tz, const char *message, void *cbdata)
 {
-       struct commit_list *list = NULL;
-       struct commit_list *result = NULL;
-       int i;
-
-       for (i = 0; i < n; i++) {
-               if (one == twos[i])
-                       /*
-                        * We do not mark this even with RESULT so we do not
-                        * have to clean it up.
-                        */
-                       return commit_list_insert(one, &result);
-       }
+       struct rev_collect *revs = cbdata;
 
-       if (parse_commit(one))
-               return NULL;
-       for (i = 0; i < n; i++) {
-               if (parse_commit(twos[i]))
-                       return NULL;
+       if (revs->initial) {
+               revs->initial = 0;
+               add_one_commit(ooid, revs);
        }
-
-       list = paint_down_to_common(one, n, twos);
-
-       while (list) {
-               struct commit_list *next = list->next;
-               if (!(list->item->object.flags & STALE))
-                       commit_list_insert_by_date(list->item, &result);
-               free(list);
-               list = next;
-       }
-       return result;
+       add_one_commit(noid, revs);
+       return 0;
 }
 
-struct commit_list *get_octopus_merge_bases(struct commit_list *in)
+struct commit *get_fork_point(const char *refname, struct commit *commit)
 {
-       struct commit_list *i, *j, *k, *ret = NULL;
+       struct object_id oid;
+       struct rev_collect revs;
+       struct commit_list *bases;
+       int i;
+       struct commit *ret = NULL;
 
-       if (!in)
-               return ret;
+       memset(&revs, 0, sizeof(revs));
+       revs.initial = 1;
+       for_each_reflog_ent(refname, collect_one_reflog_ent, &revs);
 
-       commit_list_insert(in->item, &ret);
+       if (!revs.nr && !get_oid(refname, &oid))
+               add_one_commit(&oid, &revs);
 
-       for (i = in->next; i; i = i->next) {
-               struct commit_list *new = NULL, *end = NULL;
+       for (i = 0; i < revs.nr; i++)
+               revs.commit[i]->object.flags &= ~TMP_MARK;
 
-               for (j = ret; j; j = j->next) {
-                       struct commit_list *bases;
-                       bases = get_merge_bases(i->item, j->item, 1);
-                       if (!new)
-                               new = bases;
-                       else
-                               end->next = bases;
-                       for (k = bases; k; k = k->next)
-                               end = k;
-               }
-               ret = new;
-       }
-       return ret;
-}
+       bases = get_merge_bases_many(commit, revs.nr, revs.commit);
 
-static int remove_redundant(struct commit **array, int cnt)
-{
        /*
-        * Some commit in the array may be an ancestor of
-        * another commit.  Move such commit to the end of
-        * the array, and return the number of commits that
-        * are independent from each other.
+        * There should be one and only one merge base, when we found
+        * a common ancestor among reflog entries.
         */
-       struct commit **work;
-       unsigned char *redundant;
-       int *filled_index;
-       int i, j, filled;
+       if (!bases || bases->next)
+               goto cleanup_return;
 
-       work = xcalloc(cnt, sizeof(*work));
-       redundant = xcalloc(cnt, 1);
-       filled_index = xmalloc(sizeof(*filled_index) * (cnt - 1));
+       /* And the found one must be one of the reflog entries */
+       for (i = 0; i < revs.nr; i++)
+               if (&bases->item->object == &revs.commit[i]->object)
+                       break; /* found */
+       if (revs.nr <= i)
+               goto cleanup_return;
 
-       for (i = 0; i < cnt; i++)
-               parse_commit(array[i]);
-       for (i = 0; i < cnt; i++) {
-               struct commit_list *common;
+       ret = bases->item;
 
-               if (redundant[i])
-                       continue;
-               for (j = filled = 0; j < cnt; j++) {
-                       if (i == j || redundant[j])
-                               continue;
-                       filled_index[filled] = j;
-                       work[filled++] = array[j];
-               }
-               common = paint_down_to_common(array[i], filled, work);
-               if (array[i]->object.flags & PARENT2)
-                       redundant[i] = 1;
-               for (j = 0; j < filled; j++)
-                       if (work[j]->object.flags & PARENT1)
-                               redundant[filled_index[j]] = 1;
-               clear_commit_marks(array[i], all_flags);
-               for (j = 0; j < filled; j++)
-                       clear_commit_marks(work[j], all_flags);
-               free_commit_list(common);
-       }
-
-       /* Now collect the result */
-       memcpy(work, array, sizeof(*array) * cnt);
-       for (i = filled = 0; i < cnt; i++)
-               if (!redundant[i])
-                       array[filled++] = work[i];
-       for (j = filled, i = 0; i < cnt; i++)
-               if (redundant[i])
-                       array[j++] = work[i];
-       free(work);
-       free(redundant);
-       free(filled_index);
-       return filled;
-}
-
-struct commit_list *get_merge_bases_many(struct commit *one,
-                                        int n,
-                                        struct commit **twos,
-                                        int cleanup)
-{
-       struct commit_list *list;
-       struct commit **rslt;
-       struct commit_list *result;
-       int cnt, i;
-
-       result = merge_bases_many(one, n, twos);
-       for (i = 0; i < n; i++) {
-               if (one == twos[i])
-                       return result;
-       }
-       if (!result || !result->next) {
-               if (cleanup) {
-                       clear_commit_marks(one, all_flags);
-                       clear_commit_marks_many(n, twos, all_flags);
-               }
-               return result;
-       }
-
-       /* There are more than one */
-       cnt = 0;
-       list = result;
-       while (list) {
-               list = list->next;
-               cnt++;
-       }
-       rslt = xcalloc(cnt, sizeof(*rslt));
-       for (list = result, i = 0; list; list = list->next)
-               rslt[i++] = list->item;
-       free_commit_list(result);
-
-       clear_commit_marks(one, all_flags);
-       clear_commit_marks_many(n, twos, all_flags);
-
-       cnt = remove_redundant(rslt, cnt);
-       result = NULL;
-       for (i = 0; i < cnt; i++)
-               commit_list_insert_by_date(rslt[i], &result);
-       free(rslt);
-       return result;
-}
-
-struct commit_list *get_merge_bases(struct commit *one, struct commit *two,
-                                   int cleanup)
-{
-       return get_merge_bases_many(one, 1, &two, cleanup);
-}
-
-/*
- * Is "commit" a descendant of one of the elements on the "with_commit" list?
- */
-int is_descendant_of(struct commit *commit, struct commit_list *with_commit)
-{
-       if (!with_commit)
-               return 1;
-       while (with_commit) {
-               struct commit *other;
-
-               other = with_commit->item;
-               with_commit = with_commit->next;
-               if (in_merge_bases(other, commit))
-                       return 1;
-       }
-       return 0;
-}
-
-/*
- * Is "commit" an ancestor of one of the "references"?
- */
-int in_merge_bases_many(struct commit *commit, int nr_reference, struct commit **reference)
-{
-       struct commit_list *bases;
-       int ret = 0, i;
-
-       if (parse_commit(commit))
-               return ret;
-       for (i = 0; i < nr_reference; i++)
-               if (parse_commit(reference[i]))
-                       return ret;
-
-       bases = paint_down_to_common(commit, nr_reference, reference);
-       if (commit->object.flags & PARENT2)
-               ret = 1;
-       clear_commit_marks(commit, all_flags);
-       clear_commit_marks_many(nr_reference, reference, all_flags);
+cleanup_return:
        free_commit_list(bases);
        return ret;
 }
 
-/*
- * Is "commit" an ancestor of (i.e. reachable from) the "reference"?
- */
-int in_merge_bases(struct commit *commit, struct commit *reference)
-{
-       return in_merge_bases_many(commit, 1, &reference);
-}
-
-struct commit_list *reduce_heads(struct commit_list *heads)
-{
-       struct commit_list *p;
-       struct commit_list *result = NULL, **tail = &result;
-       struct commit **array;
-       int num_head, i;
-
-       if (!heads)
-               return NULL;
-
-       /* Uniquify */
-       for (p = heads; p; p = p->next)
-               p->item->object.flags &= ~STALE;
-       for (p = heads, num_head = 0; p; p = p->next) {
-               if (p->item->object.flags & STALE)
-                       continue;
-               p->item->object.flags |= STALE;
-               num_head++;
-       }
-       array = xcalloc(num_head, sizeof(*array));
-       for (p = heads, i = 0; p; p = p->next) {
-               if (p->item->object.flags & STALE) {
-                       array[i++] = p->item;
-                       p->item->object.flags &= ~STALE;
-               }
-       }
-       num_head = remove_redundant(array, num_head);
-       for (i = 0; i < num_head; i++)
-               tail = &commit_list_insert(array[i], tail)->next;
-       return result;
-}
-
 static const char gpg_sig_header[] = "gpgsig";
 static const int gpg_sig_header_len = sizeof(gpg_sig_header) - 1;
 
@@ -1109,9 +938,14 @@ static int do_sign_commit(struct strbuf *buf, const char *keyid)
 {
        struct strbuf sig = STRBUF_INIT;
        int inspos, copypos;
+       const char *eoh;
 
        /* find the end of the header */
-       inspos = strstr(buf->buf, "\n\n") - buf->buf + 1;
+       eoh = strstr(buf->buf, "\n\n");
+       if (!eoh)
+               inspos = buf->len;
+       else
+               inspos = eoh - buf->buf + 1;
 
        if (!keyid || !*keyid)
                keyid = get_signing_key();
@@ -1178,6 +1012,40 @@ int parse_signed_commit(const struct commit *commit,
        return saw_signature;
 }
 
+int remove_signature(struct strbuf *buf)
+{
+       const char *line = buf->buf;
+       const char *tail = buf->buf + buf->len;
+       int in_signature = 0;
+       const char *sig_start = NULL;
+       const char *sig_end = NULL;
+
+       while (line < tail) {
+               const char *next = memchr(line, '\n', tail - line);
+               next = next ? next + 1 : tail;
+
+               if (in_signature && line[0] == ' ')
+                       sig_end = next;
+               else if (starts_with(line, gpg_sig_header) &&
+                        line[gpg_sig_header_len] == ' ') {
+                       sig_start = line;
+                       sig_end = next;
+                       in_signature = 1;
+               } else {
+                       if (*line == '\n')
+                               /* dump the whole remainder of the buffer */
+                               next = tail;
+                       in_signature = 0;
+               }
+               line = next;
+       }
+
+       if (sig_start)
+               strbuf_remove(buf, sig_start - buf->buf, sig_end - sig_start);
+
+       return sig_start != NULL;
+}
+
 static void handle_signed_tag(struct commit *parent, struct commit_extra_header ***tail)
 {
        struct merge_remote_desc *desc;
@@ -1189,7 +1057,7 @@ static void handle_signed_tag(struct commit *parent, struct commit_extra_header
        desc = merge_remote_util(parent);
        if (!desc || !desc->obj)
                return;
-       buf = read_sha1_file(desc->obj->sha1, &type, &size);
+       buf = read_object_file(&desc->obj->oid, &type, &size);
        if (!buf || type != OBJ_TAG)
                goto free_return;
        len = parse_signature(buf, size);
@@ -1218,72 +1086,53 @@ free_return:
        free(buf);
 }
 
-static struct {
-       char result;
-       const char *check;
-} sigcheck_gpg_status[] = {
-       { 'G', "\n[GNUPG:] GOODSIG " },
-       { 'B', "\n[GNUPG:] BADSIG " },
-       { 'U', "\n[GNUPG:] TRUST_NEVER" },
-       { 'U', "\n[GNUPG:] TRUST_UNDEFINED" },
-};
-
-static void parse_gpg_output(struct signature_check *sigc)
-{
-       const char *buf = sigc->gpg_status;
-       int i;
-
-       /* Iterate over all search strings */
-       for (i = 0; i < ARRAY_SIZE(sigcheck_gpg_status); i++) {
-               const char *found, *next;
-
-               found = skip_prefix(buf, sigcheck_gpg_status[i].check + 1);
-               if (!found) {
-                       found = strstr(buf, sigcheck_gpg_status[i].check);
-                       if (!found)
-                               continue;
-                       found += strlen(sigcheck_gpg_status[i].check);
-               }
-               sigc->result = sigcheck_gpg_status[i].result;
-               /* The trust messages are not followed by key/signer information */
-               if (sigc->result != 'U') {
-                       sigc->key = xmemdupz(found, 16);
-                       found += 17;
-                       next = strchrnul(found, '\n');
-                       sigc->signer = xmemdupz(found, next - found);
-               }
-       }
-}
-
-void check_commit_signature(const struct commit* commit, struct signature_check *sigc)
+int check_commit_signature(const struct commit *commit, struct signature_check *sigc)
 {
        struct strbuf payload = STRBUF_INIT;
        struct strbuf signature = STRBUF_INIT;
-       struct strbuf gpg_output = STRBUF_INIT;
-       struct strbuf gpg_status = STRBUF_INIT;
-       int status;
+       int ret = 1;
 
        sigc->result = 'N';
 
        if (parse_signed_commit(commit, &payload, &signature) <= 0)
                goto out;
-       status = verify_signed_buffer(payload.buf, payload.len,
-                                     signature.buf, signature.len,
-                                     &gpg_output, &gpg_status);
-       if (status && !gpg_output.len)
-               goto out;
-       sigc->gpg_output = strbuf_detach(&gpg_output, NULL);
-       sigc->gpg_status = strbuf_detach(&gpg_status, NULL);
-       parse_gpg_output(sigc);
+       ret = check_signature(payload.buf, payload.len, signature.buf,
+               signature.len, sigc);
 
  out:
-       strbuf_release(&gpg_status);
-       strbuf_release(&gpg_output);
        strbuf_release(&payload);
        strbuf_release(&signature);
+
+       return ret;
 }
 
+void verify_merge_signature(struct commit *commit, int verbosity)
+{
+       char hex[GIT_MAX_HEXSZ + 1];
+       struct signature_check signature_check;
+       memset(&signature_check, 0, sizeof(signature_check));
 
+       check_commit_signature(commit, &signature_check);
+
+       find_unique_abbrev_r(hex, &commit->object.oid, DEFAULT_ABBREV);
+       switch (signature_check.result) {
+       case 'G':
+               break;
+       case 'U':
+               die(_("Commit %s has an untrusted GPG signature, "
+                     "allegedly by %s."), hex, signature_check.signer);
+       case 'B':
+               die(_("Commit %s has a bad GPG signature "
+                     "allegedly by %s."), hex, signature_check.signer);
+       default: /* 'N' */
+               die(_("Commit %s does not have a GPG signature."), hex);
+       }
+       if (verbosity >= 0 && signature_check.result == 'G')
+               printf(_("Commit %s has a good GPG signature by %s\n"),
+                      hex, signature_check.signer);
+
+       signature_check_clear(&signature_check);
+}
 
 void append_merge_tag_headers(struct commit_list *parents,
                              struct commit_extra_header ***tail)
@@ -1316,13 +1165,28 @@ struct commit_extra_header *read_commit_extra_headers(struct commit *commit,
        return extra;
 }
 
+int for_each_mergetag(each_mergetag_fn fn, struct commit *commit, void *data)
+{
+       struct commit_extra_header *extra, *to_free;
+       int res = 0;
+
+       to_free = read_commit_extra_headers(commit, NULL);
+       for (extra = to_free; !res && extra; extra = extra->next) {
+               if (strcmp(extra->key, "mergetag"))
+                       continue; /* not a merge tag */
+               res = fn(commit, extra, data);
+       }
+       free_commit_extra_headers(to_free);
+       return res;
+}
+
 static inline int standard_header_field(const char *field, size_t len)
 {
-       return ((len == 4 && !memcmp(field, "tree ", 5)) ||
-               (len == 6 && !memcmp(field, "parent ", 7)) ||
-               (len == 6 && !memcmp(field, "author ", 7)) ||
-               (len == 9 && !memcmp(field, "committer ", 10)) ||
-               (len == 8 && !memcmp(field, "encoding ", 9)));
+       return ((len == 4 && !memcmp(field, "tree", 4)) ||
+               (len == 6 && !memcmp(field, "parent", 6)) ||
+               (len == 6 && !memcmp(field, "author", 6)) ||
+               (len == 9 && !memcmp(field, "committer", 9)) ||
+               (len == 8 && !memcmp(field, "encoding", 8)));
 }
 
 static int excluded_header_field(const char *field, size_t len, const char **exclude)
@@ -1332,8 +1196,7 @@ static int excluded_header_field(const char *field, size_t len, const char **exc
 
        while (*exclude) {
                size_t xlen = strlen(*exclude);
-               if (len == xlen &&
-                   !memcmp(field, *exclude, xlen) && field[xlen] == ' ')
+               if (len == xlen && !memcmp(field, *exclude, xlen))
                        return 1;
                exclude++;
        }
@@ -1364,12 +1227,11 @@ static struct commit_extra_header *read_commit_extra_header_lines(
                strbuf_reset(&buf);
                it = NULL;
 
-               eof = strchr(line, ' ');
-               if (next <= eof)
+               eof = memchr(line, ' ', next - line);
+               if (!eof)
                        eof = next;
-
-               if (standard_header_field(line, eof - line) ||
-                   excluded_header_field(line, eof - line, exclude))
+               else if (standard_header_field(line, eof - line) ||
+                        excluded_header_field(line, eof - line, exclude))
                        continue;
 
                it = xcalloc(1, sizeof(*it));
@@ -1395,9 +1257,8 @@ void free_commit_extra_headers(struct commit_extra_header *extra)
        }
 }
 
-int commit_tree(const char *msg, size_t msg_len,
-               const unsigned char *tree,
-               struct commit_list *parents, unsigned char *ret,
+int commit_tree(const char *msg, size_t msg_len, const struct object_id *tree,
+               struct commit_list *parents, struct object_id *ret,
                const char *author, const char *sign_commit)
 {
        struct commit_extra_header *extra = NULL, **tail = &extra;
@@ -1521,13 +1382,13 @@ static int verify_utf8(struct strbuf *buf)
 }
 
 static const char commit_utf8_warn[] =
-"Warning: commit message did not conform to UTF-8.\n"
-"You may want to amend it after fixing the message, or set the config\n"
-"variable i18n.commitencoding to the encoding your project uses.\n";
+N_("Warning: commit message did not conform to UTF-8.\n"
+   "You may want to amend it after fixing the message, or set the config\n"
+   "variable i18n.commitencoding to the encoding your project uses.\n");
 
 int commit_tree_extended(const char *msg, size_t msg_len,
-                        const unsigned char *tree,
-                        struct commit_list *parents, unsigned char *ret,
+                        const struct object_id *tree,
+                        struct commit_list *parents, struct object_id *ret,
                         const char *author, const char *sign_commit,
                         struct commit_extra_header *extra)
 {
@@ -1535,7 +1396,7 @@ int commit_tree_extended(const char *msg, size_t msg_len,
        int encoding_is_utf8;
        struct strbuf buffer;
 
-       assert_sha1_type(tree, OBJ_TREE);
+       assert_oid_type(tree, OBJ_TREE);
 
        if (memchr(msg, '\0', msg_len))
                return error("a NUL byte in commit log message not allowed.");
@@ -1544,7 +1405,7 @@ int commit_tree_extended(const char *msg, size_t msg_len,
        encoding_is_utf8 = is_encoding_utf8(git_commit_encoding);
 
        strbuf_init(&buffer, 8192); /* should avoid reallocs for the headers */
-       strbuf_addf(&buffer, "tree %s\n", sha1_to_hex(tree));
+       strbuf_addf(&buffer, "tree %s\n", oid_to_hex(tree));
 
        /*
         * NOTE! This ordering means that the same exact tree merged with a
@@ -1552,13 +1413,9 @@ int commit_tree_extended(const char *msg, size_t msg_len,
         * if everything else stays the same.
         */
        while (parents) {
-               struct commit_list *next = parents->next;
-               struct commit *parent = parents->item;
-
+               struct commit *parent = pop_commit(&parents);
                strbuf_addf(&buffer, "parent %s\n",
-                           sha1_to_hex(parent->object.sha1));
-               free(parents);
-               parents = next;
+                           oid_to_hex(&parent->object.oid));
        }
 
        /* Person/date information */
@@ -1580,32 +1437,47 @@ int commit_tree_extended(const char *msg, size_t msg_len,
 
        /* And check the encoding */
        if (encoding_is_utf8 && !verify_utf8(&buffer))
-               fprintf(stderr, commit_utf8_warn);
+               fprintf(stderr, _(commit_utf8_warn));
 
-       if (sign_commit && do_sign_commit(&buffer, sign_commit))
-               return -1;
+       if (sign_commit && do_sign_commit(&buffer, sign_commit)) {
+               result = -1;
+               goto out;
+       }
 
-       result = write_sha1_file(buffer.buf, buffer.len, commit_type, ret);
+       result = write_object_file(buffer.buf, buffer.len, commit_type, ret);
+out:
        strbuf_release(&buffer);
        return result;
 }
 
+define_commit_slab(merge_desc_slab, struct merge_remote_desc *);
+static struct merge_desc_slab merge_desc_slab = COMMIT_SLAB_INIT(1, merge_desc_slab);
+
+struct merge_remote_desc *merge_remote_util(struct commit *commit)
+{
+       return *merge_desc_slab_at(&merge_desc_slab, commit);
+}
+
+void set_merge_remote_desc(struct commit *commit,
+                          const char *name, struct object *obj)
+{
+       struct merge_remote_desc *desc;
+       FLEX_ALLOC_STR(desc, name, name);
+       desc->obj = obj;
+       *merge_desc_slab_at(&merge_desc_slab, commit) = desc;
+}
+
 struct commit *get_merge_parent(const char *name)
 {
        struct object *obj;
        struct commit *commit;
-       unsigned char sha1[20];
-       if (get_sha1(name, sha1))
+       struct object_id oid;
+       if (get_oid(name, &oid))
                return NULL;
-       obj = parse_object(sha1);
+       obj = parse_object(the_repository, &oid);
        commit = (struct commit *)peel_to_type(name, 0, obj, OBJ_COMMIT);
-       if (commit && !commit->util) {
-               struct merge_remote_desc *desc;
-               desc = xmalloc(sizeof(*desc));
-               desc->obj = obj;
-               desc->name = strdup(name);
-               commit->util = desc;
-       }
+       if (commit && !merge_remote_util(commit))
+               set_merge_remote_desc(commit, name, obj);
        return commit;
 }
 
@@ -1629,19 +1501,77 @@ struct commit *get_merge_parent(const char *name)
 struct commit_list **commit_list_append(struct commit *commit,
                                        struct commit_list **next)
 {
-       struct commit_list *new = xmalloc(sizeof(struct commit_list));
-       new->item = commit;
-       *next = new;
-       new->next = NULL;
-       return &new->next;
+       struct commit_list *new_commit = xmalloc(sizeof(struct commit_list));
+       new_commit->item = commit;
+       *next = new_commit;
+       new_commit->next = NULL;
+       return &new_commit->next;
 }
 
-void print_commit_list(struct commit_list *list,
-                      const char *format_cur,
-                      const char *format_last)
+const char *find_commit_header(const char *msg, const char *key, size_t *out_len)
 {
-       for ( ; list; list = list->next) {
-               const char *format = list->next ? format_cur : format_last;
-               printf(format, sha1_to_hex(list->item->object.sha1));
+       int key_len = strlen(key);
+       const char *line = msg;
+
+       while (line) {
+               const char *eol = strchrnul(line, '\n');
+
+               if (line == eol)
+                       return NULL;
+
+               if (eol - line > key_len &&
+                   !strncmp(line, key, key_len) &&
+                   line[key_len] == ' ') {
+                       *out_len = eol - line - key_len - 1;
+                       return line + key_len + 1;
+               }
+               line = *eol ? eol + 1 : NULL;
+       }
+       return NULL;
+}
+
+/*
+ * Inspect the given string and determine the true "end" of the log message, in
+ * order to find where to put a new Signed-off-by: line.  Ignored are
+ * trailing comment lines and blank lines.  To support "git commit -s
+ * --amend" on an existing commit, we also ignore "Conflicts:".  To
+ * support "git commit -v", we truncate at cut lines.
+ *
+ * Returns the number of bytes from the tail to ignore, to be fed as
+ * the second parameter to append_signoff().
+ */
+size_t ignore_non_trailer(const char *buf, size_t len)
+{
+       size_t boc = 0;
+       size_t bol = 0;
+       int in_old_conflicts_block = 0;
+       size_t cutoff = wt_status_locate_end(buf, len);
+
+       while (bol < cutoff) {
+               const char *next_line = memchr(buf + bol, '\n', len - bol);
+
+               if (!next_line)
+                       next_line = buf + len;
+               else
+                       next_line++;
+
+               if (buf[bol] == comment_line_char || buf[bol] == '\n') {
+                       /* is this the first of the run of comments? */
+                       if (!boc)
+                               boc = bol;
+                       /* otherwise, it is just continuing */
+               } else if (starts_with(buf + bol, "Conflicts:\n")) {
+                       in_old_conflicts_block = 1;
+                       if (!boc)
+                               boc = bol;
+               } else if (in_old_conflicts_block && buf[bol] == '\t') {
+                       ; /* a pathname in the conflicts block */
+               } else if (boc) {
+                       /* the previous was not trailing comment */
+                       boc = 0;
+                       in_old_conflicts_block = 0;
+               }
+               bol = next_line - buf;
        }
+       return boc ? len - boc : len - cutoff;
 }