+static void check_notes_merge_worktree(struct notes_merge_options *o)
+{
+ if (!o->has_worktree) {
+ /*
+ * Must establish NOTES_MERGE_WORKTREE.
+ * Abort if NOTES_MERGE_WORKTREE already exists
+ */
+ if (file_exists(git_path(NOTES_MERGE_WORKTREE))) {
+ if (advice_resolve_conflict)
+ die("You have not concluded your previous "
+ "notes merge (%s exists).\nPlease, use "
+ "'git notes merge --commit' or 'git notes "
+ "merge --reset' to commit/abort the "
+ "previous merge before you start a new "
+ "notes merge.", git_path("NOTES_MERGE_*"));
+ else
+ die("You have not concluded your notes merge "
+ "(%s exists).", git_path("NOTES_MERGE_*"));
+ }
+
+ if (safe_create_leading_directories(git_path(
+ NOTES_MERGE_WORKTREE "/.test")))
+ die_errno("unable to create directory %s",
+ git_path(NOTES_MERGE_WORKTREE));
+ o->has_worktree = 1;
+ } else if (!file_exists(git_path(NOTES_MERGE_WORKTREE)))
+ /* NOTES_MERGE_WORKTREE should already be established */
+ die("missing '%s'. This should not happen",
+ git_path(NOTES_MERGE_WORKTREE));
+}
+
+static void write_buf_to_worktree(const unsigned char *obj,
+ const char *buf, unsigned long size)
+{
+ int fd;
+ char *path = git_path(NOTES_MERGE_WORKTREE "/%s", sha1_to_hex(obj));
+ if (safe_create_leading_directories(path))
+ die_errno("unable to create directory for '%s'", path);
+ if (file_exists(path))
+ die("found existing file at '%s'", path);
+
+ fd = open(path, O_WRONLY | O_TRUNC | O_CREAT, 0666);
+ if (fd < 0)
+ die_errno("failed to open '%s'", path);
+
+ while (size > 0) {
+ long ret = write_in_full(fd, buf, size);
+ if (ret < 0) {
+ /* Ignore epipe */
+ if (errno == EPIPE)
+ break;
+ die_errno("notes-merge");
+ } else if (!ret) {
+ die("notes-merge: disk full?");
+ }
+ size -= ret;
+ buf += ret;
+ }
+
+ close(fd);
+}
+
+static void write_note_to_worktree(const unsigned char *obj,
+ const unsigned char *note)
+{
+ enum object_type type;
+ unsigned long size;
+ void *buf = read_sha1_file(note, &type, &size);
+
+ if (!buf)
+ die("cannot read note %s for object %s",
+ sha1_to_hex(note), sha1_to_hex(obj));
+ if (type != OBJ_BLOB)
+ die("blob expected in note %s for object %s",
+ sha1_to_hex(note), sha1_to_hex(obj));
+ write_buf_to_worktree(obj, buf, size);
+ free(buf);
+}
+
+static int ll_merge_in_worktree(struct notes_merge_options *o,
+ struct notes_merge_pair *p)
+{
+ mmbuffer_t result_buf;
+ mmfile_t base, local, remote;
+ int status;
+
+ read_mmblob(&base, p->base);
+ read_mmblob(&local, p->local);
+ read_mmblob(&remote, p->remote);
+
+ status = ll_merge(&result_buf, sha1_to_hex(p->obj), &base, NULL,
+ &local, o->local_ref, &remote, o->remote_ref, 0);
+
+ free(base.ptr);
+ free(local.ptr);
+ free(remote.ptr);
+
+ if ((status < 0) || !result_buf.ptr)
+ die("Failed to execute internal merge");
+
+ write_buf_to_worktree(p->obj, result_buf.ptr, result_buf.size);
+ free(result_buf.ptr);
+
+ return status;
+}
+
+static int merge_one_change_manual(struct notes_merge_options *o,
+ struct notes_merge_pair *p,
+ struct notes_tree *t)
+{
+ const char *lref = o->local_ref ? o->local_ref : "local version";
+ const char *rref = o->remote_ref ? o->remote_ref : "remote version";
+
+ trace_printf("\t\t\tmerge_one_change_manual(obj = %.7s, base = %.7s, "
+ "local = %.7s, remote = %.7s)\n",
+ sha1_to_hex(p->obj), sha1_to_hex(p->base),
+ sha1_to_hex(p->local), sha1_to_hex(p->remote));
+
+ OUTPUT(o, 2, "Auto-merging notes for %s", sha1_to_hex(p->obj));
+ check_notes_merge_worktree(o);
+ if (is_null_sha1(p->local)) {
+ /* D/F conflict, checkout p->remote */
+ assert(!is_null_sha1(p->remote));
+ OUTPUT(o, 1, "CONFLICT (delete/modify): Notes for object %s "
+ "deleted in %s and modified in %s. Version from %s "
+ "left in tree.", sha1_to_hex(p->obj), lref, rref, rref);
+ write_note_to_worktree(p->obj, p->remote);
+ } else if (is_null_sha1(p->remote)) {
+ /* D/F conflict, checkout p->local */
+ assert(!is_null_sha1(p->local));
+ OUTPUT(o, 1, "CONFLICT (delete/modify): Notes for object %s "
+ "deleted in %s and modified in %s. Version from %s "
+ "left in tree.", sha1_to_hex(p->obj), rref, lref, lref);
+ write_note_to_worktree(p->obj, p->local);
+ } else {
+ /* "regular" conflict, checkout result of ll_merge() */
+ const char *reason = "content";
+ if (is_null_sha1(p->base))
+ reason = "add/add";
+ assert(!is_null_sha1(p->local));
+ assert(!is_null_sha1(p->remote));
+ OUTPUT(o, 1, "CONFLICT (%s): Merge conflict in notes for "
+ "object %s", reason, sha1_to_hex(p->obj));
+ ll_merge_in_worktree(o, p);
+ }
+
+ trace_printf("\t\t\tremoving from partial merge result\n");
+ remove_note(t, p->obj);
+
+ return 1;
+}
+