1 files changed, 177 insertions, 166 deletions

diff --git a/builtin/am.c b/builtin/am.c
index 9daeb27225..3985f9a89f 100644
--- a/builtin/am.c
+++ b/builtin/am.c
@@ -28,6 +28,7 @@
 #include "rerere.h"
 #include "prompt.h"
 #include "mailinfo.h"
+#include "apply.h"
 #include "string-list.h"
 
 /**
@@ -109,7 +110,7 @@ struct am_state {
 	size_t msg_len;
 
 	/* when --rebasing, records the original commit the patch came from */
-	unsigned char orig_commit[GIT_SHA1_RAWSZ];
+	struct object_id orig_commit;
 
 	/* number of digits in patch filename */
 	int prec;
@@ -133,17 +134,15 @@ struct am_state {
 };
 
 /**
- * Initializes am_state with the default values. The state directory is set to
- * dir.
+ * Initializes am_state with the default values.
  */
-static void am_state_init(struct am_state *state, const char *dir)
+static void am_state_init(struct am_state *state)
 {
 	int gpgsign;
 
 	memset(state, 0, sizeof(*state));
 
-	assert(dir);
-	state->dir = xstrdup(dir);
+	state->dir = git_pathdup("rebase-apply");
 
 	state->prec = 4;
 
@@ -415,8 +414,8 @@ static void am_load(struct am_state *state)
 	read_commit_msg(state);
 
 	if (read_state_file(&sb, state, "original-commit", 1) < 0)
-		hashclr(state->orig_commit);
-	else if (get_sha1_hex(sb.buf, state->orig_commit) < 0)
+		oidclr(&state->orig_commit);
+	else if (get_oid_hex(sb.buf, &state->orig_commit) < 0)
 		die(_("could not parse %s"), am_path(state, "original-commit"));
 
 	read_state_file(&sb, state, "threeway", 1);
@@ -542,14 +541,14 @@ static int copy_notes_for_rebase(const struct am_state *state)
 	fp = xfopen(am_path(state, "rewritten"), "r");
 
 	while (!strbuf_getline_lf(&sb, fp)) {
-		unsigned char from_obj[GIT_SHA1_RAWSZ], to_obj[GIT_SHA1_RAWSZ];
+		struct object_id from_obj, to_obj;
 
 		if (sb.len != GIT_SHA1_HEXSZ * 2 + 1) {
 			ret = error(invalid_line, sb.buf);
 			goto finish;
 		}
 
-		if (get_sha1_hex(sb.buf, from_obj)) {
+		if (get_oid_hex(sb.buf, &from_obj)) {
 			ret = error(invalid_line, sb.buf);
 			goto finish;
 		}
@@ -559,14 +558,14 @@ static int copy_notes_for_rebase(const struct am_state *state)
 			goto finish;
 		}
 
-		if (get_sha1_hex(sb.buf + GIT_SHA1_HEXSZ + 1, to_obj)) {
+		if (get_oid_hex(sb.buf + GIT_SHA1_HEXSZ + 1, &to_obj)) {
 			ret = error(invalid_line, sb.buf);
 			goto finish;
 		}
 
-		if (copy_note_for_rewrite(c, from_obj, to_obj))
+		if (copy_note_for_rewrite(c, &from_obj, &to_obj))
 			ret = error(_("Failed to copy notes from '%s' to '%s'"),
-					sha1_to_hex(from_obj), sha1_to_hex(to_obj));
+					oid_to_hex(&from_obj), oid_to_hex(&to_obj));
 	}
 
 finish:
@@ -761,14 +760,18 @@ static int split_mail_conv(mail_conv_fn fn, struct am_state *state,
 		mail = mkpath("%s/%0*d", state->dir, state->prec, i + 1);
 
 		out = fopen(mail, "w");
-		if (!out)
+		if (!out) {
+			if (in != stdin)
+				fclose(in);
 			return error_errno(_("could not open '%s' for writing"),
 					   mail);
+		}
 
 		ret = fn(out, in, keep_cr);
 
 		fclose(out);
-		fclose(in);
+		if (in != stdin)
+			fclose(in);
 
 		if (ret)
 			return error(_("could not parse patch '%s'"), *paths);
@@ -876,12 +879,12 @@ static int hg_patch_to_mail(FILE *out, FILE *in, int keep_cr)
 		if (skip_prefix(sb.buf, "# User ", &str))
 			fprintf(out, "From: %s\n", str);
 		else if (skip_prefix(sb.buf, "# Date ", &str)) {
-			unsigned long timestamp;
+			timestamp_t timestamp;
 			long tz, tz2;
 			char *end;
 
 			errno = 0;
-			timestamp = strtoul(str, &end, 10);
+			timestamp = parse_timestamp(str, &end, 10);
 			if (errno)
 				return error(_("invalid timestamp"));
 
@@ -972,7 +975,7 @@ static int split_mail(struct am_state *state, enum patch_format patch_format,
 static void am_setup(struct am_state *state, enum patch_format patch_format,
 			const char **paths, int keep_cr)
 {
-	unsigned char curr_head[GIT_SHA1_RAWSZ];
+	struct object_id curr_head;
 	const char *str;
 	struct strbuf sb = STRBUF_INIT;
 
@@ -1040,15 +1043,15 @@ static void am_setup(struct am_state *state, enum patch_format patch_format,
 	else
 		write_state_text(state, "applying", "");
 
-	if (!get_sha1("HEAD", curr_head)) {
-		write_state_text(state, "abort-safety", sha1_to_hex(curr_head));
+	if (!get_oid("HEAD", &curr_head)) {
+		write_state_text(state, "abort-safety", oid_to_hex(&curr_head));
 		if (!state->rebasing)
-			update_ref("am", "ORIG_HEAD", curr_head, NULL, 0,
+			update_ref_oid("am", "ORIG_HEAD", &curr_head, NULL, 0,
 					UPDATE_REFS_DIE_ON_ERR);
 	} else {
 		write_state_text(state, "abort-safety", "");
 		if (!state->rebasing)
-			delete_ref("ORIG_HEAD", NULL, 0);
+			delete_ref(NULL, "ORIG_HEAD", NULL, 0);
 	}
 
 	/*
@@ -1068,7 +1071,7 @@ static void am_setup(struct am_state *state, enum patch_format patch_format,
  */
 static void am_next(struct am_state *state)
 {
-	unsigned char head[GIT_SHA1_RAWSZ];
+	struct object_id head;
 
 	free(state->author_name);
 	state->author_name = NULL;
@@ -1086,11 +1089,11 @@ static void am_next(struct am_state *state)
 	unlink(am_path(state, "author-script"));
 	unlink(am_path(state, "final-commit"));
 
-	hashclr(state->orig_commit);
+	oidclr(&state->orig_commit);
 	unlink(am_path(state, "original-commit"));
 
-	if (!get_sha1("HEAD", head))
-		write_state_text(state, "abort-safety", sha1_to_hex(head));
+	if (!get_oid("HEAD", &head))
+		write_state_text(state, "abort-safety", oid_to_hex(&head));
 	else
 		write_state_text(state, "abort-safety", "");
 
@@ -1118,7 +1121,7 @@ static void refresh_and_write_cache(void)
 {
 	struct lock_file *lock_file = xcalloc(1, sizeof(struct lock_file));
 
-	hold_locked_index(lock_file, 1);
+	hold_locked_index(lock_file, LOCK_DIE_ON_ERROR);
 	refresh_cache(REFRESH_QUIET);
 	if (write_locked_index(&the_index, lock_file, COMMIT_LOCK))
 		die(_("unable to write index file"));
@@ -1132,17 +1135,17 @@ static void refresh_and_write_cache(void)
  */
 static int index_has_changes(struct strbuf *sb)
 {
-	unsigned char head[GIT_SHA1_RAWSZ];
+	struct object_id head;
 	int i;
 
-	if (!get_sha1_tree("HEAD", head)) {
+	if (!get_sha1_tree("HEAD", head.hash)) {
 		struct diff_options opt;
 
 		diff_setup(&opt);
 		DIFF_OPT_SET(&opt, EXIT_WITH_STATUS);
 		if (!sb)
 			DIFF_OPT_SET(&opt, QUICK);
-		do_diff_cache(head, &opt);
+		do_diff_cache(&head, &opt);
 		diffcore_std(&opt);
 		for (i = 0; sb && i < diff_queued_diff.nr; i++) {
 			if (i)
@@ -1180,42 +1183,39 @@ static void NORETURN die_user_resolve(const struct am_state *state)
 	exit(128);
 }
 
-static void am_signoff(struct strbuf *sb)
+/**
+ * Appends signoff to the "msg" field of the am_state.
+ */
+static void am_append_signoff(struct am_state *state)
 {
 	char *cp;
 	struct strbuf mine = STRBUF_INIT;
+	struct strbuf sb = STRBUF_INIT;
 
-	/* Does it end with our own sign-off? */
+	strbuf_attach(&sb, state->msg, state->msg_len, state->msg_len);
+
+	/* our sign-off */
 	strbuf_addf(&mine, "\n%s%s\n",
 		    sign_off_header,
 		    fmt_name(getenv("GIT_COMMITTER_NAME"),
 			     getenv("GIT_COMMITTER_EMAIL")));
-	if (mine.len < sb->len &&
-	    !strcmp(mine.buf, sb->buf + sb->len - mine.len))
+
+	/* Does sb end with it already? */
+	if (mine.len < sb.len &&
+	    !strcmp(mine.buf, sb.buf + sb.len - mine.len))
 		goto exit; /* no need to duplicate */
 
 	/* Does it have any Signed-off-by: in the text */
-	for (cp = sb->buf;
+	for (cp = sb.buf;
 	     cp && *cp && (cp = strstr(cp, sign_off_header)) != NULL;
 	     cp = strchr(cp, '\n')) {
-		if (sb->buf == cp || cp[-1] == '\n')
+		if (sb.buf == cp || cp[-1] == '\n')
 			break;
 	}
 
-	strbuf_addstr(sb, mine.buf + !!cp);
+	strbuf_addstr(&sb, mine.buf + !!cp);
 exit:
 	strbuf_release(&mine);
-}
-
-/**
- * Appends signoff to the "msg" field of the am_state.
- */
-static void am_append_signoff(struct am_state *state)
-{
-	struct strbuf sb = STRBUF_INIT;
-
-	strbuf_attach(&sb, state->msg, state->msg_len, state->msg_len);
-	am_signoff(&sb);
 	state->msg = strbuf_detach(&sb, &state->msg_len);
 }
 
@@ -1275,12 +1275,8 @@ static int parse_mail(struct am_state *state, const char *mail)
 		die("BUG: invalid value for state->scissors");
 	}
 
-	mi.input = fopen(mail, "r");
-	if (!mi.input)
-		die("could not open input");
-	mi.output = fopen(am_path(state, "info"), "w");
-	if (!mi.output)
-		die("could not open output 'info'");
+	mi.input = xfopen(mail, "r");
+	mi.output = xfopen(am_path(state, "info"), "w");
 	if (mailinfo(&mi, am_path(state, "msg"), am_path(state, "patch")))
 		die("could not parse patch");
 
@@ -1312,7 +1308,7 @@ static int parse_mail(struct am_state *state, const char *mail)
 	}
 
 	if (is_empty_file(am_path(state, "patch"))) {
-		printf_ln(_("Patch is empty. Was it split wrong?"));
+		printf_ln(_("Patch is empty."));
 		die_user_resolve(state);
 	}
 
@@ -1320,9 +1316,6 @@ static int parse_mail(struct am_state *state, const char *mail)
 	strbuf_addbuf(&msg, &mi.log_message);
 	strbuf_stripspace(&msg, 0);
 
-	if (state->signoff)
-		am_signoff(&msg);
-
 	assert(!state->author_name);
 	state->author_name = strbuf_detach(&author_name, NULL);
 
@@ -1349,24 +1342,21 @@ finish:
  * Sets commit_id to the commit hash where the mail was generated from.
  * Returns 0 on success, -1 on failure.
  */
-static int get_mail_commit_sha1(unsigned char *commit_id, const char *mail)
+static int get_mail_commit_oid(struct object_id *commit_id, const char *mail)
 {
 	struct strbuf sb = STRBUF_INIT;
 	FILE *fp = xfopen(mail, "r");
 	const char *x;
+	int ret = 0;
 
-	if (strbuf_getline_lf(&sb, fp))
-		return -1;
-
-	if (!skip_prefix(sb.buf, "From ", &x))
-		return -1;
-
-	if (get_sha1_hex(x, commit_id) < 0)
-		return -1;
+	if (strbuf_getline_lf(&sb, fp) ||
+	    !skip_prefix(sb.buf, "From ", &x) ||
+	    get_oid_hex(x, commit_id) < 0)
+		ret = -1;
 
 	strbuf_release(&sb);
 	fclose(fp);
-	return 0;
+	return ret;
 }
 
 /**
@@ -1375,40 +1365,33 @@ static int get_mail_commit_sha1(unsigned char *commit_id, const char *mail)
  */
 static void get_commit_info(struct am_state *state, struct commit *commit)
 {
-	const char *buffer, *ident_line, *author_date, *msg;
+	const char *buffer, *ident_line, *msg;
 	size_t ident_len;
-	struct ident_split ident_split;
-	struct strbuf sb = STRBUF_INIT;
+	struct ident_split id;
 
 	buffer = logmsg_reencode(commit, NULL, get_commit_output_encoding());
 
 	ident_line = find_commit_header(buffer, "author", &ident_len);
 
-	if (split_ident_line(&ident_split, ident_line, ident_len) < 0) {
-		strbuf_add(&sb, ident_line, ident_len);
-		die(_("invalid ident line: %s"), sb.buf);
-	}
+	if (split_ident_line(&id, ident_line, ident_len) < 0)
+		die(_("invalid ident line: %.*s"), (int)ident_len, ident_line);
 
 	assert(!state->author_name);
-	if (ident_split.name_begin) {
-		strbuf_add(&sb, ident_split.name_begin,
-			ident_split.name_end - ident_split.name_begin);
-		state->author_name = strbuf_detach(&sb, NULL);
-	} else
+	if (id.name_begin)
+		state->author_name =
+			xmemdupz(id.name_begin, id.name_end - id.name_begin);
+	else
 		state->author_name = xstrdup("");
 
 	assert(!state->author_email);
-	if (ident_split.mail_begin) {
-		strbuf_add(&sb, ident_split.mail_begin,
-			ident_split.mail_end - ident_split.mail_begin);
-		state->author_email = strbuf_detach(&sb, NULL);
-	} else
+	if (id.mail_begin)
+		state->author_email =
+			xmemdupz(id.mail_begin, id.mail_end - id.mail_begin);
+	else
 		state->author_email = xstrdup("");
 
-	author_date = show_ident_date(&ident_split, DATE_MODE(NORMAL));
-	strbuf_addstr(&sb, author_date);
 	assert(!state->author_date);
-	state->author_date = strbuf_detach(&sb, NULL);
+	state->author_date = xstrdup(show_ident_date(&id, DATE_MODE(NORMAL)));
 
 	assert(!state->msg);
 	msg = strstr(buffer, "\n\n");
@@ -1416,6 +1399,7 @@ static void get_commit_info(struct am_state *state, struct commit *commit)
 		die(_("unable to parse commit %s"), oid_to_hex(&commit->object.oid));
 	state->msg = xstrdup(msg + 2);
 	state->msg_len = strlen(state->msg);
+	unuse_commit_buffer(commit, buffer);
 }
 
 /**
@@ -1451,14 +1435,14 @@ static void write_commit_patch(const struct am_state *state, struct commit *comm
 static void write_index_patch(const struct am_state *state)
 {
 	struct tree *tree;
-	unsigned char head[GIT_SHA1_RAWSZ];
+	struct object_id head;
 	struct rev_info rev_info;
 	FILE *fp;
 
-	if (!get_sha1_tree("HEAD", head))
-		tree = lookup_tree(head);
+	if (!get_sha1_tree("HEAD", head.hash))
+		tree = lookup_tree(&head);
 	else
-		tree = lookup_tree(EMPTY_TREE_SHA1_BIN);
+		tree = lookup_tree(&empty_tree_oid);
 
 	fp = xfopen(am_path(state, "patch"), "w");
 	init_revisions(&rev_info, NULL);
@@ -1486,19 +1470,19 @@ static void write_index_patch(const struct am_state *state)
 static int parse_mail_rebase(struct am_state *state, const char *mail)
 {
 	struct commit *commit;
-	unsigned char commit_sha1[GIT_SHA1_RAWSZ];
+	struct object_id commit_oid;
 
-	if (get_mail_commit_sha1(commit_sha1, mail) < 0)
+	if (get_mail_commit_oid(&commit_oid, mail) < 0)
 		die(_("could not parse %s"), mail);
 
-	commit = lookup_commit_or_die(commit_sha1, mail);
+	commit = lookup_commit_or_die(&commit_oid, mail);
 
 	get_commit_info(state, commit);
 
 	write_commit_patch(state, commit);
 
-	hashcpy(state->orig_commit, commit_sha1);
-	write_state_text(state, "original-commit", sha1_to_hex(commit_sha1));
+	oidcpy(&state->orig_commit, &commit_oid);
+	write_state_text(state, "original-commit", oid_to_hex(&commit_oid));
 
 	return 0;
 }
@@ -1509,39 +1493,59 @@ static int parse_mail_rebase(struct am_state *state, const char *mail)
  */
 static int run_apply(const struct am_state *state, const char *index_file)
 {
-	struct child_process cp = CHILD_PROCESS_INIT;
-
-	cp.git_cmd = 1;
-
-	if (index_file)
-		argv_array_pushf(&cp.env_array, "GIT_INDEX_FILE=%s", index_file);
+	struct argv_array apply_paths = ARGV_ARRAY_INIT;
+	struct argv_array apply_opts = ARGV_ARRAY_INIT;
+	struct apply_state apply_state;
+	int res, opts_left;
+	static struct lock_file lock_file;
+	int force_apply = 0;
+	int options = 0;
+
+	if (init_apply_state(&apply_state, NULL, &lock_file))
+		die("BUG: init_apply_state() failed");
+
+	argv_array_push(&apply_opts, "apply");
+	argv_array_pushv(&apply_opts, state->git_apply_opts.argv);
+
+	opts_left = apply_parse_options(apply_opts.argc, apply_opts.argv,
+					&apply_state, &force_apply, &options,
+					NULL);
+
+	if (opts_left != 0)
+		die("unknown option passed through to git apply");
+
+	if (index_file) {
+		apply_state.index_file = index_file;
+		apply_state.cached = 1;
+	} else
+		apply_state.check_index = 1;
 
 	/*
 	 * If we are allowed to fall back on 3-way merge, don't give false
 	 * errors during the initial attempt.
 	 */
-	if (state->threeway && !index_file) {
-		cp.no_stdout = 1;
-		cp.no_stderr = 1;
-	}
+	if (state->threeway && !index_file)
+		apply_state.apply_verbosity = verbosity_silent;
 
-	argv_array_push(&cp.args, "apply");
+	if (check_apply_state(&apply_state, force_apply))
+		die("BUG: check_apply_state() failed");
 
-	argv_array_pushv(&cp.args, state->git_apply_opts.argv);
+	argv_array_push(&apply_paths, am_path(state, "patch"));
 
-	if (index_file)
-		argv_array_push(&cp.args, "--cached");
-	else
-		argv_array_push(&cp.args, "--index");
+	res = apply_all_patches(&apply_state, apply_paths.argc, apply_paths.argv, options);
 
-	argv_array_push(&cp.args, am_path(state, "patch"));
+	argv_array_clear(&apply_paths);
+	argv_array_clear(&apply_opts);
+	clear_apply_state(&apply_state);
 
-	if (run_command(&cp))
-		return -1;
+	if (res)
+		return res;
 
-	/* Reload index as git-apply will have modified it. */
-	discard_cache();
-	read_cache_from(index_file ? index_file : get_index_file());
+	if (index_file) {
+		/* Reload index as apply_all_patches() will have modified it. */
+		discard_cache();
+		read_cache_from(index_file);
+	}
 
 	return 0;
 }
@@ -1601,7 +1605,7 @@ static int fall_back_threeway(const struct am_state *state, const char *index_pa
 		init_revisions(&rev_info, NULL);
 		rev_info.diffopt.output_format = DIFF_FORMAT_NAME_STATUS;
 		diff_opt_parse(&rev_info.diffopt, &diff_filter_str, 1, rev_info.prefix);
-		add_pending_sha1(&rev_info, "HEAD", our_tree.hash, 0);
+		add_pending_oid(&rev_info, "HEAD", &our_tree, 0);
 		diff_setup_done(&rev_info.diffopt);
 		run_diff_index(&rev_info, 1);
 	}
@@ -1652,9 +1656,8 @@ static int fall_back_threeway(const struct am_state *state, const char *index_pa
  */
 static void do_commit(const struct am_state *state)
 {
-	unsigned char tree[GIT_SHA1_RAWSZ], parent[GIT_SHA1_RAWSZ],
-		      commit[GIT_SHA1_RAWSZ];
-	unsigned char *ptr;
+	struct object_id tree, parent, commit;
+	const struct object_id *old_oid;
 	struct commit_list *parents = NULL;
 	const char *reflog_msg, *author;
 	struct strbuf sb = STRBUF_INIT;
@@ -1662,14 +1665,14 @@ static void do_commit(const struct am_state *state)
 	if (run_hook_le(NULL, "pre-applypatch", NULL))
 		exit(1);
 
-	if (write_cache_as_tree(tree, 0, NULL))
+	if (write_cache_as_tree(tree.hash, 0, NULL))
 		die(_("git write-tree failed to write a tree"));
 
-	if (!get_sha1_commit("HEAD", parent)) {
-		ptr = parent;
-		commit_list_insert(lookup_commit(parent), &parents);
+	if (!get_sha1_commit("HEAD", parent.hash)) {
+		old_oid = &parent;
+		commit_list_insert(lookup_commit(&parent), &parents);
 	} else {
-		ptr = NULL;
+		old_oid = NULL;
 		say(state, stderr, _("applying to an empty history"));
 	}
 
@@ -1681,7 +1684,7 @@ static void do_commit(const struct am_state *state)
 		setenv("GIT_COMMITTER_DATE",
 			state->ignore_date ? "" : state->author_date, 1);
 
-	if (commit_tree(state->msg, state->msg_len, tree, parents, commit,
+	if (commit_tree(state->msg, state->msg_len, tree.hash, parents, commit.hash,
 				author, state->sign_commit))
 		die(_("failed to write commit object"));
 
@@ -1692,14 +1695,15 @@ static void do_commit(const struct am_state *state)
 	strbuf_addf(&sb, "%s: %.*s", reflog_msg, linelen(state->msg),
 			state->msg);
 
-	update_ref(sb.buf, "HEAD", commit, ptr, 0, UPDATE_REFS_DIE_ON_ERR);
+	update_ref_oid(sb.buf, "HEAD", &commit, old_oid, 0,
+			UPDATE_REFS_DIE_ON_ERR);
 
 	if (state->rebasing) {
 		FILE *fp = xfopen(am_path(state, "rewritten"), "a");
 
-		assert(!is_null_sha1(state->orig_commit));
-		fprintf(fp, "%s ", sha1_to_hex(state->orig_commit));
-		fprintf(fp, "%s\n", sha1_to_hex(commit));
+		assert(!is_null_oid(&state->orig_commit));
+		fprintf(fp, "%s ", oid_to_hex(&state->orig_commit));
+		fprintf(fp, "%s\n", oid_to_hex(&commit));
 		fclose(fp);
 	}
 
@@ -1827,6 +1831,9 @@ static void am_run(struct am_state *state, int resume)
 			if (skip)
 				goto next; /* mail should be skipped */
 
+			if (state->signoff)
+				am_append_signoff(state);
+
 			write_author_script(state);
 			write_commit_msg(state);
 		}
@@ -1920,7 +1927,8 @@ static void am_resolve(struct am_state *state)
 
 	if (unmerged_cache()) {
 		printf_ln(_("You still have unmerged paths in your index.\n"
-			"Did you forget to use 'git add'?"));
+			"You should 'git add' each file with resolved conflicts to mark them as such.\n"
+			"You might run `git rm` on a file to accept \"deleted by them\" for it."));
 		die_user_resolve(state);
 	}
 
@@ -1955,7 +1963,7 @@ static int fast_forward_to(struct tree *head, struct tree *remote, int reset)
 		return -1;
 
 	lock_file = xcalloc(1, sizeof(struct lock_file));
-	hold_locked_index(lock_file, 1);
+	hold_locked_index(lock_file, LOCK_DIE_ON_ERROR);
 
 	refresh_cache(REFRESH_QUIET);
 
@@ -1995,7 +2003,7 @@ static int merge_tree(struct tree *tree)
 		return -1;
 
 	lock_file = xcalloc(1, sizeof(struct lock_file));
-	hold_locked_index(lock_file, 1);
+	hold_locked_index(lock_file, LOCK_DIE_ON_ERROR);
 
 	memset(&opts, 0, sizeof(opts));
 	opts.head_idx = 1;
@@ -2020,30 +2028,30 @@ static int merge_tree(struct tree *tree)
  * Clean the index without touching entries that are not modified between
  * `head` and `remote`.
  */
-static int clean_index(const unsigned char *head, const unsigned char *remote)
+static int clean_index(const struct object_id *head, const struct object_id *remote)
 {
 	struct tree *head_tree, *remote_tree, *index_tree;
-	unsigned char index[GIT_SHA1_RAWSZ];
+	struct object_id index;
 
 	head_tree = parse_tree_indirect(head);
 	if (!head_tree)
-		return error(_("Could not parse object '%s'."), sha1_to_hex(head));
+		return error(_("Could not parse object '%s'."), oid_to_hex(head));
 
 	remote_tree = parse_tree_indirect(remote);
 	if (!remote_tree)
-		return error(_("Could not parse object '%s'."), sha1_to_hex(remote));
+		return error(_("Could not parse object '%s'."), oid_to_hex(remote));
 
 	read_cache_unmerged();
 
 	if (fast_forward_to(head_tree, head_tree, 1))
 		return -1;
 
-	if (write_cache_as_tree(index, 0, NULL))
+	if (write_cache_as_tree(index.hash, 0, NULL))
 		return -1;
 
-	index_tree = parse_tree_indirect(index);
+	index_tree = parse_tree_indirect(&index);
 	if (!index_tree)
-		return error(_("Could not parse object '%s'."), sha1_to_hex(index));
+		return error(_("Could not parse object '%s'."), oid_to_hex(&index));
 
 	if (fast_forward_to(index_tree, remote_tree, 0))
 		return -1;
@@ -2071,14 +2079,14 @@ static void am_rerere_clear(void)
  */
 static void am_skip(struct am_state *state)
 {
-	unsigned char head[GIT_SHA1_RAWSZ];
+	struct object_id head;
 
 	am_rerere_clear();
 
-	if (get_sha1("HEAD", head))
-		hashcpy(head, EMPTY_TREE_SHA1_BIN);
+	if (get_oid("HEAD", &head))
+		hashcpy(head.hash, EMPTY_TREE_SHA1_BIN);
 
-	if (clean_index(head, head))
+	if (clean_index(&head, &head))
 		die(_("failed to clean index"));
 
 	am_next(state);
@@ -2096,24 +2104,24 @@ static void am_skip(struct am_state *state)
 static int safe_to_abort(const struct am_state *state)
 {
 	struct strbuf sb = STRBUF_INIT;
-	unsigned char abort_safety[GIT_SHA1_RAWSZ], head[GIT_SHA1_RAWSZ];
+	struct object_id abort_safety, head;
 
 	if (file_exists(am_path(state, "dirtyindex")))
 		return 0;
 
 	if (read_state_file(&sb, state, "abort-safety", 1) > 0) {
-		if (get_sha1_hex(sb.buf, abort_safety))
-			die(_("could not parse %s"), am_path(state, "abort_safety"));
+		if (get_oid_hex(sb.buf, &abort_safety))
+			die(_("could not parse %s"), am_path(state, "abort-safety"));
 	} else
-		hashclr(abort_safety);
+		oidclr(&abort_safety);
 
-	if (get_sha1("HEAD", head))
-		hashclr(head);
+	if (get_oid("HEAD", &head))
+		oidclr(&head);
 
-	if (!hashcmp(head, abort_safety))
+	if (!oidcmp(&head, &abort_safety))
 		return 1;
 
-	error(_("You seem to have moved HEAD since the last 'am' failure.\n"
+	warning(_("You seem to have moved HEAD since the last 'am' failure.\n"
 		"Not rewinding to ORIG_HEAD"));
 
 	return 0;
@@ -2124,7 +2132,7 @@ static int safe_to_abort(const struct am_state *state)
  */
 static void am_abort(struct am_state *state)
 {
-	unsigned char curr_head[GIT_SHA1_RAWSZ], orig_head[GIT_SHA1_RAWSZ];
+	struct object_id curr_head, orig_head;
 	int has_curr_head, has_orig_head;
 	char *curr_branch;
 
@@ -2135,23 +2143,23 @@ static void am_abort(struct am_state *state)
 
 	am_rerere_clear();
 
-	curr_branch = resolve_refdup("HEAD", 0, curr_head, NULL);
-	has_curr_head = !is_null_sha1(curr_head);
+	curr_branch = resolve_refdup("HEAD", 0, curr_head.hash, NULL);
+	has_curr_head = curr_branch && !is_null_oid(&curr_head);
 	if (!has_curr_head)
-		hashcpy(curr_head, EMPTY_TREE_SHA1_BIN);
+		hashcpy(curr_head.hash, EMPTY_TREE_SHA1_BIN);
 
-	has_orig_head = !get_sha1("ORIG_HEAD", orig_head);
+	has_orig_head = !get_oid("ORIG_HEAD", &orig_head);
 	if (!has_orig_head)
-		hashcpy(orig_head, EMPTY_TREE_SHA1_BIN);
+		hashcpy(orig_head.hash, EMPTY_TREE_SHA1_BIN);
 
-	clean_index(curr_head, orig_head);
+	clean_index(&curr_head, &orig_head);
 
 	if (has_orig_head)
-		update_ref("am --abort", "HEAD", orig_head,
-				has_curr_head ? curr_head : NULL, 0,
+		update_ref_oid("am --abort", "HEAD", &orig_head,
+				has_curr_head ? &curr_head : NULL, 0,
 				UPDATE_REFS_DIE_ON_ERR);
 	else if (curr_branch)
-		delete_ref(curr_branch, NULL, REF_NODEREF);
+		delete_ref(NULL, curr_branch, NULL, REF_NODEREF);
 
 	free(curr_branch);
 	am_destroy(state);
@@ -2299,9 +2307,12 @@ int cmd_am(int argc, const char **argv, const char *prefix)
 		OPT_END()
 	};
 
+	if (argc == 2 && !strcmp(argv[1], "-h"))
+		usage_with_options(usage, options);
+
 	git_config(git_am_config, NULL);
 
-	am_state_init(&state, git_path("rebase-apply"));
+	am_state_init(&state);
 
 	in_progress = am_in_progress(&state);
 	if (in_progress)