1 files changed, 504 insertions, 221 deletions

diff --git a/builtin/rebase.c b/builtin/rebase.c
index 0ee06aa363..77deebc65c 100644
--- a/builtin/rebase.c
+++ b/builtin/rebase.c
@@ -4,6 +4,7 @@
  * Copyright (c) 2018 Pratik Karki
  */
 
+#define USE_THE_INDEX_COMPATIBILITY_MACROS
 #include "builtin.h"
 #include "run-command.h"
 #include "exec-cmd.h"
@@ -23,6 +24,7 @@
 #include "revision.h"
 #include "commit-reach.h"
 #include "rerere.h"
+#include "branch.h"
 
 static char const * const builtin_rebase_usage[] = {
 	N_("git rebase [-i] [options] [--exec <cmd>] [--onto <newbase>] "
@@ -48,7 +50,10 @@ static int use_builtin_rebase(void)
 {
 	struct child_process cp = CHILD_PROCESS_INIT;
 	struct strbuf out = STRBUF_INIT;
-	int ret;
+	int ret, env = git_env_bool("GIT_TEST_REBASE_USE_BUILTIN", -1);
+
+	if (env != -1)
+		return env;
 
 	argv_array_pushl(&cp.args,
 			 "config", "--bool", "rebase.usebuiltin", NULL);
@@ -87,7 +92,7 @@ struct rebase_options {
 		REBASE_FORCE = 1<<3,
 		REBASE_INTERACTIVE_EXPLICIT = 1<<4,
 	} flags;
-	struct strbuf git_am_opt;
+	struct argv_array git_am_opts;
 	const char *action;
 	int signoff;
 	int allow_rerere_autoupdate;
@@ -100,6 +105,7 @@ struct rebase_options {
 	int rebase_merges, rebase_cousins;
 	char *strategy, *strategy_opts;
 	struct strbuf git_format_patch_opt;
+	int reschedule_failed_exec;
 };
 
 static int is_interactive(struct rebase_options *opts)
@@ -118,7 +124,7 @@ static void imply_interactive(struct rebase_options *opts, const char *option)
 	case REBASE_PRESERVE_MERGES:
 		break;
 	case REBASE_MERGE:
-		/* we silently *upgrade* --merge to --interactive if needed */
+		/* we now implement --merge via --interactive */
 	default:
 		opts->type = REBASE_INTERACTIVE; /* implied */
 		break;
@@ -181,10 +187,7 @@ static int read_basic_state(struct rebase_options *opts)
 	if (get_oid(buf.buf, &opts->orig_head))
 		return error(_("invalid orig-head: '%s'"), buf.buf);
 
-	strbuf_reset(&buf);
-	if (read_one(state_dir_path("quiet", opts), &buf))
-		return -1;
-	if (buf.len)
+	if (file_exists(state_dir_path("quiet", opts)))
 		opts->flags &= ~REBASE_NO_QUIET;
 	else
 		opts->flags |= REBASE_NO_QUIET;
@@ -242,6 +245,37 @@ static int read_basic_state(struct rebase_options *opts)
 	return 0;
 }
 
+static int write_basic_state(struct rebase_options *opts)
+{
+	write_file(state_dir_path("head-name", opts), "%s",
+		   opts->head_name ? opts->head_name : "detached HEAD");
+	write_file(state_dir_path("onto", opts), "%s",
+		   opts->onto ? oid_to_hex(&opts->onto->object.oid) : "");
+	write_file(state_dir_path("orig-head", opts), "%s",
+		   oid_to_hex(&opts->orig_head));
+	write_file(state_dir_path("quiet", opts), "%s",
+		   opts->flags & REBASE_NO_QUIET ? "" : "t");
+	if (opts->flags & REBASE_VERBOSE)
+		write_file(state_dir_path("verbose", opts), "%s", "");
+	if (opts->strategy)
+		write_file(state_dir_path("strategy", opts), "%s",
+			   opts->strategy);
+	if (opts->strategy_opts)
+		write_file(state_dir_path("strategy_opts", opts), "%s",
+			   opts->strategy_opts);
+	if (opts->allow_rerere_autoupdate >= 0)
+		write_file(state_dir_path("allow_rerere_autoupdate", opts),
+			   "-%s-rerere-autoupdate",
+			   opts->allow_rerere_autoupdate ? "" : "-no");
+	if (opts->gpg_sign_opt)
+		write_file(state_dir_path("gpg_sign_opt", opts), "%s",
+			   opts->gpg_sign_opt);
+	if (opts->signoff)
+		write_file(state_dir_path("strategy", opts), "--signoff");
+
+	return 0;
+}
+
 static int apply_autostash(struct rebase_options *opts)
 {
 	const char *path = state_dir_path("autostash", opts);
@@ -329,6 +363,166 @@ static void add_var(struct strbuf *buf, const char *name, const char *value)
 	}
 }
 
+#define GIT_REFLOG_ACTION_ENVIRONMENT "GIT_REFLOG_ACTION"
+
+#define RESET_HEAD_DETACH (1<<0)
+#define RESET_HEAD_HARD (1<<1)
+#define RESET_HEAD_RUN_POST_CHECKOUT_HOOK (1<<2)
+#define RESET_HEAD_REFS_ONLY (1<<3)
+#define RESET_ORIG_HEAD (1<<4)
+
+static int reset_head(struct object_id *oid, const char *action,
+		      const char *switch_to_branch, unsigned flags,
+		      const char *reflog_orig_head, const char *reflog_head)
+{
+	unsigned detach_head = flags & RESET_HEAD_DETACH;
+	unsigned reset_hard = flags & RESET_HEAD_HARD;
+	unsigned run_hook = flags & RESET_HEAD_RUN_POST_CHECKOUT_HOOK;
+	unsigned refs_only = flags & RESET_HEAD_REFS_ONLY;
+	unsigned update_orig_head = flags & RESET_ORIG_HEAD;
+	struct object_id head_oid;
+	struct tree_desc desc[2] = { { NULL }, { NULL } };
+	struct lock_file lock = LOCK_INIT;
+	struct unpack_trees_options unpack_tree_opts;
+	struct tree *tree;
+	const char *reflog_action;
+	struct strbuf msg = STRBUF_INIT;
+	size_t prefix_len;
+	struct object_id *orig = NULL, oid_orig,
+		*old_orig = NULL, oid_old_orig;
+	int ret = 0, nr = 0;
+
+	if (switch_to_branch && !starts_with(switch_to_branch, "refs/"))
+		BUG("Not a fully qualified branch: '%s'", switch_to_branch);
+
+	if (!refs_only && hold_locked_index(&lock, LOCK_REPORT_ON_ERROR) < 0) {
+		ret = -1;
+		goto leave_reset_head;
+	}
+
+	if ((!oid || !reset_hard) && get_oid("HEAD", &head_oid)) {
+		ret = error(_("could not determine HEAD revision"));
+		goto leave_reset_head;
+	}
+
+	if (!oid)
+		oid = &head_oid;
+
+	if (refs_only)
+		goto reset_head_refs;
+
+	memset(&unpack_tree_opts, 0, sizeof(unpack_tree_opts));
+	setup_unpack_trees_porcelain(&unpack_tree_opts, action);
+	unpack_tree_opts.head_idx = 1;
+	unpack_tree_opts.src_index = the_repository->index;
+	unpack_tree_opts.dst_index = the_repository->index;
+	unpack_tree_opts.fn = reset_hard ? oneway_merge : twoway_merge;
+	unpack_tree_opts.update = 1;
+	unpack_tree_opts.merge = 1;
+	if (!detach_head)
+		unpack_tree_opts.reset = 1;
+
+	if (repo_read_index_unmerged(the_repository) < 0) {
+		ret = error(_("could not read index"));
+		goto leave_reset_head;
+	}
+
+	if (!reset_hard && !fill_tree_descriptor(&desc[nr++], &head_oid)) {
+		ret = error(_("failed to find tree of %s"),
+			    oid_to_hex(&head_oid));
+		goto leave_reset_head;
+	}
+
+	if (!fill_tree_descriptor(&desc[nr++], oid)) {
+		ret = error(_("failed to find tree of %s"), oid_to_hex(oid));
+		goto leave_reset_head;
+	}
+
+	if (unpack_trees(nr, desc, &unpack_tree_opts)) {
+		ret = -1;
+		goto leave_reset_head;
+	}
+
+	tree = parse_tree_indirect(oid);
+	prime_cache_tree(the_repository, the_repository->index, tree);
+
+	if (write_locked_index(the_repository->index, &lock, COMMIT_LOCK) < 0) {
+		ret = error(_("could not write index"));
+		goto leave_reset_head;
+	}
+
+reset_head_refs:
+	reflog_action = getenv(GIT_REFLOG_ACTION_ENVIRONMENT);
+	strbuf_addf(&msg, "%s: ", reflog_action ? reflog_action : "rebase");
+	prefix_len = msg.len;
+
+	if (update_orig_head) {
+		if (!get_oid("ORIG_HEAD", &oid_old_orig))
+			old_orig = &oid_old_orig;
+		if (!get_oid("HEAD", &oid_orig)) {
+			orig = &oid_orig;
+			if (!reflog_orig_head) {
+				strbuf_addstr(&msg, "updating ORIG_HEAD");
+				reflog_orig_head = msg.buf;
+			}
+			update_ref(reflog_orig_head, "ORIG_HEAD", orig,
+				   old_orig, 0, UPDATE_REFS_MSG_ON_ERR);
+		} else if (old_orig)
+			delete_ref(NULL, "ORIG_HEAD", old_orig, 0);
+	}
+
+	if (!reflog_head) {
+		strbuf_setlen(&msg, prefix_len);
+		strbuf_addstr(&msg, "updating HEAD");
+		reflog_head = msg.buf;
+	}
+	if (!switch_to_branch)
+		ret = update_ref(reflog_head, "HEAD", oid, orig,
+				 detach_head ? REF_NO_DEREF : 0,
+				 UPDATE_REFS_MSG_ON_ERR);
+	else {
+		ret = update_ref(reflog_head, switch_to_branch, oid,
+				 NULL, 0, UPDATE_REFS_MSG_ON_ERR);
+		if (!ret)
+			ret = create_symref("HEAD", switch_to_branch,
+					    reflog_head);
+	}
+	if (run_hook)
+		run_hook_le(NULL, "post-checkout",
+			    oid_to_hex(orig ? orig : &null_oid),
+			    oid_to_hex(oid), "1", NULL);
+
+leave_reset_head:
+	strbuf_release(&msg);
+	rollback_lock_file(&lock);
+	while (nr)
+		free((void *)desc[--nr].buffer);
+	return ret;
+}
+
+static int move_to_original_branch(struct rebase_options *opts)
+{
+	struct strbuf orig_head_reflog = STRBUF_INIT, head_reflog = STRBUF_INIT;
+	int ret;
+
+	if (!opts->head_name)
+		return 0; /* nothing to move back to */
+
+	if (!opts->onto)
+		BUG("move_to_original_branch without onto");
+
+	strbuf_addf(&orig_head_reflog, "rebase finished: %s onto %s",
+		    opts->head_name, oid_to_hex(&opts->onto->object.oid));
+	strbuf_addf(&head_reflog, "rebase finished: returning to %s",
+		    opts->head_name);
+	ret = reset_head(NULL, "", opts->head_name, RESET_HEAD_REFS_ONLY,
+			 orig_head_reflog.buf, head_reflog.buf);
+
+	strbuf_release(&orig_head_reflog);
+	strbuf_release(&head_reflog);
+	return ret;
+}
+
 static const char *resolvemsg =
 N_("Resolve all conflicts manually, mark them as resolved with\n"
 "\"git add/rm <conflicted_files>\", then run \"git rebase --continue\".\n"
@@ -336,10 +530,130 @@ N_("Resolve all conflicts manually, mark them as resolved with\n"
 "To abort and get back to the state before \"git rebase\", run "
 "\"git rebase --abort\".");
 
+static int run_am(struct rebase_options *opts)
+{
+	struct child_process am = CHILD_PROCESS_INIT;
+	struct child_process format_patch = CHILD_PROCESS_INIT;
+	struct strbuf revisions = STRBUF_INIT;
+	int status;
+	char *rebased_patches;
+
+	am.git_cmd = 1;
+	argv_array_push(&am.args, "am");
+
+	if (opts->action && !strcmp("continue", opts->action)) {
+		argv_array_push(&am.args, "--resolved");
+		argv_array_pushf(&am.args, "--resolvemsg=%s", resolvemsg);
+		if (opts->gpg_sign_opt)
+			argv_array_push(&am.args, opts->gpg_sign_opt);
+		status = run_command(&am);
+		if (status)
+			return status;
+
+		return move_to_original_branch(opts);
+	}
+	if (opts->action && !strcmp("skip", opts->action)) {
+		argv_array_push(&am.args, "--skip");
+		argv_array_pushf(&am.args, "--resolvemsg=%s", resolvemsg);
+		status = run_command(&am);
+		if (status)
+			return status;
+
+		return move_to_original_branch(opts);
+	}
+	if (opts->action && !strcmp("show-current-patch", opts->action)) {
+		argv_array_push(&am.args, "--show-current-patch");
+		return run_command(&am);
+	}
+
+	strbuf_addf(&revisions, "%s...%s",
+		    oid_to_hex(opts->root ?
+			       /* this is now equivalent to !opts->upstream */
+			       &opts->onto->object.oid :
+			       &opts->upstream->object.oid),
+		    oid_to_hex(&opts->orig_head));
+
+	rebased_patches = xstrdup(git_path("rebased-patches"));
+	format_patch.out = open(rebased_patches,
+				O_WRONLY | O_CREAT | O_TRUNC, 0666);
+	if (format_patch.out < 0) {
+		status = error_errno(_("could not open '%s' for writing"),
+				     rebased_patches);
+		free(rebased_patches);
+		argv_array_clear(&am.args);
+		return status;
+	}
+
+	format_patch.git_cmd = 1;
+	argv_array_pushl(&format_patch.args, "format-patch", "-k", "--stdout",
+			 "--full-index", "--cherry-pick", "--right-only",
+			 "--src-prefix=a/", "--dst-prefix=b/", "--no-renames",
+			 "--no-cover-letter", "--pretty=mboxrd", "--topo-order", NULL);
+	if (opts->git_format_patch_opt.len)
+		argv_array_split(&format_patch.args,
+				 opts->git_format_patch_opt.buf);
+	argv_array_push(&format_patch.args, revisions.buf);
+	if (opts->restrict_revision)
+		argv_array_pushf(&format_patch.args, "^%s",
+				 oid_to_hex(&opts->restrict_revision->object.oid));
+
+	status = run_command(&format_patch);
+	if (status) {
+		unlink(rebased_patches);
+		free(rebased_patches);
+		argv_array_clear(&am.args);
+
+		reset_head(&opts->orig_head, "checkout", opts->head_name, 0,
+			   "HEAD", NULL);
+		error(_("\ngit encountered an error while preparing the "
+			"patches to replay\n"
+			"these revisions:\n"
+			"\n    %s\n\n"
+			"As a result, git cannot rebase them."),
+		      opts->revisions);
+
+		strbuf_release(&revisions);
+		return status;
+	}
+	strbuf_release(&revisions);
+
+	am.in = open(rebased_patches, O_RDONLY);
+	if (am.in < 0) {
+		status = error_errno(_("could not open '%s' for reading"),
+				     rebased_patches);
+		free(rebased_patches);
+		argv_array_clear(&am.args);
+		return status;
+	}
+
+	argv_array_pushv(&am.args, opts->git_am_opts.argv);
+	argv_array_push(&am.args, "--rebasing");
+	argv_array_pushf(&am.args, "--resolvemsg=%s", resolvemsg);
+	argv_array_push(&am.args, "--patch-format=mboxrd");
+	if (opts->allow_rerere_autoupdate > 0)
+		argv_array_push(&am.args, "--rerere-autoupdate");
+	else if (opts->allow_rerere_autoupdate == 0)
+		argv_array_push(&am.args, "--no-rerere-autoupdate");
+	if (opts->gpg_sign_opt)
+		argv_array_push(&am.args, opts->gpg_sign_opt);
+	status = run_command(&am);
+	unlink(rebased_patches);
+	free(rebased_patches);
+
+	if (!status) {
+		return move_to_original_branch(opts);
+	}
+
+	if (is_directory(opts->state_dir))
+		write_basic_state(opts);
+
+	return status;
+}
+
 static int run_specific_rebase(struct rebase_options *opts)
 {
 	const char *argv[] = { NULL, NULL };
-	struct strbuf script_snippet = STRBUF_INIT;
+	struct strbuf script_snippet = STRBUF_INIT, buf = STRBUF_INIT;
 	int status;
 	const char *backend, *backend_func;
 
@@ -350,7 +664,8 @@ static int run_specific_rebase(struct rebase_options *opts)
 		argv_array_pushf(&child.env_array, "GIT_CHERRY_PICK_HELP=%s",
 				 resolvemsg);
 		if (!(opts->flags & REBASE_INTERACTIVE_EXPLICIT)) {
-			argv_array_push(&child.env_array, "GIT_EDITOR=:");
+			argv_array_push(&child.env_array,
+					"GIT_SEQUENCE_EDITOR=:");
 			opts->autosquash = 0;
 		}
 
@@ -411,11 +726,18 @@ static int run_specific_rebase(struct rebase_options *opts)
 			argv_array_push(&child.args, opts->gpg_sign_opt);
 		if (opts->signoff)
 			argv_array_push(&child.args, "--signoff");
+		if (opts->reschedule_failed_exec)
+			argv_array_push(&child.args, "--reschedule-failed-exec");
 
 		status = run_command(&child);
 		goto finished_rebase;
 	}
 
+	if (opts->type == REBASE_AM) {
+		status = run_am(opts);
+		goto finished_rebase;
+	}
+
 	add_var(&script_snippet, "GIT_DIR", absolute_path(get_git_dir()));
 	add_var(&script_snippet, "state_dir", opts->state_dir);
 
@@ -433,7 +755,9 @@ static int run_specific_rebase(struct rebase_options *opts)
 		oid_to_hex(&opts->restrict_revision->object.oid) : NULL);
 	add_var(&script_snippet, "GIT_QUIET",
 		opts->flags & REBASE_NO_QUIET ? "" : "t");
-	add_var(&script_snippet, "git_am_opt", opts->git_am_opt.buf);
+	sq_quote_argv_pretty(&buf, opts->git_am_opts.argv);
+	add_var(&script_snippet, "git_am_opt", buf.buf);
+	strbuf_release(&buf);
 	add_var(&script_snippet, "verbose",
 		opts->flags & REBASE_VERBOSE ? "t" : "");
 	add_var(&script_snippet, "diffstat",
@@ -469,7 +793,7 @@ static int run_specific_rebase(struct rebase_options *opts)
 	if (is_interactive(opts) &&
 	    !(opts->flags & REBASE_INTERACTIVE_EXPLICIT)) {
 		strbuf_addstr(&script_snippet,
-			      "GIT_EDITOR=:; export GIT_EDITOR; ");
+			      "GIT_SEQUENCE_EDITOR=:; export GIT_SEQUENCE_EDITOR; ");
 		opts->autosquash = 0;
 	}
 
@@ -478,10 +802,6 @@ static int run_specific_rebase(struct rebase_options *opts)
 		backend = "git-rebase--am";
 		backend_func = "git_rebase__am";
 		break;
-	case REBASE_MERGE:
-		backend = "git-rebase--merge";
-		backend_func = "git_rebase__merge";
-		break;
 	case REBASE_PRESERVE_MERGES:
 		backend = "git-rebase--preserve-merges";
 		backend_func = "git_rebase__preserve_merges";
@@ -520,112 +840,6 @@ finished_rebase:
 	return status ? -1 : 0;
 }
 
-#define GIT_REFLOG_ACTION_ENVIRONMENT "GIT_REFLOG_ACTION"
-
-static int reset_head(struct object_id *oid, const char *action,
-		      const char *switch_to_branch, int detach_head,
-		      const char *reflog_orig_head, const char *reflog_head)
-{
-	struct object_id head_oid;
-	struct tree_desc desc;
-	struct lock_file lock = LOCK_INIT;
-	struct unpack_trees_options unpack_tree_opts;
-	struct tree *tree;
-	const char *reflog_action;
-	struct strbuf msg = STRBUF_INIT;
-	size_t prefix_len;
-	struct object_id *orig = NULL, oid_orig,
-		*old_orig = NULL, oid_old_orig;
-	int ret = 0;
-
-	if (switch_to_branch && !starts_with(switch_to_branch, "refs/"))
-		BUG("Not a fully qualified branch: '%s'", switch_to_branch);
-
-	if (hold_locked_index(&lock, LOCK_REPORT_ON_ERROR) < 0)
-		return -1;
-
-	if (!oid) {
-		if (get_oid("HEAD", &head_oid)) {
-			rollback_lock_file(&lock);
-			return error(_("could not determine HEAD revision"));
-		}
-		oid = &head_oid;
-	}
-
-	memset(&unpack_tree_opts, 0, sizeof(unpack_tree_opts));
-	setup_unpack_trees_porcelain(&unpack_tree_opts, action);
-	unpack_tree_opts.head_idx = 1;
-	unpack_tree_opts.src_index = the_repository->index;
-	unpack_tree_opts.dst_index = the_repository->index;
-	unpack_tree_opts.fn = oneway_merge;
-	unpack_tree_opts.update = 1;
-	unpack_tree_opts.merge = 1;
-	if (!detach_head)
-		unpack_tree_opts.reset = 1;
-
-	if (read_index_unmerged(the_repository->index) < 0) {
-		rollback_lock_file(&lock);
-		return error(_("could not read index"));
-	}
-
-	if (!fill_tree_descriptor(&desc, oid)) {
-		error(_("failed to find tree of %s"), oid_to_hex(oid));
-		rollback_lock_file(&lock);
-		free((void *)desc.buffer);
-		return -1;
-	}
-
-	if (unpack_trees(1, &desc, &unpack_tree_opts)) {
-		rollback_lock_file(&lock);
-		free((void *)desc.buffer);
-		return -1;
-	}
-
-	tree = parse_tree_indirect(oid);
-	prime_cache_tree(the_repository->index, tree);
-
-	if (write_locked_index(the_repository->index, &lock, COMMIT_LOCK) < 0)
-		ret = error(_("could not write index"));
-	free((void *)desc.buffer);
-
-	if (ret)
-		return ret;
-
-	reflog_action = getenv(GIT_REFLOG_ACTION_ENVIRONMENT);
-	strbuf_addf(&msg, "%s: ", reflog_action ? reflog_action : "rebase");
-	prefix_len = msg.len;
-
-	if (!get_oid("ORIG_HEAD", &oid_old_orig))
-		old_orig = &oid_old_orig;
-	if (!get_oid("HEAD", &oid_orig)) {
-		orig = &oid_orig;
-		if (!reflog_orig_head) {
-			strbuf_addstr(&msg, "updating ORIG_HEAD");
-			reflog_orig_head = msg.buf;
-		}
-		update_ref(reflog_orig_head, "ORIG_HEAD", orig, old_orig, 0,
-			   UPDATE_REFS_MSG_ON_ERR);
-	} else if (old_orig)
-		delete_ref(NULL, "ORIG_HEAD", old_orig, 0);
-	if (!reflog_head) {
-		strbuf_setlen(&msg, prefix_len);
-		strbuf_addstr(&msg, "updating HEAD");
-		reflog_head = msg.buf;
-	}
-	if (!switch_to_branch)
-		ret = update_ref(reflog_head, "HEAD", oid, orig, REF_NO_DEREF,
-				 UPDATE_REFS_MSG_ON_ERR);
-	else {
-		ret = create_symref("HEAD", switch_to_branch, msg.buf);
-		if (!ret)
-			ret = update_ref(reflog_head, "HEAD", oid, NULL, 0,
-					 UPDATE_REFS_MSG_ON_ERR);
-	}
-
-	strbuf_release(&msg);
-	return ret;
-}
-
 static int rebase_config(const char *var, const char *value, void *data)
 {
 	struct rebase_options *opts = data;
@@ -655,6 +869,11 @@ static int rebase_config(const char *var, const char *value, void *data)
 		return 0;
 	}
 
+	if (!strcmp(var, "rebase.reschedulefailedexec")) {
+		opts->reschedule_failed_exec = git_config_bool(var, value);
+		return 0;
+	}
+
 	return git_default_config(var, value, data);
 }
 
@@ -703,6 +922,9 @@ static int parse_opt_merge(const struct option *opt, const char *arg, int unset)
 {
 	struct rebase_options *opts = opt->value;
 
+	BUG_ON_OPT_NEG(unset);
+	BUG_ON_OPT_ARG(arg);
+
 	if (!is_interactive(opts))
 		opts->type = REBASE_MERGE;
 
@@ -715,6 +937,9 @@ static int parse_opt_interactive(const struct option *opt, const char *arg,
 {
 	struct rebase_options *opts = opt->value;
 
+	BUG_ON_OPT_NEG(unset);
+	BUG_ON_OPT_ARG(arg);
+
 	opts->type = REBASE_INTERACTIVE;
 	opts->flags |= REBASE_INTERACTIVE_EXPLICIT;
 
@@ -751,12 +976,42 @@ static void NORETURN error_on_missing_default_upstream(void)
 	exit(1);
 }
 
+static void set_reflog_action(struct rebase_options *options)
+{
+	const char *env;
+	struct strbuf buf = STRBUF_INIT;
+
+	if (!is_interactive(options))
+		return;
+
+	env = getenv(GIT_REFLOG_ACTION_ENVIRONMENT);
+	if (env && strcmp("rebase", env))
+		return; /* only override it if it is "rebase" */
+
+	strbuf_addf(&buf, "rebase -i (%s)", options->action);
+	setenv(GIT_REFLOG_ACTION_ENVIRONMENT, buf.buf, 1);
+	strbuf_release(&buf);
+}
+
+static int check_exec_cmd(const char *cmd)
+{
+	if (strchr(cmd, '\n'))
+		return error(_("exec commands cannot contain newlines"));
+
+	/* Does the command consist purely of whitespace? */
+	if (!cmd[strspn(cmd, " \t\r\f\v")])
+		return error(_("empty exec command"));
+
+	return 0;
+}
+
+
 int cmd_rebase(int argc, const char **argv, const char *prefix)
 {
 	struct rebase_options options = {
 		.type = REBASE_UNSPECIFIED,
 		.flags = REBASE_NO_QUIET,
-		.git_am_opt = STRBUF_INIT,
+		.git_am_opts = ARGV_ARRAY_INIT,
 		.allow_rerere_autoupdate  = -1,
 		.allow_empty_message = 1,
 		.git_format_patch_opt = STRBUF_INIT,
@@ -777,12 +1032,15 @@ int cmd_rebase(int argc, const char **argv, const char *prefix)
 		ACTION_EDIT_TODO,
 		ACTION_SHOW_CURRENT_PATCH,
 	} action = NO_ACTION;
-	int committer_date_is_author_date = 0;
-	int ignore_date = 0;
-	int ignore_whitespace = 0;
+	static const char *action_names[] = { N_("undefined"),
+					      N_("continue"),
+					      N_("skip"),
+					      N_("abort"),
+					      N_("quit"),
+					      N_("edit_todo"),
+					      N_("show_current_patch"),
+					      NULL };
 	const char *gpg_sign = NULL;
-	int opt_c = -1;
-	struct string_list whitespace = STRING_LIST_INIT_NODUP;
 	struct string_list exec = STRING_LIST_INIT_NODUP;
 	const char *rebase_merges = NULL;
 	int fork_point = -1;
@@ -804,15 +1062,20 @@ int cmd_rebase(int argc, const char **argv, const char *prefix)
 		{OPTION_NEGBIT, 'n', "no-stat", &options.flags, NULL,
 			N_("do not show diffstat of what changed upstream"),
 			PARSE_OPT_NOARG, NULL, REBASE_DIFFSTAT },
-		OPT_BOOL(0, "ignore-whitespace", &ignore_whitespace,
-			 N_("passed to 'git apply'")),
 		OPT_BOOL(0, "signoff", &options.signoff,
 			 N_("add a Signed-off-by: line to each commit")),
-		OPT_BOOL(0, "committer-date-is-author-date",
-			 &committer_date_is_author_date,
-			 N_("passed to 'git am'")),
-		OPT_BOOL(0, "ignore-date", &ignore_date,
-			 N_("passed to 'git am'")),
+		OPT_PASSTHRU_ARGV(0, "ignore-whitespace", &options.git_am_opts,
+				  NULL, N_("passed to 'git am'"),
+				  PARSE_OPT_NOARG),
+		OPT_PASSTHRU_ARGV(0, "committer-date-is-author-date",
+				  &options.git_am_opts, NULL,
+				  N_("passed to 'git am'"), PARSE_OPT_NOARG),
+		OPT_PASSTHRU_ARGV(0, "ignore-date", &options.git_am_opts, NULL,
+				  N_("passed to 'git am'"), PARSE_OPT_NOARG),
+		OPT_PASSTHRU_ARGV('C', NULL, &options.git_am_opts, N_("n"),
+				  N_("passed to 'git apply'"), 0),
+		OPT_PASSTHRU_ARGV(0, "whitespace", &options.git_am_opts,
+				  N_("action"), N_("passed to 'git apply'"), 0),
 		OPT_BIT('f', "force-rebase", &options.flags,
 			N_("cherry-pick all commits, even if unchanged"),
 			REBASE_FORCE),
@@ -846,7 +1109,7 @@ int cmd_rebase(int argc, const char **argv, const char *prefix)
 			       "them"), REBASE_PRESERVE_MERGES),
 		OPT_BOOL(0, "rerere-autoupdate",
 			 &options.allow_rerere_autoupdate,
-			 N_("allow rerere to update index  with resolved "
+			 N_("allow rerere to update index with resolved "
 			    "conflict")),
 		OPT_BOOL('k', "keep-empty", &options.keep_empty,
 			 N_("preserve empty commits during rebase")),
@@ -856,10 +1119,6 @@ int cmd_rebase(int argc, const char **argv, const char *prefix)
 		{ OPTION_STRING, 'S', "gpg-sign", &gpg_sign, N_("key-id"),
 			N_("GPG-sign commits"),
 			PARSE_OPT_OPTARG, NULL, (intptr_t) "" },
-		OPT_STRING_LIST(0, "whitespace", &whitespace,
-				N_("whitespace"), N_("passed to 'git apply'")),
-		OPT_SET_INT('C', NULL, &opt_c, N_("passed to 'git apply'"),
-			    REBASE_AM),
 		OPT_BOOL(0, "autostash", &options.autostash,
 			 N_("automatically stash/stash pop before and after")),
 		OPT_STRING_LIST('x', "exec", &exec, N_("exec"),
@@ -882,8 +1141,12 @@ int cmd_rebase(int argc, const char **argv, const char *prefix)
 				   "strategy")),
 		OPT_BOOL(0, "root", &options.root,
 			 N_("rebase all reachable commits up to the root(s)")),
+		OPT_BOOL(0, "reschedule-failed-exec",
+			 &options.reschedule_failed_exec,
+			 N_("automatically re-schedule any `exec` that fails")),
 		OPT_END(),
 	};
+	int i;
 
 	/*
 	 * NEEDSWORK: Once the builtin rebase has been tested enough
@@ -956,11 +1219,21 @@ int cmd_rebase(int argc, const char **argv, const char *prefix)
 
 	if (action != NO_ACTION && !in_progress)
 		die(_("No rebase in progress?"));
+	setenv(GIT_REFLOG_ACTION_ENVIRONMENT, "rebase", 0);
 
 	if (action == ACTION_EDIT_TODO && !is_interactive(&options))
 		die(_("The --edit-todo action can only be used during "
 		      "interactive rebase."));
 
+	if (trace2_is_enabled()) {
+		if (is_interactive(&options))
+			trace2_cmd_mode("interactive");
+		else if (exec.nr)
+			trace2_cmd_mode("interactive-exec");
+		else
+			trace2_cmd_mode(action_names[action]);
+	}
+
 	switch (action) {
 	case ACTION_CONTINUE: {
 		struct object_id head;
@@ -968,22 +1241,22 @@ int cmd_rebase(int argc, const char **argv, const char *prefix)
 		int fd;
 
 		options.action = "continue";
+		set_reflog_action(&options);
 
 		/* Sanity check */
 		if (get_oid("HEAD", &head))
 			die(_("Cannot read HEAD"));
 
 		fd = hold_locked_index(&lock_file, 0);
-		if (read_index(the_repository->index) < 0)
+		if (repo_read_index(the_repository) < 0)
 			die(_("could not read index"));
 		refresh_index(the_repository->index, REFRESH_QUIET, NULL, NULL,
 			      NULL);
 		if (0 <= fd)
-			update_index_if_able(the_repository->index,
-					     &lock_file);
+			repo_update_index_if_able(the_repository, &lock_file);
 		rollback_lock_file(&lock_file);
 
-		if (has_unstaged_changes(1)) {
+		if (has_unstaged_changes(the_repository, 1)) {
 			puts(_("You must edit all merge conflicts and then\n"
 			       "mark them as resolved using git add"));
 			exit(1);
@@ -996,12 +1269,15 @@ int cmd_rebase(int argc, const char **argv, const char *prefix)
 		struct string_list merge_rr = STRING_LIST_INIT_DUP;
 
 		options.action = "skip";
+		set_reflog_action(&options);
 
-		rerere_clear(&merge_rr);
+		rerere_clear(the_repository, &merge_rr);
 		string_list_clear(&merge_rr, 1);
 
-		if (reset_head(NULL, "reset", NULL, 0, NULL, NULL) < 0)
+		if (reset_head(NULL, "reset", NULL, RESET_HEAD_HARD,
+			       NULL, NULL) < 0)
 			die(_("could not discard worktree changes"));
+		remove_branch_state(the_repository);
 		if (read_basic_state(&options))
 			exit(1);
 		goto run_rebase;
@@ -1009,16 +1285,19 @@ int cmd_rebase(int argc, const char **argv, const char *prefix)
 	case ACTION_ABORT: {
 		struct string_list merge_rr = STRING_LIST_INIT_DUP;
 		options.action = "abort";
+		set_reflog_action(&options);
 
-		rerere_clear(&merge_rr);
+		rerere_clear(the_repository, &merge_rr);
 		string_list_clear(&merge_rr, 1);
 
 		if (read_basic_state(&options))
 			exit(1);
 		if (reset_head(&options.orig_head, "reset",
-			       options.head_name, 0, NULL, NULL) < 0)
+			       options.head_name, RESET_HEAD_HARD,
+			       NULL, NULL) < 0)
 			die(_("could not move back to %s"),
 			    oid_to_hex(&options.orig_head));
+		remove_branch_state(the_repository);
 		ret = finish_rebase(&options);
 		goto cleanup;
 	}
@@ -1064,22 +1343,31 @@ int cmd_rebase(int argc, const char **argv, const char *prefix)
 		    state_dir_base, cmd_live_rebase, buf.buf);
 	}
 
-	if (!(options.flags & REBASE_NO_QUIET))
-		strbuf_addstr(&options.git_am_opt, " -q");
-
-	if (committer_date_is_author_date) {
-		strbuf_addstr(&options.git_am_opt,
-			      " --committer-date-is-author-date");
-		options.flags |= REBASE_FORCE;
+	for (i = 0; i < options.git_am_opts.argc; i++) {
+		const char *option = options.git_am_opts.argv[i], *p;
+		if (!strcmp(option, "--committer-date-is-author-date") ||
+		    !strcmp(option, "--ignore-date") ||
+		    !strcmp(option, "--whitespace=fix") ||
+		    !strcmp(option, "--whitespace=strip"))
+			options.flags |= REBASE_FORCE;
+		else if (skip_prefix(option, "-C", &p)) {
+			while (*p)
+				if (!isdigit(*(p++)))
+					die(_("switch `C' expects a "
+					      "numerical value"));
+		} else if (skip_prefix(option, "--whitespace=", &p)) {
+			if (*p && strcmp(p, "warn") && strcmp(p, "nowarn") &&
+			    strcmp(p, "error") && strcmp(p, "error-all"))
+				die("Invalid whitespace option: '%s'", p);
+		}
 	}
 
-	if (ignore_whitespace)
-		strbuf_addstr(&options.git_am_opt, " --ignore-whitespace");
+	for (i = 0; i < exec.nr; i++)
+		if (check_exec_cmd(exec.items[i].string))
+			exit(1);
 
-	if (ignore_date) {
-		strbuf_addstr(&options.git_am_opt, " --ignore-date");
-		options.flags |= REBASE_FORCE;
-	}
+	if (!(options.flags & REBASE_NO_QUIET))
+		argv_array_push(&options.git_am_opts, "-q");
 
 	if (options.keep_empty)
 		imply_interactive(&options, "--keep-empty");
@@ -1089,23 +1377,6 @@ int cmd_rebase(int argc, const char **argv, const char *prefix)
 		options.gpg_sign_opt = xstrfmt("-S%s", gpg_sign);
 	}
 
-	if (opt_c >= 0)
-		strbuf_addf(&options.git_am_opt, " -C%d", opt_c);
-
-	if (whitespace.nr) {
-		int i;
-
-		for (i = 0; i < whitespace.nr; i++) {
-			const char *item = whitespace.items[i].string;
-
-			strbuf_addf(&options.git_am_opt, " --whitespace=%s",
-				    item);
-
-			if ((!strcmp(item, "fix")) || (!strcmp(item, "strip")))
-				options.flags |= REBASE_FORCE;
-		}
-	}
-
 	if (exec.nr) {
 		int i;
 
@@ -1159,6 +1430,9 @@ int cmd_rebase(int argc, const char **argv, const char *prefix)
 		}
 	}
 
+	if (options.type == REBASE_MERGE)
+		imply_interactive(&options, "--merge");
+
 	if (options.root && !options.onto_name)
 		imply_interactive(&options, "--root without --onto");
 
@@ -1181,52 +1455,49 @@ int cmd_rebase(int argc, const char **argv, const char *prefix)
 		break;
 	}
 
-	if (options.git_am_opt.len) {
-		const char *p;
+	if (options.reschedule_failed_exec && !is_interactive(&options))
+		die(_("%s requires an interactive rebase"), "--reschedule-failed-exec");
 
+	if (options.git_am_opts.argc) {
 		/* all am options except -q are compatible only with --am */
-		strbuf_reset(&buf);
-		strbuf_addbuf(&buf, &options.git_am_opt);
-		strbuf_addch(&buf, ' ');
-		while ((p = strstr(buf.buf, " -q ")))
-			strbuf_splice(&buf, p - buf.buf, 4, " ", 1);
-		strbuf_trim(&buf);
-
-		if (is_interactive(&options) && buf.len)
-			die(_("error: cannot combine interactive options "
-			      "(--interactive, --exec, --rebase-merges, "
-			      "--preserve-merges, --keep-empty, --root + "
-			      "--onto) with am options (%s)"), buf.buf);
-		if (options.type == REBASE_MERGE && buf.len)
-			die(_("error: cannot combine merge options (--merge, "
-			      "--strategy, --strategy-option) with am options "
-			      "(%s)"), buf.buf);
+		for (i = options.git_am_opts.argc - 1; i >= 0; i--)
+			if (strcmp(options.git_am_opts.argv[i], "-q"))
+				break;
+
+		if (is_interactive(&options) && i >= 0)
+			die(_("cannot combine am options with either "
+			      "interactive or merge options"));
 	}
 
 	if (options.signoff) {
 		if (options.type == REBASE_PRESERVE_MERGES)
 			die("cannot combine '--signoff' with "
 			    "'--preserve-merges'");
-		strbuf_addstr(&options.git_am_opt, " --signoff");
+		argv_array_push(&options.git_am_opts, "--signoff");
 		options.flags |= REBASE_FORCE;
 	}
 
-	if (options.type == REBASE_PRESERVE_MERGES)
+	if (options.type == REBASE_PRESERVE_MERGES) {
 		/*
 		 * Note: incompatibility with --signoff handled in signoff block above
 		 * Note: incompatibility with --interactive is just a strong warning;
 		 *       git-rebase.txt caveats with "unless you know what you are doing"
 		 */
 		if (options.rebase_merges)
-			die(_("error: cannot combine '--preserve-merges' with "
+			die(_("cannot combine '--preserve-merges' with "
 			      "'--rebase-merges'"));
 
+		if (options.reschedule_failed_exec)
+			die(_("error: cannot combine '--preserve-merges' with "
+			      "'--reschedule-failed-exec'"));
+	}
+
 	if (options.rebase_merges) {
 		if (strategy_options.nr)
-			die(_("error: cannot combine '--rebase-merges' with "
+			die(_("cannot combine '--rebase-merges' with "
 			      "'--strategy-option'"));
 		if (options.strategy)
-			die(_("error: cannot combine '--rebase-merges' with "
+			die(_("cannot combine '--rebase-merges' with "
 			      "'--strategy'"));
 	}
 
@@ -1338,7 +1609,7 @@ int cmd_rebase(int argc, const char **argv, const char *prefix)
 			get_fork_point(options.upstream_name, head);
 	}
 
-	if (read_index(the_repository->index) < 0)
+	if (repo_read_index(the_repository) < 0)
 		die(_("could not read index"));
 
 	if (options.autostash) {
@@ -1348,10 +1619,11 @@ int cmd_rebase(int argc, const char **argv, const char *prefix)
 		fd = hold_locked_index(&lock_file, 0);
 		refresh_cache(REFRESH_QUIET);
 		if (0 <= fd)
-			update_index_if_able(&the_index, &lock_file);
+			repo_update_index_if_able(the_repository, &lock_file);
 		rollback_lock_file(&lock_file);
 
-		if (has_unstaged_changes(1) || has_uncommitted_changes(1)) {
+		if (has_unstaged_changes(the_repository, 1) ||
+		    has_uncommitted_changes(the_repository, 1)) {
 			const char *autostash =
 				state_dir_path("autostash", &options);
 			struct child_process stash = CHILD_PROCESS_INIT;
@@ -1380,7 +1652,7 @@ int cmd_rebase(int argc, const char **argv, const char *prefix)
 			write_file(autostash, "%s", oid_to_hex(&oid));
 			printf(_("Created autostash: %s\n"), buf.buf);
 			if (reset_head(&head->object.oid, "reset --hard",
-				       NULL, 0, NULL, NULL) < 0)
+				       NULL, RESET_HEAD_HARD, NULL, NULL) < 0)
 				die(_("could not reset --hard"));
 			printf(_("HEAD is now at %s"),
 			       find_unique_abbrev(&head->object.oid,
@@ -1392,12 +1664,12 @@ int cmd_rebase(int argc, const char **argv, const char *prefix)
 			putchar('\n');
 
 			if (discard_index(the_repository->index) < 0 ||
-				read_index(the_repository->index) < 0)
+				repo_read_index(the_repository) < 0)
 				die(_("could not read index"));
 		}
 	}
 
-	if (require_clean_work_tree("rebase",
+	if (require_clean_work_tree(the_repository, "rebase",
 				    _("Please commit or stash them."), 1, 1)) {
 		ret = 1;
 		goto cleanup;
@@ -1431,11 +1703,13 @@ int cmd_rebase(int argc, const char **argv, const char *prefix)
 				}
 
 				strbuf_reset(&buf);
-				strbuf_addf(&buf, "rebase: checkout %s",
+				strbuf_addf(&buf, "%s: checkout %s",
+					    getenv(GIT_REFLOG_ACTION_ENVIRONMENT),
 					    options.switch_to);
 				if (reset_head(&oid, "checkout",
-					       options.head_name, 0,
-					       NULL, NULL) < 0) {
+					       options.head_name,
+					       RESET_HEAD_RUN_POST_CHECKOUT_HOOK,
+					       NULL, buf.buf) < 0) {
 					ret = !!error(_("could not switch to "
 							"%s"),
 						      options.switch_to);
@@ -1472,10 +1746,15 @@ int cmd_rebase(int argc, const char **argv, const char *prefix)
 	if (options.flags & REBASE_DIFFSTAT) {
 		struct diff_options opts;
 
-		if (options.flags & REBASE_VERBOSE)
-			printf(_("Changes from %s to %s:\n"),
-				oid_to_hex(&merge_base),
-				oid_to_hex(&options.onto->object.oid));
+		if (options.flags & REBASE_VERBOSE) {
+			if (is_null_oid(&merge_base))
+				printf(_("Changes to %s:\n"),
+				       oid_to_hex(&options.onto->object.oid));
+			else
+				printf(_("Changes from %s to %s:\n"),
+				       oid_to_hex(&merge_base),
+				       oid_to_hex(&options.onto->object.oid));
+		}
 
 		/* We want color (if set), but no pager */
 		diff_setup(&opts);
@@ -1485,8 +1764,9 @@ int cmd_rebase(int argc, const char **argv, const char *prefix)
 			DIFF_FORMAT_SUMMARY | DIFF_FORMAT_DIFFSTAT;
 		opts.detect_rename = DIFF_DETECT_RENAME;
 		diff_setup_done(&opts);
-		diff_tree_oid(&merge_base, &options.onto->object.oid,
-			      "", &opts);
+		diff_tree_oid(is_null_oid(&merge_base) ?
+			      the_hash_algo->empty_tree : &merge_base,
+			      &options.onto->object.oid, "", &opts);
 		diffcore_std(&opts);
 		diff_flush(&opts);
 	}
@@ -1499,9 +1779,12 @@ int cmd_rebase(int argc, const char **argv, const char *prefix)
 		printf(_("First, rewinding head to replay your work on top of "
 			 "it...\n"));
 
-	strbuf_addf(&msg, "rebase: checkout %s", options.onto_name);
-	if (reset_head(&options.onto->object.oid, "checkout", NULL, 1,
-	    NULL, msg.buf))
+	strbuf_addf(&msg, "%s: checkout %s",
+		    getenv(GIT_REFLOG_ACTION_ENVIRONMENT), options.onto_name);
+	if (reset_head(&options.onto->object.oid, "checkout", NULL,
+		       RESET_HEAD_DETACH | RESET_ORIG_HEAD | 
+		       RESET_HEAD_RUN_POST_CHECKOUT_HOOK,
+		       NULL, msg.buf))
 		die(_("Could not detach HEAD"));
 	strbuf_release(&msg);
 
@@ -1511,13 +1794,13 @@ int cmd_rebase(int argc, const char **argv, const char *prefix)
 	 */
 	strbuf_reset(&msg);
 	if (!oidcmp(&merge_base, &options.orig_head)) {
-		printf(_("Fast-forwarded %s to %s. \n"),
+		printf(_("Fast-forwarded %s to %s.\n"),
 			branch_name, options.onto_name);
 		strbuf_addf(&msg, "rebase finished: %s onto %s",
 			options.head_name ? options.head_name : "detached HEAD",
 			oid_to_hex(&options.onto->object.oid));
-		reset_head(NULL, "Fast-forwarded", options.head_name, 0,
-			   "HEAD", msg.buf);
+		reset_head(NULL, "Fast-forwarded", options.head_name,
+			   RESET_HEAD_REFS_ONLY, "HEAD", msg.buf);
 		strbuf_release(&msg);
 		ret = !!finish_rebase(&options);
 		goto cleanup;