1 files changed, 1091 insertions, 165 deletions

diff --git a/sequencer.c b/sequencer.c
index 30b10ba..77afeca 100644
--- a/sequencer.c
+++ b/sequencer.c
@@ -16,6 +16,9 @@
 #include "refs.h"
 #include "argv-array.h"
 #include "quote.h"
+#include "trailer.h"
+#include "log-tree.h"
+#include "wt-status.h"
 
 #define GIT_REFLOG_ACTION "GIT_REFLOG_ACTION"
 
@@ -27,7 +30,61 @@ GIT_PATH_FUNC(git_path_seq_dir, "sequencer")
 static GIT_PATH_FUNC(git_path_todo_file, "sequencer/todo")
 static GIT_PATH_FUNC(git_path_opts_file, "sequencer/opts")
 static GIT_PATH_FUNC(git_path_head_file, "sequencer/head")
+static GIT_PATH_FUNC(git_path_abort_safety_file, "sequencer/abort-safety")
 
+static GIT_PATH_FUNC(rebase_path, "rebase-merge")
+/*
+ * The file containing rebase commands, comments, and empty lines.
+ * This file is created by "git rebase -i" then edited by the user. As
+ * the lines are processed, they are removed from the front of this
+ * file and written to the tail of 'done'.
+ */
+static GIT_PATH_FUNC(rebase_path_todo, "rebase-merge/git-rebase-todo")
+/*
+ * The rebase command lines that have already been processed. A line
+ * is moved here when it is first handled, before any associated user
+ * actions.
+ */
+static GIT_PATH_FUNC(rebase_path_done, "rebase-merge/done")
+/*
+ * The file to keep track of how many commands were already processed (e.g.
+ * for the prompt).
+ */
+static GIT_PATH_FUNC(rebase_path_msgnum, "rebase-merge/msgnum");
+/*
+ * The file to keep track of how many commands are to be processed in total
+ * (e.g. for the prompt).
+ */
+static GIT_PATH_FUNC(rebase_path_msgtotal, "rebase-merge/end");
+/*
+ * The commit message that is planned to be used for any changes that
+ * need to be committed following a user interaction.
+ */
+static GIT_PATH_FUNC(rebase_path_message, "rebase-merge/message")
+/*
+ * The file into which is accumulated the suggested commit message for
+ * squash/fixup commands. When the first of a series of squash/fixups
+ * is seen, the file is created and the commit message from the
+ * previous commit and from the first squash/fixup commit are written
+ * to it. The commit message for each subsequent squash/fixup commit
+ * is appended to the file as it is processed.
+ *
+ * The first line of the file is of the form
+ *     # This is a combination of $count commits.
+ * where $count is the number of commits whose messages have been
+ * written to the file so far (including the initial "pick" commit).
+ * Each time that a commit message is processed, this line is read and
+ * updated. It is deleted just before the combined commit is made.
+ */
+static GIT_PATH_FUNC(rebase_path_squash_msg, "rebase-merge/message-squash")
+/*
+ * If the current series of squash/fixups has not yet included a squash
+ * command, then this file exists and holds the commit message of the
+ * original "pick" commit.  (If the series ends without a "squash"
+ * command, then this can be used as the commit message of the combined
+ * commit without opening the editor.)
+ */
+static GIT_PATH_FUNC(rebase_path_fixup_msg, "rebase-merge/message-fixup")
 /*
  * A script to set the GIT_AUTHOR_NAME, GIT_AUTHOR_EMAIL, and
  * GIT_AUTHOR_DATE that will be used for the commit that is currently
@@ -35,51 +92,60 @@ static GIT_PATH_FUNC(git_path_head_file, "sequencer/head")
  */
 static GIT_PATH_FUNC(rebase_path_author_script, "rebase-merge/author-script")
 /*
+ * When an "edit" rebase command is being processed, the SHA1 of the
+ * commit to be edited is recorded in this file.  When "git rebase
+ * --continue" is executed, if there are any staged changes then they
+ * will be amended to the HEAD commit, but only provided the HEAD
+ * commit is still the commit to be edited.  When any other rebase
+ * command is processed, this file is deleted.
+ */
+static GIT_PATH_FUNC(rebase_path_amend, "rebase-merge/amend")
+/*
+ * When we stop at a given patch via the "edit" command, this file contains
+ * the abbreviated commit name of the corresponding patch.
+ */
+static GIT_PATH_FUNC(rebase_path_stopped_sha, "rebase-merge/stopped-sha")
+/*
+ * For the post-rewrite hook, we make a list of rewritten commits and
+ * their new sha1s.  The rewritten-pending list keeps the sha1s of
+ * commits that have been processed, but not committed yet,
+ * e.g. because they are waiting for a 'squash' command.
+ */
+static GIT_PATH_FUNC(rebase_path_rewritten_list, "rebase-merge/rewritten-list")
+static GIT_PATH_FUNC(rebase_path_rewritten_pending,
+	"rebase-merge/rewritten-pending")
+/*
  * The following files are written by git-rebase just after parsing the
  * command-line (and are only consumed, not modified, by the sequencer).
  */
 static GIT_PATH_FUNC(rebase_path_gpg_sign_opt, "rebase-merge/gpg_sign_opt")
+static GIT_PATH_FUNC(rebase_path_orig_head, "rebase-merge/orig-head")
+static GIT_PATH_FUNC(rebase_path_verbose, "rebase-merge/verbose")
+static GIT_PATH_FUNC(rebase_path_head_name, "rebase-merge/head-name")
+static GIT_PATH_FUNC(rebase_path_onto, "rebase-merge/onto")
+static GIT_PATH_FUNC(rebase_path_autostash, "rebase-merge/autostash")
+static GIT_PATH_FUNC(rebase_path_strategy, "rebase-merge/strategy")
+static GIT_PATH_FUNC(rebase_path_strategy_opts, "rebase-merge/strategy_opts")
 
-/* We will introduce the 'interactive rebase' mode later */
 static inline int is_rebase_i(const struct replay_opts *opts)
 {
-	return 0;
+	return opts->action == REPLAY_INTERACTIVE_REBASE;
 }
 
 static const char *get_dir(const struct replay_opts *opts)
 {
+	if (is_rebase_i(opts))
+		return rebase_path();
 	return git_path_seq_dir();
 }
 
 static const char *get_todo_path(const struct replay_opts *opts)
 {
+	if (is_rebase_i(opts))
+		return rebase_path_todo();
 	return git_path_todo_file();
 }
 
-static int is_rfc2822_line(const char *buf, int len)
-{
-	int i;
-
-	for (i = 0; i < len; i++) {
-		int ch = buf[i];
-		if (ch == ':')
-			return 1;
-		if (!isalnum(ch) && ch != '-')
-			break;
-	}
-
-	return 0;
-}
-
-static int is_cherry_picked_from_line(const char *buf, int len)
-{
-	/*
-	 * We only care that it looks roughly like (cherry picked from ...)
-	 */
-	return len > strlen(cherry_picked_prefix) + 1 &&
-		starts_with(buf, cherry_picked_prefix) && buf[len - 1] == ')';
-}
-
 /*
  * Returns 0 for non-conforming footer
  * Returns 1 for conforming footer
@@ -89,49 +155,25 @@ static int is_cherry_picked_from_line(const char *buf, int len)
 static int has_conforming_footer(struct strbuf *sb, struct strbuf *sob,
 	int ignore_footer)
 {
-	char prev;
-	int i, k;
-	int len = sb->len - ignore_footer;
-	const char *buf = sb->buf;
-	int found_sob = 0;
-
-	/* footer must end with newline */
-	if (!len || buf[len - 1] != '\n')
-		return 0;
+	struct trailer_info info;
+	int i;
+	int found_sob = 0, found_sob_last = 0;
 
-	prev = '\0';
-	for (i = len - 1; i > 0; i--) {
-		char ch = buf[i];
-		if (prev == '\n' && ch == '\n') /* paragraph break */
-			break;
-		prev = ch;
-	}
+	trailer_info_get(&info, sb->buf);
 
-	/* require at least one blank line */
-	if (prev != '\n' || buf[i] != '\n')
+	if (info.trailer_start == info.trailer_end)
 		return 0;
 
-	/* advance to start of last paragraph */
-	while (i < len - 1 && buf[i] == '\n')
-		i++;
-
-	for (; i < len; i = k) {
-		int found_rfc2822;
-
-		for (k = i; k < len && buf[k] != '\n'; k++)
-			; /* do nothing */
-		k++;
+	for (i = 0; i < info.trailer_nr; i++)
+		if (sob && !strncmp(info.trailers[i], sob->buf, sob->len)) {
+			found_sob = 1;
+			if (i == info.trailer_nr - 1)
+				found_sob_last = 1;
+		}
 
-		found_rfc2822 = is_rfc2822_line(buf + i, k - i - 1);
-		if (found_rfc2822 && sob &&
-		    !strncmp(buf + i, sob->buf, sob->len))
-			found_sob = k;
+	trailer_info_release(&info);
 
-		if (!(found_rfc2822 ||
-		      is_cherry_picked_from_line(buf + i, k - i - 1)))
-			return 0;
-	}
-	if (found_sob == i)
+	if (found_sob_last)
 		return 3;
 	if (found_sob)
 		return 2;
@@ -168,7 +210,15 @@ int sequencer_remove_state(struct replay_opts *opts)
 
 static const char *action_name(const struct replay_opts *opts)
 {
-	return opts->action == REPLAY_REVERT ? N_("revert") : N_("cherry-pick");
+	switch (opts->action) {
+	case REPLAY_REVERT:
+		return N_("revert");
+	case REPLAY_PICK:
+		return N_("cherry-pick");
+	case REPLAY_INTERACTIVE_REBASE:
+		return N_("rebase -i");
+	}
+	die(_("Unknown action: %d"), opts->action);
 }
 
 struct commit_message {
@@ -310,6 +360,20 @@ static int error_dirty_index(struct replay_opts *opts)
 	return -1;
 }
 
+static void update_abort_safety_file(void)
+{
+	struct object_id head;
+
+	/* Do nothing on a single-pick */
+	if (!file_exists(git_path_seq_dir()))
+		return;
+
+	if (!get_oid("HEAD", &head))
+		write_file(git_path_abort_safety_file(), "%s", oid_to_hex(&head));
+	else
+		write_file(git_path_abort_safety_file(), "%s", "");
+}
+
 static int fast_forward_to(const unsigned char *to, const unsigned char *from,
 			int unborn, struct replay_opts *opts)
 {
@@ -339,6 +403,7 @@ static int fast_forward_to(const unsigned char *to, const unsigned char *from,
 	strbuf_release(&sb);
 	strbuf_release(&err);
 	ref_transaction_free(transaction);
+	update_abort_safety_file();
 	return 0;
 }
 
@@ -370,7 +435,7 @@ static int do_recursive_merge(struct commit *base, struct commit *next,
 	char **xopt;
 	static struct lock_file index_lock;
 
-	hold_locked_index(&index_lock, 1);
+	hold_locked_index(&index_lock, LOCK_DIE_ON_ERROR);
 
 	read_cache();
 
@@ -378,6 +443,8 @@ static int do_recursive_merge(struct commit *base, struct commit *next,
 	o.ancestor = base ? base_label : "(empty tree)";
 	o.branch1 = "HEAD";
 	o.branch2 = next ? next_label : "(empty tree)";
+	if (is_rebase_i(opts))
+		o.buffer_output = 2;
 
 	head_tree = parse_tree_indirect(head);
 	next_tree = next ? next->tree : empty_tree();
@@ -389,13 +456,17 @@ static int do_recursive_merge(struct commit *base, struct commit *next,
 	clean = merge_trees(&o,
 			    head_tree,
 			    next_tree, base_tree, &result);
+	if (is_rebase_i(opts) && clean <= 0)
+		fputs(o.obuf.buf, stdout);
 	strbuf_release(&o.obuf);
 	if (clean < 0)
 		return clean;
 
 	if (active_cache_changed &&
 	    write_locked_index(&the_index, &index_lock, COMMIT_LOCK))
-		/* TRANSLATORS: %s will be "revert" or "cherry-pick" */
+		/* TRANSLATORS: %s will be "revert", "cherry-pick" or
+		 * "rebase -i".
+		 */
 		return error(_("%s: Unable to write new index file"),
 			_(action_name(opts)));
 	rollback_lock_file(&index_lock);
@@ -440,19 +511,64 @@ static int is_index_unchanged(void)
 	return !hashcmp(active_cache_tree->sha1, head_commit->tree->object.oid.hash);
 }
 
+static int write_author_script(const char *message)
+{
+	struct strbuf buf = STRBUF_INIT;
+	const char *eol;
+	int res;
+
+	for (;;)
+		if (!*message || starts_with(message, "\n")) {
+missing_author:
+			/* Missing 'author' line? */
+			unlink(rebase_path_author_script());
+			return 0;
+		} else if (skip_prefix(message, "author ", &message))
+			break;
+		else if ((eol = strchr(message, '\n')))
+			message = eol + 1;
+		else
+			goto missing_author;
+
+	strbuf_addstr(&buf, "GIT_AUTHOR_NAME='");
+	while (*message && *message != '\n' && *message != '\r')
+		if (skip_prefix(message, " <", &message))
+			break;
+		else if (*message != '\'')
+			strbuf_addch(&buf, *(message++));
+		else
+			strbuf_addf(&buf, "'\\\\%c'", *(message++));
+	strbuf_addstr(&buf, "'\nGIT_AUTHOR_EMAIL='");
+	while (*message && *message != '\n' && *message != '\r')
+		if (skip_prefix(message, "> ", &message))
+			break;
+		else if (*message != '\'')
+			strbuf_addch(&buf, *(message++));
+		else
+			strbuf_addf(&buf, "'\\\\%c'", *(message++));
+	strbuf_addstr(&buf, "'\nGIT_AUTHOR_DATE='@");
+	while (*message && *message != '\n' && *message != '\r')
+		if (*message != '\'')
+			strbuf_addch(&buf, *(message++));
+		else
+			strbuf_addf(&buf, "'\\\\%c'", *(message++));
+	res = write_message(buf.buf, buf.len, rebase_path_author_script(), 1);
+	strbuf_release(&buf);
+	return res;
+}
+
 /*
- * Read the author-script file into an environment block, ready for use in
- * run_command(), that can be free()d afterwards.
+ * Read a list of environment variable assignments (such as the author-script
+ * file) into an environment block. Returns -1 on error, 0 otherwise.
  */
-static char **read_author_script(void)
+static int read_env_script(struct argv_array *env)
 {
 	struct strbuf script = STRBUF_INIT;
 	int i, count = 0;
-	char *p, *p2, **env;
-	size_t env_size;
+	char *p, *p2;
 
 	if (strbuf_read_file(&script, rebase_path_author_script(), 256) <= 0)
-		return NULL;
+		return -1;
 
 	for (p = script.buf; *p; p++)
 		if (skip_prefix(p, "'\\\\''", (const char **)&p2))
@@ -464,19 +580,12 @@ static char **read_author_script(void)
 			count++;
 		}
 
-	env_size = (count + 1) * sizeof(*env);
-	strbuf_grow(&script, env_size);
-	memmove(script.buf + env_size, script.buf, script.len);
-	p = script.buf + env_size;
-	env = (char **)strbuf_detach(&script, NULL);
-
-	for (i = 0; i < count; i++) {
-		env[i] = p;
+	for (i = 0, p = script.buf; i < count; i++) {
+		argv_array_push(env, p);
 		p += strlen(p) + 1;
 	}
-	env[count] = NULL;
 
-	return env;
+	return 0;
 }
 
 static const char staged_changes_advice[] =
@@ -493,6 +602,12 @@ N_("you have staged changes in your working tree\n"
 "\n"
 "  git rebase --continue\n");
 
+#define ALLOW_EMPTY (1<<0)
+#define EDIT_MSG    (1<<1)
+#define AMEND_MSG   (1<<2)
+#define CLEANUP_MSG (1<<3)
+#define VERIFY_MSG  (1<<4)
+
 /*
  * If we are cherry-pick, and if the merge did not result in
  * hand-editing, we will hit this commit and inherit the original
@@ -506,17 +621,20 @@ N_("you have staged changes in your working tree\n"
  * author metadata.
  */
 static int run_git_commit(const char *defmsg, struct replay_opts *opts,
-			  int allow_empty, int edit, int amend,
-			  int cleanup_commit_message)
+			  unsigned int flags)
 {
-	char **env = NULL;
-	struct argv_array array;
-	int rc;
+	struct child_process cmd = CHILD_PROCESS_INIT;
 	const char *value;
 
+	cmd.git_cmd = 1;
+
 	if (is_rebase_i(opts)) {
-		env = read_author_script();
-		if (!env) {
+		if (!(flags & EDIT_MSG)) {
+			cmd.stdout_to_stderr = 1;
+			cmd.err = -1;
+		}
+
+		if (read_env_script(&cmd.env_array)) {
 			const char *gpg_opt = gpg_sign_opt_quoted(opts);
 
 			return error(_(staged_changes_advice),
@@ -524,39 +642,48 @@ static int run_git_commit(const char *defmsg, struct replay_opts *opts,
 		}
 	}
 
-	argv_array_init(&array);
-	argv_array_push(&array, "commit");
-	argv_array_push(&array, "-n");
+	argv_array_push(&cmd.args, "commit");
 
-	if (amend)
-		argv_array_push(&array, "--amend");
+	if (!(flags & VERIFY_MSG))
+		argv_array_push(&cmd.args, "-n");
+	if ((flags & AMEND_MSG))
+		argv_array_push(&cmd.args, "--amend");
 	if (opts->gpg_sign)
-		argv_array_pushf(&array, "-S%s", opts->gpg_sign);
+		argv_array_pushf(&cmd.args, "-S%s", opts->gpg_sign);
 	if (opts->signoff)
-		argv_array_push(&array, "-s");
+		argv_array_push(&cmd.args, "-s");
 	if (defmsg)
-		argv_array_pushl(&array, "-F", defmsg, NULL);
-	if (cleanup_commit_message)
-		argv_array_push(&array, "--cleanup=strip");
-	if (edit)
-		argv_array_push(&array, "-e");
-	else if (!cleanup_commit_message &&
+		argv_array_pushl(&cmd.args, "-F", defmsg, NULL);
+	if ((flags & CLEANUP_MSG))
+		argv_array_push(&cmd.args, "--cleanup=strip");
+	if ((flags & EDIT_MSG))
+		argv_array_push(&cmd.args, "-e");
+	else if (!(flags & CLEANUP_MSG) &&
 		 !opts->signoff && !opts->record_origin &&
 		 git_config_get_value("commit.cleanup", &value))
-		argv_array_push(&array, "--cleanup=verbatim");
+		argv_array_push(&cmd.args, "--cleanup=verbatim");
 
-	if (allow_empty)
-		argv_array_push(&array, "--allow-empty");
+	if ((flags & ALLOW_EMPTY))
+		argv_array_push(&cmd.args, "--allow-empty");
 
 	if (opts->allow_empty_message)
-		argv_array_push(&array, "--allow-empty-message");
+		argv_array_push(&cmd.args, "--allow-empty-message");
 
-	rc = run_command_v_opt_cd_env(array.argv, RUN_GIT_CMD, NULL,
-			(const char *const *)env);
-	argv_array_clear(&array);
-	free(env);
+	if (cmd.err == -1) {
+		/* hide stderr on success */
+		struct strbuf buf = STRBUF_INIT;
+		int rc = pipe_command(&cmd,
+				      NULL, 0,
+				      /* stdout is already redirected */
+				      NULL, 0,
+				      &buf, 0);
+		if (rc)
+			fputs(buf.buf, stderr);
+		strbuf_release(&buf);
+		return rc;
+	}
 
-	return rc;
+	return run_command(&cmd);
 }
 
 static int is_original_commit_empty(struct commit *commit)
@@ -617,27 +744,196 @@ static int allow_empty(struct replay_opts *opts, struct commit *commit)
 		return 1;
 }
 
+/*
+ * Note that ordering matters in this enum. Not only must it match the mapping
+ * below, it is also divided into several sections that matter.  When adding
+ * new commands, make sure you add it in the right section.
+ */
 enum todo_command {
+	/* commands that handle commits */
 	TODO_PICK = 0,
-	TODO_REVERT
+	TODO_REVERT,
+	TODO_EDIT,
+	TODO_REWORD,
+	TODO_FIXUP,
+	TODO_SQUASH,
+	/* commands that do something else than handling a single commit */
+	TODO_EXEC,
+	/* commands that do nothing but are counted for reporting progress */
+	TODO_NOOP,
+	TODO_DROP,
+	/* comments (not counted for reporting progress) */
+	TODO_COMMENT
 };
 
-static const char *todo_command_strings[] = {
-	"pick",
-	"revert"
+static struct {
+	char c;
+	const char *str;
+} todo_command_info[] = {
+	{ 'p', "pick" },
+	{ 0,   "revert" },
+	{ 'e', "edit" },
+	{ 'r', "reword" },
+	{ 'f', "fixup" },
+	{ 's', "squash" },
+	{ 'x', "exec" },
+	{ 0,   "noop" },
+	{ 'd', "drop" },
+	{ 0,   NULL }
 };
 
 static const char *command_to_string(const enum todo_command command)
 {
-	if ((size_t)command < ARRAY_SIZE(todo_command_strings))
-		return todo_command_strings[command];
+	if (command < TODO_COMMENT)
+		return todo_command_info[command].str;
 	die("Unknown command: %d", command);
 }
 
+static int is_noop(const enum todo_command command)
+{
+	return TODO_NOOP <= command;
+}
+
+static int is_fixup(enum todo_command command)
+{
+	return command == TODO_FIXUP || command == TODO_SQUASH;
+}
+
+static int update_squash_messages(enum todo_command command,
+		struct commit *commit, struct replay_opts *opts)
+{
+	struct strbuf buf = STRBUF_INIT;
+	int count, res;
+	const char *message, *body;
+
+	if (file_exists(rebase_path_squash_msg())) {
+		struct strbuf header = STRBUF_INIT;
+		char *eol, *p;
+
+		if (strbuf_read_file(&buf, rebase_path_squash_msg(), 2048) <= 0)
+			return error(_("could not read '%s'"),
+				rebase_path_squash_msg());
+
+		p = buf.buf + 1;
+		eol = strchrnul(buf.buf, '\n');
+		if (buf.buf[0] != comment_line_char ||
+		    (p += strcspn(p, "0123456789\n")) == eol)
+			return error(_("unexpected 1st line of squash message:"
+				       "\n\n\t%.*s"),
+				     (int)(eol - buf.buf), buf.buf);
+		count = strtol(p, NULL, 10);
+
+		if (count < 1)
+			return error(_("invalid 1st line of squash message:\n"
+				       "\n\t%.*s"),
+				     (int)(eol - buf.buf), buf.buf);
+
+		strbuf_addf(&header, "%c ", comment_line_char);
+		strbuf_addf(&header,
+			    _("This is a combination of %d commits."), ++count);
+		strbuf_splice(&buf, 0, eol - buf.buf, header.buf, header.len);
+		strbuf_release(&header);
+	} else {
+		unsigned char head[20];
+		struct commit *head_commit;
+		const char *head_message, *body;
+
+		if (get_sha1("HEAD", head))
+			return error(_("need a HEAD to fixup"));
+		if (!(head_commit = lookup_commit_reference(head)))
+			return error(_("could not read HEAD"));
+		if (!(head_message = get_commit_buffer(head_commit, NULL)))
+			return error(_("could not read HEAD's commit message"));
+
+		find_commit_subject(head_message, &body);
+		if (write_message(body, strlen(body),
+				  rebase_path_fixup_msg(), 0)) {
+			unuse_commit_buffer(head_commit, head_message);
+			return error(_("cannot write '%s'"),
+				     rebase_path_fixup_msg());
+		}
+
+		count = 2;
+		strbuf_addf(&buf, "%c ", comment_line_char);
+		strbuf_addf(&buf, _("This is a combination of %d commits."),
+			    count);
+		strbuf_addf(&buf, "\n%c ", comment_line_char);
+		strbuf_addstr(&buf, _("This is the 1st commit message:"));
+		strbuf_addstr(&buf, "\n\n");
+		strbuf_addstr(&buf, body);
+
+		unuse_commit_buffer(head_commit, head_message);
+	}
+
+	if (!(message = get_commit_buffer(commit, NULL)))
+		return error(_("could not read commit message of %s"),
+			     oid_to_hex(&commit->object.oid));
+	find_commit_subject(message, &body);
+
+	if (command == TODO_SQUASH) {
+		unlink(rebase_path_fixup_msg());
+		strbuf_addf(&buf, "\n%c ", comment_line_char);
+		strbuf_addf(&buf, _("This is the commit message #%d:"), count);
+		strbuf_addstr(&buf, "\n\n");
+		strbuf_addstr(&buf, body);
+	} else if (command == TODO_FIXUP) {
+		strbuf_addf(&buf, "\n%c ", comment_line_char);
+		strbuf_addf(&buf, _("The commit message #%d will be skipped:"),
+			    count);
+		strbuf_addstr(&buf, "\n\n");
+		strbuf_add_commented_lines(&buf, body, strlen(body));
+	} else
+		return error(_("unknown command: %d"), command);
+	unuse_commit_buffer(commit, message);
+
+	res = write_message(buf.buf, buf.len, rebase_path_squash_msg(), 0);
+	strbuf_release(&buf);
+	return res;
+}
+
+static void flush_rewritten_pending(void) {
+	struct strbuf buf = STRBUF_INIT;
+	unsigned char newsha1[20];
+	FILE *out;
+
+	if (strbuf_read_file(&buf, rebase_path_rewritten_pending(), 82) > 0 &&
+			!get_sha1("HEAD", newsha1) &&
+			(out = fopen(rebase_path_rewritten_list(), "a"))) {
+		char *bol = buf.buf, *eol;
+
+		while (*bol) {
+			eol = strchrnul(bol, '\n');
+			fprintf(out, "%.*s %s\n", (int)(eol - bol),
+					bol, sha1_to_hex(newsha1));
+			if (!*eol)
+				break;
+			bol = eol + 1;
+		}
+		fclose(out);
+		unlink(rebase_path_rewritten_pending());
+	}
+	strbuf_release(&buf);
+}
+
+static void record_in_rewritten(struct object_id *oid,
+		enum todo_command next_command) {
+	FILE *out = fopen(rebase_path_rewritten_pending(), "a");
+
+	if (!out)
+		return;
+
+	fprintf(out, "%s\n", oid_to_hex(oid));
+	fclose(out);
+
+	if (!is_fixup(next_command))
+		flush_rewritten_pending();
+}
 
 static int do_pick_commit(enum todo_command command, struct commit *commit,
-		struct replay_opts *opts)
+		struct replay_opts *opts, int final_fixup)
 {
+	unsigned int flags = opts->edit ? EDIT_MSG : 0;
+	const char *msg_file = opts->edit ? NULL : git_path_merge_msg();
 	unsigned char head[20];
 	struct commit *base, *next, *parent;
 	const char *base_label, *next_label;
@@ -663,9 +959,8 @@ static int do_pick_commit(enum todo_command command, struct commit *commit,
 	}
 	discard_cache();
 
-	if (!commit->parents) {
+	if (!commit->parents)
 		parent = NULL;
-	}
 	else if (commit->parents->next) {
 		/* Reverting or cherry-picking a merge commit */
 		int cnt;
@@ -689,11 +984,25 @@ static int do_pick_commit(enum todo_command command, struct commit *commit,
 	else
 		parent = commit->parents->item;
 
-	if (opts->allow_ff &&
-	    ((parent && !hashcmp(parent->object.oid.hash, head)) ||
-	     (!parent && unborn)))
-		return fast_forward_to(commit->object.oid.hash, head, unborn, opts);
+	if (get_message(commit, &msg) != 0)
+		return error(_("cannot get commit message for %s"),
+			oid_to_hex(&commit->object.oid));
 
+	if (opts->allow_ff && !is_fixup(command) &&
+	    ((parent && !hashcmp(parent->object.oid.hash, head)) ||
+	     (!parent && unborn))) {
+		if (is_rebase_i(opts))
+			write_author_script(msg.message);
+		res = fast_forward_to(commit->object.oid.hash, head, unborn,
+			opts);
+		if (res || command != TODO_REWORD)
+			goto leave;
+		flags |= EDIT_MSG | AMEND_MSG;
+		if (command == TODO_REWORD)
+			flags |= VERIFY_MSG;
+		msg_file = NULL;
+		goto fast_forward_edit;
+	}
 	if (parent && parse_commit(parent) < 0)
 		/* TRANSLATORS: The first %s will be a "todo" command like
 		   "revert" or "pick", the second %s a SHA1. */
@@ -701,10 +1010,6 @@ static int do_pick_commit(enum todo_command command, struct commit *commit,
 			command_to_string(command),
 			oid_to_hex(&parent->object.oid));
 
-	if (get_message(commit, &msg) != 0)
-		return error(_("cannot get commit message for %s"),
-			oid_to_hex(&commit->object.oid));
-
 	/*
 	 * "commit" is an existing commit.  We would want to apply
 	 * the difference it introduces since its first parent "prev"
@@ -735,14 +1040,9 @@ static int do_pick_commit(enum todo_command command, struct commit *commit,
 		next = commit;
 		next_label = msg.label;
 
-		/*
-		 * Append the commit log message to msgbuf; it starts
-		 * after the tree, parent, author, committer
-		 * information followed by "\n\n".
-		 */
-		p = strstr(msg.message, "\n\n");
-		if (p)
-			strbuf_addstr(&msgbuf, skip_blank_lines(p + 2));
+		/* Append the commit log message to msgbuf. */
+		if (find_commit_subject(msg.message, &p))
+			strbuf_addstr(&msgbuf, p);
 
 		if (opts->record_origin) {
 			if (!has_conforming_footer(&msgbuf, NULL, 0))
@@ -753,7 +1053,32 @@ static int do_pick_commit(enum todo_command command, struct commit *commit,
 		}
 	}
 
-	if (!opts->strategy || !strcmp(opts->strategy, "recursive") || command == TODO_REVERT) {
+	if (command == TODO_REWORD)
+		flags |= EDIT_MSG | VERIFY_MSG;
+	else if (is_fixup(command)) {
+		if (update_squash_messages(command, commit, opts))
+			return -1;
+		flags |= AMEND_MSG;
+		if (!final_fixup)
+			msg_file = rebase_path_squash_msg();
+		else if (file_exists(rebase_path_fixup_msg())) {
+			flags |= CLEANUP_MSG;
+			msg_file = rebase_path_fixup_msg();
+		} else {
+			const char *dest = git_path("SQUASH_MSG");
+			unlink(dest);
+			if (copy_file(dest, rebase_path_squash_msg(), 0666))
+				return error(_("could not rename '%s' to '%s'"),
+					     rebase_path_squash_msg(), dest);
+			unlink(git_path("MERGE_MSG"));
+			msg_file = dest;
+			flags |= EDIT_MSG;
+		}
+	}
+
+	if (is_rebase_i(opts) && write_author_script(msg.message) < 0)
+		res = -1;
+	else if (!opts->strategy || !strcmp(opts->strategy, "recursive") || command == TODO_REVERT) {
 		res = do_recursive_merge(base, next, base_label, next_label,
 					 head, &msgbuf, opts);
 		if (res < 0)
@@ -806,13 +1131,20 @@ static int do_pick_commit(enum todo_command command, struct commit *commit,
 	if (allow < 0) {
 		res = allow;
 		goto leave;
-	}
+	} else if (allow)
+		flags |= ALLOW_EMPTY;
 	if (!opts->no_commit)
-		res = run_git_commit(opts->edit ? NULL : git_path_merge_msg(),
-				     opts, allow, opts->edit, 0, 0);
+fast_forward_edit:
+		res = run_git_commit(msg_file, opts, flags);
+
+	if (!res && final_fixup) {
+		unlink(rebase_path_fixup_msg());
+		unlink(rebase_path_squash_msg());
+	}
 
 leave:
 	free_message(commit, &msg);
+	update_abort_safety_file();
 
 	return res;
 }
@@ -867,6 +1199,7 @@ struct todo_list {
 	struct strbuf buf;
 	struct todo_item *items;
 	int nr, alloc, current;
+	int done_nr, total_nr;
 };
 
 #define TODO_LIST_INIT { STRBUF_INIT }
@@ -894,20 +1227,45 @@ static int parse_insn_line(struct todo_item *item, const char *bol, char *eol)
 	/* left-trim */
 	bol += strspn(bol, " \t");
 
-	for (i = 0; i < ARRAY_SIZE(todo_command_strings); i++)
-		if (skip_prefix(bol, todo_command_strings[i], &bol)) {
+	if (bol == eol || *bol == '\r' || *bol == comment_line_char) {
+		item->command = TODO_COMMENT;
+		item->commit = NULL;
+		item->arg = bol;
+		item->arg_len = eol - bol;
+		return 0;
+	}
+
+	for (i = 0; i < TODO_COMMENT; i++)
+		if (skip_prefix(bol, todo_command_info[i].str, &bol)) {
+			item->command = i;
+			break;
+		} else if (bol[1] == ' ' && *bol == todo_command_info[i].c) {
+			bol++;
 			item->command = i;
 			break;
 		}
-	if (i >= ARRAY_SIZE(todo_command_strings))
+	if (i >= TODO_COMMENT)
 		return -1;
 
+	if (item->command == TODO_NOOP) {
+		item->commit = NULL;
+		item->arg = bol;
+		item->arg_len = eol - bol;
+		return 0;
+	}
+
 	/* Eat up extra spaces/ tabs before object name */
 	padding = strspn(bol, " \t");
 	if (!padding)
 		return -1;
 	bol += padding;
 
+	if (item->command == TODO_EXEC) {
+		item->arg = bol;
+		item->arg_len = (int)(eol - bol);
+		return 0;
+	}
+
 	end_of_object_name = (char *) bol + strcspn(bol, " \t\n");
 	saved = *end_of_object_name;
 	*end_of_object_name = '\0';
@@ -928,7 +1286,7 @@ static int parse_insn_buffer(char *buf, struct todo_list *todo_list)
 {
 	struct todo_item *item;
 	char *p = buf, *next_p;
-	int i, res = 0;
+	int i, res = 0, fixup_okay = file_exists(rebase_path_done());
 
 	for (i = 1; *p; i++, p = next_p) {
 		char *eol = strchrnul(p, '\n');
@@ -943,14 +1301,32 @@ static int parse_insn_buffer(char *buf, struct todo_list *todo_list)
 		if (parse_insn_line(item, p, eol)) {
 			res = error(_("invalid line %d: %.*s"),
 				i, (int)(eol - p), p);
-			item->command = -1;
+			item->command = TODO_NOOP;
 		}
+
+		if (fixup_okay)
+			; /* do nothing */
+		else if (is_fixup(item->command))
+			return error(_("cannot '%s' without a previous commit"),
+				command_to_string(item->command));
+		else if (!is_noop(item->command))
+			fixup_okay = 1;
 	}
-	if (!todo_list->nr)
-		return error(_("no commits parsed."));
+
 	return res;
 }
 
+static int count_commands(struct todo_list *todo_list)
+{
+	int count = 0, i;
+
+	for (i = 0; i < todo_list->nr; i++)
+		if (todo_list->items[i].command != TODO_COMMENT)
+			count++;
+
+	return count;
+}
+
 static int read_populate_todo(struct todo_list *todo_list,
 			struct replay_opts *opts)
 {
@@ -968,8 +1344,16 @@ static int read_populate_todo(struct todo_list *todo_list,
 	close(fd);
 
 	res = parse_insn_buffer(todo_list->buf.buf, todo_list);
-	if (res)
+	if (res) {
+		if (is_rebase_i(opts))
+			return error(_("please fix this using "
+				       "'git rebase --edit-todo'."));
 		return error(_("unusable instruction sheet: '%s'"), todo_file);
+	}
+
+	if (!todo_list->nr &&
+	    (!is_rebase_i(opts) || !file_exists(rebase_path_done())))
+		return error(_("no commits parsed."));
 
 	if (!is_rebase_i(opts)) {
 		enum todo_command valid =
@@ -985,6 +1369,26 @@ static int read_populate_todo(struct todo_list *todo_list,
 				return error(_("cannot revert during a cherry-pick."));
 	}
 
+	if (is_rebase_i(opts)) {
+		struct todo_list done = TODO_LIST_INIT;
+		FILE *f = fopen(rebase_path_msgtotal(), "w");
+
+		if (strbuf_read_file(&done.buf, rebase_path_done(), 0) > 0 &&
+				!parse_insn_buffer(done.buf.buf, &done))
+			todo_list->done_nr = count_commands(&done);
+		else
+			todo_list->done_nr = 0;
+
+		todo_list->total_nr = todo_list->done_nr
+			+ count_commands(todo_list);
+		todo_list_release(&done);
+
+		if (f) {
+			fprintf(f, "%d\n", todo_list->total_nr);
+			fclose(f);
+		}
+	}
+
 	return 0;
 }
 
@@ -1033,6 +1437,26 @@ static int populate_opts_cb(const char *key, const char *value, void *data)
 	return 0;
 }
 
+static void read_strategy_opts(struct replay_opts *opts, struct strbuf *buf)
+{
+	int i;
+
+	strbuf_reset(buf);
+	if (!read_oneliner(buf, rebase_path_strategy(), 0))
+		return;
+	opts->strategy = strbuf_detach(buf, NULL);
+	if (!read_oneliner(buf, rebase_path_strategy_opts(), 0))
+		return;
+
+	opts->xopts_nr = split_cmdline(buf->buf, (const char ***)&opts->xopts);
+	for (i = 0; i < opts->xopts_nr; i++) {
+		const char *arg = opts->xopts[i];
+
+		skip_prefix(arg, "--", &arg);
+		opts->xopts[i] = xstrdup(arg);
+	}
+}
+
 static int read_populate_opts(struct replay_opts *opts)
 {
 	if (is_rebase_i(opts)) {
@@ -1046,6 +1470,11 @@ static int read_populate_opts(struct replay_opts *opts)
 				opts->gpg_sign = xstrdup(buf.buf + 2);
 			}
 		}
+
+		if (file_exists(rebase_path_verbose()))
+			opts->verbose = 1;
+
+		read_strategy_opts(opts, &buf);
 		strbuf_release(&buf);
 
 		return 0;
@@ -1070,7 +1499,7 @@ static int walk_revs_populate_todo(struct todo_list *todo_list,
 {
 	enum todo_command command = opts->action == REPLAY_PICK ?
 		TODO_PICK : TODO_REVERT;
-	const char *command_string = todo_command_strings[command];
+	const char *command_string = todo_command_info[command].str;
 	struct commit *commit;
 
 	if (prepare_revs(opts))
@@ -1101,8 +1530,7 @@ static int create_seq_dir(void)
 		error(_("a cherry-pick or revert is already in progress"));
 		advise(_("try \"git cherry-pick (--continue | --quit | --abort)\""));
 		return -1;
-	}
-	else if (mkdir(git_path_seq_dir(), 0777) < 0)
+	} else if (mkdir(git_path_seq_dir(), 0777) < 0)
 		return error_errno(_("could not create sequencer directory '%s'"),
 				   git_path_seq_dir());
 	return 0;
@@ -1132,9 +1560,34 @@ static int save_head(const char *head)
 	return 0;
 }
 
+static int rollback_is_safe(void)
+{
+	struct strbuf sb = STRBUF_INIT;
+	struct object_id expected_head, actual_head;
+
+	if (strbuf_read_file(&sb, git_path_abort_safety_file(), 0) >= 0) {
+		strbuf_trim(&sb);
+		if (get_oid_hex(sb.buf, &expected_head)) {
+			strbuf_release(&sb);
+			die(_("could not parse %s"), git_path_abort_safety_file());
+		}
+		strbuf_release(&sb);
+	}
+	else if (errno == ENOENT)
+		oidclr(&expected_head);
+	else
+		die_errno(_("could not read '%s'"), git_path_abort_safety_file());
+
+	if (get_oid("HEAD", &actual_head))
+		oidclr(&actual_head);
+
+	return !oidcmp(&actual_head, &expected_head);
+}
+
 static int reset_for_rollback(const unsigned char *sha1)
 {
 	const char *argv[4];	/* reset --merge <arg> + NULL */
+
 	argv[0] = "reset";
 	argv[1] = "--merge";
 	argv[2] = sha1_to_hex(sha1);
@@ -1189,6 +1642,12 @@ int sequencer_rollback(struct replay_opts *opts)
 		error(_("cannot abort from a branch yet to be born"));
 		goto fail;
 	}
+
+	if (!rollback_is_safe()) {
+		/* Do not error, just do not rollback */
+		warning(_("You seem to have moved HEAD. "
+			  "Not rewinding, check your HEAD!"));
+	} else
 	if (reset_for_rollback(sha1))
 		goto fail;
 	strbuf_release(&buf);
@@ -1204,6 +1663,13 @@ static int save_todo(struct todo_list *todo_list, struct replay_opts *opts)
 	const char *todo_path = get_todo_path(opts);
 	int next = todo_list->current, offset, fd;
 
+	/*
+	 * rebase -i writes "git-rebase-todo" without the currently executing
+	 * command, appending it to "done" instead.
+	 */
+	if (is_rebase_i(opts))
+		next++;
+
 	fd = hold_lock_file_for_update(&todo_lock, todo_path, 0);
 	if (fd < 0)
 		return error_errno(_("could not lock '%s'"), todo_path);
@@ -1214,6 +1680,23 @@ static int save_todo(struct todo_list *todo_list, struct replay_opts *opts)
 		return error_errno(_("could not write to '%s'"), todo_path);
 	if (commit_lock_file(&todo_lock) < 0)
 		return error(_("failed to finalize '%s'."), todo_path);
+
+	if (is_rebase_i(opts)) {
+		const char *done_path = rebase_path_done();
+		int fd = open(done_path, O_CREAT | O_WRONLY | O_APPEND, 0666);
+		int prev_offset = !next ? 0 :
+			todo_list->items[next - 1].offset_in_buf;
+
+		if (fd >= 0 && offset > prev_offset &&
+		    write_in_full(fd, todo_list->buf.buf + prev_offset,
+				  offset - prev_offset) < 0) {
+			close(fd);
+			return error_errno(_("could not write to '%s'"),
+					   done_path);
+		}
+		if (fd >= 0)
+			close(fd);
+	}
 	return 0;
 }
 
@@ -1252,9 +1735,228 @@ static int save_opts(struct replay_opts *opts)
 	return res;
 }
 
+static int make_patch(struct commit *commit, struct replay_opts *opts)
+{
+	struct strbuf buf = STRBUF_INIT;
+	struct rev_info log_tree_opt;
+	const char *subject, *p;
+	int res = 0;
+
+	p = short_commit_name(commit);
+	if (write_message(p, strlen(p), rebase_path_stopped_sha(), 1) < 0)
+		return -1;
+
+	strbuf_addf(&buf, "%s/patch", get_dir(opts));
+	memset(&log_tree_opt, 0, sizeof(log_tree_opt));
+	init_revisions(&log_tree_opt, NULL);
+	log_tree_opt.abbrev = 0;
+	log_tree_opt.diff = 1;
+	log_tree_opt.diffopt.output_format = DIFF_FORMAT_PATCH;
+	log_tree_opt.disable_stdin = 1;
+	log_tree_opt.no_commit_id = 1;
+	log_tree_opt.diffopt.file = fopen(buf.buf, "w");
+	log_tree_opt.diffopt.use_color = GIT_COLOR_NEVER;
+	if (!log_tree_opt.diffopt.file)
+		res |= error_errno(_("could not open '%s'"), buf.buf);
+	else {
+		res |= log_tree_commit(&log_tree_opt, commit);
+		fclose(log_tree_opt.diffopt.file);
+	}
+	strbuf_reset(&buf);
+
+	strbuf_addf(&buf, "%s/message", get_dir(opts));
+	if (!file_exists(buf.buf)) {
+		const char *commit_buffer = get_commit_buffer(commit, NULL);
+		find_commit_subject(commit_buffer, &subject);
+		res |= write_message(subject, strlen(subject), buf.buf, 1);
+		unuse_commit_buffer(commit, commit_buffer);
+	}
+	strbuf_release(&buf);
+
+	return res;
+}
+
+static int intend_to_amend(void)
+{
+	unsigned char head[20];
+	char *p;
+
+	if (get_sha1("HEAD", head))
+		return error(_("cannot read HEAD"));
+
+	p = sha1_to_hex(head);
+	return write_message(p, strlen(p), rebase_path_amend(), 1);
+}
+
+static int error_with_patch(struct commit *commit,
+	const char *subject, int subject_len,
+	struct replay_opts *opts, int exit_code, int to_amend)
+{
+	if (make_patch(commit, opts))
+		return -1;
+
+	if (to_amend) {
+		if (intend_to_amend())
+			return -1;
+
+		fprintf(stderr, "You can amend the commit now, with\n"
+			"\n"
+			"  git commit --amend %s\n"
+			"\n"
+			"Once you are satisfied with your changes, run\n"
+			"\n"
+			"  git rebase --continue\n", gpg_sign_opt_quoted(opts));
+	} else if (exit_code)
+		fprintf(stderr, "Could not apply %s... %.*s\n",
+			short_commit_name(commit), subject_len, subject);
+
+	return exit_code;
+}
+
+static int error_failed_squash(struct commit *commit,
+	struct replay_opts *opts, int subject_len, const char *subject)
+{
+	if (rename(rebase_path_squash_msg(), rebase_path_message()))
+		return error(_("could not rename '%s' to '%s'"),
+			rebase_path_squash_msg(), rebase_path_message());
+	unlink(rebase_path_fixup_msg());
+	unlink(git_path("MERGE_MSG"));
+	if (copy_file(git_path("MERGE_MSG"), rebase_path_message(), 0666))
+		return error(_("could not copy '%s' to '%s'"),
+			     rebase_path_message(), git_path("MERGE_MSG"));
+	return error_with_patch(commit, subject, subject_len, opts, 1, 0);
+}
+
+static int do_exec(const char *command_line)
+{
+	const char *child_argv[] = { NULL, NULL };
+	int dirty, status;
+
+	fprintf(stderr, "Executing: %s\n", command_line);
+	child_argv[0] = command_line;
+	status = run_command_v_opt(child_argv, RUN_USING_SHELL);
+
+	/* force re-reading of the cache */
+	if (discard_cache() < 0 || read_cache() < 0)
+		return error(_("could not read index"));
+
+	dirty = require_clean_work_tree("rebase", NULL, 1, 1);
+
+	if (status) {
+		warning(_("execution failed: %s\n%s"
+			  "You can fix the problem, and then run\n"
+			  "\n"
+			  "  git rebase --continue\n"
+			  "\n"),
+			command_line,
+			dirty ? N_("and made changes to the index and/or the "
+				"working tree\n") : "");
+		if (status == 127)
+			/* command not found */
+			status = 1;
+	} else if (dirty) {
+		warning(_("execution succeeded: %s\nbut "
+			  "left changes to the index and/or the working tree\n"
+			  "Commit or stash your changes, and then run\n"
+			  "\n"
+			  "  git rebase --continue\n"
+			  "\n"), command_line);
+		status = 1;
+	}
+
+	return status;
+}
+
+static int is_final_fixup(struct todo_list *todo_list)
+{
+	int i = todo_list->current;
+
+	if (!is_fixup(todo_list->items[i].command))
+		return 0;
+
+	while (++i < todo_list->nr)
+		if (is_fixup(todo_list->items[i].command))
+			return 0;
+		else if (!is_noop(todo_list->items[i].command))
+			break;
+	return 1;
+}
+
+static enum todo_command peek_command(struct todo_list *todo_list, int offset)
+{
+	int i;
+
+	for (i = todo_list->current + offset; i < todo_list->nr; i++)
+		if (!is_noop(todo_list->items[i].command))
+			return todo_list->items[i].command;
+
+	return -1;
+}
+
+static int apply_autostash(struct replay_opts *opts)
+{
+	struct strbuf stash_sha1 = STRBUF_INIT;
+	struct child_process child = CHILD_PROCESS_INIT;
+	int ret = 0;
+
+	if (!read_oneliner(&stash_sha1, rebase_path_autostash(), 1)) {
+		strbuf_release(&stash_sha1);
+		return 0;
+	}
+	strbuf_trim(&stash_sha1);
+
+	child.git_cmd = 1;
+	argv_array_push(&child.args, "stash");
+	argv_array_push(&child.args, "apply");
+	argv_array_push(&child.args, stash_sha1.buf);
+	if (!run_command(&child))
+		printf(_("Applied autostash."));
+	else {
+		struct child_process store = CHILD_PROCESS_INIT;
+
+		store.git_cmd = 1;
+		argv_array_push(&store.args, "stash");
+		argv_array_push(&store.args, "store");
+		argv_array_push(&store.args, "-m");
+		argv_array_push(&store.args, "autostash");
+		argv_array_push(&store.args, "-q");
+		argv_array_push(&store.args, stash_sha1.buf);
+		if (run_command(&store))
+			ret = error(_("cannot store %s"), stash_sha1.buf);
+		else
+			printf(_("Applying autostash resulted in conflicts.\n"
+				"Your changes are safe in the stash.\n"
+				"You can run \"git stash pop\" or"
+				" \"git stash drop\" at any time.\n"));
+	}
+
+	strbuf_release(&stash_sha1);
+	return ret;
+}
+
+static const char *reflog_message(struct replay_opts *opts,
+	const char *sub_action, const char *fmt, ...)
+{
+	va_list ap;
+	static struct strbuf buf = STRBUF_INIT;
+
+	va_start(ap, fmt);
+	strbuf_reset(&buf);
+	strbuf_addstr(&buf, action_name(opts));
+	if (sub_action)
+		strbuf_addf(&buf, " (%s)", sub_action);
+	if (fmt) {
+		strbuf_addstr(&buf, ": ");
+		strbuf_vaddf(&buf, fmt, ap);
+	}
+	va_end(ap);
+
+	return buf.buf;
+}
+
 static int pick_commits(struct todo_list *todo_list, struct replay_opts *opts)
 {
-	int res;
+	int res = 0;
 
 	setenv(GIT_REFLOG_ACTION, action_name(opts), 0);
 	if (opts->allow_ff)
@@ -1267,12 +1969,180 @@ static int pick_commits(struct todo_list *todo_list, struct replay_opts *opts)
 		struct todo_item *item = todo_list->items + todo_list->current;
 		if (save_todo(todo_list, opts))
 			return -1;
-		res = do_pick_commit(item->command, item->commit, opts);
+		if (is_rebase_i(opts)) {
+			if (item->command != TODO_COMMENT) {
+				FILE *f = fopen(rebase_path_msgnum(), "w");
+
+				todo_list->done_nr++;
+
+				if (f) {
+					fprintf(f, "%d\n", todo_list->done_nr);
+					fclose(f);
+				}
+				fprintf(stderr, "Rebasing (%d/%d)%s",
+					todo_list->done_nr,
+					todo_list->total_nr,
+					opts->verbose ? "\n" : "\r");
+			}
+			unlink(rebase_path_message());
+			unlink(rebase_path_author_script());
+			unlink(rebase_path_stopped_sha());
+			unlink(rebase_path_amend());
+		}
+		if (item->command <= TODO_SQUASH) {
+			if (is_rebase_i(opts))
+				setenv("GIT_REFLOG_ACTION", reflog_message(opts,
+					command_to_string(item->command), NULL),
+					1);
+			res = do_pick_commit(item->command, item->commit,
+					opts, is_final_fixup(todo_list));
+			if (is_rebase_i(opts) && res < 0) {
+				/* Reschedule */
+				todo_list->current--;
+				if (save_todo(todo_list, opts))
+					return -1;
+			}
+			if (item->command == TODO_EDIT) {
+				struct commit *commit = item->commit;
+				if (!res)
+					fprintf(stderr,
+						_("Stopped at %s...  %.*s\n"),
+						short_commit_name(commit),
+						item->arg_len, item->arg);
+				return error_with_patch(commit,
+					item->arg, item->arg_len, opts, res,
+					!res);
+			}
+			if (is_rebase_i(opts) && !res)
+				record_in_rewritten(&item->commit->object.oid,
+					peek_command(todo_list, 1));
+			if (res && is_fixup(item->command)) {
+				if (res == 1)
+					intend_to_amend();
+				return error_failed_squash(item->commit, opts,
+					item->arg_len, item->arg);
+			} else if (res && is_rebase_i(opts))
+				return res | error_with_patch(item->commit,
+					item->arg, item->arg_len, opts, res,
+					item->command == TODO_REWORD);
+		} else if (item->command == TODO_EXEC) {
+			char *end_of_arg = (char *)(item->arg + item->arg_len);
+			int saved = *end_of_arg;
+
+			*end_of_arg = '\0';
+			res = do_exec(item->arg);
+			*end_of_arg = saved;
+		} else if (!is_noop(item->command))
+			return error(_("unknown command %d"), item->command);
+
 		todo_list->current++;
 		if (res)
 			return res;
 	}
 
+	if (is_rebase_i(opts)) {
+		struct strbuf head_ref = STRBUF_INIT, buf = STRBUF_INIT;
+		struct stat st;
+
+		/* Stopped in the middle, as planned? */
+		if (todo_list->current < todo_list->nr)
+			return 0;
+
+		if (read_oneliner(&head_ref, rebase_path_head_name(), 0) &&
+				starts_with(head_ref.buf, "refs/")) {
+			const char *msg;
+			unsigned char head[20], orig[20];
+			int res;
+
+			if (get_sha1("HEAD", head)) {
+				res = error(_("cannot read HEAD"));
+cleanup_head_ref:
+				strbuf_release(&head_ref);
+				strbuf_release(&buf);
+				return res;
+			}
+			if (!read_oneliner(&buf, rebase_path_orig_head(), 0) ||
+					get_sha1_hex(buf.buf, orig)) {
+				res = error(_("could not read orig-head"));
+				goto cleanup_head_ref;
+			}
+			if (!read_oneliner(&buf, rebase_path_onto(), 0)) {
+				res = error(_("could not read 'onto'"));
+				goto cleanup_head_ref;
+			}
+			msg = reflog_message(opts, "finish", "%s onto %s",
+				head_ref.buf, buf.buf);
+			if (update_ref(msg, head_ref.buf, head, orig,
+					REF_NODEREF, UPDATE_REFS_MSG_ON_ERR)) {
+				res = error(_("could not update %s"),
+					head_ref.buf);
+				goto cleanup_head_ref;
+			}
+			msg = reflog_message(opts, "finish", "returning to %s",
+				head_ref.buf);
+			if (create_symref("HEAD", head_ref.buf, msg)) {
+				res = error(_("could not update HEAD to %s"),
+					head_ref.buf);
+				goto cleanup_head_ref;
+			}
+			strbuf_reset(&buf);
+		}
+
+		if (opts->verbose) {
+			struct rev_info log_tree_opt;
+			struct object_id orig, head;
+
+			memset(&log_tree_opt, 0, sizeof(log_tree_opt));
+			init_revisions(&log_tree_opt, NULL);
+			log_tree_opt.diff = 1;
+			log_tree_opt.diffopt.output_format =
+				DIFF_FORMAT_DIFFSTAT;
+			log_tree_opt.disable_stdin = 1;
+
+			if (read_oneliner(&buf, rebase_path_orig_head(), 0) &&
+			    !get_sha1(buf.buf, orig.hash) &&
+			    !get_sha1("HEAD", head.hash)) {
+				diff_tree_sha1(orig.hash, head.hash,
+					       "", &log_tree_opt.diffopt);
+				log_tree_diff_flush(&log_tree_opt);
+			}
+		}
+		flush_rewritten_pending();
+		if (!stat(rebase_path_rewritten_list(), &st) &&
+				st.st_size > 0) {
+			struct child_process child = CHILD_PROCESS_INIT;
+			const char *post_rewrite_hook =
+				find_hook("post-rewrite");
+
+			child.in = open(rebase_path_rewritten_list(), O_RDONLY);
+			child.git_cmd = 1;
+			argv_array_push(&child.args, "notes");
+			argv_array_push(&child.args, "copy");
+			argv_array_push(&child.args, "--for-rewrite=rebase");
+			/* we don't care if this copying failed */
+			run_command(&child);
+
+			if (post_rewrite_hook) {
+				struct child_process hook = CHILD_PROCESS_INIT;
+
+				hook.in = open(rebase_path_rewritten_list(),
+					O_RDONLY);
+				hook.stdout_to_stderr = 1;
+				argv_array_push(&hook.args, post_rewrite_hook);
+				argv_array_push(&hook.args, "rebase");
+				/* we don't care if this hook failed */
+				run_command(&hook);
+			}
+		}
+		apply_autostash(opts);
+
+		fprintf(stderr, "Successfully rebased and updated %s.\n",
+			head_ref.buf);
+
+		strbuf_release(&buf);
+		strbuf_release(&head_ref);
+	}
+
 	/*
 	 * Sequence of picks finished successfully; cleanup by
 	 * removing the .git/sequencer directory
@@ -1290,6 +2160,47 @@ static int continue_single_pick(void)
 	return run_command_v_opt(argv, RUN_GIT_CMD);
 }
 
+static int commit_staged_changes(struct replay_opts *opts)
+{
+	unsigned int flags = ALLOW_EMPTY | EDIT_MSG;
+
+	if (has_unstaged_changes(1))
+		return error(_("cannot rebase: You have unstaged changes."));
+	if (!has_uncommitted_changes(0)) {
+		const char *cherry_pick_head = git_path("CHERRY_PICK_HEAD");
+
+		if (file_exists(cherry_pick_head) && unlink(cherry_pick_head))
+			return error(_("could not remove CHERRY_PICK_HEAD"));
+		return 0;
+	}
+
+	if (file_exists(rebase_path_amend())) {
+		struct strbuf rev = STRBUF_INIT;
+		unsigned char head[20], to_amend[20];
+
+		if (get_sha1("HEAD", head))
+			return error(_("cannot amend non-existing commit"));
+		if (!read_oneliner(&rev, rebase_path_amend(), 0))
+			return error(_("invalid file: '%s'"), rebase_path_amend());
+		if (get_sha1_hex(rev.buf, to_amend))
+			return error(_("invalid contents: '%s'"),
+				rebase_path_amend());
+		if (hashcmp(head, to_amend))
+			return error(_("\nYou have uncommitted changes in your "
+				       "working tree. Please, commit them\n"
+				       "first and then run 'git rebase "
+				       "--continue' again."));
+
+		strbuf_release(&rev);
+		flags |= AMEND_MSG;
+	}
+
+	if (run_git_commit(rebase_path_message(), opts, flags))
+		return error(_("could not commit staged changes."));
+	unlink(rebase_path_amend());
+	return 0;
+}
+
 int sequencer_continue(struct replay_opts *opts)
 {
 	struct todo_list todo_list = TODO_LIST_INIT;
@@ -1298,25 +2209,39 @@ int sequencer_continue(struct replay_opts *opts)
 	if (read_and_refresh_cache(opts))
 		return -1;
 
-	if (!file_exists(get_todo_path(opts)))
+	if (is_rebase_i(opts)) {
+		if (commit_staged_changes(opts))
+			return -1;
+	} else if (!file_exists(get_todo_path(opts)))
 		return continue_single_pick();
 	if (read_populate_opts(opts))
 		return -1;
 	if ((res = read_populate_todo(&todo_list, opts)))
 		goto release_todo_list;
 
-	/* Verify that the conflict has been resolved */
-	if (file_exists(git_path_cherry_pick_head()) ||
-	    file_exists(git_path_revert_head())) {
-		res = continue_single_pick();
-		if (res)
+	if (!is_rebase_i(opts)) {
+		/* Verify that the conflict has been resolved */
+		if (file_exists(git_path_cherry_pick_head()) ||
+		    file_exists(git_path_revert_head())) {
+			res = continue_single_pick();
+			if (res)
+				goto release_todo_list;
+		}
+		if (index_differs_from("HEAD", 0, 0)) {
+			res = error_dirty_index(opts);
 			goto release_todo_list;
+		}
+		todo_list.current++;
+	} else if (file_exists(rebase_path_stopped_sha())) {
+		struct strbuf buf = STRBUF_INIT;
+		struct object_id oid;
+
+		if (read_oneliner(&buf, rebase_path_stopped_sha(), 1) &&
+		    !get_sha1_committish(buf.buf, oid.hash))
+			record_in_rewritten(&oid, peek_command(&todo_list, 0));
+		strbuf_release(&buf);
 	}
-	if (index_differs_from("HEAD", 0, 0)) {
-		res = error_dirty_index(opts);
-		goto release_todo_list;
-	}
-	todo_list.current++;
+
 	res = pick_commits(&todo_list, opts);
 release_todo_list:
 	todo_list_release(&todo_list);
@@ -1327,7 +2252,7 @@ static int single_pick(struct commit *cmit, struct replay_opts *opts)
 {
 	setenv(GIT_REFLOG_ACTION, action_name(opts), 0);
 	return do_pick_commit(opts->action == REPLAY_PICK ?
-		TODO_PICK : TODO_REVERT, cmit, opts);
+		TODO_PICK : TODO_REVERT, cmit, opts, 0);
 }
 
 int sequencer_pick_revisions(struct replay_opts *opts)
@@ -1393,6 +2318,7 @@ int sequencer_pick_revisions(struct replay_opts *opts)
 		return -1;
 	if (save_opts(opts))
 		return -1;
+	update_abort_safety_file();
 	res = pick_commits(&todo_list, opts);
 	todo_list_release(&todo_list);
 	return res;