Merge branch 'pw/sequencer-in-process-commit'

The sequencer infrastructure is shared across "git cherry-pick",
"git rebase -i", etc., and has always spawned "git commit" when it
needs to create a commit.  It has been taught to do so internally,
when able, by reusing the codepath "git commit" itself uses, which
gives performance boost for a few tens of percents in some sample
scenarios.

* pw/sequencer-in-process-commit:
  sequencer: run 'prepare-commit-msg' hook
  t7505: add tests for cherry-pick and rebase -i/-p
  t7505: style fixes
  sequencer: assign only free()able strings to gpg_sign
  sequencer: improve config handling
  t3512/t3513: remove KNOWN_FAILURE_CHERRY_PICK_SEES_EMPTY_COMMIT=1
  sequencer: try to commit without forking 'git commit'
  sequencer: load commit related config
  sequencer: simplify adding Signed-off-by: trailer
  commit: move print_commit_summary() to libgit
  commit: move post-rewrite code to libgit
  Add a function to update HEAD after creating a commit
  commit: move empty message checks to libgit
  t3404: check intermediate squash messages

11 files changed, 765 insertions, 280 deletions

diff --git a/builtin/commit.c b/builtin/commit.c
index 4610e3d8e3..5dd766af28 100644
--- a/builtin/commit.c
+++ b/builtin/commit.c
@@ -31,9 +31,7 @@
 #include "gpg-interface.h"
 #include "column.h"
 #include "sequencer.h"
-#include "notes-utils.h"
 #include "mailmap.h"
-#include "sigchain.h"
 
 static const char * const builtin_commit_usage[] = {
 	N_("git commit [<options>] [--] <pathspec>..."),
@@ -45,31 +43,6 @@ static const char * const builtin_status_usage[] = {
 	NULL
 };
 
-static const char implicit_ident_advice_noconfig[] =
-N_("Your name and email address were configured automatically based\n"
-"on your username and hostname. Please check that they are accurate.\n"
-"You can suppress this message by setting them explicitly. Run the\n"
-"following command and follow the instructions in your editor to edit\n"
-"your configuration file:\n"
-"\n"
-"    git config --global --edit\n"
-"\n"
-"After doing this, you may fix the identity used for this commit with:\n"
-"\n"
-"    git commit --amend --reset-author\n");
-
-static const char implicit_ident_advice_config[] =
-N_("Your name and email address were configured automatically based\n"
-"on your username and hostname. Please check that they are accurate.\n"
-"You can suppress this message by setting them explicitly:\n"
-"\n"
-"    git config --global user.name \"Your Name\"\n"
-"    git config --global user.email you@example.com\n"
-"\n"
-"After doing this, you may fix the identity used for this commit with:\n"
-"\n"
-"    git commit --amend --reset-author\n");
-
 static const char empty_amend_advice[] =
 N_("You asked to amend the most recent commit, but doing so would make\n"
 "it empty. You can repeat your command with --allow-empty, or you can\n"
@@ -93,8 +66,6 @@ N_("If you wish to skip this commit, use:\n"
 "Then \"git cherry-pick --continue\" will resume cherry-picking\n"
 "the remaining commits.\n");
 
-static GIT_PATH_FUNC(git_path_commit_editmsg, "COMMIT_EDITMSG")
-
 static const char *use_message_buffer;
 static struct lock_file index_lock; /* real index */
 static struct lock_file false_lock; /* used only for partial commits */
@@ -128,12 +99,7 @@ static char *sign_commit;
  * if editor is used, and only the whitespaces if the message
  * is specified explicitly.
  */
-static enum {
-	CLEANUP_SPACE,
-	CLEANUP_NONE,
-	CLEANUP_SCISSORS,
-	CLEANUP_ALL
-} cleanup_mode;
+static enum commit_msg_cleanup_mode cleanup_mode;
 static const char *cleanup_arg;
 
 static enum commit_whence whence;
@@ -673,7 +639,7 @@ static int prepare_to_commit(const char *index_file, const char *prefix,
 	struct strbuf sb = STRBUF_INIT;
 	const char *hook_arg1 = NULL;
 	const char *hook_arg2 = NULL;
-	int clean_message_contents = (cleanup_mode != CLEANUP_NONE);
+	int clean_message_contents = (cleanup_mode != COMMIT_MSG_CLEANUP_NONE);
 	int old_display_comment_prefix;
 
 	/* This checks and barfs if author is badly specified */
@@ -814,7 +780,7 @@ static int prepare_to_commit(const char *index_file, const char *prefix,
 		struct ident_split ci, ai;
 
 		if (whence != FROM_COMMIT) {
-			if (cleanup_mode == CLEANUP_SCISSORS)
+			if (cleanup_mode == COMMIT_MSG_CLEANUP_SCISSORS)
 				wt_status_add_cut_line(s->fp);
 			status_printf_ln(s, GIT_COLOR_NORMAL,
 			    whence == FROM_MERGE
@@ -834,14 +800,15 @@ static int prepare_to_commit(const char *index_file, const char *prefix,
 		}
 
 		fprintf(s->fp, "\n");
-		if (cleanup_mode == CLEANUP_ALL)
+		if (cleanup_mode == COMMIT_MSG_CLEANUP_ALL)
 			status_printf(s, GIT_COLOR_NORMAL,
 				_("Please enter the commit message for your changes."
 				  " Lines starting\nwith '%c' will be ignored, and an empty"
 				  " message aborts the commit.\n"), comment_line_char);
-		else if (cleanup_mode == CLEANUP_SCISSORS && whence == FROM_COMMIT)
+		else if (cleanup_mode == COMMIT_MSG_CLEANUP_SCISSORS &&
+			 whence == FROM_COMMIT)
 			wt_status_add_cut_line(s->fp);
-		else /* CLEANUP_SPACE, that is. */
+		else /* COMMIT_MSG_CLEANUP_SPACE, that is. */
 			status_printf(s, GIT_COLOR_NORMAL,
 				_("Please enter the commit message for your changes."
 				  " Lines starting\n"
@@ -986,65 +953,6 @@ static int prepare_to_commit(const char *index_file, const char *prefix,
 	return 1;
 }
 
-static int rest_is_empty(struct strbuf *sb, int start)
-{
-	int i, eol;
-	const char *nl;
-
-	/* Check if the rest is just whitespace and Signed-off-by's. */
-	for (i = start; i < sb->len; i++) {
-		nl = memchr(sb->buf + i, '\n', sb->len - i);
-		if (nl)
-			eol = nl - sb->buf;
-		else
-			eol = sb->len;
-
-		if (strlen(sign_off_header) <= eol - i &&
-		    starts_with(sb->buf + i, sign_off_header)) {
-			i = eol;
-			continue;
-		}
-		while (i < eol)
-			if (!isspace(sb->buf[i++]))
-				return 0;
-	}
-
-	return 1;
-}
-
-/*
- * Find out if the message in the strbuf contains only whitespace and
- * Signed-off-by lines.
- */
-static int message_is_empty(struct strbuf *sb)
-{
-	if (cleanup_mode == CLEANUP_NONE && sb->len)
-		return 0;
-	return rest_is_empty(sb, 0);
-}
-
-/*
- * See if the user edited the message in the editor or left what
- * was in the template intact
- */
-static int template_untouched(struct strbuf *sb)
-{
-	struct strbuf tmpl = STRBUF_INIT;
-	const char *start;
-
-	if (cleanup_mode == CLEANUP_NONE && sb->len)
-		return 0;
-
-	if (!template_file || strbuf_read_file(&tmpl, template_file, 0) <= 0)
-		return 0;
-
-	strbuf_stripspace(&tmpl, cleanup_mode == CLEANUP_ALL);
-	if (!skip_prefix(sb->buf, tmpl.buf, &start))
-		start = sb->buf;
-	strbuf_release(&tmpl);
-	return rest_is_empty(sb, start - sb->buf);
-}
-
 static const char *find_author_by_nickname(const char *name)
 {
 	struct rev_info revs;
@@ -1229,15 +1137,17 @@ static int parse_and_validate_options(int argc, const char *argv[],
 	if (argc == 0 && (also || (only && !amend && !allow_empty)))
 		die(_("No paths with --include/--only does not make sense."));
 	if (!cleanup_arg || !strcmp(cleanup_arg, "default"))
-		cleanup_mode = use_editor ? CLEANUP_ALL : CLEANUP_SPACE;
+		cleanup_mode = use_editor ? COMMIT_MSG_CLEANUP_ALL :
+					    COMMIT_MSG_CLEANUP_SPACE;
 	else if (!strcmp(cleanup_arg, "verbatim"))
-		cleanup_mode = CLEANUP_NONE;
+		cleanup_mode = COMMIT_MSG_CLEANUP_NONE;
 	else if (!strcmp(cleanup_arg, "whitespace"))
-		cleanup_mode = CLEANUP_SPACE;
+		cleanup_mode = COMMIT_MSG_CLEANUP_SPACE;
 	else if (!strcmp(cleanup_arg, "strip"))
-		cleanup_mode = CLEANUP_ALL;
+		cleanup_mode = COMMIT_MSG_CLEANUP_ALL;
 	else if (!strcmp(cleanup_arg, "scissors"))
-		cleanup_mode = use_editor ? CLEANUP_SCISSORS : CLEANUP_SPACE;
+		cleanup_mode = use_editor ? COMMIT_MSG_CLEANUP_SCISSORS :
+					    COMMIT_MSG_CLEANUP_SPACE;
 	else
 		die(_("Invalid cleanup mode %s"), cleanup_arg);
 
@@ -1439,98 +1349,6 @@ int cmd_status(int argc, const char **argv, const char *prefix)
 	return 0;
 }
 
-static const char *implicit_ident_advice(void)
-{
-	char *user_config = expand_user_path("~/.gitconfig", 0);
-	char *xdg_config = xdg_config_home("config");
-	int config_exists = file_exists(user_config) || file_exists(xdg_config);
-
-	free(user_config);
-	free(xdg_config);
-
-	if (config_exists)
-		return _(implicit_ident_advice_config);
-	else
-		return _(implicit_ident_advice_noconfig);
-
-}
-
-static void print_summary(const char *prefix, const struct object_id *oid,
-			  int initial_commit)
-{
-	struct rev_info rev;
-	struct commit *commit;
-	struct strbuf format = STRBUF_INIT;
-	const char *head;
-	struct pretty_print_context pctx = {0};
-	struct strbuf author_ident = STRBUF_INIT;
-	struct strbuf committer_ident = STRBUF_INIT;
-
-	commit = lookup_commit(oid);
-	if (!commit)
-		die(_("couldn't look up newly created commit"));
-	if (parse_commit(commit))
-		die(_("could not parse newly created commit"));
-
-	strbuf_addstr(&format, "format:%h] %s");
-
-	format_commit_message(commit, "%an <%ae>", &author_ident, &pctx);
-	format_commit_message(commit, "%cn <%ce>", &committer_ident, &pctx);
-	if (strbuf_cmp(&author_ident, &committer_ident)) {
-		strbuf_addstr(&format, "\n Author: ");
-		strbuf_addbuf_percentquote(&format, &author_ident);
-	}
-	if (author_date_is_interesting()) {
-		struct strbuf date = STRBUF_INIT;
-		format_commit_message(commit, "%ad", &date, &pctx);
-		strbuf_addstr(&format, "\n Date: ");
-		strbuf_addbuf_percentquote(&format, &date);
-		strbuf_release(&date);
-	}
-	if (!committer_ident_sufficiently_given()) {
-		strbuf_addstr(&format, "\n Committer: ");
-		strbuf_addbuf_percentquote(&format, &committer_ident);
-		if (advice_implicit_identity) {
-			strbuf_addch(&format, '\n');
-			strbuf_addstr(&format, implicit_ident_advice());
-		}
-	}
-	strbuf_release(&author_ident);
-	strbuf_release(&committer_ident);
-
-	init_revisions(&rev, prefix);
-	setup_revisions(0, NULL, &rev, NULL);
-
-	rev.diff = 1;
-	rev.diffopt.output_format =
-		DIFF_FORMAT_SHORTSTAT | DIFF_FORMAT_SUMMARY;
-
-	rev.verbose_header = 1;
-	rev.show_root_diff = 1;
-	get_commit_format(format.buf, &rev);
-	rev.always_show_header = 0;
-	rev.diffopt.detect_rename = DIFF_DETECT_RENAME;
-	rev.diffopt.break_opt = 0;
-	diff_setup_done(&rev.diffopt);
-
-	head = resolve_ref_unsafe("HEAD", 0, NULL, NULL);
-	if (!head)
-		die_errno(_("unable to resolve HEAD after creating commit"));
-	if (!strcmp(head, "HEAD"))
-		head = _("detached HEAD");
-	else
-		skip_prefix(head, "refs/heads/", &head);
-	printf("[%s%s ", head, initial_commit ? _(" (root-commit)") : "");
-
-	if (!log_tree_commit(&rev, commit)) {
-		rev.always_show_header = 1;
-		rev.use_terminator = 1;
-		log_tree_commit(&rev, commit);
-	}
-
-	strbuf_release(&format);
-}
-
 static int git_commit_config(const char *k, const char *v, void *cb)
 {
 	struct wt_status *s = cb;
@@ -1560,37 +1378,6 @@ static int git_commit_config(const char *k, const char *v, void *cb)
 	return git_status_config(k, v, s);
 }
 
-static int run_rewrite_hook(const struct object_id *oldoid,
-			    const struct object_id *newoid)
-{
-	struct child_process proc = CHILD_PROCESS_INIT;
-	const char *argv[3];
-	int code;
-	struct strbuf sb = STRBUF_INIT;
-
-	argv[0] = find_hook("post-rewrite");
-	if (!argv[0])
-		return 0;
-
-	argv[1] = "amend";
-	argv[2] = NULL;
-
-	proc.argv = argv;
-	proc.in = -1;
-	proc.stdout_to_stderr = 1;
-
-	code = start_command(&proc);
-	if (code)
-		return code;
-	strbuf_addf(&sb, "%s %s\n", oid_to_hex(oldoid), oid_to_hex(newoid));
-	sigchain_push(SIGPIPE, SIG_IGN);
-	write_in_full(proc.in, sb.buf, sb.len);
-	close(proc.in);
-	strbuf_release(&sb);
-	sigchain_pop(SIGPIPE);
-	return finish_command(&proc);
-}
-
 int run_commit_hook(int editor_is_used, const char *index_file, const char *name, ...)
 {
 	struct argv_array hook_env = ARGV_ARRAY_INIT;
@@ -1673,13 +1460,11 @@ int cmd_commit(int argc, const char **argv, const char *prefix)
 	struct strbuf sb = STRBUF_INIT;
 	struct strbuf author_ident = STRBUF_INIT;
 	const char *index_file, *reflog_msg;
-	char *nl;
 	struct object_id oid;
 	struct commit_list *parents = NULL;
 	struct stat statbuf;
 	struct commit *current_head = NULL;
 	struct commit_extra_header *extra = NULL;
-	struct ref_transaction *transaction;
 	struct strbuf err = STRBUF_INIT;
 
 	if (argc == 2 && !strcmp(argv[1], "-h"))
@@ -1770,17 +1555,17 @@ int cmd_commit(int argc, const char **argv, const char *prefix)
 	}
 
 	if (verbose || /* Truncate the message just before the diff, if any. */
-	    cleanup_mode == CLEANUP_SCISSORS)
+	    cleanup_mode == COMMIT_MSG_CLEANUP_SCISSORS)
 		strbuf_setlen(&sb, wt_status_locate_end(sb.buf, sb.len));
-	if (cleanup_mode != CLEANUP_NONE)
-		strbuf_stripspace(&sb, cleanup_mode == CLEANUP_ALL);
+	if (cleanup_mode != COMMIT_MSG_CLEANUP_NONE)
+		strbuf_stripspace(&sb, cleanup_mode == COMMIT_MSG_CLEANUP_ALL);
 
-	if (message_is_empty(&sb) && !allow_empty_message) {
+	if (message_is_empty(&sb, cleanup_mode) && !allow_empty_message) {
 		rollback_index_files();
 		fprintf(stderr, _("Aborting commit due to empty commit message.\n"));
 		exit(1);
 	}
-	if (template_untouched(&sb) && !allow_empty_message) {
+	if (template_untouched(&sb, template_file, cleanup_mode) && !allow_empty_message) {
 		rollback_index_files();
 		fprintf(stderr, _("Aborting commit; you did not edit the message.\n"));
 		exit(1);
@@ -1802,25 +1587,11 @@ int cmd_commit(int argc, const char **argv, const char *prefix)
 	strbuf_release(&author_ident);
 	free_commit_extra_headers(extra);
 
-	nl = strchr(sb.buf, '\n');
-	if (nl)
-		strbuf_setlen(&sb, nl + 1 - sb.buf);
-	else
-		strbuf_addch(&sb, '\n');
-	strbuf_insert(&sb, 0, reflog_msg, strlen(reflog_msg));
-	strbuf_insert(&sb, strlen(reflog_msg), ": ", 2);
-
-	transaction = ref_transaction_begin(&err);
-	if (!transaction ||
-	    ref_transaction_update(transaction, "HEAD", &oid,
-				   current_head
-				   ? &current_head->object.oid : &null_oid,
-				   0, sb.buf, &err) ||
-	    ref_transaction_commit(transaction, &err)) {
+	if (update_head_with_reflog(current_head, &oid, reflog_msg, &sb,
+				    &err)) {
 		rollback_index_files();
 		die("%s", err.buf);
 	}
-	ref_transaction_free(transaction);
 
 	unlink(git_path_cherry_pick_head());
 	unlink(git_path_revert_head());
@@ -1837,17 +1608,17 @@ int cmd_commit(int argc, const char **argv, const char *prefix)
 	rerere(0);
 	run_commit_hook(use_editor, get_index_file(), "post-commit", NULL);
 	if (amend && !no_post_rewrite) {
-		struct notes_rewrite_cfg *cfg;
-		cfg = init_copy_notes_for_rewrite("amend");
-		if (cfg) {
-			/* we are amending, so current_head is not NULL */
-			copy_note_for_rewrite(cfg, &current_head->object.oid, &oid);
-			finish_copy_notes_for_rewrite(cfg, "Notes added by 'git commit --amend'");
-		}
-		run_rewrite_hook(&current_head->object.oid, &oid);
+		commit_post_rewrite(current_head, &oid);
+	}
+	if (!quiet) {
+		unsigned int flags = 0;
+
+		if (!current_head)
+			flags |= SUMMARY_INITIAL_COMMIT;
+		if (author_date_is_interesting())
+			flags |= SUMMARY_SHOW_AUTHOR_DATE;
+		print_commit_summary(prefix, &oid, flags);
 	}
-	if (!quiet)
-		print_summary(prefix, &oid, !current_head);
 
 	UNLEAK(err);
 	UNLEAK(sb);
diff --git a/builtin/rebase--helper.c b/builtin/rebase--helper.c
index 7daee544b7..00faf14d07 100644
--- a/builtin/rebase--helper.c
+++ b/builtin/rebase--helper.c
@@ -43,7 +43,7 @@ int cmd_rebase__helper(int argc, const char **argv, const char *prefix)
 		OPT_END()
 	};
 
-	git_config(git_default_config, NULL);
+	sequencer_init_config(&opts);
 	git_config_get_bool("rebase.abbreviatecommands", &abbreviate_commands);
 
 	opts.action = REPLAY_INTERACTIVE_REBASE;
diff --git a/builtin/revert.c b/builtin/revert.c
index b9d927eb09..76f0a35b07 100644
--- a/builtin/revert.c
+++ b/builtin/revert.c
@@ -208,7 +208,7 @@ int cmd_revert(int argc, const char **argv, const char *prefix)
 	if (isatty(0))
 		opts.edit = 1;
 	opts.action = REPLAY_REVERT;
-	git_config(git_default_config, NULL);
+	sequencer_init_config(&opts);
 	res = run_sequencer(argc, argv, &opts);
 	if (res < 0)
 		die(_("revert failed"));
@@ -221,7 +221,7 @@ int cmd_cherry_pick(int argc, const char **argv, const char *prefix)
 	int res;
 
 	opts.action = REPLAY_PICK;
-	git_config(git_default_config, NULL);
+	sequencer_init_config(&opts);
 	res = run_sequencer(argc, argv, &opts);
 	if (res < 0)
 		die(_("cherry-pick failed"));
diff --git a/sequencer.c b/sequencer.c
index 4d3f60594c..5bfdc40442 100644
--- a/sequencer.c
+++ b/sequencer.c
@@ -1,10 +1,10 @@
 #include "cache.h"
 #include "config.h"
 #include "lockfile.h"
-#include "sequencer.h"
 #include "dir.h"
 #include "object.h"
 #include "commit.h"
+#include "sequencer.h"
 #include "tag.h"
 #include "run-command.h"
 #include "exec_cmd.h"
@@ -21,12 +21,16 @@
 #include "log-tree.h"
 #include "wt-status.h"
 #include "hashmap.h"
+#include "notes-utils.h"
+#include "sigchain.h"
 
 #define GIT_REFLOG_ACTION "GIT_REFLOG_ACTION"
 
 const char sign_off_header[] = "Signed-off-by: ";
 static const char cherry_picked_prefix[] = "(cherry picked from commit ";
 
+GIT_PATH_FUNC(git_path_commit_editmsg, "COMMIT_EDITMSG")
+
 GIT_PATH_FUNC(git_path_seq_dir, "sequencer")
 
 static GIT_PATH_FUNC(git_path_todo_file, "sequencer/todo")
@@ -130,6 +134,51 @@ static GIT_PATH_FUNC(rebase_path_strategy, "rebase-merge/strategy")
 static GIT_PATH_FUNC(rebase_path_strategy_opts, "rebase-merge/strategy_opts")
 static GIT_PATH_FUNC(rebase_path_allow_rerere_autoupdate, "rebase-merge/allow_rerere_autoupdate")
 
+static int git_sequencer_config(const char *k, const char *v, void *cb)
+{
+	struct replay_opts *opts = cb;
+	int status;
+
+	if (!strcmp(k, "commit.cleanup")) {
+		const char *s;
+
+		status = git_config_string(&s, k, v);
+		if (status)
+			return status;
+
+		if (!strcmp(s, "verbatim"))
+			opts->default_msg_cleanup = COMMIT_MSG_CLEANUP_NONE;
+		else if (!strcmp(s, "whitespace"))
+			opts->default_msg_cleanup = COMMIT_MSG_CLEANUP_SPACE;
+		else if (!strcmp(s, "strip"))
+			opts->default_msg_cleanup = COMMIT_MSG_CLEANUP_ALL;
+		else if (!strcmp(s, "scissors"))
+			opts->default_msg_cleanup = COMMIT_MSG_CLEANUP_SPACE;
+		else
+			warning(_("invalid commit message cleanup mode '%s'"),
+				  s);
+
+		return status;
+	}
+
+	if (!strcmp(k, "commit.gpgsign")) {
+		opts->gpg_sign = git_config_bool(k, v) ? xstrdup("") : NULL;
+		return 0;
+	}
+
+	status = git_gpg_config(k, v, NULL);
+	if (status)
+		return status;
+
+	return git_diff_basic_config(k, v, NULL);
+}
+
+void sequencer_init_config(struct replay_opts *opts)
+{
+	opts->default_msg_cleanup = COMMIT_MSG_CLEANUP_NONE;
+	git_config(git_sequencer_config, opts);
+}
+
 static inline int is_rebase_i(const struct replay_opts *opts)
 {
 	return opts->action == REPLAY_INTERACTIVE_REBASE;
@@ -478,9 +527,6 @@ static int do_recursive_merge(struct commit *base, struct commit *next,
 			_(action_name(opts)));
 	rollback_lock_file(&index_lock);
 
-	if (opts->signoff)
-		append_signoff(msgbuf, 0, 0);
-
 	if (!clean)
 		append_conflicts_hint(msgbuf);
 
@@ -596,6 +642,18 @@ static int read_env_script(struct argv_array *env)
 	return 0;
 }
 
+static char *get_author(const char *message)
+{
+	size_t len;
+	const char *a;
+
+	a = find_commit_header(message, "author", &len);
+	if (a)
+		return xmemdupz(a, len);
+
+	return NULL;
+}
+
 static const char staged_changes_advice[] =
 N_("you have staged changes in your working tree\n"
 "If these changes are meant to be squashed into the previous commit, run:\n"
@@ -658,8 +716,6 @@ static int run_git_commit(const char *defmsg, struct replay_opts *opts,
 		argv_array_push(&cmd.args, "--amend");
 	if (opts->gpg_sign)
 		argv_array_pushf(&cmd.args, "-S%s", opts->gpg_sign);
-	if (opts->signoff)
-		argv_array_push(&cmd.args, "-s");
 	if (defmsg)
 		argv_array_pushl(&cmd.args, "-F", defmsg, NULL);
 	if ((flags & CLEANUP_MSG))
@@ -694,6 +750,461 @@ static int run_git_commit(const char *defmsg, struct replay_opts *opts,
 	return run_command(&cmd);
 }
 
+static int rest_is_empty(const struct strbuf *sb, int start)
+{
+	int i, eol;
+	const char *nl;
+
+	/* Check if the rest is just whitespace and Signed-off-by's. */
+	for (i = start; i < sb->len; i++) {
+		nl = memchr(sb->buf + i, '\n', sb->len - i);
+		if (nl)
+			eol = nl - sb->buf;
+		else
+			eol = sb->len;
+
+		if (strlen(sign_off_header) <= eol - i &&
+		    starts_with(sb->buf + i, sign_off_header)) {
+			i = eol;
+			continue;
+		}
+		while (i < eol)
+			if (!isspace(sb->buf[i++]))
+				return 0;
+	}
+
+	return 1;
+}
+
+/*
+ * Find out if the message in the strbuf contains only whitespace and
+ * Signed-off-by lines.
+ */
+int message_is_empty(const struct strbuf *sb,
+		     enum commit_msg_cleanup_mode cleanup_mode)
+{
+	if (cleanup_mode == COMMIT_MSG_CLEANUP_NONE && sb->len)
+		return 0;
+	return rest_is_empty(sb, 0);
+}
+
+/*
+ * See if the user edited the message in the editor or left what
+ * was in the template intact
+ */
+int template_untouched(const struct strbuf *sb, const char *template_file,
+		       enum commit_msg_cleanup_mode cleanup_mode)
+{
+	struct strbuf tmpl = STRBUF_INIT;
+	const char *start;
+
+	if (cleanup_mode == COMMIT_MSG_CLEANUP_NONE && sb->len)
+		return 0;
+
+	if (!template_file || strbuf_read_file(&tmpl, template_file, 0) <= 0)
+		return 0;
+
+	strbuf_stripspace(&tmpl, cleanup_mode == COMMIT_MSG_CLEANUP_ALL);
+	if (!skip_prefix(sb->buf, tmpl.buf, &start))
+		start = sb->buf;
+	strbuf_release(&tmpl);
+	return rest_is_empty(sb, start - sb->buf);
+}
+
+int update_head_with_reflog(const struct commit *old_head,
+			    const struct object_id *new_head,
+			    const char *action, const struct strbuf *msg,
+			    struct strbuf *err)
+{
+	struct ref_transaction *transaction;
+	struct strbuf sb = STRBUF_INIT;
+	const char *nl;
+	int ret = 0;
+
+	if (action) {
+		strbuf_addstr(&sb, action);
+		strbuf_addstr(&sb, ": ");
+	}
+
+	nl = strchr(msg->buf, '\n');
+	if (nl) {
+		strbuf_add(&sb, msg->buf, nl + 1 - msg->buf);
+	} else {
+		strbuf_addbuf(&sb, msg);
+		strbuf_addch(&sb, '\n');
+	}
+
+	transaction = ref_transaction_begin(err);
+	if (!transaction ||
+	    ref_transaction_update(transaction, "HEAD", new_head,
+				   old_head ? &old_head->object.oid : &null_oid,
+				   0, sb.buf, err) ||
+	    ref_transaction_commit(transaction, err)) {
+		ret = -1;
+	}
+	ref_transaction_free(transaction);
+	strbuf_release(&sb);
+
+	return ret;
+}
+
+static int run_rewrite_hook(const struct object_id *oldoid,
+			    const struct object_id *newoid)
+{
+	struct child_process proc = CHILD_PROCESS_INIT;
+	const char *argv[3];
+	int code;
+	struct strbuf sb = STRBUF_INIT;
+
+	argv[0] = find_hook("post-rewrite");
+	if (!argv[0])
+		return 0;
+
+	argv[1] = "amend";
+	argv[2] = NULL;
+
+	proc.argv = argv;
+	proc.in = -1;
+	proc.stdout_to_stderr = 1;
+
+	code = start_command(&proc);
+	if (code)
+		return code;
+	strbuf_addf(&sb, "%s %s\n", oid_to_hex(oldoid), oid_to_hex(newoid));
+	sigchain_push(SIGPIPE, SIG_IGN);
+	write_in_full(proc.in, sb.buf, sb.len);
+	close(proc.in);
+	strbuf_release(&sb);
+	sigchain_pop(SIGPIPE);
+	return finish_command(&proc);
+}
+
+void commit_post_rewrite(const struct commit *old_head,
+			 const struct object_id *new_head)
+{
+	struct notes_rewrite_cfg *cfg;
+
+	cfg = init_copy_notes_for_rewrite("amend");
+	if (cfg) {
+		/* we are amending, so old_head is not NULL */
+		copy_note_for_rewrite(cfg, &old_head->object.oid, new_head);
+		finish_copy_notes_for_rewrite(cfg, "Notes added by 'git commit --amend'");
+	}
+	run_rewrite_hook(&old_head->object.oid, new_head);
+}
+
+static int run_prepare_commit_msg_hook(struct strbuf *msg, const char *commit)
+{
+	struct argv_array hook_env = ARGV_ARRAY_INIT;
+	int ret;
+	const char *name;
+
+	name = git_path_commit_editmsg();
+	if (write_message(msg->buf, msg->len, name, 0))
+		return -1;
+
+	argv_array_pushf(&hook_env, "GIT_INDEX_FILE=%s", get_index_file());
+	argv_array_push(&hook_env, "GIT_EDITOR=:");
+	if (commit)
+		ret = run_hook_le(hook_env.argv, "prepare-commit-msg", name,
+				  "commit", commit, NULL);
+	else
+		ret = run_hook_le(hook_env.argv, "prepare-commit-msg", name,
+				  "message", NULL);
+	if (ret)
+		ret = error(_("'prepare-commit-msg' hook failed"));
+	argv_array_clear(&hook_env);
+
+	return ret;
+}
+
+static const char implicit_ident_advice_noconfig[] =
+N_("Your name and email address were configured automatically based\n"
+"on your username and hostname. Please check that they are accurate.\n"
+"You can suppress this message by setting them explicitly. Run the\n"
+"following command and follow the instructions in your editor to edit\n"
+"your configuration file:\n"
+"\n"
+"    git config --global --edit\n"
+"\n"
+"After doing this, you may fix the identity used for this commit with:\n"
+"\n"
+"    git commit --amend --reset-author\n");
+
+static const char implicit_ident_advice_config[] =
+N_("Your name and email address were configured automatically based\n"
+"on your username and hostname. Please check that they are accurate.\n"
+"You can suppress this message by setting them explicitly:\n"
+"\n"
+"    git config --global user.name \"Your Name\"\n"
+"    git config --global user.email you@example.com\n"
+"\n"
+"After doing this, you may fix the identity used for this commit with:\n"
+"\n"
+"    git commit --amend --reset-author\n");
+
+static const char *implicit_ident_advice(void)
+{
+	char *user_config = expand_user_path("~/.gitconfig", 0);
+	char *xdg_config = xdg_config_home("config");
+	int config_exists = file_exists(user_config) || file_exists(xdg_config);
+
+	free(user_config);
+	free(xdg_config);
+
+	if (config_exists)
+		return _(implicit_ident_advice_config);
+	else
+		return _(implicit_ident_advice_noconfig);
+
+}
+
+void print_commit_summary(const char *prefix, const struct object_id *oid,
+			  unsigned int flags)
+{
+	struct rev_info rev;
+	struct commit *commit;
+	struct strbuf format = STRBUF_INIT;
+	const char *head;
+	struct pretty_print_context pctx = {0};
+	struct strbuf author_ident = STRBUF_INIT;
+	struct strbuf committer_ident = STRBUF_INIT;
+
+	commit = lookup_commit(oid);
+	if (!commit)
+		die(_("couldn't look up newly created commit"));
+	if (parse_commit(commit))
+		die(_("could not parse newly created commit"));
+
+	strbuf_addstr(&format, "format:%h] %s");
+
+	format_commit_message(commit, "%an <%ae>", &author_ident, &pctx);
+	format_commit_message(commit, "%cn <%ce>", &committer_ident, &pctx);
+	if (strbuf_cmp(&author_ident, &committer_ident)) {
+		strbuf_addstr(&format, "\n Author: ");
+		strbuf_addbuf_percentquote(&format, &author_ident);
+	}
+	if (flags & SUMMARY_SHOW_AUTHOR_DATE) {
+		struct strbuf date = STRBUF_INIT;
+
+		format_commit_message(commit, "%ad", &date, &pctx);
+		strbuf_addstr(&format, "\n Date: ");
+		strbuf_addbuf_percentquote(&format, &date);
+		strbuf_release(&date);
+	}
+	if (!committer_ident_sufficiently_given()) {
+		strbuf_addstr(&format, "\n Committer: ");
+		strbuf_addbuf_percentquote(&format, &committer_ident);
+		if (advice_implicit_identity) {
+			strbuf_addch(&format, '\n');
+			strbuf_addstr(&format, implicit_ident_advice());
+		}
+	}
+	strbuf_release(&author_ident);
+	strbuf_release(&committer_ident);
+
+	init_revisions(&rev, prefix);
+	setup_revisions(0, NULL, &rev, NULL);
+
+	rev.diff = 1;
+	rev.diffopt.output_format =
+		DIFF_FORMAT_SHORTSTAT | DIFF_FORMAT_SUMMARY;
+
+	rev.verbose_header = 1;
+	rev.show_root_diff = 1;
+	get_commit_format(format.buf, &rev);
+	rev.always_show_header = 0;
+	rev.diffopt.detect_rename = DIFF_DETECT_RENAME;
+	rev.diffopt.break_opt = 0;
+	diff_setup_done(&rev.diffopt);
+
+	head = resolve_ref_unsafe("HEAD", 0, NULL, NULL);
+	if (!head)
+		die_errno(_("unable to resolve HEAD after creating commit"));
+	if (!strcmp(head, "HEAD"))
+		head = _("detached HEAD");
+	else
+		skip_prefix(head, "refs/heads/", &head);
+	printf("[%s%s ", head, (flags & SUMMARY_INITIAL_COMMIT) ?
+						_(" (root-commit)") : "");
+
+	if (!log_tree_commit(&rev, commit)) {
+		rev.always_show_header = 1;
+		rev.use_terminator = 1;
+		log_tree_commit(&rev, commit);
+	}
+
+	strbuf_release(&format);
+}
+
+static int parse_head(struct commit **head)
+{
+	struct commit *current_head;
+	struct object_id oid;
+
+	if (get_oid("HEAD", &oid)) {
+		current_head = NULL;
+	} else {
+		current_head = lookup_commit_reference(&oid);
+		if (!current_head)
+			return error(_("could not parse HEAD"));
+		if (oidcmp(&oid, &current_head->object.oid)) {
+			warning(_("HEAD %s is not a commit!"),
+				oid_to_hex(&oid));
+		}
+		if (parse_commit(current_head))
+			return error(_("could not parse HEAD commit"));
+	}
+	*head = current_head;
+
+	return 0;
+}
+
+/*
+ * Try to commit without forking 'git commit'. In some cases we need
+ * to run 'git commit' to display an error message
+ *
+ * Returns:
+ *  -1 - error unable to commit
+ *   0 - success
+ *   1 - run 'git commit'
+ */
+static int try_to_commit(struct strbuf *msg, const char *author,
+			 struct replay_opts *opts, unsigned int flags,
+			 struct object_id *oid)
+{
+	struct object_id tree;
+	struct commit *current_head;
+	struct commit_list *parents = NULL;
+	struct commit_extra_header *extra = NULL;
+	struct strbuf err = STRBUF_INIT;
+	struct strbuf commit_msg = STRBUF_INIT;
+	char *amend_author = NULL;
+	const char *hook_commit = NULL;
+	enum commit_msg_cleanup_mode cleanup;
+	int res = 0;
+
+	if (parse_head(&current_head))
+		return -1;
+
+	if (flags & AMEND_MSG) {
+		const char *exclude_gpgsig[] = { "gpgsig", NULL };
+		const char *out_enc = get_commit_output_encoding();
+		const char *message = logmsg_reencode(current_head, NULL,
+						      out_enc);
+
+		if (!msg) {
+			const char *orig_message = NULL;
+
+			find_commit_subject(message, &orig_message);
+			msg = &commit_msg;
+			strbuf_addstr(msg, orig_message);
+			hook_commit = "HEAD";
+		}
+		author = amend_author = get_author(message);
+		unuse_commit_buffer(current_head, message);
+		if (!author) {
+			res = error(_("unable to parse commit author"));
+			goto out;
+		}
+		parents = copy_commit_list(current_head->parents);
+		extra = read_commit_extra_headers(current_head, exclude_gpgsig);
+	} else if (current_head) {
+		commit_list_insert(current_head, &parents);
+	}
+
+	if (write_cache_as_tree(tree.hash, 0, NULL)) {
+		res = error(_("git write-tree failed to write a tree"));
+		goto out;
+	}
+
+	if (!(flags & ALLOW_EMPTY) && !oidcmp(current_head ?
+					      &current_head->tree->object.oid :
+					      &empty_tree_oid, &tree)) {
+		res = 1; /* run 'git commit' to display error message */
+		goto out;
+	}
+
+	if (find_hook("prepare-commit-msg")) {
+		res = run_prepare_commit_msg_hook(msg, hook_commit);
+		if (res)
+			goto out;
+		if (strbuf_read_file(&commit_msg, git_path_commit_editmsg(),
+				     2048) < 0) {
+			res = error_errno(_("unable to read commit message "
+					      "from '%s'"),
+					    git_path_commit_editmsg());
+			goto out;
+		}
+		msg = &commit_msg;
+	}
+
+	cleanup = (flags & CLEANUP_MSG) ? COMMIT_MSG_CLEANUP_ALL :
+					  opts->default_msg_cleanup;
+
+	if (cleanup != COMMIT_MSG_CLEANUP_NONE)
+		strbuf_stripspace(msg, cleanup == COMMIT_MSG_CLEANUP_ALL);
+	if (!opts->allow_empty_message && message_is_empty(msg, cleanup)) {
+		res = 1; /* run 'git commit' to display error message */
+		goto out;
+	}
+
+	if (commit_tree_extended(msg->buf, msg->len, tree.hash, parents,
+				 oid->hash, author, opts->gpg_sign, extra)) {
+		res = error(_("failed to write commit object"));
+		goto out;
+	}
+
+	if (update_head_with_reflog(current_head, oid,
+				    getenv("GIT_REFLOG_ACTION"), msg, &err)) {
+		res = error("%s", err.buf);
+		goto out;
+	}
+
+	if (flags & AMEND_MSG)
+		commit_post_rewrite(current_head, oid);
+
+out:
+	free_commit_extra_headers(extra);
+	strbuf_release(&err);
+	strbuf_release(&commit_msg);
+	free(amend_author);
+
+	return res;
+}
+
+static int do_commit(const char *msg_file, const char *author,
+		     struct replay_opts *opts, unsigned int flags)
+{
+	int res = 1;
+
+	if (!(flags & EDIT_MSG) && !(flags & VERIFY_MSG)) {
+		struct object_id oid;
+		struct strbuf sb = STRBUF_INIT;
+
+		if (msg_file && strbuf_read_file(&sb, msg_file, 2048) < 0)
+			return error_errno(_("unable to read commit message "
+					     "from '%s'"),
+					   msg_file);
+
+		res = try_to_commit(msg_file ? &sb : NULL, author, opts, flags,
+				    &oid);
+		strbuf_release(&sb);
+		if (!res) {
+			unlink(git_path_cherry_pick_head());
+			unlink(git_path_merge_msg());
+			if (!is_rebase_i(opts))
+				print_commit_summary(NULL, &oid,
+						SUMMARY_SHOW_AUTHOR_DATE);
+			return res;
+		}
+	}
+	if (res == 1)
+		return run_git_commit(msg_file, opts, flags);
+
+	return res;
+}
+
 static int is_original_commit_empty(struct commit *commit)
 {
 	const struct object_id *ptree_oid;
@@ -952,6 +1463,7 @@ static int do_pick_commit(enum todo_command command, struct commit *commit,
 	struct object_id head;
 	struct commit *base, *next, *parent;
 	const char *base_label, *next_label;
+	char *author = NULL;
 	struct commit_message msg = { NULL, NULL, NULL, NULL };
 	struct strbuf msgbuf = STRBUF_INIT;
 	int res, unborn = 0, allow;
@@ -1066,6 +1578,8 @@ static int do_pick_commit(enum todo_command command, struct commit *commit,
 			strbuf_addstr(&msgbuf, oid_to_hex(&commit->object.oid));
 			strbuf_addstr(&msgbuf, ")\n");
 		}
+		if (!is_fixup(command))
+			author = get_author(msg.message);
 	}
 
 	if (command == TODO_REWORD)
@@ -1091,6 +1605,9 @@ static int do_pick_commit(enum todo_command command, struct commit *commit,
 		}
 	}
 
+	if (opts->signoff)
+		append_signoff(&msgbuf, 0, 0);
+
 	if (is_rebase_i(opts) && write_author_script(msg.message) < 0)
 		res = -1;
 	else if (!opts->strategy || !strcmp(opts->strategy, "recursive") || command == TODO_REVERT) {
@@ -1148,9 +1665,13 @@ static int do_pick_commit(enum todo_command command, struct commit *commit,
 		goto leave;
 	} else if (allow)
 		flags |= ALLOW_EMPTY;
-	if (!opts->no_commit)
+	if (!opts->no_commit) {
 fast_forward_edit:
-		res = run_git_commit(msg_file, opts, flags);
+		if (author || command == TODO_REVERT || (flags & AMEND_MSG))
+			res = do_commit(msg_file, author, opts, flags);
+		else
+			res = error(_("unable to parse commit author"));
+	}
 
 	if (!res && final_fixup) {
 		unlink(rebase_path_fixup_msg());
@@ -1159,6 +1680,7 @@ fast_forward_edit:
 
 leave:
 	free_message(commit, &msg);
+	free(author);
 	update_abort_safety_file();
 
 	return res;
diff --git a/sequencer.h b/sequencer.h
index 81f6d7d393..e45b178dfc 100644
--- a/sequencer.h
+++ b/sequencer.h
@@ -1,6 +1,7 @@
 #ifndef SEQUENCER_H
 #define SEQUENCER_H
 
+const char *git_path_commit_editmsg(void);
 const char *git_path_seq_dir(void);
 
 #define APPEND_SIGNOFF_DEDUP (1u << 0)
@@ -11,6 +12,13 @@ enum replay_action {
 	REPLAY_INTERACTIVE_REBASE
 };
 
+enum commit_msg_cleanup_mode {
+	COMMIT_MSG_CLEANUP_SPACE,
+	COMMIT_MSG_CLEANUP_NONE,
+	COMMIT_MSG_CLEANUP_SCISSORS,
+	COMMIT_MSG_CLEANUP_ALL
+};
+
 struct replay_opts {
 	enum replay_action action;
 
@@ -29,6 +37,7 @@ struct replay_opts {
 	int mainline;
 
 	char *gpg_sign;
+	enum commit_msg_cleanup_mode default_msg_cleanup;
 
 	/* Merge strategy */
 	char *strategy;
@@ -40,6 +49,8 @@ struct replay_opts {
 };
 #define REPLAY_OPTS_INIT { -1 }
 
+/* Call this to setup defaults before parsing command line options */
+void sequencer_init_config(struct replay_opts *opts);
 int sequencer_pick_revisions(struct replay_opts *opts);
 int sequencer_continue(struct replay_opts *opts);
 int sequencer_rollback(struct replay_opts *opts);
@@ -61,5 +72,19 @@ extern const char sign_off_header[];
 
 void append_signoff(struct strbuf *msgbuf, int ignore_footer, unsigned flag);
 void append_conflicts_hint(struct strbuf *msgbuf);
+int message_is_empty(const struct strbuf *sb,
+		     enum commit_msg_cleanup_mode cleanup_mode);
+int template_untouched(const struct strbuf *sb, const char *template_file,
+		       enum commit_msg_cleanup_mode cleanup_mode);
+int update_head_with_reflog(const struct commit *old_head,
+			    const struct object_id *new_head,
+			    const char *action, const struct strbuf *msg,
+			    struct strbuf *err);
+void commit_post_rewrite(const struct commit *current_head,
+			 const struct object_id *new_head);
 
+#define SUMMARY_INITIAL_COMMIT   (1 << 0)
+#define SUMMARY_SHOW_AUTHOR_DATE (1 << 1)
+void print_commit_summary(const char *prefix, const struct object_id *oid,
+			  unsigned int flags);
 #endif
diff --git a/t/t3404-rebase-interactive.sh b/t/t3404-rebase-interactive.sh
index 481a350090..ef2887bd85 100755
--- a/t/t3404-rebase-interactive.sh
+++ b/t/t3404-rebase-interactive.sh
@@ -453,6 +453,10 @@ test_expect_success C_LOCALE_OUTPUT 'squash and fixup generate correct log messa
 		git rebase -i $base &&
 	git cat-file commit HEAD | sed -e 1,/^\$/d > actual-squash-fixup &&
 	test_cmp expect-squash-fixup actual-squash-fixup &&
+	git cat-file commit HEAD@{2} |
+		grep "^# This is a combination of 3 commits\."  &&
+	git cat-file commit HEAD@{3} |
+		grep "^# This is a combination of 2 commits\."  &&
 	git checkout to-be-rebased &&
 	git branch -D squash-fixup
 '
@@ -1336,6 +1340,16 @@ test_expect_success 'editor saves as CR/LF' '
 
 SQ="'"
 test_expect_success 'rebase -i --gpg-sign=<key-id>' '
+	test_when_finished "test_might_fail git rebase --abort" &&
+	set_fake_editor &&
+	FAKE_LINES="edit 1" git rebase -i --gpg-sign="\"S I Gner\"" HEAD^ \
+		>out 2>err &&
+	test_i18ngrep "$SQ-S\"S I Gner\"$SQ" err
+'
+
+test_expect_success 'rebase -i --gpg-sign=<key-id> overrides commit.gpgSign' '
+	test_when_finished "test_might_fail git rebase --abort" &&
+	test_config commit.gpgsign true &&
 	set_fake_editor &&
 	FAKE_LINES="edit 1" git rebase -i --gpg-sign="\"S I Gner\"" HEAD^ \
 		>out 2>err &&
diff --git a/t/t3512-cherry-pick-submodule.sh b/t/t3512-cherry-pick-submodule.sh
index ce48c4fcca..bd78287841 100755
--- a/t/t3512-cherry-pick-submodule.sh
+++ b/t/t3512-cherry-pick-submodule.sh
@@ -5,7 +5,6 @@ test_description='cherry-pick can handle submodules'
 . ./test-lib.sh
 . "$TEST_DIRECTORY"/lib-submodule-update.sh
 
-KNOWN_FAILURE_CHERRY_PICK_SEES_EMPTY_COMMIT=1
 KNOWN_FAILURE_NOFF_MERGE_DOESNT_CREATE_EMPTY_SUBMODULE_DIR=1
 KNOWN_FAILURE_NOFF_MERGE_ATTEMPTS_TO_MERGE_REMOVED_SUBMODULE_FILES=1
 test_submodule_switch "git cherry-pick"
diff --git a/t/t3513-revert-submodule.sh b/t/t3513-revert-submodule.sh
index db9378142a..5e39fcdb66 100755
--- a/t/t3513-revert-submodule.sh
+++ b/t/t3513-revert-submodule.sh
@@ -25,7 +25,6 @@ git_revert () {
 	git revert HEAD
 }
 
-KNOWN_FAILURE_CHERRY_PICK_SEES_EMPTY_COMMIT=1
 KNOWN_FAILURE_NOFF_MERGE_DOESNT_CREATE_EMPTY_SUBMODULE_DIR=1
 test_submodule_switch "git_revert"
 
diff --git a/t/t7505-prepare-commit-msg-hook.sh b/t/t7505-prepare-commit-msg-hook.sh
index b13f72975e..1f43b3cd4c 100755
--- a/t/t7505-prepare-commit-msg-hook.sh
+++ b/t/t7505-prepare-commit-msg-hook.sh
@@ -4,6 +4,38 @@ test_description='prepare-commit-msg hook'
 
 . ./test-lib.sh
 
+test_expect_success 'set up commits for rebasing' '
+	test_commit root &&
+	test_commit a a a &&
+	test_commit b b b &&
+	git checkout -b rebase-me root &&
+	test_commit rebase-a a aa &&
+	test_commit rebase-b b bb &&
+	for i in $(test_seq 1 13)
+	do
+		test_commit rebase-$i c $i
+	done &&
+	git checkout master &&
+
+	cat >rebase-todo <<-EOF
+	pick $(git rev-parse rebase-a)
+	pick $(git rev-parse rebase-b)
+	fixup $(git rev-parse rebase-1)
+	fixup $(git rev-parse rebase-2)
+	pick $(git rev-parse rebase-3)
+	fixup $(git rev-parse rebase-4)
+	squash $(git rev-parse rebase-5)
+	reword $(git rev-parse rebase-6)
+	squash $(git rev-parse rebase-7)
+	fixup $(git rev-parse rebase-8)
+	fixup $(git rev-parse rebase-9)
+	edit $(git rev-parse rebase-10)
+	squash $(git rev-parse rebase-11)
+	squash $(git rev-parse rebase-12)
+	edit $(git rev-parse rebase-13)
+	EOF
+'
+
 test_expect_success 'with no hook' '
 
 	echo "foo" > file &&
@@ -31,17 +63,41 @@ mkdir -p "$HOOKDIR"
 echo "#!$SHELL_PATH" > "$HOOK"
 cat >> "$HOOK" <<'EOF'
 
-if test "$2" = commit; then
-  source=$(git rev-parse "$3")
+GIT_DIR=$(git rev-parse --git-dir)
+if test -d "$GIT_DIR/rebase-merge"
+then
+	rebasing=1
 else
-  source=${2-default}
+	rebasing=0
 fi
-if test "$GIT_EDITOR" = :; then
-  sed -e "1s/.*/$source (no editor)/" "$1" > msg.tmp
+
+get_last_cmd () {
+	tail -n1 "$GIT_DIR/rebase-merge/done" | {
+		read cmd id _
+		git log --pretty="[$cmd %s]" -n1 $id
+	}
+}
+
+if test "$2" = commit
+then
+	if test $rebasing = 1
+	then
+		source="$3"
+	else
+		source=$(git rev-parse "$3")
+	fi
 else
-  sed -e "1s/.*/$source/" "$1" > msg.tmp
+	source=${2-default}
+fi
+test "$GIT_EDITOR" = : && source="$source (no editor)"
+
+if test $rebasing = 1
+then
+	echo "$source $(get_last_cmd)" >"$1"
+else
+	sed -e "1s/.*/$source/" "$1" >msg.tmp
+	mv msg.tmp "$1"
 fi
-mv msg.tmp "$1"
 exit 0
 EOF
 chmod +x "$HOOK"
@@ -156,6 +212,63 @@ test_expect_success 'with hook and editor (merge)' '
 	test "$(git log -1 --pretty=format:%s)" = "merge"
 '
 
+test_rebase () {
+	expect=$1 &&
+	mode=$2 &&
+	test_expect_$expect C_LOCALE_OUTPUT "with hook (rebase $mode)" '
+		test_when_finished "\
+			git rebase --abort
+			git checkout -f master
+			git branch -D tmp" &&
+		git checkout -b tmp rebase-me &&
+		GIT_SEQUENCE_EDITOR="cp rebase-todo" &&
+		GIT_EDITOR="\"$FAKE_EDITOR\"" &&
+		(
+			export GIT_SEQUENCE_EDITOR GIT_EDITOR &&
+			test_must_fail git rebase $mode b &&
+			echo x >a &&
+			git add a &&
+			test_must_fail git rebase --continue &&
+			echo x >b &&
+			git add b &&
+			git commit &&
+			git rebase --continue &&
+			echo y >a &&
+			git add a &&
+			git commit &&
+			git rebase --continue &&
+			echo y >b &&
+			git add b &&
+			git rebase --continue
+		) &&
+		if test $mode = -p # reword amended after pick
+		then
+			n=18
+		else
+			n=17
+		fi &&
+		git log --pretty=%s -g -n$n HEAD@{1} >actual &&
+		test_cmp "$TEST_DIRECTORY/t7505/expected-rebase$mode" actual
+	'
+}
+
+test_rebase success -i
+test_rebase success -p
+
+test_expect_success 'with hook (cherry-pick)' '
+	test_when_finished "git checkout -f master" &&
+	git checkout -B other b &&
+	git cherry-pick rebase-1 &&
+	test "$(git log -1 --pretty=format:%s)" = "message (no editor)"
+'
+
+test_expect_success 'with hook and editor (cherry-pick)' '
+	test_when_finished "git checkout -f master" &&
+	git checkout -B other b &&
+	git cherry-pick -e rebase-1 &&
+	test "$(git log -1 --pretty=format:%s)" = merge
+'
+
 cat > "$HOOK" <<'EOF'
 #!/bin/sh
 exit 1
@@ -197,4 +310,11 @@ test_expect_success 'with failing hook (merge)' '
 
 '
 
+test_expect_success C_LOCALE_OUTPUT 'with failing hook (cherry-pick)' '
+	test_when_finished "git checkout -f master" &&
+	git checkout -B other b &&
+	test_must_fail git cherry-pick rebase-1 2>actual &&
+	test $(grep -c prepare-commit-msg actual) = 1
+'
+
 test_done
diff --git a/t/t7505/expected-rebase-i b/t/t7505/expected-rebase-i
new file mode 100644
index 0000000000..c514bdbb94
--- /dev/null
+++ b/t/t7505/expected-rebase-i
@@ -0,0 +1,17 @@
+message [edit rebase-13]
+message (no editor) [edit rebase-13]
+message [squash rebase-12]
+message (no editor) [squash rebase-11]
+default [edit rebase-10]
+message (no editor) [edit rebase-10]
+message [fixup rebase-9]
+message (no editor) [fixup rebase-8]
+message (no editor) [squash rebase-7]
+message [reword rebase-6]
+message [squash rebase-5]
+message (no editor) [fixup rebase-4]
+message (no editor) [pick rebase-3]
+message (no editor) [fixup rebase-2]
+message (no editor) [fixup rebase-1]
+merge [pick rebase-b]
+message [pick rebase-a]
diff --git a/t/t7505/expected-rebase-p b/t/t7505/expected-rebase-p
new file mode 100644
index 0000000000..93bada596e
--- /dev/null
+++ b/t/t7505/expected-rebase-p
@@ -0,0 +1,18 @@
+message [edit rebase-13]
+message (no editor) [edit rebase-13]
+message [squash rebase-12]
+message (no editor) [squash rebase-11]
+default [edit rebase-10]
+message (no editor) [edit rebase-10]
+message [fixup rebase-9]
+message (no editor) [fixup rebase-8]
+message (no editor) [squash rebase-7]
+HEAD [reword rebase-6]
+message (no editor) [reword rebase-6]
+message [squash rebase-5]
+message (no editor) [fixup rebase-4]
+message (no editor) [pick rebase-3]
+message (no editor) [fixup rebase-2]
+message (no editor) [fixup rebase-1]
+merge [pick rebase-b]
+message [pick rebase-a]