Merge branch 'jn/maint-sequencer-fixes'

* jn/maint-sequencer-fixes:
  revert: stop creating and removing sequencer-old directory
  Revert "reset: Make reset remove the sequencer state"
  revert: do not remove state until sequence is finished
  revert: allow single-pick in the middle of cherry-pick sequence
  revert: pass around rev-list args in already-parsed form
  revert: allow cherry-pick --continue to commit before resuming
  revert: give --continue handling its own function

6 files changed, 252 insertions, 126 deletions

diff --git a/branch.c b/branch.c
index a715a11749..c2e625f40c 100644
--- a/branch.c
+++ b/branch.c
@@ -3,7 +3,6 @@
 #include "refs.h"
 #include "remote.h"
 #include "commit.h"
-#include "sequencer.h"
 
 struct tracking {
 	struct refspec spec;
@@ -280,5 +279,4 @@ void remove_branch_state(void)
 	unlink(git_path("MERGE_MSG"));
 	unlink(git_path("MERGE_MODE"));
 	unlink(git_path("SQUASH_MSG"));
-	remove_sequencer_state(0);
 }
diff --git a/builtin/revert.c b/builtin/revert.c
index 1ea525c10e..028bcbcd75 100644
--- a/builtin/revert.c
+++ b/builtin/revert.c
@@ -60,13 +60,14 @@ struct replay_opts {
 	int allow_rerere_auto;
 
 	int mainline;
-	int commit_argc;
-	const char **commit_argv;
 
 	/* Merge strategy */
 	const char *strategy;
 	const char **xopts;
 	size_t xopts_nr, xopts_alloc;
+
+	/* Only used by REPLAY_NONE */
+	struct rev_info *revs;
 };
 
 #define GIT_REFLOG_ACTION "GIT_REFLOG_ACTION"
@@ -169,9 +170,9 @@ static void parse_args(int argc, const char **argv, struct replay_opts *opts)
 			die(_("program error"));
 	}
 
-	opts->commit_argc = parse_options(argc, argv, NULL, options, usage_str,
-					PARSE_OPT_KEEP_ARGV0 |
-					PARSE_OPT_KEEP_UNKNOWN);
+	argc = parse_options(argc, argv, NULL, options, usage_str,
+			PARSE_OPT_KEEP_ARGV0 |
+			PARSE_OPT_KEEP_UNKNOWN);
 
 	/* Check for incompatible subcommands */
 	verify_opt_mutually_compatible(me,
@@ -213,9 +214,6 @@ static void parse_args(int argc, const char **argv, struct replay_opts *opts)
 				NULL);
 	}
 
-	else if (opts->commit_argc < 2)
-		usage_with_options(usage_str, options);
-
 	if (opts->allow_ff)
 		verify_opt_compatible(me, "--ff",
 				"--signoff", opts->signoff,
@@ -223,7 +221,20 @@ static void parse_args(int argc, const char **argv, struct replay_opts *opts)
 				"-x", opts->record_origin,
 				"--edit", opts->edit,
 				NULL);
-	opts->commit_argv = argv;
+
+	if (opts->subcommand != REPLAY_NONE) {
+		opts->revs = NULL;
+	} else {
+		opts->revs = xmalloc(sizeof(*opts->revs));
+		init_revisions(opts->revs, NULL);
+		opts->revs->no_walk = 1;
+		if (argc < 2)
+			usage_with_options(usage_str, options);
+		argc = setup_revisions(argc, argv, opts->revs, NULL);
+	}
+
+	if (argc > 1)
+		usage_with_options(usage_str, options);
 }
 
 struct commit_message {
@@ -631,23 +642,15 @@ static int do_pick_commit(struct commit *commit, struct replay_opts *opts)
 	return res;
 }
 
-static void prepare_revs(struct rev_info *revs, struct replay_opts *opts)
+static void prepare_revs(struct replay_opts *opts)
 {
-	int argc;
-
-	init_revisions(revs, NULL);
-	revs->no_walk = 1;
 	if (opts->action != REVERT)
-		revs->reverse = 1;
-
-	argc = setup_revisions(opts->commit_argc, opts->commit_argv, revs, NULL);
-	if (argc > 1)
-		usage(*revert_or_cherry_pick_usage(opts));
+		opts->revs->reverse ^= 1;
 
-	if (prepare_revision_walk(revs))
+	if (prepare_revision_walk(opts->revs))
 		die(_("revision walk setup failed"));
 
-	if (!revs->commits)
+	if (!opts->revs->commits)
 		die(_("empty commit set passed"));
 }
 
@@ -844,14 +847,13 @@ static void read_populate_opts(struct replay_opts **opts_ptr)
 static void walk_revs_populate_todo(struct commit_list **todo_list,
 				struct replay_opts *opts)
 {
-	struct rev_info revs;
 	struct commit *commit;
 	struct commit_list **next;
 
-	prepare_revs(&revs, opts);
+	prepare_revs(opts);
 
 	next = todo_list;
-	while ((commit = get_revision(&revs)))
+	while ((commit = get_revision(opts->revs)))
 		next = commit_list_append(commit, next);
 }
 
@@ -942,7 +944,7 @@ static int sequencer_rollback(struct replay_opts *opts)
 	}
 	if (reset_for_rollback(sha1))
 		goto fail;
-	remove_sequencer_state(1);
+	remove_sequencer_state();
 	strbuf_release(&buf);
 	return 0;
 fail:
@@ -1016,33 +1018,64 @@ static int pick_commits(struct commit_list *todo_list, struct replay_opts *opts)
 	for (cur = todo_list; cur; cur = cur->next) {
 		save_todo(cur, opts);
 		res = do_pick_commit(cur->item, opts);
-		if (res) {
-			if (!cur->next)
-				/*
-				 * An error was encountered while
-				 * picking the last commit; the
-				 * sequencer state is useless now --
-				 * the user simply needs to resolve
-				 * the conflict and commit
-				 */
-				remove_sequencer_state(0);
+		if (res)
 			return res;
-		}
 	}
 
 	/*
 	 * Sequence of picks finished successfully; cleanup by
 	 * removing the .git/sequencer directory
 	 */
-	remove_sequencer_state(1);
+	remove_sequencer_state();
 	return 0;
 }
 
+static int continue_single_pick(void)
+{
+	const char *argv[] = { "commit", NULL };
+
+	if (!file_exists(git_path("CHERRY_PICK_HEAD")) &&
+	    !file_exists(git_path("REVERT_HEAD")))
+		return error(_("no cherry-pick or revert in progress"));
+	return run_command_v_opt(argv, RUN_GIT_CMD);
+}
+
+static int sequencer_continue(struct replay_opts *opts)
+{
+	struct commit_list *todo_list = NULL;
+
+	if (!file_exists(git_path(SEQ_TODO_FILE)))
+		return continue_single_pick();
+	read_populate_opts(&opts);
+	read_populate_todo(&todo_list, opts);
+
+	/* Verify that the conflict has been resolved */
+	if (file_exists(git_path("CHERRY_PICK_HEAD")) ||
+	    file_exists(git_path("REVERT_HEAD"))) {
+		int ret = continue_single_pick();
+		if (ret)
+			return ret;
+	}
+	if (index_differs_from("HEAD", 0))
+		return error_dirty_index(opts);
+	todo_list = todo_list->next;
+	return pick_commits(todo_list, opts);
+}
+
+static int single_pick(struct commit *cmit, struct replay_opts *opts)
+{
+	setenv(GIT_REFLOG_ACTION, action_name(opts), 0);
+	return do_pick_commit(cmit, opts);
+}
+
 static int pick_revisions(struct replay_opts *opts)
 {
 	struct commit_list *todo_list = NULL;
 	unsigned char sha1[20];
 
+	if (opts->subcommand == REPLAY_NONE)
+		assert(opts->revs);
+
 	read_and_refresh_cache(opts);
 
 	/*
@@ -1051,21 +1084,32 @@ static int pick_revisions(struct replay_opts *opts)
 	 * one that is being continued
 	 */
 	if (opts->subcommand == REPLAY_REMOVE_STATE) {
-		remove_sequencer_state(1);
+		remove_sequencer_state();
 		return 0;
 	}
 	if (opts->subcommand == REPLAY_ROLLBACK)
 		return sequencer_rollback(opts);
-	if (opts->subcommand == REPLAY_CONTINUE) {
-		if (!file_exists(git_path(SEQ_TODO_FILE)))
-			return error(_("No %s in progress"), action_name(opts));
-		read_populate_opts(&opts);
-		read_populate_todo(&todo_list, opts);
-
-		/* Verify that the conflict has been resolved */
-		if (!index_differs_from("HEAD", 0))
-			todo_list = todo_list->next;
-		return pick_commits(todo_list, opts);
+	if (opts->subcommand == REPLAY_CONTINUE)
+		return sequencer_continue(opts);
+
+	/*
+	 * If we were called as "git cherry-pick <commit>", just
+	 * cherry-pick/revert it, set CHERRY_PICK_HEAD /
+	 * REVERT_HEAD, and don't touch the sequencer state.
+	 * This means it is possible to cherry-pick in the middle
+	 * of a cherry-pick sequence.
+	 */
+	if (opts->revs->cmdline.nr == 1 &&
+	    opts->revs->cmdline.rev->whence == REV_CMD_REV &&
+	    opts->revs->no_walk &&
+	    !opts->revs->cmdline.rev->flags) {
+		struct commit *cmit;
+		if (prepare_revision_walk(opts->revs))
+			die(_("revision walk setup failed"));
+		cmit = get_revision(opts->revs);
+		if (!cmit || get_revision(opts->revs))
+			die("BUG: expected exactly one commit from walk");
+		return single_pick(cmit, opts);
 	}
 
 	/*
diff --git a/sequencer.c b/sequencer.c
index bc2c046aab..d1f28a6945 100644
--- a/sequencer.c
+++ b/sequencer.c
@@ -3,17 +3,11 @@
 #include "strbuf.h"
 #include "dir.h"
 
-void remove_sequencer_state(int aggressive)
+void remove_sequencer_state(void)
 {
 	struct strbuf seq_dir = STRBUF_INIT;
-	struct strbuf seq_old_dir = STRBUF_INIT;
 
 	strbuf_addf(&seq_dir, "%s", git_path(SEQ_DIR));
-	strbuf_addf(&seq_old_dir, "%s", git_path(SEQ_OLD_DIR));
-	remove_dir_recursively(&seq_old_dir, 0);
-	rename(git_path(SEQ_DIR), git_path(SEQ_OLD_DIR));
-	if (aggressive)
-		remove_dir_recursively(&seq_old_dir, 0);
+	remove_dir_recursively(&seq_dir, 0);
 	strbuf_release(&seq_dir);
-	strbuf_release(&seq_old_dir);
 }
diff --git a/sequencer.h b/sequencer.h
index f435fdb4b1..2d4528f292 100644
--- a/sequencer.h
+++ b/sequencer.h
@@ -2,19 +2,11 @@
 #define SEQUENCER_H
 
 #define SEQ_DIR		"sequencer"
-#define SEQ_OLD_DIR	"sequencer-old"
 #define SEQ_HEAD_FILE	"sequencer/head"
 #define SEQ_TODO_FILE	"sequencer/todo"
 #define SEQ_OPTS_FILE	"sequencer/opts"
 
-/*
- * Removes SEQ_OLD_DIR and renames SEQ_DIR to SEQ_OLD_DIR, ignoring
- * any errors.  Intended to be used by 'git reset'.
- *
- * With the aggressive flag, it additionally removes SEQ_OLD_DIR,
- * ignoring any errors.  Inteded to be used by the sequencer's
- * '--quit' subcommand.
- */
-void remove_sequencer_state(int aggressive);
+/* Removes SEQ_DIR. */
+extern void remove_sequencer_state(void);
 
 #endif
diff --git a/t/t3510-cherry-pick-sequence.sh b/t/t3510-cherry-pick-sequence.sh
index 2c4c1c851d..e80050e1fe 100755
--- a/t/t3510-cherry-pick-sequence.sh
+++ b/t/t3510-cherry-pick-sequence.sh
@@ -2,6 +2,7 @@
 
 test_description='Test cherry-pick continuation features
 
+ +  conflicting: rewrites unrelated to conflicting
   + yetanotherpick: rewrites foo to e
   + anotherpick: rewrites foo to d
   + picked: rewrites foo to c
@@ -27,6 +28,7 @@ test_cmp_rev () {
 }
 
 test_expect_success setup '
+	git config advice.detachedhead false
 	echo unrelated >unrelated &&
 	git add unrelated &&
 	test_commit initial foo a &&
@@ -35,8 +37,8 @@ test_expect_success setup '
 	test_commit picked foo c &&
 	test_commit anotherpick foo d &&
 	test_commit yetanotherpick foo e &&
-	git config advice.detachedhead false
-
+	pristine_detach initial &&
+	test_commit conflicting unrelated
 '
 
 test_expect_success 'cherry-pick persists data on failure' '
@@ -48,6 +50,18 @@ test_expect_success 'cherry-pick persists data on failure' '
 	test_path_is_file .git/sequencer/opts
 '
 
+test_expect_success 'cherry-pick mid-cherry-pick-sequence' '
+	pristine_detach initial &&
+	test_must_fail git cherry-pick base..anotherpick &&
+	test_cmp_rev picked CHERRY_PICK_HEAD &&
+	# "oops, I forgot that these patches rely on the change from base"
+	git checkout HEAD foo &&
+	git cherry-pick base &&
+	git cherry-pick picked &&
+	git cherry-pick --continue &&
+	git diff --exit-code anotherpick
+'
+
 test_expect_success 'cherry-pick persists opts correctly' '
 	pristine_detach initial &&
 	test_must_fail git cherry-pick -s -m 1 --strategy=recursive -X patience -X ours base..anotherpick &&
@@ -189,10 +203,10 @@ test_expect_success '--abort refuses to clobber unrelated change, harder case' '
 	test_cmp_rev initial HEAD
 '
 
-test_expect_success 'cherry-pick cleans up sequencer state when one commit is left' '
+test_expect_success 'cherry-pick still writes sequencer state when one commit is left' '
 	pristine_detach initial &&
 	test_must_fail git cherry-pick base..picked &&
-	test_path_is_missing .git/sequencer &&
+	test_path_is_dir .git/sequencer &&
 	echo "resolved" >foo &&
 	git add foo &&
 	git commit &&
@@ -213,7 +227,7 @@ test_expect_success 'cherry-pick cleans up sequencer state when one commit is le
 	test_cmp expect actual
 '
 
-test_expect_failure '--abort after last commit in sequence' '
+test_expect_success '--abort after last commit in sequence' '
 	pristine_detach initial &&
 	test_must_fail git cherry-pick base..picked &&
 	git cherry-pick --abort &&
@@ -243,7 +257,66 @@ test_expect_success '--continue complains when there are unresolved conflicts' '
 	test_must_fail git cherry-pick --continue
 '
 
-test_expect_success '--continue continues after conflicts are resolved' '
+test_expect_success '--continue of single cherry-pick' '
+	pristine_detach initial &&
+	echo c >expect &&
+	test_must_fail git cherry-pick picked &&
+	echo c >foo &&
+	git add foo &&
+	git cherry-pick --continue &&
+
+	test_cmp expect foo &&
+	test_cmp_rev initial HEAD^ &&
+	git diff --exit-code HEAD &&
+	test_must_fail git rev-parse --verify CHERRY_PICK_HEAD
+'
+
+test_expect_success '--continue of single revert' '
+	pristine_detach initial &&
+	echo resolved >expect &&
+	echo "Revert \"picked\"" >expect.msg &&
+	test_must_fail git revert picked &&
+	echo resolved >foo &&
+	git add foo &&
+	git cherry-pick --continue &&
+
+	git diff --exit-code HEAD &&
+	test_cmp expect foo &&
+	test_cmp_rev initial HEAD^ &&
+	git diff-tree -s --pretty=tformat:%s HEAD >msg &&
+	test_cmp expect.msg msg &&
+	test_must_fail git rev-parse --verify CHERRY_PICK_HEAD &&
+	test_must_fail git rev-parse --verify REVERT_HEAD
+'
+
+test_expect_success '--continue after resolving conflicts' '
+	pristine_detach initial &&
+	echo d >expect &&
+	cat >expect.log <<-\EOF &&
+	OBJID
+	:100644 100644 OBJID OBJID M	foo
+	OBJID
+	:100644 100644 OBJID OBJID M	foo
+	OBJID
+	:100644 100644 OBJID OBJID M	unrelated
+	OBJID
+	:000000 100644 OBJID OBJID A	foo
+	:000000 100644 OBJID OBJID A	unrelated
+	EOF
+	test_must_fail git cherry-pick base..anotherpick &&
+	echo c >foo &&
+	git add foo &&
+	git cherry-pick --continue &&
+	{
+		git rev-list HEAD |
+		git diff-tree --root --stdin |
+		sed "s/$_x40/OBJID/g"
+	} >actual.log &&
+	test_cmp expect foo &&
+	test_cmp expect.log actual.log
+'
+
+test_expect_success '--continue after resolving conflicts and committing' '
 	pristine_detach initial &&
 	test_must_fail git cherry-pick base..anotherpick &&
 	echo "c" >foo &&
@@ -270,6 +343,29 @@ test_expect_success '--continue continues after conflicts are resolved' '
 	test_cmp expect actual
 '
 
+test_expect_success '--continue asks for help after resolving patch to nil' '
+	pristine_detach conflicting &&
+	test_must_fail git cherry-pick initial..picked &&
+
+	test_cmp_rev unrelatedpick CHERRY_PICK_HEAD &&
+	git checkout HEAD -- unrelated &&
+	test_must_fail git cherry-pick --continue 2>msg &&
+	test_i18ngrep "The previous cherry-pick is now empty" msg
+'
+
+test_expect_success 'follow advice and skip nil patch' '
+	pristine_detach conflicting &&
+	test_must_fail git cherry-pick initial..picked &&
+
+	git checkout HEAD -- unrelated &&
+	test_must_fail git cherry-pick --continue &&
+	git reset &&
+	git cherry-pick --continue &&
+
+	git rev-list initial..HEAD >commits &&
+	test_line_count = 3 commits
+'
+
 test_expect_success '--continue respects opts' '
 	pristine_detach initial &&
 	test_must_fail git cherry-pick -x base..anotherpick &&
@@ -288,6 +384,29 @@ test_expect_success '--continue respects opts' '
 	grep "cherry picked from" anotherpick_msg
 '
 
+test_expect_success '--continue of single-pick respects -x' '
+	pristine_detach initial &&
+	test_must_fail git cherry-pick -x picked &&
+	echo c >foo &&
+	git add foo &&
+	git cherry-pick --continue &&
+	test_path_is_missing .git/sequencer &&
+	git cat-file commit HEAD >msg &&
+	grep "cherry picked from" msg
+'
+
+test_expect_success '--continue respects -x in first commit in multi-pick' '
+	pristine_detach initial &&
+	test_must_fail git cherry-pick -x picked anotherpick &&
+	echo c >foo &&
+	git add foo &&
+	git cherry-pick --continue &&
+	test_path_is_missing .git/sequencer &&
+	git cat-file commit HEAD^ >msg &&
+	picked=$(git rev-parse --verify picked) &&
+	grep "cherry picked from.*$picked" msg
+'
+
 test_expect_success '--signoff is not automatically propagated to resolved conflict' '
 	pristine_detach initial &&
 	test_must_fail git cherry-pick --signoff base..anotherpick &&
@@ -306,6 +425,32 @@ test_expect_success '--signoff is not automatically propagated to resolved confl
 	grep "Signed-off-by:" anotherpick_msg
 '
 
+test_expect_success '--signoff dropped for implicit commit of resolution, multi-pick case' '
+	pristine_detach initial &&
+	test_must_fail git cherry-pick -s picked anotherpick &&
+	echo c >foo &&
+	git add foo &&
+	git cherry-pick --continue &&
+
+	git diff --exit-code HEAD &&
+	test_cmp_rev initial HEAD^^ &&
+	git cat-file commit HEAD^ >msg &&
+	! grep Signed-off-by: msg
+'
+
+test_expect_success 'sign-off needs to be reaffirmed after conflict resolution, single-pick case' '
+	pristine_detach initial &&
+	test_must_fail git cherry-pick -s picked &&
+	echo c >foo &&
+	git add foo &&
+	git cherry-pick --continue &&
+
+	git diff --exit-code HEAD &&
+	test_cmp_rev initial HEAD^ &&
+	git cat-file commit HEAD >msg &&
+	! grep Signed-off-by: msg
+'
+
 test_expect_success 'malformed instruction sheet 1' '
 	pristine_detach initial &&
 	test_must_fail git cherry-pick base..anotherpick &&
@@ -328,4 +473,9 @@ test_expect_success 'malformed instruction sheet 2' '
 	test_must_fail git cherry-pick --continue
 '
 
+test_expect_success 'empty commit set' '
+	pristine_detach initial &&
+	test_expect_code 128 git cherry-pick base..base
+'
+
 test_done
diff --git a/t/t7106-reset-sequence.sh b/t/t7106-reset-sequence.sh
deleted file mode 100755
index 83f7ea59c9..0000000000
--- a/t/t7106-reset-sequence.sh
+++ /dev/null
@@ -1,52 +0,0 @@
-#!/bin/sh
-
-test_description='Test interaction of reset --hard with sequencer
-
-  + anotherpick: rewrites foo to d
-  + picked: rewrites foo to c
-  + unrelatedpick: rewrites unrelated to reallyunrelated
-  + base: rewrites foo to b
-  + initial: writes foo as a, unrelated as unrelated
-'
-
-. ./test-lib.sh
-
-pristine_detach () {
-	git cherry-pick --quit &&
-	git checkout -f "$1^0" &&
-	git read-tree -u --reset HEAD &&
-	git clean -d -f -f -q -x
-}
-
-test_expect_success setup '
-	echo unrelated >unrelated &&
-	git add unrelated &&
-	test_commit initial foo a &&
-	test_commit base foo b &&
-	test_commit unrelatedpick unrelated reallyunrelated &&
-	test_commit picked foo c &&
-	test_commit anotherpick foo d &&
-	git config advice.detachedhead false
-
-'
-
-test_expect_success 'reset --hard cleans up sequencer state, providing one-level undo' '
-	pristine_detach initial &&
-	test_must_fail git cherry-pick base..anotherpick &&
-	test_path_is_dir .git/sequencer &&
-	git reset --hard &&
-	test_path_is_missing .git/sequencer &&
-	test_path_is_dir .git/sequencer-old &&
-	git reset --hard &&
-	test_path_is_missing .git/sequencer-old
-'
-
-test_expect_success 'cherry-pick --abort does not leave sequencer-old dir' '
-	pristine_detach initial &&
-	test_must_fail git cherry-pick base..anotherpick &&
-	git cherry-pick --abort &&
-	test_path_is_missing .git/sequencer &&
-	test_path_is_missing .git/sequencer-old
-'
-
-test_done