sequencer: fix edit handling for cherry-pick and revert messages

save_opts() should save any non-default values.  It was intended to do
this, but since most options in struct replay_opts default to 0, it only
saved non-zero values.  Unfortunately, this does not always work for
options.edit.  Roughly speaking, options.edit had a default value of 0
for cherry-pick but a default value of 1 for revert.  Make save_opts()
record a value whenever it differs from the default.

options.edit was also overly simplistic; we had more than two cases.
The behavior that previously existed was as follows:

                       Non-conflict commits    Right after Conflict
    revert             Edit iff isatty(0)      Edit (ignore isatty(0))
    cherry-pick        No edit                 See above
    Specify --edit     Edit (ignore isatty(0)) See above
    Specify --no-edit  (*)                     See above

    (*) Before stopping for conflicts, No edit is the behavior.  After
        stopping for conflicts, the --no-edit flag is not saved so see
        the first two rows.

However, the expected behavior is:

                       Non-conflict commits    Right after Conflict
    revert             Edit iff isatty(0)      Edit iff isatty(0)
    cherry-pick        No edit                 Edit iff isatty(0)
    Specify --edit     Edit (ignore isatty(0)) Edit (ignore isatty(0))
    Specify --no-edit  No edit                 No edit

In order to get the expected behavior, we need to change options.edit
to a tri-state: unspecified, false, or true.  When specified, we follow
what it says.  When unspecified, we need to check whether the current
commit being created is resolving a conflict as well as consulting
options.action and isatty(0).  While at it, add a should_edit() utility
function that compresses options.edit down to a boolean based on the
additional information for the non-conflict case.

continue_single_pick() is the function responsible for resuming after
conflict cases, regardless of whether there is one commit being picked
or many.  Make this function stop assuming edit behavior in all cases,
so that it can correctly handle !isatty(0) and specific requests to not
edit the commit message.

Reported-by: Renato Botelho <[email protected]>
Signed-off-by: Elijah Newren <[email protected]>
Reviewed-by: Johannes Schindelin <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: newren

builtin/revert.c

@@ -182,7 +182,7 @@ static int run_sequencer(int argc, const char **argv, struct replay_opts *opts)
 				"--signoff", opts->signoff,
 				"--no-commit", opts->no_commit,
 				"-x", opts->record_origin,
-				"--edit", opts->edit,
+				"--edit", opts->edit > 0,
 				NULL);
 
 	if (cmd) {
@@ -230,8 +230,6 @@ int cmd_revert(int argc, const char **argv, const char *prefix)
 	struct replay_opts opts = REPLAY_OPTS_INIT;
 	int res;
 
-	if (isatty(0))
-		opts.edit = 1;
 	opts.action = REPLAY_REVERT;
 	sequencer_init_config(&opts);
 	res = run_sequencer(argc, argv, &opts);

sequencer.c

@@ -1860,14 +1860,25 @@ static void record_in_rewritten(struct object_id *oid,
 		flush_rewritten_pending();
 }
 
+static int should_edit(struct replay_opts *opts) {
+	if (opts->edit < 0)
+		/*
+		 * Note that we only handle the case of non-conflicted
+		 * commits; continue_single_pick() handles the conflicted
+		 * commits itself instead of calling this function.
+		 */
+		return (opts->action == REPLAY_REVERT && isatty(0)) ? 1 : 0;
+	return opts->edit;
+}
+
 static int do_pick_commit(struct repository *r,
 			  enum todo_command command,
 			  struct commit *commit,
 			  struct replay_opts *opts,
 			  int final_fixup, int *check_todo)
 {
-	unsigned int flags = opts->edit ? EDIT_MSG : 0;
-	const char *msg_file = opts->edit ? NULL : git_path_merge_msg(r);
+	unsigned int flags = should_edit(opts) ? EDIT_MSG : 0;
+	const char *msg_file = should_edit(opts) ? NULL : git_path_merge_msg(r);
 	struct object_id head;
 	struct commit *base, *next, *parent;
 	const char *base_label, *next_label;
@@ -3101,9 +3112,9 @@ static int save_opts(struct replay_opts *opts)
 	if (opts->no_commit)
 		res |= git_config_set_in_file_gently(opts_file,
 					"options.no-commit", "true");
-	if (opts->edit)
-		res |= git_config_set_in_file_gently(opts_file,
-					"options.edit", "true");
+	if (opts->edit >= 0)
+		res |= git_config_set_in_file_gently(opts_file, "options.edit",
+						     opts->edit ? "true" : "false");
 	if (opts->allow_empty)
 		res |= git_config_set_in_file_gently(opts_file,
 					"options.allow-empty", "true");
@@ -4077,7 +4088,7 @@ static int pick_commits(struct repository *r,
 	prev_reflog_action = xstrdup(getenv(GIT_REFLOG_ACTION));
 	if (opts->allow_ff)
 		assert(!(opts->signoff || opts->no_commit ||
-			 opts->record_origin || opts->edit ||
+			 opts->record_origin || should_edit(opts) ||
 			 opts->committer_date_is_author_date ||
 			 opts->ignore_date));
 	if (read_and_refresh_cache(r, opts))
@@ -4370,14 +4381,33 @@ static int pick_commits(struct repository *r,
 	return sequencer_remove_state(opts);
 }
 
-static int continue_single_pick(struct repository *r)
+static int continue_single_pick(struct repository *r, struct replay_opts *opts)
 {
-	const char *argv[] = { "commit", NULL };
+	struct strvec argv = STRVEC_INIT;
+	int ret;
 
 	if (!refs_ref_exists(get_main_ref_store(r), "CHERRY_PICK_HEAD") &&
 	    !refs_ref_exists(get_main_ref_store(r), "REVERT_HEAD"))
 		return error(_("no cherry-pick or revert in progress"));
-	return run_command_v_opt(argv, RUN_GIT_CMD);
+
+	strvec_push(&argv, "commit");
+
+	/*
+	 * continue_single_pick() handles the case of recovering from a
+	 * conflict.  should_edit() doesn't handle that case; for a conflict,
+	 * we want to edit if the user asked for it, or if they didn't specify
+	 * and stdin is a tty.
+	 */
+	if (!opts->edit || (opts->edit < 0 && !isatty(0)))
+		/*
+		 * Include --cleanup=strip as well because we don't want the
+		 * "# Conflicts:" messages.
+		 */
+		strvec_pushl(&argv, "--no-edit", "--cleanup=strip", NULL);
+
+	ret = run_command_v_opt(argv.v, RUN_GIT_CMD);
+	strvec_clear(&argv);
+	return ret;
 }
 
 static int commit_staged_changes(struct repository *r,
@@ -4547,7 +4577,7 @@ int sequencer_continue(struct repository *r, struct replay_opts *opts)
 			goto release_todo_list;
 		}
 	} else if (!file_exists(get_todo_path(opts)))
-		return continue_single_pick(r);
+		return continue_single_pick(r, opts);
 	else if ((res = read_populate_todo(r, &todo_list, opts)))
 		goto release_todo_list;
 
@@ -4556,7 +4586,7 @@ int sequencer_continue(struct repository *r, struct replay_opts *opts)
 		if (refs_ref_exists(get_main_ref_store(r),
 				    "CHERRY_PICK_HEAD") ||
 		    refs_ref_exists(get_main_ref_store(r), "REVERT_HEAD")) {
-			res = continue_single_pick(r);
+			res = continue_single_pick(r, opts);
 			if (res)
 				goto release_todo_list;
 		}

sequencer.h

@@ -31,8 +31,10 @@ enum commit_msg_cleanup_mode {
 struct replay_opts {
 	enum replay_action action;
 
-	/* Boolean options */
+	/* Tri-state options: unspecified, false, or true */
 	int edit;
+
+	/* Boolean options */
 	int record_origin;
 	int no_commit;
 	int signoff;
@@ -71,7 +73,7 @@ struct replay_opts {
 	/* Only used by REPLAY_NONE */
 	struct rev_info *revs;
 };
-#define REPLAY_OPTS_INIT { .action = -1, .current_fixups = STRBUF_INIT }
+#define REPLAY_OPTS_INIT { .edit = -1, .action = -1, .current_fixups = STRBUF_INIT }
 
 /*
  * Note that ordering matters in this enum. Not only must it match the mapping

t/t3510-cherry-pick-sequence.sh

@@ -65,7 +65,7 @@ test_expect_success 'cherry-pick persists opts correctly' '
 	# gets interrupted, use a high-enough number that is larger
 	# than the number of parents of any commit we have created
 	mainline=4 &&
-	test_expect_code 128 git cherry-pick -s -m $mainline --strategy=recursive -X patience -X ours initial..anotherpick &&
+	test_expect_code 128 git cherry-pick -s -m $mainline --strategy=recursive -X patience -X ours --edit initial..anotherpick &&
 	test_path_is_dir .git/sequencer &&
 	test_path_is_file .git/sequencer/head &&
 	test_path_is_file .git/sequencer/todo &&
@@ -84,6 +84,36 @@ test_expect_success 'cherry-pick persists opts correctly' '
 	ours
 	EOF
 	git config --file=.git/sequencer/opts --get-all options.strategy-option >actual &&
+	test_cmp expect actual &&
+	echo "true" >expect &&
+	git config --file=.git/sequencer/opts --get-all options.edit >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'revert persists opts correctly' '
+	pristine_detach initial &&
+	# to make sure that the session to revert a sequence
+	# gets interrupted, revert commits that are not in the history
+	# of HEAD.
+	test_expect_code 1 git revert -s --strategy=recursive -X patience -X ours --no-edit picked yetanotherpick &&
+	test_path_is_dir .git/sequencer &&
+	test_path_is_file .git/sequencer/head &&
+	test_path_is_file .git/sequencer/todo &&
+	test_path_is_file .git/sequencer/opts &&
+	echo "true" >expect &&
+	git config --file=.git/sequencer/opts --get-all options.signoff >actual &&
+	test_cmp expect actual &&
+	echo "recursive" >expect &&
+	git config --file=.git/sequencer/opts --get-all options.strategy >actual &&
+	test_cmp expect actual &&
+	cat >expect <<-\EOF &&
+	patience
+	ours
+	EOF
+	git config --file=.git/sequencer/opts --get-all options.strategy-option >actual &&
+	test_cmp expect actual &&
+	echo "false" >expect &&
+	git config --file=.git/sequencer/opts --get-all options.edit >actual &&
 	test_cmp expect actual
 '