Re: [PATCH v2 2/3] sequencer: make commit options more extensible

[Junio C Hamano <gitster@pobox.com>]

Junio C Hamano <gitster@pobox.com> writes:

> As this thing is about fixing a regression visible to end users, I
> may get around to fixing things up myself, but I have other topics
> to attend to, so...

So I ended up with this version before merging it to 'next'.  

I moved 'allow' back on the line it is declared, but left it
uninitialized because it is unconditionally assigned to before its
value is looked at.

Also the updated log message stresses more about the reason why
piling new parameters on top is a bad practice, and it is a good
idea to do this clean-up now.  Compared to that, the reason why this
clean-up was not done before and left as maintenance burden is much
less important to the readers of the log.

-- >8 --
From: Johannes Schindelin <johannes.schindelin@gmx.de>
Date: Thu, 23 Mar 2017 17:07:11 +0100
Subject: [PATCH] sequencer: make commit options more extensible

So far every time we need to tweak the behaviour of run_git_commit()
we have been adding a "int" parameter to it.  As the function gains
parameters and different callsites having different needs, this is
becoming a maintenance burden.  When a new knob needs to be added to
address a specific need for a single callsite, all the other callsites
need to add a "no, I do not want anything special with respect to the
new knob" argument.

Consolidate the existing four parameters into a flag word to make it
more maintainable, as we will be adding a new one to the mix soon.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 sequencer.c | 48 ++++++++++++++++++++++++++----------------------
 1 file changed, 26 insertions(+), 22 deletions(-)

diff --git a/sequencer.c b/sequencer.c
index 8183a83c1f..677e6ef764 100644
--- a/sequencer.c
+++ b/sequencer.c
@@ -602,6 +602,11 @@ 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)
+
 /*
  * If we are cherry-pick, and if the merge did not result in
  * hand-editing, we will hit this commit and inherit the original
@@ -615,8 +620,7 @@ 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)
 {
 	struct child_process cmd = CHILD_PROCESS_INIT;
 	const char *value;
@@ -624,7 +628,7 @@ static int run_git_commit(const char *defmsg, struct replay_opts *opts,
 	cmd.git_cmd = 1;
 
 	if (is_rebase_i(opts)) {
-		if (!edit) {
+		if (!(flags & EDIT_MSG)) {
 			cmd.stdout_to_stderr = 1;
 			cmd.err = -1;
 		}
@@ -640,7 +644,7 @@ static int run_git_commit(const char *defmsg, struct replay_opts *opts,
 	argv_array_push(&cmd.args, "commit");
 	argv_array_push(&cmd.args, "-n");
 
-	if (amend)
+	if ((flags & AMEND_MSG))
 		argv_array_push(&cmd.args, "--amend");
 	if (opts->gpg_sign)
 		argv_array_pushf(&cmd.args, "-S%s", opts->gpg_sign);
@@ -648,16 +652,16 @@ static int run_git_commit(const char *defmsg, struct replay_opts *opts,
 		argv_array_push(&cmd.args, "-s");
 	if (defmsg)
 		argv_array_pushl(&cmd.args, "-F", defmsg, NULL);
-	if (cleanup_commit_message)
+	if ((flags & CLEANUP_MSG))
 		argv_array_push(&cmd.args, "--cleanup=strip");
-	if (edit)
+	if ((flags & EDIT_MSG))
 		argv_array_push(&cmd.args, "-e");
-	else if (!cleanup_commit_message &&
+	else if (!(flags & CLEANUP_MSG) &&
 		 !opts->signoff && !opts->record_origin &&
 		 git_config_get_value("commit.cleanup", &value))
 		argv_array_push(&cmd.args, "--cleanup=verbatim");
 
-	if (allow_empty)
+	if ((flags & ALLOW_EMPTY))
 		argv_array_push(&cmd.args, "--allow-empty");
 
 	if (opts->allow_empty_message)
@@ -926,14 +930,14 @@ static void record_in_rewritten(struct object_id *oid,
 static int do_pick_commit(enum todo_command command, struct commit *commit,
 		struct replay_opts *opts, int final_fixup)
 {
-	int edit = opts->edit, cleanup_commit_message = 0;
-	const char *msg_file = edit ? NULL : git_path_merge_msg();
+	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;
 	struct commit_message msg = { NULL, NULL, NULL, NULL };
 	struct strbuf msgbuf = STRBUF_INIT;
-	int res, unborn = 0, amend = 0, allow = 0;
+	int res, unborn = 0, allow;
 
 	if (opts->no_commit) {
 		/*
@@ -991,7 +995,7 @@ static int do_pick_commit(enum todo_command command, struct commit *commit,
 			opts);
 		if (res || command != TODO_REWORD)
 			goto leave;
-		edit = amend = 1;
+		flags |= EDIT_MSG | AMEND_MSG;
 		msg_file = NULL;
 		goto fast_forward_edit;
 	}
@@ -1046,15 +1050,15 @@ static int do_pick_commit(enum todo_command command, struct commit *commit,
 	}
 
 	if (command == TODO_REWORD)
-		edit = 1;
+		flags |= EDIT_MSG;
 	else if (is_fixup(command)) {
 		if (update_squash_messages(command, commit, opts))
 			return -1;
-		amend = 1;
+		flags |= AMEND_MSG;
 		if (!final_fixup)
 			msg_file = rebase_path_squash_msg();
 		else if (file_exists(rebase_path_fixup_msg())) {
-			cleanup_commit_message = 1;
+			flags |= CLEANUP_MSG;
 			msg_file = rebase_path_fixup_msg();
 		} else {
 			const char *dest = git_path("SQUASH_MSG");
@@ -1064,7 +1068,7 @@ static int do_pick_commit(enum todo_command command, struct commit *commit,
 					     rebase_path_squash_msg(), dest);
 			unlink(git_path("MERGE_MSG"));
 			msg_file = dest;
-			edit = 1;
+			flags |= EDIT_MSG;
 		}
 	}
 
@@ -1123,11 +1127,11 @@ 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)
 fast_forward_edit:
-		res = run_git_commit(msg_file, opts, allow, edit, amend,
-				     cleanup_commit_message);
+		res = run_git_commit(msg_file, opts, flags);
 
 	if (!res && final_fixup) {
 		unlink(rebase_path_fixup_msg());
@@ -2154,7 +2158,7 @@ static int continue_single_pick(void)
 
 static int commit_staged_changes(struct replay_opts *opts)
 {
-	int amend = 0;
+	unsigned int flags = ALLOW_EMPTY | EDIT_MSG;
 
 	if (has_unstaged_changes(1))
 		return error(_("cannot rebase: You have unstaged changes."));
@@ -2184,10 +2188,10 @@ static int commit_staged_changes(struct replay_opts *opts)
 				       "--continue' again."));
 
 		strbuf_release(&rev);
-		amend = 1;
+		flags |= AMEND_MSG;
 	}
 
-	if (run_git_commit(rebase_path_message(), opts, 1, 1, amend, 0))
+	if (run_git_commit(rebase_path_message(), opts, flags))
 		return error(_("could not commit staged changes."));
 	unlink(rebase_path_amend());
 	return 0;
-- 
2.12.2-430-ge0ef7fe78c