sequencer: lib'ify save_opts()

Instead of dying there, let the caller high up in the callchain notice
the error and handle it (by dying, still).

The only caller of save_opts(), sequencer_pick_revisions() can already
return errors, so its caller must be already prepared to handle error
returns, and with this step, we make it notice an error return from
this function.

So this is a safe conversion to make save_opts() callable from new
callers that want it not to die, without changing the external
behaviour of anything existing.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

sequencer.c

@@ -970,37 +970,39 @@ static int save_todo(struct commit_list *todo_list, struct replay_opts *opts)
 	return 0;
 }
 
-static void save_opts(struct replay_opts *opts)
+static int save_opts(struct replay_opts *opts)
 {
 	const char *opts_file = git_path_opts_file();
+	int res = 0;
 
 	if (opts->no_commit)
-		git_config_set_in_file(opts_file, "options.no-commit", "true");
+		res |= git_config_set_in_file_gently(opts_file, "options.no-commit", "true");
 	if (opts->edit)
-		git_config_set_in_file(opts_file, "options.edit", "true");
+		res |= git_config_set_in_file_gently(opts_file, "options.edit", "true");
 	if (opts->signoff)
-		git_config_set_in_file(opts_file, "options.signoff", "true");
+		res |= git_config_set_in_file_gently(opts_file, "options.signoff", "true");
 	if (opts->record_origin)
-		git_config_set_in_file(opts_file, "options.record-origin", "true");
+		res |= git_config_set_in_file_gently(opts_file, "options.record-origin", "true");
 	if (opts->allow_ff)
-		git_config_set_in_file(opts_file, "options.allow-ff", "true");
+		res |= git_config_set_in_file_gently(opts_file, "options.allow-ff", "true");
 	if (opts->mainline) {
 		struct strbuf buf = STRBUF_INIT;
 		strbuf_addf(&buf, "%d", opts->mainline);
-		git_config_set_in_file(opts_file, "options.mainline", buf.buf);
+		res |= git_config_set_in_file_gently(opts_file, "options.mainline", buf.buf);
 		strbuf_release(&buf);
 	}
 	if (opts->strategy)
-		git_config_set_in_file(opts_file, "options.strategy", opts->strategy);
+		res |= git_config_set_in_file_gently(opts_file, "options.strategy", opts->strategy);
 	if (opts->gpg_sign)
-		git_config_set_in_file(opts_file, "options.gpg-sign", opts->gpg_sign);
+		res |= git_config_set_in_file_gently(opts_file, "options.gpg-sign", opts->gpg_sign);
 	if (opts->xopts) {
 		int i;
 		for (i = 0; i < opts->xopts_nr; i++)
-			git_config_set_multivar_in_file(opts_file,
+			res |= git_config_set_multivar_in_file_gently(opts_file,
 							"options.strategy-option",
 							opts->xopts[i], "^$", 0);
 	}
+	return res;
 }
 
 static int pick_commits(struct commit_list *todo_list, struct replay_opts *opts)
@@ -1147,7 +1149,8 @@ int sequencer_pick_revisions(struct replay_opts *opts)
 		return error(_("Can't revert as initial commit"));
 	if (save_head(sha1_to_hex(sha1)))
 		return -1;
-	save_opts(opts);
+	if (save_opts(opts))
+		return -1;
 	return pick_commits(todo_list, opts);
 }