Stop caring about empty commands, just treat as a null command.

cfg.c

@@ -125,8 +125,6 @@ load_cfg(const char *path, struct client *c, struct cmdq_item *item, int flags,
 
 	pr = cmd_parse_from_file(f, &pi);
 	fclose(f);
-	if (pr->status == CMD_PARSE_EMPTY)
-		return (0);
 	if (pr->status == CMD_PARSE_ERROR) {
 		cfg_add_cause("%s", pr->error);
 		free(pr->error);
@@ -179,8 +177,6 @@ load_cfg_from_buffer(const void *buf, size_t len, const char *path,
 	pi.c = c;
 
 	pr = cmd_parse_from_buffer(buf, len, &pi);
-	if (pr->status == CMD_PARSE_EMPTY)
-		return (0);
 	if (pr->status == CMD_PARSE_ERROR) {
 		cfg_add_cause("%s", pr->error);
 		free(pr->error);

cmd-bind-key.c

@@ -75,9 +75,6 @@ cmd_bind_key_exec(struct cmd *self, struct cmdq_item *item)
 			cmd_free_argv(argc, argv);
 		}
 		switch (pr->status) {
-		case CMD_PARSE_EMPTY:
-			cmdq_error(item, "empty command");
-			return (CMD_RETURN_ERROR);
 		case CMD_PARSE_ERROR:
 			cmdq_error(item, "%s", pr->error);
 			free(pr->error);

cmd-if-shell.c

@@ -159,8 +159,6 @@ cmd_if_shell_callback(struct job *job)
 
 	pr = cmd_parse_from_string(cmd, &cdata->input);
 	switch (pr->status) {
-	case CMD_PARSE_EMPTY:
-		break;
 	case CMD_PARSE_ERROR:
 		if (cdata->item != NULL)
 		       cmdq_error(cdata->item, "%s", pr->error);

cmd-parse.y

@@ -744,7 +744,8 @@ cmd_parse_expand_alias(struct cmd_parse_command *cmd,
 
 	first = TAILQ_FIRST(&cmd->arguments);
 	if (first == NULL || first->type != CMD_PARSE_STRING) {
-		pr->status = CMD_PARSE_EMPTY;
+		pr->status = CMD_PARSE_SUCCESS;
+		pr->cmdlist = cmd_list_new();
 		return (1);
 	}
 	name = first->string;
@@ -840,7 +841,8 @@ cmd_parse_build_commands(struct cmd_parse_commands *cmds,
 
 	/* Check for an empty list. */
 	if (TAILQ_EMPTY(cmds)) {
-		pr->status = CMD_PARSE_EMPTY;
+		pr->status = CMD_PARSE_SUCCESS;
+		pr->cmdlist = cmd_list_new();
 		return;
 	}
  	cmd_parse_log_commands(cmds, __func__);
@@ -942,8 +944,6 @@ cmd_parse_and_insert(const char *s, struct cmd_parse_input *pi,
 
 	pr = cmd_parse_from_string(s, pi);
 	switch (pr->status) {
-	case CMD_PARSE_EMPTY:
-		break;
 	case CMD_PARSE_ERROR:
 		if (error != NULL)
 			*error = pr->error;
@@ -968,8 +968,6 @@ cmd_parse_and_append(const char *s, struct cmd_parse_input *pi,
 
 	pr = cmd_parse_from_string(s, pi);
 	switch (pr->status) {
-	case CMD_PARSE_EMPTY:
-		break;
 	case CMD_PARSE_ERROR:
 		if (error != NULL)
 			*error = pr->error;
@@ -1000,9 +998,8 @@ cmd_parse_from_buffer(const void *buf, size_t len, struct cmd_parse_input *pi)
 	memset(&pr, 0, sizeof pr);
 
 	if (len == 0) {
-		pr.status = CMD_PARSE_EMPTY;
+		pr.status = CMD_PARSE_SUCCESS;
-		pr.cmdlist = NULL;
+		pr.cmdlist = cmd_list_new();
-		pr.error = NULL;
 		return (&pr);
 	}
 

cmd-queue.c

@@ -478,6 +478,13 @@ cmdq_remove_group(struct cmdq_item *item)
 	}
 }
 
+/* Empty command callback. */
+static enum cmd_retval
+cmdq_empty_command(__unused struct cmdq_item *item, __unused void *data)
+{
+	return (CMD_RETURN_NORMAL);
+}
+
 /* Get a command for the command queue. */
 struct cmdq_item *
 cmdq_get_command(struct cmd_list *cmdlist, struct cmdq_state *state)
@@ -487,12 +494,14 @@ cmdq_get_command(struct cmd_list *cmdlist, struct cmdq_state *state)
 	const struct cmd_entry	*entry;
 	int			 created = 0;
 
+	if ((cmd = cmd_list_first(cmdlist)) == NULL)
+		return (cmdq_get_callback(cmdq_empty_command, NULL));
+
 	if (state == NULL) {
 		state = cmdq_new_state(NULL, NULL, 0);
 		created = 1;
 	}
 
-	cmd = cmd_list_first(cmdlist);
 	while (cmd != NULL) {
 		entry = cmd_get_entry(cmd);
 

options.c

@@ -443,10 +443,6 @@ options_array_set(struct options_entry *o, u_int idx, const char *value,
 	if (OPTIONS_IS_COMMAND(o)) {
 		pr = cmd_parse_from_string(value, NULL);
 		switch (pr->status) {
-		case CMD_PARSE_EMPTY:
-			if (cause != NULL)
-				*cause = xstrdup("empty command");
-			return (-1);
 		case CMD_PARSE_ERROR:
 			if (cause != NULL)
 				*cause = pr->error;

server-client.c

@@ -2151,9 +2151,6 @@ server_client_dispatch_command(struct client *c, struct imsg *imsg)
 
 	pr = cmd_parse_from_arguments(argc, argv, NULL);
 	switch (pr->status) {
-	case CMD_PARSE_EMPTY:
-		cause = xstrdup("empty command");
-		goto error;
 	case CMD_PARSE_ERROR:
 		cause = pr->error;
 		goto error;

tmux.h

@@ -1417,7 +1417,6 @@ enum cmd_retval {
 
 /* Command parse result. */
 enum cmd_parse_status {
-	CMD_PARSE_EMPTY,
 	CMD_PARSE_ERROR,
 	CMD_PARSE_SUCCESS
 };

window-customize.c

@@ -1185,9 +1185,6 @@ window_customize_set_command_callback(struct client *c, void *itemdata,
 
 	pr = cmd_parse_from_string(s, NULL);
 	switch (pr->status) {
-	case CMD_PARSE_EMPTY:
-		error = xstrdup("empty command");
-		goto fail;
 	case CMD_PARSE_ERROR:
 		error = pr->error;
 		goto fail;