From a888ce9963053c790c6ee9bf64cc53d95f0f9c09 Mon Sep 17 00:00:00 2001
From: nicm <nicm>
Date: Mon, 20 Jun 2022 07:59:37 +0000
Subject: [PATCH] Do not display configuration file errors in a pane when in
 control mode, instead report them with a %config-error notification. GitHub
 issue 3193.

---
 cfg.c             | 24 +++++++++++++++++++++---
 cmd-new-session.c |  2 +-
 tmux.1            |  2 ++
 3 files changed, 24 insertions(+), 4 deletions(-)

diff --git a/cfg.c b/cfg.c
index d32e5ff1..e92ce36f 100644
--- a/cfg.c
+++ b/cfg.c
@@ -52,8 +52,7 @@ cfg_done(__unused struct cmdq_item *item, __unused void *data)
 		return (CMD_RETURN_NORMAL);
 	cfg_finished = 1;
 
-	if (!RB_EMPTY(&sessions))
-		cfg_show_causes(RB_MIN(sessions, &sessions));
+	cfg_show_causes(NULL);
 
 	if (cfg_item != NULL)
 		cmdq_continue(cfg_item);
@@ -239,11 +238,29 @@ cfg_print_causes(struct cmdq_item *item)
 void
 cfg_show_causes(struct session *s)
 {
+	struct client			*c = TAILQ_FIRST(&clients);
 	struct window_pane		*wp;
 	struct window_mode_entry	*wme;
 	u_int				 i;
 
-	if (s == NULL || cfg_ncauses == 0)
+	if (cfg_ncauses == 0)
+		return;
+
+	if (c != NULL && (c->flags & CLIENT_CONTROL)) {
+		for (i = 0; i < cfg_ncauses; i++) {
+			control_write(c, "%%config-error %s", cfg_causes[i]);
+			free(cfg_causes[i]);
+		}
+		goto out;
+	}
+
+	if (s == NULL) {
+		if (c != NULL && c->session != NULL)
+			s = c->session;
+		else
+			s = RB_MIN(sessions, &sessions);
+	}
+	if (s == NULL || s->attached == 0) /* wait for an attached session */
 		return;
 	wp = s->curw->window->active;
 
@@ -255,6 +272,7 @@ cfg_show_causes(struct session *s)
 		free(cfg_causes[i]);
 	}
 
+out:
 	free(cfg_causes);
 	cfg_causes = NULL;
 	cfg_ncauses = 0;
diff --git a/cmd-new-session.c b/cmd-new-session.c
index cb9abfb3..b946f049 100644
--- a/cmd-new-session.c
+++ b/cmd-new-session.c
@@ -335,7 +335,7 @@ cmd_new_session_exec(struct cmd *self, struct cmdq_item *item)
 
 	/*
 	 * If there are still configuration file errors to display, put the new
-	 * session's current window into more mode and display them now.
+	 * session's current window into view mode and display them now.
 	 */
 	if (cfg_finished)
 		cfg_show_causes(s);
diff --git a/tmux.1 b/tmux.1
index f06a42a4..44b96eb7 100644
--- a/tmux.1
+++ b/tmux.1
@@ -6529,6 +6529,8 @@ The client is now attached to the session with ID
 .Ar session-id ,
 which is named
 .Ar name .
+.It Ic %config-error Ar error
+An error has happened in a configuration file.
 .It Ic %continue Ar pane-id
 The pane has been continued after being paused (if the
 .Ar pause-after