From bd0fb22f0a206a73ec3f41322571d56d9d7d7c5d Mon Sep 17 00:00:00 2001
From: nicm <nicm>
Date: Mon, 4 Jan 2021 08:43:16 +0000
Subject: [PATCH] Add a variant of remain-on-exit that only keeps the pane if
 the program failed, GitHub issue 2513.

---
 options-table.c |  8 ++++++--
 server-fn.c     | 16 ++++++++++++----
 tmux.1          |  5 ++++-
 3 files changed, 22 insertions(+), 7 deletions(-)

diff --git a/options-table.c b/options-table.c
index 34a4c57b..a8276c86 100644
--- a/options-table.c
+++ b/options-table.c
@@ -69,6 +69,9 @@ static const char *options_table_set_clipboard_list[] = {
 static const char *options_table_window_size_list[] = {
 	"largest", "smallest", "manual", "latest", NULL
 };
+static const char *options_table_remain_on_exit_list[] = {
+	"off", "on", "failed", NULL
+};
 
 /* Status line format. */
 #define OPTIONS_TABLE_STATUS_FORMAT1 \
@@ -949,11 +952,12 @@ const struct options_table_entry options_table[] = {
 	},
 
 	{ .name = "remain-on-exit",
-	  .type = OPTIONS_TABLE_FLAG,
+	  .type = OPTIONS_TABLE_CHOICE,
 	  .scope = OPTIONS_TABLE_WINDOW|OPTIONS_TABLE_PANE,
+	  .choices = options_table_remain_on_exit_list,
 	  .default_num = 0,
 	  .text = "Whether panes should remain ('on') or be automatically "
-		  "killed ('off') when the program inside exits."
+		  "killed ('off' or 'failed') when the program inside exits."
 	},
 
 	{ .name = "synchronize-panes",
diff --git a/server-fn.c b/server-fn.c
index d2465569..d0e06c0f 100644
--- a/server-fn.c
+++ b/server-fn.c
@@ -314,6 +314,7 @@ server_destroy_pane(struct window_pane *wp, int notify)
 	struct grid_cell	 gc;
 	time_t			 t;
 	char			 tim[26];
+	int			 remain_on_exit;
 
 	if (wp->fd != -1) {
 		bufferevent_free(wp->event);
@@ -322,10 +323,17 @@ server_destroy_pane(struct window_pane *wp, int notify)
 		wp->fd = -1;
 	}
 
-	if (options_get_number(wp->options, "remain-on-exit")) {
-		if (~wp->flags & PANE_STATUSREADY)
-			return;
-
+	remain_on_exit = options_get_number(wp->options, "remain-on-exit");
+	if (remain_on_exit != 0 && (~wp->flags & PANE_STATUSREADY))
+		return;
+	switch (remain_on_exit) {
+	case 0:
+		break;
+	case 2:
+		if (WIFEXITED(wp->status) && WEXITSTATUS(wp->status) == 0)
+			break;
+		/* FALLTHROUGH */
+	case 1:
 		if (wp->flags & PANE_STATUSDRAWN)
 			return;
 		wp->flags |= PANE_STATUSDRAWN;
diff --git a/tmux.1 b/tmux.1
index 1376df95..941305e3 100644
--- a/tmux.1
+++ b/tmux.1
@@ -4181,10 +4181,13 @@ interactive application starts and restores it on exit, so that any output
 visible before the application starts reappears unchanged after it exits.
 .Pp
 .It Xo Ic remain-on-exit
-.Op Ic on | off
+.Op Ic on | off | failed
 .Xc
 A pane with this flag set is not destroyed when the program running in it
 exits.
+If set to
+.Ic failed ,
+then only when the program exit status is not zero.
 The pane may be reactivated with the
 .Ic respawn-pane
 command.