Move the nested check from client to server and compare the client tty

name to all the pane pty names instead of comparing socket paths. This
means that "new -d" will work without unsetting $TMUX.

1 files changed, 12 insertions, 7 deletions

diff --git a/cmd-new-session.c b/cmd-new-session.c
index 9c767489..0fb849e2 100644
--- a/cmd-new-session.c
+++ b/cmd-new-session.c
@@ -41,7 +41,7 @@ const struct cmd_entry cmd_new_session_entry = {
 	"[-AdDP] [-c start-directory] [-F format] [-n window-name] "
 	"[-s session-name] " CMD_TARGET_SESSION_USAGE " [-x width] "
 	"[-y height] [command]",
-	CMD_STARTSERVER|CMD_CANTNEST,
+	CMD_STARTSERVER,
 	cmd_new_session_exec
 };
 
@@ -145,15 +145,20 @@ cmd_new_session_exec(struct cmd *self, struct cmd_q *cmdq)
 	}
 
 	/*
-	 * Save the termios settings, part of which is used for new windows in
-	 * this session.
+	 * If this is a new client, check for nesting and save the termios
+	 * settings (part of which is used for new windows in this session).
 	 *
-	 * This is read again with tcgetattr() rather than using tty.tio as if
-	 * detached, tty_open won't be called. Because of this, it must be done
-	 * before opening the terminal as that calls tcsetattr() to prepare for
-	 * tmux taking over.
+	 * tcgetattr() is used rather than using tty.tio since if the client is
+	 * detached, tty_open won't be called. It must be done before opening
+	 * the terminal as that calls tcsetattr() to prepare for tmux taking
+	 * over.
 	 */
 	if (!detached && !already_attached && c->tty.fd != -1) {
+		if (server_client_check_nested(cmdq->client)) {
+			cmdq_error(cmdq, "sessions should be nested with care, "
+			    "unset $TMUX to force");
+			return (CMD_RETURN_ERROR);
+		}
 		if (tcgetattr(c->tty.fd, &tio) != 0)
 			fatal("tcgetattr failed");
 		tiop = &tio;