From c364a7142c10af9a82b0ef19a3ef204b605a225d Mon Sep 17 00:00:00 2001
From: Nicholas Marriott <nicholas.marriott@gmail.com>
Date: Fri, 15 May 2020 17:40:24 +0100
Subject: [PATCH] Only forward extended keys if the application has requested
 them, even though we use the CSI u sequence and xterm uses CSI 27 ~ - this is
 what mintty does as well.

---
 input-keys.c |  2 ++
 input.c      | 17 +++++++++++++++++
 tmux.h       |  5 +++--
 3 files changed, 22 insertions(+), 2 deletions(-)

diff --git a/input-keys.c b/input-keys.c
index b7c02ccd..07f102b8 100644
--- a/input-keys.c
+++ b/input-keys.c
@@ -496,6 +496,8 @@ input_key(struct screen *s, struct bufferevent *bev, key_code key)
 	}
 
 	/* No builtin key sequence; construct an extended key sequence. */
+	if (~s->mode & MODE_KEXTENDED)
+		goto missing;
 	outkey = (key & KEYC_MASK_KEY);
 	if (outkey >= KEYC_BASE) {
 		switch (outkey) {
diff --git a/input.c b/input.c
index 70681e61..a8ca9478 100644
--- a/input.c
+++ b/input.c
@@ -241,6 +241,8 @@ enum input_csi_type {
 	INPUT_CSI_HPA,
 	INPUT_CSI_ICH,
 	INPUT_CSI_IL,
+	INPUT_CSI_MODOFF,
+	INPUT_CSI_MODSET,
 	INPUT_CSI_RCP,
 	INPUT_CSI_REP,
 	INPUT_CSI_RM,
@@ -288,7 +290,9 @@ static const struct input_table_entry input_csi_table[] = {
 	{ 'h', "?", INPUT_CSI_SM_PRIVATE },
 	{ 'l', "",  INPUT_CSI_RM },
 	{ 'l', "?", INPUT_CSI_RM_PRIVATE },
+	{ 'm', ">", INPUT_CSI_MODSET },
 	{ 'm', "",  INPUT_CSI_SGR },
+	{ 'n', ">", INPUT_CSI_MODOFF },
 	{ 'n', "",  INPUT_CSI_DSR },
 	{ 'q', " ", INPUT_CSI_DECSCUSR },
 	{ 'q', ">", INPUT_CSI_XDA },
@@ -1380,6 +1384,19 @@ input_csi_dispatch(struct input_ctx *ictx)
 		if (n != -1 && m != -1)
 			screen_write_cursormove(sctx, m - 1, n - 1, 1);
 		break;
+	case INPUT_CSI_MODSET:
+		n = input_get(ictx, 0, 1, 1);
+		m = input_get(ictx, 1, 1, 1);
+		if (n == 0 || (n == 4 && m == 0))
+			screen_write_mode_clear(sctx, MODE_KEXTENDED);
+		else if (n == 4 && (m == 1 || m == 2))
+			screen_write_mode_set(sctx, MODE_KEXTENDED);
+		break;
+	case INPUT_CSI_MODOFF:
+		n = input_get(ictx, 0, 1, 1);
+		if (n == 4)
+			screen_write_mode_clear(sctx, MODE_KEXTENDED);
+		break;
 	case INPUT_CSI_WINOPS:
 		input_csi_dispatch_winops(ictx);
 		break;
diff --git a/tmux.h b/tmux.h
index d814aa6c..65164ccc 100644
--- a/tmux.h
+++ b/tmux.h
@@ -579,8 +579,8 @@ struct msg_write_close {
 #define MODE_CURSOR 0x1
 #define MODE_INSERT 0x2
 #define MODE_KCURSOR 0x4
-#define MODE_KKEYPAD 0x8	/* set = application, clear = number */
-#define MODE_WRAP 0x10		/* whether lines wrap */
+#define MODE_KKEYPAD 0x8
+#define MODE_WRAP 0x10
 #define MODE_MOUSE_STANDARD 0x20
 #define MODE_MOUSE_BUTTON 0x40
 #define MODE_BLINKING 0x80
@@ -591,6 +591,7 @@ struct msg_write_close {
 #define MODE_MOUSE_ALL 0x1000
 #define MODE_ORIGIN 0x2000
 #define MODE_CRLF 0x4000
+#define MODE_KEXTENDED 0x8000
 
 #define ALL_MODES 0xffffff
 #define ALL_MOUSE_MODES (MODE_MOUSE_STANDARD|MODE_MOUSE_BUTTON|MODE_MOUSE_ALL)