commit 65f1dc428315ae9d7f362e10c668557c1379e7af
from: jamin <acdimalev@gmail.com>
via: Hiltjo Posthuma <hiltjo@codemadness.org>
date: Thu Dec 30 17:37:17 2021 UTC

Fix overtyping wide characters.

Overtyping the first half of a wide character with the
second half of a wide character results in display garbage.
This is because the trailing dummy is not cleaned up.

i.e.  ATTR_WIDE, ATTR_WDUMMY, ATTR_WDUMMY

Here is a short script for demonstrating the behavior:

	#!/bin/sh
	alias printf=/usr/bin/printf
	printf こんにちは！; sleep 2
	printf '\x1b[5D'; sleep 2
	printf へ; sleep 2
	printf ' '; sleep 2
	echo

commit - a0467c802d4f86ed162486e3453dd61181423902
commit + 65f1dc428315ae9d7f362e10c668557c1379e7af
blob - de2dd0ec88c489ac332b223fdef10923198c62d0
blob + 51049ba22b86cb7f13d99b1c880504c0362ba320
--- st.c
+++ st.c
@@ -2507,6 +2507,10 @@ check_control_code:
 	if (width == 2) {
 		gp->mode |= ATTR_WIDE;
 		if (term.c.x+1 < term.col) {
+			if (gp[1].mode == ATTR_WIDE && term.c.x+2 < term.col) {
+				gp[2].u = ' ';
+				gp[2].mode &= ~ATTR_WDUMMY;
+			}
 			gp[1].u = '\0';
 			gp[1].mode = ATTR_WDUMMY;
 		}