[hackers] [st] Fix overtyping wide characters. || jamin

[git]

commit 65f1dc428315ae9d7f362e10c668557c1379e7af
Author:     jamin <acdima...@gmail.com>
AuthorDate: Wed Dec 29 09:07:17 2021 -0800
Commit:     Hiltjo Posthuma <hil...@codemadness.org>
CommitDate: Thu Dec 30 18:37:17 2021 +0100

    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

diff --git a/st.c b/st.c
index de2dd0e..51049ba 100644
--- a/st.c
+++ b/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;
                }