[hackers] [st] Fix for wide character being incorrectly cleared on MODE_INSERT || Shi Tian

[git]

commit 3a6d6d740110e6ee1b092d05ad746244eedabe4b
Author:     Shi Tian <shit...@cock.li>
AuthorDate: Sun Jun 25 05:38:33 2023 +0000
Commit:     Hiltjo Posthuma <hil...@codemadness.org>
CommitDate: Sun Jun 25 11:59:06 2023 +0200

    Fix for wide character being incorrectly cleared on MODE_INSERT
    
    Under insert mode, when inserting a normal character in front of
    a wide character, the affected region is shifted to the right by
    one cell. However, the empty cell is reset as if being a part of a
    wide character, causing the following cell being mishandled as a
    dummy cell.
    To reproduce the bug:
            printf '\033[4h' # set MODE_INSERT
            printf 妳好
            printf '\033[4D'
            printf 'x'
            printf '\033[4l\n'

diff --git a/st.c b/st.c
index 134e724..623376e 100644
--- a/st.c
+++ b/st.c
@@ -2471,8 +2471,10 @@ check_control_code:
                gp = &term.line[term.c.y][term.c.x];
        }
 
-       if (IS_SET(MODE_INSERT) && term.c.x+width < term.col)
+       if (IS_SET(MODE_INSERT) && term.c.x+width < term.col) {
                memmove(gp+width, gp, (term.col - term.c.x - width) * 
sizeof(Glyph));
+               gp->mode &= ~ATTR_WIDE;
+       }
 
        if (term.c.x+width > term.col) {
                tnewline(1);