Commit: patch 9.2.0227: MS-Windows: CSI sequences may be written to screen

[Christian Brabandt]

patch 9.2.0227: MS-Windows: CSI sequences may be written to screen

Commit: https://github.com/vim/vim/commit/aeb716ea77d4fbb43cf3e2e787d4b1dd5ea8366a
Author: Yasuhiro Matsumoto <matt...@gmail.com>
Date: Sun Mar 22 17:05:14 2026 +0000

patch 9.2.0227: MS-Windows: CSI sequences may be written to screen

Problem: MS-Windows: CSI sequences may be written to screen
(after v9.2.0200).
Solution: Move the CSI parsing and skipping logic outside of the USE_VTP
guard in mch_write() so that sequences are always consumed
even if VTP is inactive (Yasuhiro Matsumoto).

After v9.2.0200 added send_decrqm_modes(), running vim -u NONE -U NONE
-N on Windows displays raw ESC[?2026$p on screen. This is because
USE_VTP is false when termguicolors is off and t_colors < 256, and the
CSI skip logic in mch_write() was inside the if (USE_VTP) block, so
s/len were never advanced and the escape sequence leaked out as plain
text.

Move the CSI parsing/skipping outside the USE_VTP guard so sequences are
always consumed. Only the vtp_printf() pass-through for DECSCUSR (q)
remains conditional on USE_VTP.

related: #19755
closes: #19762

Signed-off-by: Yasuhiro Matsumoto <matt...@gmail.com>
Signed-off-by: Christian Brabandt <c...@256bit.org>

diff --git a/src/os_win32.c b/src/os_win32.c
index 0174068f0..e24c40cf3 100644
--- a/src/os_win32.c
+++ b/src/os_win32.c
@@ -7440,30 +7440,25 @@ notsgr:
}
else if (s[0] == ESC && len >= 3-1 && s[1] == '[')
{
- // When USE_VTP is active, CSI sequences written through
- // write_chars() are interpreted by the console's VTP parser,
- // generating responses (e.g. DECRQM) that end up in the
- // input buffer as unwanted keystrokes. Parse the sequence
- // and only pass through known safe ones (e.g. DECSCUSR for
- // cursor shape), discard the rest.
- if (USE_VTP)
+ // CSI sequences should not be written as plain text to the
+ // console. Parse the sequence and skip over it. When
+ // USE_VTP is active, pass through known safe ones (e.g.
+ // DECSCUSR for cursor shape) via vtp_printf().
+ int l = 2;
+
+ // skip parameter and intermediate bytes (0x20-0x3F)
+ while (s + l < end && s[l] >= 0x20 && s[l] <= 0x3F)
+ l++;
+ // skip the final byte (0x40-0x7E)
+ if (s + l < end && s[l] >= 0x40 && s[l] <= 0x7E)
{
- int l = 2;
-
- // skip parameter and intermediate bytes (0x20-0x3F)
- while (s + l < end && s[l] >= 0x20 && s[l] <= 0x3F)
- l++;
- // skip the final byte (0x40-0x7E)
- if (s + l < end && s[l] >= 0x40 && s[l] <= 0x7E)
- {
- // DECSCUSR (cursor style): pass through to terminal
- if (s[l] == 'q')
- vtp_printf("%.*s", l + 1, s);
- l++;
- }
- len -= l - 1;
- s += l;
+ // DECSCUSR (cursor style): pass through to terminal
+ if (USE_VTP && s[l] == 'q')
+ vtp_printf("%.*s", l + 1, s);
+ l++;
}
+ len -= l - 1;
+ s += l;
}
else
{
diff --git a/src/version.c b/src/version.c
index f5693b6a7..ca86462ff 100644
--- a/src/version.c
+++ b/src/version.c
@@ -734,6 +734,8 @@ static char *(features[]) =

static int included_patches[] =
{ /* Add new patch number below this line */
+/**/
+ 227,
/**/
226,
/**/