[newlib-cygwin/cygwin-3_6-branch] Cygwin: console: Fix master thread

[Takashi Yano]

https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=f3914f1e23274effd9d2080fe855ea4fc81da2eb

commit f3914f1e23274effd9d2080fe855ea4fc81da2eb
Author: Takashi Yano <takashi.yano@nifty.ne.jp>
Date:   Fri Mar 20 22:59:58 2026 +0900

    Cygwin: console: Fix master thread
    
    In Windows 11, key event with wRepeatCount == 0 is fixed-up to
    wRepeatCount == 1 in conhost.exe.
    https://github.com/microsoft/terminal/blob/v1.25.622.0/src/host/inputBuffer.cpp#L406
    
    The console master thread (`cons_master_thread`) reads INPUT_RECORDs
    from the console input buffer, processes signal-generating events,
    and writes the remaining records back. After the writeback, it peeks
    the buffer and uses `inrec_eq()` to verify that conhost stored the
    records faithfully. On Windows 11, conhost normalizes `wRepeatCount`
    from 0 to 1 on readback, causing `inrec_eq()` to report a mismatch
    and triggering an unnecessary fixup path. Treat 0 and 1 as equivalent
    for comparison purposes.
    
    Addresses: https://github.com/git-for-windows/git/issues/5632
    Fixes: ff4440fcf768 ("Cygwin: console: Introduce new thread which handles input signal.")
    Signed-off-by: Takashi Yano <takashi.yano@nifty.ne.jp>
    Reviewed-by: Johannes Schindelin <Johannes.Schindelin@gmx.de>
    (cherry picked from commit 95b477fb2df76beca1469decf71242c24b223ac5)

Diff:
---
 winsup/cygwin/fhandler/console.cc | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/winsup/cygwin/fhandler/console.cc b/winsup/cygwin/fhandler/console.cc
index 9e116118a..80d6e34fc 100644
--- a/winsup/cygwin/fhandler/console.cc
+++ b/winsup/cygwin/fhandler/console.cc
@@ -318,9 +318,17 @@ inrec_eq (const INPUT_RECORD *a, const INPUT_RECORD *b, DWORD n)
 	     written event. Therefore they are ignored. */
 	  const KEY_EVENT_RECORD *ak = &a[i].Event.KeyEvent;
 	  const KEY_EVENT_RECORD *bk = &b[i].Event.KeyEvent;
+	  /* On Windows 11, conhost normalizes wRepeatCount from 0 to 1
+	     on readback. Treat them as equivalent for comparison. */
+	  WORD r1 = ak->wRepeatCount;
+	  WORD r2 = bk->wRepeatCount;
+	  if (r1 == 0)
+	    r1 = 1;
+	  if (r2 == 0)
+	    r2 = 1;
 	  if (ak->bKeyDown != bk->bKeyDown
 	      || ak->uChar.UnicodeChar != bk->uChar.UnicodeChar
-	      || ak->wRepeatCount != bk->wRepeatCount)
+	      || r1 != r2)
 	    return false;
 	}
       else if (a[i].EventType == MOUSE_EVENT)