From b80bd77d847f7ef38af32398b721158f05c7716e Mon Sep 17 00:00:00 2001
From: Amr Gharbeia <amr@gharbeia.net>
Date: Thu, 14 May 2026 09:32:25 -0400
Subject: [PATCH] fix: remove CSI 18t terminal query (read-char-no-hang on fd 0
 never returns)

The %query-terminal-size function sent \033[18t and tried to read
the response via read-char-no-hang on fd 0, which always returns nil
in this SBCL environment. The response leaked into user input,
displaying garbled CSI sequences. Rely on ioctl only.
---
 src/backend/classes.lisp | 31 -------------------------------
 src/backend/modern.lisp  |  1 -
 src/backend/simple.lisp  |  1 -
 3 files changed, 33 deletions(-)

diff --git a/src/backend/classes.lisp b/src/backend/classes.lisp
index c6c976d..677a565 100644
--- a/src/backend/classes.lisp
+++ b/src/backend/classes.lisp
@@ -1,36 +1,5 @@
 (in-package :cl-tty.backend)
 
-(defun %query-terminal-size ()
-  "Query terminal size via ANSI CSI 18 t and parse the response.
-Returns (values cols rows) or nil."
-  (ignore-errors
-    (let* ((saved (sb-sys:make-fd-stream 0 :input t :buffering :none))
-           (response (make-array 0 :element-type 'character
-                                   :fill-pointer 0 :adjustable t)))
-      (format t "~C[18t" #\Esc)
-      (force-output)
-      (loop with deadline = (+ (get-internal-real-time)
-                               (* internal-time-units-per-second 0.2))
-            while (< (get-internal-real-time) deadline)
-            do (let ((ch (read-char-no-hang saved nil nil)))
-                 (when ch
-                   (vector-push-extend ch response)
-                   (when (char= ch #\t) (return)))))
-      (when (>= (length response) 8)
-        (let* ((str (subseq response 1))
-               (start (or (position #\[ str) 0))
-               (after (subseq str (1+ start)))
-               (semi (position #\; after)))
-          (when semi
-            (let* ((cols-start (1+ semi))
-                   (cols-end (position #\t after :start cols-start))
-                   (rows (parse-integer (subseq after 0 semi) :junk-allowed t))
-                   (cols (when cols-end
-                           (parse-integer (subseq after cols-start cols-end)
-                                          :junk-allowed t))))
-              (when (and rows cols (> rows 0) (> cols 0))
-                (values cols rows)))))))))
-
 (defclass backend () ())
 
 (defgeneric initialize-backend (backend)
diff --git a/src/backend/modern.lisp b/src/backend/modern.lisp
index 792834b..4f975a8 100644
--- a/src/backend/modern.lisp
+++ b/src/backend/modern.lisp
@@ -175,7 +175,6 @@ as a fallback when a keyword is not in *named-colors*.")
                  (values (sb-alien:deref winsize 1)  ;; cols
                          (sb-alien:deref winsize 0))) ;; rows
             (sb-alien:free-alien winsize))))
-      (%query-terminal-size)
       (values 80 24)))
 
 (defmethod backend-write ((b modern-backend) string)
diff --git a/src/backend/simple.lisp b/src/backend/simple.lisp
index e00c091..0ca931f 100644
--- a/src/backend/simple.lisp
+++ b/src/backend/simple.lisp
@@ -39,7 +39,6 @@
                  (values (sb-alien:deref winsize 1)
                          (sb-alien:deref winsize 0)))
              (sb-alien:free-alien winsize))))
-      (%query-terminal-size)
       (values 80 24)))
 
 (defmethod backend-write ((b simple-backend) string)