From f56ff4849f47be3645c47097f795e7781f059f80 Mon Sep 17 00:00:00 2001
From: Amr Gharbeia <amr@gharbeia.net>
Date: Fri, 15 May 2026 08:33:24 -0400
Subject: [PATCH] fix!: eliminate cat subprocess, use direct stdin reads, fix
 parens
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Cat subprocess (uiop:launch-program '("cat") :input :interactive) was
unreliable — the process would exit immediately in some environments,
breaking ALL keyboard input. Root cause: uiop's :input :interactive mode
opened /dev/tty which failed under specific process-group configurations.

Replace with direct read-char-no-hang on *standard-input*. The bash script
sets stty -icanon -echo -ixon before launching sbcl, so SBCL's stdin is
already in raw mode. No subprocess needed.

Also fixed pre-existing paren imbalance in tui-main (2 extra opens).
---
 org/channel-tui-main.org | 39 +++++++++++----------------------------
 1 file changed, 11 insertions(+), 28 deletions(-)

diff --git a/org/channel-tui-main.org b/org/channel-tui-main.org
index 3502b4f..7d98454 100644
--- a/org/channel-tui-main.org
+++ b/org/channel-tui-main.org
@@ -876,8 +876,8 @@ supplied (e.g. \"/\"), pre-fill the select filter with it."
     (:down (lambda (e) (declare (ignore e)) (on-key :down)))
     (:escape (lambda (e) (declare (ignore e)) (on-key :escape)))))
 
-(defvar *cat-proc* nil "Cat subprocess for keyboard input")
-(defvar *tty-in* nil "Stream from cat subprocess stdout")
+(defvar *cat-proc* nil "Cat subprocess for keyboard input (unused — direct stdin reads)")
+(defvar *tty-in* nil "Stream from cat subprocess stdout (unused — direct stdin reads)")
 
 (defun tui-main ()
   (init-state)
@@ -899,27 +899,12 @@ supplied (e.g. \"/\"), pre-fill the select filter with it."
         (error ()
           (add-msg :system "* Swank unavailable *"))))
     (cl-tty.backend:with-terminal (be w h)
-        ;; Disable echo only — keep canonical mode (line input). stty raw
-        ;; breaks read on fd 0 in this SBCL environment, but -echo alone
-        ;; works. A cat subprocess inherits the terminal and provides
-        ;; bytes through a pipe that SBCL reads reliably.
-         ;; stty -icanon -echo is set by the bash script before exec sbcl.
-         ;; A cat subprocess reads keyboard input from the terminal.
-          ;; Global vars for cat subprocess — avoid lexical let* scope issue
-          (progn
-            (setq *cat-proc* (uiop:launch-program '("stdbuf" "-o0" "cat")
-                                              :output :stream
-                                              :input :interactive
-                                              :stderr nil)
-                  *tty-in* (uiop:process-info-output *cat-proc*)))
-          (add-msg :system (format nil "* cat pid=~a *" (uiop:process-info-pid *cat-proc*)))
-          ;; Guard against nil w/h from backend-size
-          (setq w (or (and (numberp w) (> w 0) w) 80)
-                h (or (and (numberp h) (> h 0) h) 24))
-          ;; Log backend info and terminal dimensions
-          (let ((backend-type (if (typep be 'cl-tty.backend:modern-backend)
-                                  "modern" "simple")))
-            (add-msg :system (format nil "* ~a backend ~dx~d *" backend-type w h)))
+          ;; stty -icanon -echo -ixon is set by the bash script.
+          ;; We read directly from SBCL's stdin (fd 0) since the
+          ;; terminal is in raw mode — no cat subprocess needed.
+          (add-msg :system (format nil "* ~a backend ~dx~d *"
+                                   (if (typep be 'cl-tty.backend:modern-backend) "modern" "simple")
+                                   w h))
           ;; Initial dirty all to trigger first redraw in loop
           (setq w (or (and (numberp w) (> w 0) w) 80)
                 h (or (and (numberp h) (> h 0) h) 24))
@@ -978,7 +963,7 @@ supplied (e.g. \"/\"), pre-fill the select filter with it."
                ;; Keyboard reader: block on cat pipe with 0.1s timeout.
                (handler-case
                    (sb-ext:with-timeout 0.1
-                     (let ((raw-ch (read-char *tty-in* nil nil)))
+                      (let ((raw-ch (read-char-no-hang *standard-input* nil nil)))
                        (when raw-ch
                          (let ((code (char-code raw-ch)))
                            (queue-event
@@ -1068,10 +1053,8 @@ supplied (e.g. \"/\"), pre-fill the select filter with it."
                                                (format nil "> ~a" filter)
                                                (theme-color :input-prompt) nil))
                    (cl-tty.backend:end-sync be))
-                (sleep 0.1))
-             (uiop:terminate-process *cat-proc*))
-            (add-msg :system (format nil "* cat ~a ended *" (uiop:process-info-pid *cat-proc*))))
-           (progn (disconnect-daemon))))
+                 (sleep 0.1))
+               (progn (disconnect-daemon))))))
 #+END_SRC
 
 * Test Suite