From bca5d6a52500e72ec4de69c38f6fb2324df4b503 Mon Sep 17 00:00:00 2001
From: Gabriel Schneider <gbrls@0x4200.cafe>
Date: Mon, 6 Jul 2026 12:45:47 -0300
Subject: tty shell: leave the terminal clean on every exit path. Root causes:
 vaxis.Tty.init makes the tty raw but run() never called tty.deinit (termios
 stayed raw -> no echo, staircased output in the spawner shell); the pty
 reader tasks were never joined (Kill-quit hung the exit in the runtime
 thread-join with readers blocked in read(2), and finished readers dumped
 DebugAllocator leak traces onto the tty). Fix: defer tty.deinit() (runs last,
 after vx.deinit flushes its resets); cancel each pty reader at teardown
 (cancel interrupts the blocked read) then close masters and drain the loop
 queue (queued pty_read/paste bytes are gpa-owned); await the reader on
 pty_eof before closing; readPty posts its eof via tryPostEvent so a
 post-cancel full queue can't re-block; root panic handler wraps
 vaxis.recover() so a panic restores cooked mode/main screen/mouse before the
 trace prints (vaxis.Panic itself is stale: references
 std.debug.FormattedPanic which 0.16 dropped). Verified with a scripted pty
 harness (bash spawner, DSR replies): both quit paths (exit-EOF of last pane,
 middle-click Kill) end with rmcup+cursor+sgr+mouse-off and identical stty -a
 before/after, no leak spew, prompt back in 0.5s; snap suite 18/18.

---
 src/tty.zig | 28 ++++++++++++++++++++++------
 1 file changed, 22 insertions(+), 6 deletions(-)

(limited to 'src/tty.zig')

diff --git a/src/tty.zig b/src/tty.zig
index d9821343..f2b36ed4 100644
--- a/src/tty.zig
+++ b/src/tty.zig
@@ -40,6 +40,7 @@ pub fn run(init: std.process.Init, opts: pardes.Options) !void {
 
     var tty_buf: [0x10000]u8 = undefined;
     var tty = try vaxis.Tty.init(io, &tty_buf);
+    defer tty.deinit(); // restore cooked termios LAST, after vx flushed its resets
     var vx = try vaxis.init(io, gpa, init.environ_map, .{ .system_clipboard_allocator = gpa });
     defer vx.deinit(gpa, tty.writer());
     try vx.enterAltScreen(tty.writer());
@@ -65,14 +66,26 @@ pub fn run(init: std.process.Init, opts: pardes.Options) !void {
 
     var kitty_handles: [pardes.MAX_PANES]?vaxis.Image = @splat(null);
     var ptys: [pardes.MAX_PANES]?Pty = @splat(null);
-    defer for (&ptys) |*slot| if (slot.*) |*pt| {
-        _ = linux.close(pt.file.handle);
-        slot.* = null;
-    };
+    var loop: Loop = .init(io, &tty, &vx);
+    defer {
+        // reap the reader tasks (cancel interrupts a blocked read) before
+        // closing the masters — the runtime joins those threads on exit and a
+        // reader stuck in read(2) would hang the process — then drain the
+        // queue: leftover events own gpa bytes and would dump as leaks.
+        for (&ptys) |*slot| if (slot.*) |*pt| {
+            pt.reader.cancel(io) catch {};
+            _ = linux.close(pt.file.handle);
+            slot.* = null;
+        };
+        while (loop.tryEvent() catch null) |ev| switch (ev) {
+            .pty_read => |pr| gpa.free(pr.bytes),
+            .paste => |b| gpa.free(@constCast(b)),
+            else => {},
+        };
+    }
 
     // Perform the initial spawns BEFORE any worker thread exists: forkpty from
     // a multithreaded process can wedge the child before exec.
-    var loop: Loop = .init(io, &tty, &vx);
     drainEffects(core, &ptys, io, gpa, &loop, &vx, &tty, false);
 
     try loop.start();
@@ -104,6 +117,7 @@ pub fn run(init: std.process.Init, opts: pardes.Options) !void {
             },
             .pty_eof => |id| {
                 if (ptys[id]) |*pt| {
+                    pt.reader.await(io) catch {}; // reader just finished; join it or its future leaks
                     _ = linux.close(pt.file.handle);
                     ptys[id] = null;
                 }
@@ -301,7 +315,9 @@ fn readPty(io: std.Io, gpa: std.mem.Allocator, pty: std.Io.File, id: usize, loop
             break;
         };
     }
-    loop.postEvent(.{ .pty_eof = id }) catch {};
+    // non-blocking: a teardown cancel only unblocks one wait, so a blocking
+    // post into a full queue here could hang the exit
+    _ = loop.tryPostEvent(.{ .pty_eof = id }) catch {};
 }
 
 /// The effective codepoint the way vaxis Key.matches sees it: a single-char
-- 
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