From acd9e032a147f4aa7ad49110dc2f4fb945e7a9bb Mon Sep 17 00:00:00 2001
From: Gabriel Schneider <gbrls@0x4200.cafe>
Date: Sun, 27 Sep 2026 20:14:04 -0300
Subject: Keep a pane's filesystem state on the Pane instead of a slot-indexed
 table

addr, limit, the event queue and its readers, pty/data's queue, a waiting
run and the /log announcement flag lived in p.fs.panes[slot], reset when
the pane went; a reused slot is how the bug class came in. acme keeps the
same state on its Window (editors/acme/dat.h:226-266), so now Pane.fs
holds it: announced, retired (noteRetire, which still answers a waiting
run and drops the listener count first) and freed with the pane itself.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---
 src/pardes.zig | 23 +++++++++++++----------
 1 file changed, 13 insertions(+), 10 deletions(-)

(limited to 'src/pardes.zig')

diff --git a/src/pardes.zig b/src/pardes.zig
index a38eb837..7ae9cf32 100644
--- a/src/pardes.zig
+++ b/src/pardes.zig
@@ -6826,8 +6826,7 @@ pub const Pardes = struct {
         const watched = (if (pane.file) |f| f.output == null else false) or pane.hasPdf();
         for (p.panes, 0..) |slot, id| if (slot == pane) {
             if (watched) p.emit(.{ .watch = .{ .pane = @intCast(id), .on = false } });
-            ctlfs.events.noteRetire(p, id, pane);
-            p.fs.forget(p.gpa, id);
+            ctlfs.events.noteRetire(p, pane);
             // ...and so do bytes still queued for the pty it no longer has.
             p.dropPendingWrite(id);
         };
@@ -6854,6 +6853,7 @@ pub const Pardes = struct {
         for (pane.ed_redo[0..pane.ed_redo_len]) |sn| if (sn.ovl) |o| p.gpa.free(o.text);
         panes.Terminal.deinitEmulator(pane, p.gpa);
         pane.clearCwd();
+        pane.fs.deinit(p.gpa);
         p.gpa.destroy(pane);
     }
 
@@ -6872,7 +6872,9 @@ pub const Pardes = struct {
         pane.serial = p.next_serial;
         p.rects[id] = .{};
         p.panes[id] = pane;
-        ctlfs.events.noteInstall(p, id);
+        // /log hears of it once the update that made it ends, when it has
+        // its file, name and place (`ctlfs.events.announce`).
+        pane.fs.unannounced = true;
     }
 
     pub fn newShell(p: *Pardes, id: usize, cwd: []const u8) !*Pane {
@@ -7029,10 +7031,10 @@ pub const Pardes = struct {
     }
 
     pub fn acknowledgeShell(p: *Pardes, id: usize, executable: []const u8, prompt_marks: bool) void {
-        if (id < MAX_PANES) {
-            ctlfs.pty.shellGone(p, id); // a respawn replaced whatever ran
-            p.fs.panes[id].unmarked = !prompt_marks;
-        }
+        if (id < MAX_PANES) if (p.panes[id]) |pane| {
+            ctlfs.pty.shellGone(p, pane); // a respawn replaced whatever ran
+            pane.fs.unmarked = !prompt_marks;
+        };
         if (id < MAX_PANES) panes.Terminal.shellSpawned(p, id, prompt_marks);
         if (p.settings.shell.effective.set(executable))
             p.settings.shell.pending = false;
@@ -7913,9 +7915,9 @@ pub const Pardes = struct {
         if (p.fs.listeners == 0) return;
         for (p.panes, 0..) |slot, id| {
             const pane = slot orelse continue;
-            if (!p.fs.scripted(id)) continue;
+            if (pane.fs.readers == 0) continue;
             const tag = p.tagText(p.scratch.allocator(), pane) catch continue;
-            const snap = &p.fs.panes[id].tag_snap;
+            const snap = &pane.fs.tag_snap;
             if (std.mem.eql(u8, snap.items, tag)) continue;
             if (snap.capacity != 0 or snap.items.len != 0)
                 ctlfs.events.noteReplace(p, id, true, snap.items, tag);
@@ -12462,7 +12464,8 @@ pub const Pardes = struct {
         operand: PointerOperand,
         chorded: bool,
     ) bool {
-        if (!p.fs.scripted(id)) return false;
+        const scripted = p.panes[id] orelse return false;
+        if (scripted.fs.readers == 0) return false;
         const is_look = cmd == config.look_cmd;
         const action: ctlfs.events.Action = if (is_look)
             (if (on_tag) .tag_look else .body_look)
-- 
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