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 <[email protected]>

1 files changed, 1 insertions, 13 deletions

diff --git a/src/fs.zig b/src/fs.zig
index 50a446dc..c2e88b10 100644
--- a/src/fs.zig
+++ b/src/fs.zig
@@ -586,7 +586,7 @@ test "virtual body writes can read their input from the same pane" {
     try write(p, path, pane.file.?.content);
     try std.testing.expectEqualStrings("same pane contents\n", pane.file.?.content);
     try std.testing.expectEqual(@as(usize, 2), pane.file.?.history.undo_len);
-    const events = &p.fs.panes[p.active].events;
+    const events = &p.panes[p.active].?.fs.events;
     try std.testing.expect(std.mem.startsWith(u8, events.peek().?, "ED"));
     events.pop();
     try std.testing.expect(std.mem.startsWith(u8, events.peek().?, "EI"));
@@ -1240,7 +1240,6 @@ pub const Namespace = struct {
     snapshots: [tree.screen.snapshot_slots]tree.screen.Snapshot = @splat(.{}),
     runs: [tree.pty.run_slots]tree.pty.Run = @splat(.{}),
     out: std.ArrayList(u8) = .empty,
-    panes: [MAX_PANES]tree.pane.State = @splat(.{}),
     listeners: u16 = 0,
     origin: u8 = 'K',
     /// Reads that found nothing yet, one per open that can wait: the log's
@@ -1269,7 +1268,6 @@ pub const Namespace = struct {
         st.os_paths.deinit(gpa);
         for (st.snapshots) |snapshot| if (snapshot.bytes) |bytes| gpa.free(bytes);
         for (&st.runs) |*slot| slot.reset(gpa, 0);
-        for (&st.panes) |*pf| pf.deinit(gpa);
         st.log.deinit(gpa);
         st.out.deinit(gpa);
     }
@@ -1292,16 +1290,6 @@ pub const Namespace = struct {
         st.out.ensureTotalCapacity(gpa, tree.out_reserve) catch {};
         return &st.out;
     }
-
-    pub fn forget(st: *Namespace, gpa: std.mem.Allocator, id: usize) void {
-        if (id >= MAX_PANES) return;
-        st.listeners -= @min(st.listeners, st.panes[id].readers);
-        st.panes[id].deinit(gpa);
-    }
-
-    pub fn scripted(st: *const Namespace, id: usize) bool {
-        return id < MAX_PANES and st.panes[id].readers != 0;
-    }
 };
 
 pub fn unmount(p: *Pardes, name: []const u8) !void {