mux: fix stale local/remote window id mapping in mux client

When closing the all mux tabs in a window, the remote will close
the window. If the local has a mixture of local and remote tabs
then subsequent attempts to spawn a tab in that window would
fail due to reusing the stale remote window id.

This commit purges the local/remote mappings that are (probably)
dead when the remote indicates that a pane has been removed.

The mapping should be re-established as needed later on.

refs: https://github.com/wez/wezterm/issues/2614

docs/changelog.md

@@ -78,6 +78,9 @@ As features stabilize some brief notes about them will accumulate here.
   [#2559](https://github.com/wez/wezterm/issues/2559)
 * Missing validation of conflicting domain names
   [#2618](https://github.com/wez/wezterm/issues/2618)
+* Creating tabs in a multiplexing domain could fail after previously closing
+  all tabs connected to that domain in that window
+  [#2614](https://github.com/wez/wezterm/issues/2614)
 
 #### Changed
 * Removed Last Resort fallback font

wezterm-client/src/domain.rs

@@ -37,6 +37,51 @@ impl ClientInner {
         map.get(&remote_window_id).cloned()
     }
 
+    pub(crate) fn expire_stale_mappings(&self) {
+        let mux = Mux::get().unwrap();
+
+        self.remote_to_local_pane
+            .lock()
+            .unwrap()
+            .retain(|_remote_pane_id, local_pane_id| mux.get_pane(*local_pane_id).is_some());
+
+        self.remote_to_local_tab
+            .lock()
+            .unwrap()
+            .retain(
+                |_remote_tab_id, local_tab_id| match mux.get_tab(*local_tab_id) {
+                    Some(tab) => {
+                        for pos in tab.iter_panes_ignoring_zoom() {
+                            if pos.pane.domain_id() == self.local_domain_id {
+                                return true;
+                            }
+                        }
+                        false
+                    }
+                    None => false,
+                },
+            );
+
+        self.remote_to_local_window
+            .lock()
+            .unwrap()
+            .retain(
+                |_remote_window_id, local_window_id| match mux.get_window(*local_window_id) {
+                    Some(w) => {
+                        for tab in w.iter() {
+                            for pos in tab.iter_panes_ignoring_zoom() {
+                                if pos.pane.domain_id() == self.local_domain_id {
+                                    return true;
+                                }
+                            }
+                        }
+                        false
+                    }
+                    None => false,
+                },
+            );
+    }
+
     fn record_remote_to_local_window_mapping(
         &self,
         remote_window_id: WindowId,

wezterm-client/src/pane/clientpane.rs

@@ -168,6 +168,8 @@ impl ClientPane {
                 self.renderable.borrow().inner.borrow_mut().dead = true;
                 let mux = Mux::get().unwrap();
                 mux.prune_dead_windows();
+
+                self.client.expire_stale_mappings();
             }
             _ => bail!("unhandled unilateral pdu: {:?}", pdu),
         };