wezterm connect unix could exit on startup

This is a similar race condition to one we had before with the
multiplexer, where the connection UI made us think that we didn't
need to start a new process.

Additionally, the attach method would unconditionally create a
new client without checking whether we already had one.

wezterm-client/src/domain.rs

@@ -474,6 +474,11 @@ impl Domain for ClientDomain {
     }
 
     async fn attach(&self) -> anyhow::Result<()> {
+        if self.state() == DomainState::Attached {
+            // Already attached
+            return Ok(());
+        }
+
         let domain_id = self.local_domain_id;
         let config = self.config.clone();
 

wezterm-gui/src/main.rs

@@ -267,9 +267,6 @@ async fn spawn_tab_in_default_domain_if_mux_is_empty(
 ) -> anyhow::Result<()> {
     let mux = Mux::get().unwrap();
 
-    if !mux.is_empty() {
-        return Ok(());
-    }
     let domain = mux.default_domain();
     domain.attach().await?;