Explain runtime invariants and avoid redundant unwraps

shell/ferese-polkit-agent/src/main.rs

@@ -136,7 +136,10 @@ impl Agent {
         let cancelled = Arc::new(AtomicBool::new(false));
 
         {
-            let mut active = self.active.lock().unwrap();
+            let mut active = self
+                .active
+                .lock()
+                .expect("authentication session ownership must remain consistent across callbacks");
             if active.contains_key(&cookie) {
                 return Err(zbus::fdo::Error::Failed("Duplicate request".into()));
             }
@@ -166,7 +169,10 @@ impl Agent {
         })
         .await;
 
-        self.active.lock().unwrap().remove(&cookie);
+        self.active
+            .lock()
+            .expect("authentication session ownership must remain consistent across callbacks")
+            .remove(&cookie);
         match result.map_err(|error| zbus::fdo::Error::Failed(error.to_string()))? {
             Ok(true) => Ok(()),
             Ok(false) => Err(zbus::fdo::Error::Failed("Authentication cancelled".into())),
@@ -175,7 +181,12 @@ impl Agent {
     }
 
     fn cancel_authentication(&self, cookie: String) {
-        if let Some(cancelled) = self.active.lock().unwrap().get(&cookie) {
+        if let Some(cancelled) = self
+            .active
+            .lock()
+            .expect("authentication session ownership must remain consistent across callbacks")
+            .get(&cookie)
+        {
             cancelled.store(true, Ordering::Release);
         }
     }

shell/ferese-polkit-agent/src/prompt.rs

@@ -153,11 +153,17 @@ fn read_events(
     for line in lines {
         let Ok(line) = line else { break };
         if let Ok(event) = serde_json::from_str(&line) {
-            queue.lock().unwrap().push_back(event);
+            queue
+                .lock()
+                .expect("authentication prompt queue must remain consistent across workers")
+                .push_back(event);
         }
     }
     // The agent owns this pipe. EOF (including agent death) closes the prompt.
-    queue.lock().unwrap().push_back(PromptEvent::Cancel);
+    queue
+        .lock()
+        .expect("authentication prompt queue must remain consistent across workers")
+        .push_back(PromptEvent::Cancel);
 }
 
 pub fn run() -> Result<(), Box<dyn std::error::Error>> {
@@ -348,7 +354,12 @@ impl cosmic::Application for Prompt {
                 self.material = result.ok();
             }
             Message::Tick => {
-                let events: Vec<_> = self.incoming.lock().unwrap().drain(..).collect();
+                let events: Vec<_> = self
+                    .incoming
+                    .lock()
+                    .expect("authentication prompt queue must remain consistent across workers")
+                    .drain(..)
+                    .collect();
                 let mut refocus = false;
                 for event in events {
                     match event {

shell/ferese-polkit-agent/src/session.rs

@@ -469,7 +469,9 @@ fn run_session(
     } else if stopped {
         Ok(SessionOutcome::Cancelled)
     } else {
-        Ok(SessionOutcome::Completed(outcome.unwrap()))
+        Ok(SessionOutcome::Completed(outcome.expect(
+            "the session loop finished only after receiving a completion outcome",
+        )))
     }
 }