Fix: return failure when PhoneAPI times out (#3136)

* Add debug options for RP2040

* Rename: "observed" should be plural: "observables"

* PhoneAPI: return failure on timeout
In `onNotify()`, when disconnected, PhoneAPI removed itself from the list of observers that was looped through in `notifyObservers()`. We should exit that loop in that case.

src/mesh/MeshService.cpp

@@ -108,8 +108,9 @@ void MeshService::loop()
             (void)sendQueueStatusToPhone(qs, 0, 0);
     }
     if (oldFromNum != fromNum) { // We don't want to generate extra notifies for multiple new packets
-        fromNumChanged.notifyObservers(fromNum);
-        oldFromNum = fromNum;
+        int result = fromNumChanged.notifyObservers(fromNum);
+        if (result == 0) // If any observer returns non-zero, we will try again
+            oldFromNum = fromNum;
     }
 }
 

src/mesh/PhoneAPI.cpp

@@ -62,15 +62,17 @@ void PhoneAPI::close()
     }
 }
 
-void PhoneAPI::checkConnectionTimeout()
+bool PhoneAPI::checkConnectionTimeout()
 {
     if (isConnected()) {
         bool newContact = checkIsConnected();
         if (!newContact) {
             LOG_INFO("Lost phone connection\n");
             close();
+            return true;
         }
     }
+    return false;
 }
 
 /**
@@ -461,8 +463,8 @@ bool PhoneAPI::handleToRadioPacket(meshtastic_MeshPacket &p)
 /// If the mesh service tells us fromNum has changed, tell the phone
 int PhoneAPI::onNotify(uint32_t newValue)
 {
-    checkConnectionTimeout(); // a handy place to check if we've heard from the phone (since the BLE version doesn't call this
-                              // from idle)
+    bool timeout = checkConnectionTimeout(); // a handy place to check if we've heard from the phone (since the BLE version
+                                             // doesn't call this from idle)
 
     if (state == STATE_SEND_PACKETS) {
         LOG_INFO("Telling client we have new packets %u\n", newValue);
@@ -471,5 +473,5 @@ int PhoneAPI::onNotify(uint32_t newValue)
         LOG_DEBUG("(Client not yet interested in packets)\n");
     }
 
-    return 0;
+    return timeout ? -1 : 0; // If we timed out, MeshService should stop iterating through observers as we just removed one
 }

src/mesh/PhoneAPI.h

@@ -108,8 +108,8 @@ class PhoneAPI
     /// Hookable to find out when connection changes
     virtual void onConnectionChanged(bool connected) {}
 
-    /// If we haven't heard from the other side in a while then say not connected
-    void checkConnectionTimeout();
+    /// If we haven't heard from the other side in a while then say not connected. Returns true if timeout occurred
+    bool checkConnectionTimeout();
 
     /// Check the current underlying physical link to see if the client is currently connected
     virtual bool checkIsConnected() = 0;
@@ -142,4 +142,4 @@ class PhoneAPI
 
     /// If the mesh service tells us fromNum has changed, tell the phone
     virtual int onNotify(uint32_t newValue) override;
-};
+};