Report bridge error to server, kill bridge right away if it fails

Signed-off-by: falkTX <falktx@falktx.com>

source/backend/engine/CarlaEngineBridge.cpp

@@ -264,7 +264,22 @@ public:
     void idle() noexcept override
     {
         CarlaPlugin* const plugin(pData->plugins[0].plugin);
-        CARLA_SAFE_ASSERT_RETURN(plugin != nullptr,);
+
+        if (plugin == nullptr)
+        {
+            if (const uint32_t length = static_cast<uint32_t>(pData->lastError.length()))
+            {
+                const CarlaMutexLocker _cml(fShmNonRtServerControl.mutex);
+                fShmNonRtServerControl.writeOpcode(kPluginBridgeNonRtServerError);
+                fShmNonRtServerControl.writeUInt(length);
+                fShmNonRtServerControl.writeCustomData(pData->lastError.buffer(), length);
+                fShmNonRtServerControl.commitWrite();
+            }
+
+            signalThreadShouldExit();
+            callback(true, true, ENGINE_CALLBACK_QUIT, 0, 0, 0, 0, 0.0f, nullptr);
+            return;
+        }
 
         const bool wasFirstIdle(fFirstIdle);
 

source/bridges-plugin/CarlaBridgePlugin.cpp

@@ -637,8 +637,16 @@ int main(int argc, char* argv[])
             const char* const lastError(carla_get_last_error());
             carla_stderr("Plugin failed to load, error was:\n%s", lastError);
 
-            //if (useBridge)
-            //    bridge.sendOscBridgeError(lastError);
+            if (useBridge)
+            {
+                // do a single idle so that we can send error message to server
+                gIdle();
+
+#ifdef CARLA_OS_UNIX
+                // kill ourselves now if we can't load plugin in bridge mode
+                ::kill(::getpid(), SIGKILL);
+#endif
+            }
         }
     }