Merge pull request #1539 from aws-lumberyard-dev/Prefabs/GameModeNewProjectCrash

Fix issue where new projects would crash when exiting game mode

Code/Framework/AzToolsFramework/AzToolsFramework/Entity/PrefabEditorEntityOwnershipService.cpp

@@ -504,7 +504,7 @@ namespace AzToolsFramework
                     copy.CopyFrom(templateReference->get().GetPrefabDom(), copy.GetAllocator(), false);
                     context.AddPrefab(DefaultMainSpawnableName, AZStd::move(copy));
                     m_playInEditorData.m_converter.ProcessPrefab(context);
-                    if (context.HasCompletedSuccessfully())
+                    if (context.HasCompletedSuccessfully() && !context.GetProcessedObjects().empty())
                     {
                         static constexpr size_t NoRootSpawnable = AZStd::numeric_limits<size_t>::max();
                         size_t rootSpawnableIndex = NoRootSpawnable;
@@ -551,6 +551,13 @@ namespace AzToolsFramework
                             m_playInEditorData.m_entities.Reset(m_playInEditorData.m_assets[rootSpawnableIndex]);
                             m_playInEditorData.m_entities.SpawnAllEntities();
                         }
+                        else
+                        {
+                            AZ_Error("Prefab", false,
+                                "Processing of the level prefab failed to produce a root spawnable while entering game mode. "
+                                "Unable to fully enter game mode.");
+                            return;
+                        }
 
                         // This is a workaround until the replacement for GameEntityContext is done
                         AzFramework::GameEntityContextEventBus::Broadcast(
@@ -558,7 +565,9 @@ namespace AzToolsFramework
                     }
                     else
                     {
-                        AZ_Error("Prefab", false, "Failed to convert the prefab into assets.");
+                        AZ_Error("Prefab", false,
+                            "Failed to convert the prefab into assets. "
+                            "Confirm that the 'PlayInEditor' prefab processor stack is capable of producing a useable product asset.");
                         return;
                     }
                 }
@@ -596,6 +605,10 @@ namespace AzToolsFramework
             }
             m_playInEditorData.m_deactivatedEntities.clear();
 
+            AZ_Assert(m_playInEditorData.m_entities.IsSet(),
+                "Invalid Game Mode Entities Container encountered after play-in-editor stopped. "
+                "Confirm that the container was initialized correctly");
+
             m_playInEditorData.m_entities.DespawnAllEntities();
             m_playInEditorData.m_entities.Alert(
                 [assets = AZStd::move(m_playInEditorData.m_assets)]([[maybe_unused]]uint32_t generation) mutable

Gems/Multiplayer/Code/CMakeLists.txt

@@ -151,7 +151,7 @@ if (PAL_TRAIT_BUILD_HOST_TOOLS)
     )
 
     # use the Multiplayer.Editor module in tools like the Editor:  Such tools also get the visual debug view:
-    ly_create_alias(NAME Multiplayer.Tools     NAMESPACE Gem TARGETS Gem::Multiplayer.Editor Gem::Multiplayer.Debug)
+    ly_create_alias(NAME Multiplayer.Tools     NAMESPACE Gem TARGETS Gem::Multiplayer.Editor Gem::Multiplayer.Debug Gem::Multiplayer.Builders)
 endif()
 
 if (PAL_TRAIT_BUILD_TESTS_SUPPORTED)