Merge pull request #568 from openmultiplayer/supported-version

Check supported major version when loading components.

Author: AmyrAhmady

SDK/include/component.hpp

@@ -6,6 +6,8 @@
 #define BUILD_NUMBER 0
 #endif
 
+#define OMP_VERSION_SUPPORTED 1
+
 /// Should always be used in classes inheriting IExtension
 #define PROVIDE_EXT_UID(uuid)                 \
 	static constexpr UID ExtensionIID = uuid; \
@@ -190,6 +192,17 @@ struct IEarlyConfig;
 /// A component interface
 struct IComponent : public IExtensible, public IUIDProvider
 {
+	/// The idea is for the SDK to be totally forward compatible, so code built at any time will
+	/// always work, thanks to ABI compatibility.  This method is an emergency trap door, just in
+	/// case that's ever not the problem.  Check which major version this component was built for,
+	/// if it isn't the current major version, fail to load it.  Always just returns a constant,
+	/// recompiling will often be enough to upgrade.  `virtual` and `final` to be the vtable, but it
+	/// can't be overridden because it is a constant.
+	virtual int supportedVersion() const final
+	{
+		return OMP_VERSION_SUPPORTED;
+	}
+
 	/// Get the component's name
 	virtual StringView componentName() const = 0;
 

Server/Source/core_impl.hpp

@@ -973,25 +973,29 @@ class Core final : public ICore, public PlayerConnectEventHandler, public Consol
 			return nullptr;
 		}
 		IComponent* component = OnComponentLoad();
-		if (component != nullptr)
+		if (component == nullptr)
 		{
-			SemanticVersion ver = component->componentVersion();
-			printLn(
-				"\tSuccessfully loaded component %.*s (%u.%u.%u.%u) with UID %016llx",
-				PRINT_VIEW(component->componentName()),
-				ver.major,
-				ver.minor,
-				ver.patch,
-				ver.prerel,
-				component->getUID());
-			return component;
+			printLn("\tFailed to load component.");
+			LIBRARY_FREE(componentLib);
+			return nullptr;
 		}
-		else
+		int supports = component->supportedVersion();
+		if (supports != OMP_VERSION_MAJOR)
 		{
-			printLn("\tFailed to load component.");
+			printLn("\tFailed to load component: Built for open.mp version %d, now on %d.", supports, OMP_VERSION_MAJOR);
 			LIBRARY_FREE(componentLib);
 			return nullptr;
 		}
+		SemanticVersion ver = component->componentVersion();
+		printLn(
+			"\tSuccessfully loaded component %.*s (%u.%u.%u.%u) with UID %016llx",
+			PRINT_VIEW(component->componentName()),
+			ver.major,
+			ver.minor,
+			ver.patch,
+			ver.prerel,
+			component->getUID());
+		return component;
 	}
 
 	void loadComponents(const ghc::filesystem::path& path)