Handle None being passed to register_resource_outputs

changelog/pending/20221102--sdk-python--handle-none-being-passed-to-register_resource_outputs.yaml

@@ -0,0 +1,4 @@
+changes:
+- type: fix
+  scope: sdk/python
+  description: Handle None being passed to register_resource_outputs.

sdk/python/lib/pulumi/runtime/resource.py

@@ -682,6 +682,9 @@ def register_resource_outputs(
 ):
     async def do_register_resource_outputs():
         urn = await res.urn.future()
+        # serialize_properties expects a collection (empty is fine) but not None, but this is called pretty
+        # much directly by users who could pass None in (although the type hints say they shouldn't).
+        outputs = {} if outputs is None else outputs
         serialized_props = await rpc.serialize_properties(outputs, {})
         log.debug(
             f"register resource outputs prepared: urn={urn}, props={serialized_props}"