Lazy warnings about unsupported handlers

Signed-off-by: IlyaOvodov <b@ovdv.ru>

Author: IlyaOvodov

onnx_tf/backend.py

@@ -250,6 +250,8 @@ def _onnx_node_to_tensorflow_op(cls,
     if handlers:
       handler = handlers[node.domain].get(node.op_type, None) if node.domain in handlers else None
       if handler:
+        if hasattr(handler, "WARNINGS"):
+          common.logger.warning(handler.WARNINGS)
         return handler.handle(node, tensor_dict=tensor_dict, strict=strict)
 
     raise BackendIsNotSupposedToImplementIt("{} is not implemented.".format(node.op_type))

onnx_tf/common/handler_helper.py

@@ -29,11 +29,13 @@ def get_all_backend_handlers(opset_dict):
             domain=handler.DOMAIN,
             max_inclusive_version=version).since_version
       except RuntimeError:
-        common.logger.debug("Fail to get since_version of {} in domain `{}` "
+        handler.WARNINGS = (((handler.WARNINGS + "\n") if hasattr(handler, "WARNINGS") else "") +
+                      "Fail to get since_version of {} in domain `{}` "
                       "with max_inclusive_version={}. Set to 1.".format(
                           handler.ONNX_OP, handler.DOMAIN, version))
     else:
-      common.logger.debug("Unknown op {} in domain `{}`.".format(
+      handler.WARNINGS = (((handler.WARNINGS + "\n") if hasattr(handler, "WARNINGS") else "") +
+          "Unknown op {} in domain `{}`.".format(
           handler.ONNX_OP, handler.DOMAIN or "ai.onnx"))
     handler.SINCE_VERSION = since_version
     handlers.setdefault(domain, {})[handler.ONNX_OP] = handler