Query iterator only throws exeption once (#252)

## What is the goal of this PR?

Revert previous changes from #247 and #248, which made query queues and iterators throw the same error idempotently. However, this goes counter to standard usage of iterators and queues, which are not meant to behave idempotently (each item is only returned once, and if they have an error they should no longer be used). 


## What are the changes implemented in this PR?

* remove idempotent error state of collectors and queues, which back query iterators
  * note that we still store the error on the transaction bidirectional stream, in case the server throws an exception when there are no query iterators active
  

Note: mirrors change from typedb/typedb-driver#372

Author: flyingsilverfin

typedb/stream/bidirectional_stream.py

@@ -19,7 +19,7 @@
 # under the License.
 #
 from queue import Empty, Queue
-from typing import TypeVar, Iterator, Union, Generic, List
+from typing import TypeVar, Iterator, Union
 from uuid import uuid4, UUID
 
 import typedb_protocol.common.transaction_pb2 as transaction_proto
@@ -133,8 +133,7 @@ def __init__(self, request_id: UUID, stream: "BidirectionalStream"):
             self._stream = stream
 
         def get(self) -> T:
-            value = self._stream.fetch(self._request_id)
-            return value
+            return self._stream.fetch(self._request_id)
 
 
 class RequestIterator(Iterator[Union[transaction_proto.Transaction.Req, StopIteration]]):

typedb/stream/response_collector.py

@@ -24,8 +24,8 @@
 from typing import Generic, TypeVar, Dict, Optional
 from uuid import UUID
 
-from typedb.common.exception import TypeDBClientException, TRANSACTION_CLOSED, ILLEGAL_STATE, \
-    TRANSACTION_CLOSED_WITH_ERRORS
+from grpc import RpcError
+from typedb.common.exception import TypeDBClientException, TRANSACTION_CLOSED, ILLEGAL_STATE
 
 R = TypeVar('R')
 
@@ -54,26 +54,23 @@ class Queue(Generic[R]):
 
         def __init__(self):
             self._response_queue: queue.Queue[Response] = queue.Queue()
-            self._error: TypeDBClientException = None
 
         def get(self, block: bool) -> R:
             response = self._response_queue.get(block=block)
             if response.is_value():
                 return response.value
-            elif response.is_done():
-                self._raise_transaction_closed_error()
+            elif response.is_done() and response.error is None:
+                raise TypeDBClientException.of(TRANSACTION_CLOSED)
+            elif response.is_done() and response.error is not None:
+                raise TypeDBClientException.of_rpc(response.error)
             else:
                 raise TypeDBClientException.of(ILLEGAL_STATE)
 
-        def _raise_transaction_closed_error(self):
-            raise TypeDBClientException.of(TRANSACTION_CLOSED_WITH_ERRORS, self._error) if self._error else TypeDBClientException.of(TRANSACTION_CLOSED)
-
         def put(self, response: R):
             self._response_queue.put(ValueResponse(response))
 
         def close(self, error: Optional[TypeDBClientException]):
-            self._error = error
-            self._response_queue.put(DoneResponse())
+            self._response_queue.put(DoneResponse(error))
 
 
 class Response:
@@ -96,8 +93,8 @@ def is_value(self):
 
 class DoneResponse(Response):
 
-    def __init__(self):
-        pass
+    def __init__(self, error: Optional[RpcError]):
+        self.error = error
 
     def is_done(self):
         return True

typedb/stream/response_part_iterator.py

@@ -74,9 +74,7 @@ def _has_next(self) -> bool:
             raise TypeDBClientException.of(ILLEGAL_STATE)
 
     def __next__(self) -> transaction_proto.Transaction.ResPart:
-        if self._bidirectional_stream.get_error() is not None:
-            raise self._bidirectional_stream.get_error()
-        elif not self._has_next():
+        if not self._has_next():
             raise StopIteration
         else:
             self._state = ResponsePartIterator.State.EMPTY