Don't attempt to reset closed connections.

neo4j/io/__init__.py

@@ -726,9 +726,9 @@ def release(self, *connections):
         """
         with self.lock:
             for connection in connections:
-                if not (connection.is_reset
-                        or connection.defunct()
-                        or connection.closed()):
+                if not (connection.defunct()
+                        or connection.closed()
+                        or connection.is_reset):
                     try:
                         connection.reset()
                     except (Neo4jError, DriverError, BoltError) as e:

neo4j/io/_bolt3.py

@@ -124,11 +124,12 @@ def _on_server_state_change(self, old_state, new_state):
 
     @property
     def is_reset(self):
-        if self.responses:
-            # We can't be sure of the server's state as there are still pending
-            # responses. Unless the last message we sent was RESET. In that case
-            # the server state will always be READY when we're done.
-            return self.responses[-1].message == "reset"
+        # We can't be sure of the server's state if there are still pending
+        # responses. Unless the last message we sent was RESET. In that case
+        # the server state will always be READY when we're done.
+        if (self.responses and self.responses[-1]
+                and self.responses[-1].message == "reset"):
+            return True
         return self._server_state_manager.state == ServerStates.READY
 
     @property

neo4j/io/_bolt4.py

@@ -82,11 +82,12 @@ def _on_server_state_change(self, old_state, new_state):
 
     @property
     def is_reset(self):
-        if self.responses:
-            # We can't be sure of the server's state as there are still pending
-            # responses. Unless the last message we sent was RESET. In that case
-            # the server state will always be READY when we're done.
-            return self.responses[-1].message == "reset"
+        # We can't be sure of the server's state if there are still pending
+        # responses. Unless the last message we sent was RESET. In that case
+        # the server state will always be READY when we're done.
+        if (self.responses and self.responses[-1]
+                and self.responses[-1].message == "reset"):
+            return True
         return self._server_state_manager.state == ServerStates.READY
 
     @property

neo4j/work/simple.py

@@ -91,7 +91,7 @@ def __init__(self, pool, session_config):
     def __del__(self):
         try:
             self.close()
-        except OSError:
+        except (OSError, ServiceUnavailable, SessionExpired):
             pass
 
     def __enter__(self):

neo4j/work/transaction.py

@@ -172,7 +172,9 @@ def rollback(self):
 
         metadata = {}
         try:
-            if not self._connection.is_reset:
+            if not (self._connection.defunct()
+                    or self._connection.closed()
+                    or self._connection.is_reset):
                 # DISCARD pending records then do a rollback.
                 self._consume_results()
                 self._connection.rollback(on_success=metadata.update)

tests/unit/io/test_neo4j_pool.py

@@ -161,3 +161,37 @@ def break_connection():
     assert cx2.addr == cx1.addr
     assert cx1 not in pool.connections[cx1.addr]
     assert cx2 in pool.connections[cx2.addr]
+
+
+def test_release_resets_connections(opener):
+    pool = Neo4jPool(opener, PoolConfig(), WorkspaceConfig(), ROUTER_ADDRESS)
+    cx1 = pool.acquire(READ_ACCESS, 30, "test_db", None)
+    cx1.is_reset_mock.return_value = False
+    cx1.is_reset_mock.reset_mock()
+    pool.release(cx1)
+    cx1.is_reset_mock.assert_called_once()
+    cx1.reset.assert_called_once()
+
+
+def test_release_does_not_resets_closed_connections(opener):
+    pool = Neo4jPool(opener, PoolConfig(), WorkspaceConfig(), ROUTER_ADDRESS)
+    cx1 = pool.acquire(READ_ACCESS, 30, "test_db", None)
+    cx1.closed.return_value = True
+    cx1.closed.reset_mock()
+    cx1.is_reset_mock.reset_mock()
+    pool.release(cx1)
+    cx1.closed.assert_called_once()
+    cx1.is_reset_mock.asset_not_called()
+    cx1.reset.asset_not_called()
+
+
+def test_release_does_not_resets_defunct_connections(opener):
+    pool = Neo4jPool(opener, PoolConfig(), WorkspaceConfig(), ROUTER_ADDRESS)
+    cx1 = pool.acquire(READ_ACCESS, 30, "test_db", None)
+    cx1.defunct.return_value = True
+    cx1.defunct.reset_mock()
+    cx1.is_reset_mock.reset_mock()
+    pool.release(cx1)
+    cx1.defunct.assert_called_once()
+    cx1.is_reset_mock.asset_not_called()
+    cx1.reset.asset_not_called()

tests/unit/work/_fake_connection.py

@@ -33,7 +33,7 @@ class FakeConnection(mock.NonCallableMagicMock):
 
     def __init__(self, *args, **kwargs):
         super().__init__(*args, **kwargs)
-        self.attach_mock(mock.PropertyMock(return_value=True), "is_reset")
+        self.attach_mock(mock.Mock(return_value=True), "is_reset_mock")
         self.attach_mock(mock.Mock(return_value=False), "defunct")
         self.attach_mock(mock.Mock(return_value=False), "stale")
         self.attach_mock(mock.Mock(return_value=False), "closed")
@@ -43,6 +43,13 @@ def close_side_effect():
 
         self.attach_mock(mock.Mock(side_effect=close_side_effect), "close")
 
+    @property
+    def is_reset(self):
+        if self.closed.return_value or self.defunct.return_value:
+            raise AssertionError("is_reset should not be called on a closed or "
+                                 "defunct connection.")
+        return self.is_reset_mock()
+
     def fetch_message(self, *args, **kwargs):
         if self.callbacks:
             cb = self.callbacks.pop(0)
@@ -78,13 +85,13 @@ def callback():
                             else:
                                 cb()
                 self.callbacks.append(callback)
-                return parent.__getattr__(name)(*args, **kwargs)
 
             return func
 
+        method_mock = parent.__getattr__(name)
         if name in ("run", "commit", "pull", "rollback", "discard"):
-            return build_message_handler(name)
-        return parent.__getattr__(name)
+            method_mock.side_effect = build_message_handler(name)
+        return method_mock
 
 
 @pytest.fixture

tests/unit/work/test_transaction.py

@@ -19,7 +19,10 @@
 # limitations under the License.
 
 from uuid import uuid4
-from unittest.mock import MagicMock
+from unittest.mock import (
+    MagicMock,
+    NonCallableMagicMock,
+)
 
 import pytest
 
@@ -129,3 +132,59 @@ def test_transaction_run_takes_no_query_object(fake_connection):
     tx = Transaction(fake_connection, 2, on_closed, on_error)
     with pytest.raises(ValueError):
         tx.run(Query("RETURN 1"))
+
+
+def test_transaction_rollbacks_on_open_connections(fake_connection):
+    tx = Transaction(fake_connection, 2,
+                     lambda *args, **kwargs: None,
+                     lambda *args, **kwargs: None)
+    with tx as tx_:
+        fake_connection.is_reset_mock.return_value = False
+        fake_connection.is_reset_mock.reset_mock()
+        tx_.rollback()
+        fake_connection.is_reset_mock.assert_called_once()
+        fake_connection.reset.assert_not_called()
+        fake_connection.rollback.assert_called_once()
+
+
+def test_transaction_no_rollback_on_reset_connections(fake_connection):
+    tx = Transaction(fake_connection, 2,
+                     lambda *args, **kwargs: None,
+                     lambda *args, **kwargs: None)
+    with tx as tx_:
+        fake_connection.is_reset_mock.return_value = True
+        fake_connection.is_reset_mock.reset_mock()
+        tx_.rollback()
+        fake_connection.is_reset_mock.assert_called_once()
+        fake_connection.reset.asset_not_called()
+        fake_connection.rollback.asset_not_called()
+
+
+def test_transaction_no_rollback_on_closed_connections(fake_connection):
+    tx = Transaction(fake_connection, 2,
+                     lambda *args, **kwargs: None,
+                     lambda *args, **kwargs: None)
+    with tx as tx_:
+        fake_connection.closed.return_value = True
+        fake_connection.closed.reset_mock()
+        fake_connection.is_reset_mock.reset_mock()
+        tx_.rollback()
+        fake_connection.closed.assert_called_once()
+        fake_connection.is_reset_mock.asset_not_called()
+        fake_connection.reset.asset_not_called()
+        fake_connection.rollback.asset_not_called()
+
+
+def test_transaction_no_rollback_on_defunct_connections(fake_connection):
+    tx = Transaction(fake_connection, 2,
+                     lambda *args, **kwargs: None,
+                     lambda *args, **kwargs: None)
+    with tx as tx_:
+        fake_connection.defunct.return_value = True
+        fake_connection.defunct.reset_mock()
+        fake_connection.is_reset_mock.reset_mock()
+        tx_.rollback()
+        fake_connection.defunct.assert_called_once()
+        fake_connection.is_reset_mock.asset_not_called()
+        fake_connection.reset.asset_not_called()
+        fake_connection.rollback.asset_not_called()