Don't try to rollback a closed transaction (#531)

* Don't try to rollback a closed transaction
* Clean up transaction error handling

Author: robsdedude

neo4j/work/simple.py

@@ -26,11 +26,11 @@
     sleep,
 )
 
-from neo4j.conf import SessionConfig
 from neo4j.api import (
     READ_ACCESS,
     WRITE_ACCESS,
 )
+from neo4j.conf import SessionConfig
 from neo4j.data import DataHydrator
 from neo4j.exceptions import (
     ClientError,
@@ -337,7 +337,7 @@ def _run_transaction(self, access_mode, transaction_function, *args, **kwargs):
                 try:
                     result = transaction_function(tx, *args, **kwargs)
                 except Exception:
-                    tx.rollback()
+                    tx.close()
                     raise
                 else:
                     tx.commit()

neo4j/work/transaction.py

@@ -139,8 +139,8 @@ def commit(self):
         if self._closed:
             raise TransactionError("Transaction closed")
         metadata = {}
-        self._consume_results()  # DISCARD pending records then do a commit.
         try:
+            self._consume_results()  # DISCARD pending records then do a commit.
             self._connection.commit(on_success=metadata.update)
             self._connection.send_all()
             self._connection.fetch_all()
@@ -159,18 +159,19 @@ def rollback(self):
         if self._closed:
             raise TransactionError("Transaction closed")
         metadata = {}
-        if not self._connection._is_reset:
-            self._consume_results()  # DISCARD pending records then do a rollback.
-            self._connection.rollback(on_success=metadata.update)
-            self._connection.send_all()
-            self._connection.fetch_all()
-        self._closed = True
-        self._on_closed()
+        try:
+            if not self._connection._is_reset:
+                # DISCARD pending records then do a rollback.
+                self._consume_results()
+                self._connection.rollback(on_success=metadata.update)
+                self._connection.send_all()
+                self._connection.fetch_all()
+        finally:
+            self._closed = True
+            self._on_closed()
 
     def close(self):
         """Close this transaction, triggering a ROLLBACK if not closed.
-
-        :raise TransactionError: if the transaction could not perform a ROLLBACK.
         """
         if self._closed:
             return