diff options
Diffstat (limited to 'lib/sqlalchemy/engine/util.py')
| -rw-r--r-- | lib/sqlalchemy/engine/util.py | 23 |
1 files changed, 21 insertions, 2 deletions
diff --git a/lib/sqlalchemy/engine/util.py b/lib/sqlalchemy/engine/util.py index 732ae7fa1..e88b9ebf3 100644 --- a/lib/sqlalchemy/engine/util.py +++ b/lib/sqlalchemy/engine/util.py @@ -98,6 +98,23 @@ class TransactionalContext: def _transaction_is_closed(self): raise NotImplementedError() + def _rollback_can_be_called(self): + """indicates the object is in a state that is known to be acceptable + for rollback() to be called. + + This does not necessarily mean rollback() will succeed or not raise + an error, just that there is currently no state detected that indicates + rollback() would fail or emit warnings. + + It also does not mean that there's a transaction in progress, as + it is usually safe to call rollback() even if no transaction is + present. + + .. versionadded:: 1.4.28 + + """ + raise NotImplementedError() + def _get_subject(self): raise NotImplementedError() @@ -143,7 +160,8 @@ class TransactionalContext: self.commit() except: with util.safe_reraise(): - self.rollback() + if self._rollback_can_be_called(): + self.rollback() finally: if not out_of_band_exit: subject._trans_context_manager = self._outer_trans_ctx @@ -154,7 +172,8 @@ class TransactionalContext: if not self._transaction_is_closed(): self.close() else: - self.rollback() + if self._rollback_can_be_called(): + self.rollback() finally: if not out_of_band_exit: subject._trans_context_manager = self._outer_trans_ctx |