diff options
| -rw-r--r-- | doc/build/changelog/changelog_08.rst | 8 | ||||
| -rw-r--r-- | lib/sqlalchemy/orm/events.py | 108 | ||||
| -rw-r--r-- | lib/sqlalchemy/orm/session.py | 33 | ||||
| -rw-r--r-- | lib/sqlalchemy/sql/expression.py | 9 | ||||
| -rw-r--r-- | test/orm/test_transaction.py | 12 |
5 files changed, 151 insertions, 19 deletions
diff --git a/doc/build/changelog/changelog_08.rst b/doc/build/changelog/changelog_08.rst index 89fcd87d0..218700ba8 100644 --- a/doc/build/changelog/changelog_08.rst +++ b/doc/build/changelog/changelog_08.rst @@ -8,6 +8,14 @@ .. change:: :tags: bug, orm + :tickets: 2662 + + A clear error message is emitted if an event handler + attempts to emit SQL on a Session within the after_commit() + handler, where there is not a viable transaction in progress. + + .. change:: + :tags: bug, orm :tickets: 2665 Detection of a primary key change within the process diff --git a/lib/sqlalchemy/orm/events.py b/lib/sqlalchemy/orm/events.py index 5b66c72ff..cea07bcf0 100644 --- a/lib/sqlalchemy/orm/events.py +++ b/lib/sqlalchemy/orm/events.py @@ -1118,41 +1118,103 @@ class SessionEvents(event.Events): def after_transaction_create(self, session, transaction): """Execute when a new :class:`.SessionTransaction` is created. + This event differs from :meth:`~.SessionEvents.after_begin` + in that it occurs for each :class:`.SessionTransaction` + overall, as opposed to when transactions are begun + on individual database connections. It is also invoked + for nested transactions and subtransactions, and is always + matched by a corresponding + :meth:`~.SessionEvents.after_transaction_end` event + (assuming normal operation of the :class:`.Session`). + :param session: the target :class:`.Session`. :param transaction: the target :class:`.SessionTransaction`. .. versionadded:: 0.8 + .. seealso:: + + :meth:`~.SessionEvents.after_transaction_end` + """ def after_transaction_end(self, session, transaction): """Execute when the span of a :class:`.SessionTransaction` ends. + This event differs from :meth:`~.SessionEvents.after_commit` + in that it corresponds to all :class:`.SessionTransaction` + objects in use, including those for nested transactions + and subtransactions, and is always matched by a corresponding + :meth:`~.SessionEvents.after_transaction_create` event. + :param session: the target :class:`.Session`. :param transaction: the target :class:`.SessionTransaction`. .. versionadded:: 0.8 + .. seealso:: + + :meth:`~.SessionEvents.after_transaction_create` + """ def before_commit(self, session): """Execute before commit is called. - Note that this may not be per-flush if a longer running - transaction is ongoing. + .. note:: + + The :meth:`.before_commit` hook is *not* per-flush, + that is, the :class:`.Session` can emit SQL to the database + many times within the scope of a transaction. + For interception of these events, use the :meth:`~.SessionEvents.before_flush`, + :meth:`~.SessionEvents.after_flush`, or :meth:`~.SessionEvents.after_flush_postexec` + events. :param session: The target :class:`.Session`. + .. seealso:: + + :meth:`~.SessionEvents.after_commit` + + :meth:`~.SessionEvents.after_begin` + + :meth:`~.SessionEvents.after_transaction_create` + + :meth:`~.SessionEvents.after_transaction_end` + """ def after_commit(self, session): """Execute after a commit has occurred. - Note that this may not be per-flush if a longer running - transaction is ongoing. + .. note:: + + The :meth:`~.SessionEvents.after_commit` hook is *not* per-flush, + that is, the :class:`.Session` can emit SQL to the database + many times within the scope of a transaction. + For interception of these events, use the :meth:`~.SessionEvents.before_flush`, + :meth:`~.SessionEvents.after_flush`, or :meth:`~.SessionEvents.after_flush_postexec` + events. + + .. note:: + + The :class:`.Session` is not in an active tranasction + when the :meth:`~.SessionEvents.after_commit` event is invoked, and therefore + can not emit SQL. To emit SQL corresponding to every transaction, + use the :meth:`~.SessionEvents.before_commit` event. :param session: The target :class:`.Session`. + .. seealso:: + + :meth:`~.SessionEvents.before_commit` + + :meth:`~.SessionEvents.after_begin` + + :meth:`~.SessionEvents.after_transaction_create` + + :meth:`~.SessionEvents.after_transaction_end` + """ def after_rollback(self, session): @@ -1211,6 +1273,12 @@ class SessionEvents(event.Events): objects which can be passed to the :meth:`.Session.flush` method (note this usage is deprecated). + .. seealso:: + + :meth:`~.SessionEvents.after_flush` + + :meth:`~.SessionEvents.after_flush_postexec` + """ def after_flush(self, session, flush_context): @@ -1225,6 +1293,12 @@ class SessionEvents(event.Events): :param flush_context: Internal :class:`.UOWTransaction` object which handles the details of the flush. + .. seealso:: + + :meth:`~.SessionEvents.before_flush` + + :meth:`~.SessionEvents.after_flush_postexec` + """ def after_flush_postexec(self, session, flush_context): @@ -1239,6 +1313,14 @@ class SessionEvents(event.Events): :param session: The target :class:`.Session`. :param flush_context: Internal :class:`.UOWTransaction` object which handles the details of the flush. + + + .. seealso:: + + :meth:`~.SessionEvents.before_flush` + + :meth:`~.SessionEvents.after_flush` + """ def after_begin(self, session, transaction, connection): @@ -1249,6 +1331,16 @@ class SessionEvents(event.Events): :param connection: The :class:`~.engine.Connection` object which will be used for SQL statements. + .. seealso:: + + :meth:`~.SessionEvents.before_commit` + + :meth:`~.SessionEvents.after_commit` + + :meth:`~.SessionEvents.after_transaction_create` + + :meth:`~.SessionEvents.after_transaction_end` + """ def before_attach(self, session, instance): @@ -1262,6 +1354,10 @@ class SessionEvents(event.Events): :meth:`.before_attach` is provided for those cases where the item should not yet be part of the session state. + .. seealso:: + + :meth:`~.SessionEvents.after_attach` + """ def after_attach(self, session, instance): @@ -1280,6 +1376,10 @@ class SessionEvents(event.Events): yet complete) consider the new :meth:`.before_attach` event. + .. seealso:: + + :meth:`~.SessionEvents.before_attach` + """ def after_bulk_update(self, session, query, query_context, result): diff --git a/lib/sqlalchemy/orm/session.py b/lib/sqlalchemy/orm/session.py index 2915fd4c8..5fb9b514d 100644 --- a/lib/sqlalchemy/orm/session.py +++ b/lib/sqlalchemy/orm/session.py @@ -57,6 +57,10 @@ class _SessionClassMethods(object): return object_session(instance) +ACTIVE = util.symbol('ACTIVE') +PREPARED = util.symbol('PREPARED') +DEACTIVE = util.symbol('DEACTIVE') + class SessionTransaction(object): """A :class:`.Session`-level transaction. @@ -144,8 +148,7 @@ class SessionTransaction(object): self._connections = {} self._parent = parent self.nested = nested - self._active = True - self._prepared = False + self._state = ACTIVE if not parent and nested: raise sa_exc.InvalidRequestError( "Can't start a SAVEPOINT transaction when no existing " @@ -159,11 +162,17 @@ class SessionTransaction(object): @property def is_active(self): - return self.session is not None and self._active + return self.session is not None and self._state is ACTIVE def _assert_is_active(self): self._assert_is_open() - if not self._active: + if self._state is PREPARED: + raise sa_exc.InvalidRequestError( + "This session is in 'prepared' state, where no further " + "SQL can be emitted until the transaction is fully " + "committed." + ) + elif self._state is DEACTIVE: if self._rollback_exception: raise sa_exc.InvalidRequestError( "This Session's transaction has been rolled back " @@ -327,12 +336,11 @@ class SessionTransaction(object): self.rollback() raise - self._deactivate() - self._prepared = True + self._state = PREPARED def commit(self): self._assert_is_open() - if not self._prepared: + if self._state is not PREPARED: self._prepare_impl() if self._parent is None or self.nested: @@ -355,14 +363,14 @@ class SessionTransaction(object): for subtransaction in stx._iterate_parents(upto=self): subtransaction.close() - if self.is_active or self._prepared: + if self._state in (ACTIVE, PREPARED): for transaction in self._iterate_parents(): if transaction._parent is None or transaction.nested: transaction._rollback_impl() - transaction._deactivate() + transaction._state = DEACTIVE break else: - transaction._deactivate() + transaction._state = DEACTIVE sess = self.session @@ -393,9 +401,6 @@ class SessionTransaction(object): self.session.dispatch.after_rollback(self.session) - def _deactivate(self): - self._active = False - def close(self): self.session.transaction = self._parent if self._parent is None: @@ -406,7 +411,7 @@ class SessionTransaction(object): else: transaction.close() - self._deactivate() + self._state = DEACTIVE if self.session.dispatch.after_transaction_end: self.session.dispatch.after_transaction_end(self.session, self) diff --git a/lib/sqlalchemy/sql/expression.py b/lib/sqlalchemy/sql/expression.py index 90837f4ab..490004e39 100644 --- a/lib/sqlalchemy/sql/expression.py +++ b/lib/sqlalchemy/sql/expression.py @@ -2604,7 +2604,14 @@ class FromClause(Selectable): **params) def select(self, whereclause=None, **params): - """return a SELECT of this :class:`.FromClause`.""" + """return a SELECT of this :class:`.FromClause`. + + .. seealso:: + + :func:`~.sql.expression.select` - general purpose + method which allows for arbitrary column lists. + + """ return select([self], whereclause, **params) diff --git a/test/orm/test_transaction.py b/test/orm/test_transaction.py index 28735bd11..7df6ecf91 100644 --- a/test/orm/test_transaction.py +++ b/test/orm/test_transaction.py @@ -358,6 +358,18 @@ class SessionTransactionTest(FixtureTest): sess.begin, subtransactions=True) sess.close() + def test_no_sql_during_prepare(self): + sess = create_session(bind=testing.db, autocommit=False) + + @event.listens_for(sess, "after_commit") + def go(session): + session.execute("select 1") + assert_raises_message(sa_exc.InvalidRequestError, + "This session is in 'prepared' state, where no " + "further SQL can be emitted until the " + "transaction is fully committed.", + sess.commit) + def _inactive_flushed_session_fixture(self): users, User = self.tables.users, self.classes.User |