sqlalchemy/test/engine/test_pool.py

import collections
import random
import threading
import time
import weakref

import sqlalchemy as tsa
from sqlalchemy import create_engine
from sqlalchemy import event
from sqlalchemy import pool
from sqlalchemy import select
from sqlalchemy import testing
from sqlalchemy.engine import default
from sqlalchemy.pool.base import _AsyncConnDialect
from sqlalchemy.pool.base import _ConnDialect
from sqlalchemy.testing import assert_raises
from sqlalchemy.testing import assert_raises_context_ok
from sqlalchemy.testing import assert_warns_message
from sqlalchemy.testing import eq_
from sqlalchemy.testing import expect_raises
from sqlalchemy.testing import fixtures
from sqlalchemy.testing import is_
from sqlalchemy.testing import is_none
from sqlalchemy.testing import is_not
from sqlalchemy.testing import is_not_none
from sqlalchemy.testing import is_true
from sqlalchemy.testing import mock
from sqlalchemy.testing.engines import testing_engine
from sqlalchemy.testing.mock import ANY
from sqlalchemy.testing.mock import call
from sqlalchemy.testing.mock import Mock
from sqlalchemy.testing.mock import patch
from sqlalchemy.testing.util import gc_collect
from sqlalchemy.testing.util import lazy_gc

join_timeout = 10


def MockDBAPI():  # noqa
    def cursor():
        return Mock()

    def connect(*arg, **kw):
        def close():
            conn.closed = True

        # mock seems like it might have an issue logging
        # call_count correctly under threading, not sure.
        # adding a side_effect for close seems to help.
        conn = Mock(
            cursor=Mock(side_effect=cursor),
            close=Mock(side_effect=close),
            closed=False,
        )
        return conn

    def shutdown(value):
        if value:
            db.connect = Mock(side_effect=Exception("connect failed"))
        else:
            db.connect = Mock(side_effect=connect)
        db.is_shutdown = value

    db = Mock(
        connect=Mock(side_effect=connect), shutdown=shutdown, is_shutdown=False
    )
    return db


class PoolTestBase(fixtures.TestBase):
    def setup_test(self):
        pool.clear_managers()
        self._teardown_conns = []

    def teardown_test(self):
        for ref in self._teardown_conns:
            conn = ref()
            if conn:
                conn.close()

    @classmethod
    def teardown_test_class(cls):
        pool.clear_managers()

    def _with_teardown(self, connection):
        self._teardown_conns.append(weakref.ref(connection))
        return connection

    def _queuepool_fixture(self, **kw):
        dbapi, pool = self._queuepool_dbapi_fixture(**kw)
        return pool

    def _queuepool_dbapi_fixture(self, **kw):
        dbapi = MockDBAPI()
        _is_asyncio = kw.pop("_is_asyncio", False)
        _has_terminate = kw.pop("_has_terminate", False)
        p = pool.QueuePool(creator=lambda: dbapi.connect("foo.db"), **kw)
        if _is_asyncio:
            p._is_asyncio = True
            p._dialect = _AsyncConnDialect()
        if _has_terminate:
            p._dialect.has_terminate = True
        return dbapi, p


class PoolTest(PoolTestBase):
    @testing.fails_on(
        "+pyodbc", "pyodbc cursor doesn't implement tuple __eq__"
    )
    @testing.fails_on("+pg8000", "returns [1], not (1,)")
    def test_cursor_iterable(self):
        conn = testing.db.raw_connection()
        cursor = conn.cursor()
        cursor.execute(str(select(1).compile(testing.db)))
        expected = [(1,)]
        for row in cursor:
            eq_(row, expected.pop(0))

    def test_no_connect_on_recreate(self):
        def creator():
            raise Exception("no creates allowed")

        for cls in (
            pool.SingletonThreadPool,
            pool.StaticPool,
            pool.QueuePool,
            pool.NullPool,
            pool.AssertionPool,
        ):
            p = cls(creator=creator)
            p.dispose()
            p2 = p.recreate()
            assert p2.__class__ is cls

            mock_dbapi = MockDBAPI()
            p = cls(creator=mock_dbapi.connect)
            conn = p.connect()
            conn.close()
            mock_dbapi.connect.side_effect = Exception("error!")
            p.dispose()
            p.recreate()

    def test_info(self):
        p = self._queuepool_fixture(pool_size=1, max_overflow=0)

        c = p.connect()
        self.assert_(not c.info)
        self.assert_(c.info is c._connection_record.info)

        c.info["foo"] = "bar"
        c.close()
        del c

        c = p.connect()
        self.assert_("foo" in c.info)

        c.invalidate()
        c = p.connect()
        self.assert_("foo" not in c.info)

        c.info["foo2"] = "bar2"
        c.detach()
        self.assert_("foo2" in c.info)

        c2 = p.connect()
        is_not(c.dbapi_connection, c2.dbapi_connection)
        assert not c2.info
        assert "foo2" in c.info

    def test_rec_info(self):
        p = self._queuepool_fixture(pool_size=1, max_overflow=0)

        c = p.connect()
        self.assert_(not c.record_info)
        self.assert_(c.record_info is c._connection_record.record_info)

        c.record_info["foo"] = "bar"
        c.close()
        del c

        c = p.connect()
        self.assert_("foo" in c.record_info)

        c.invalidate()
        c = p.connect()
        self.assert_("foo" in c.record_info)

        c.record_info["foo2"] = "bar2"
        c.detach()
        is_(c.record_info, None)
        is_(c._connection_record, None)

        c2 = p.connect()

        assert c2.record_info
        assert "foo2" in c2.record_info

    def test_rec_unconnected(self):
        # test production of a _ConnectionRecord with an
        # initially unconnected state.

        dbapi = MockDBAPI()
        p1 = pool.Pool(creator=lambda: dbapi.connect("foo.db"))

        r1 = pool._ConnectionRecord(p1, connect=False)

        assert not r1.dbapi_connection
        c1 = r1.get_connection()
        is_(c1, r1.dbapi_connection)
        is_(c1, r1.connection)
        is_(c1, r1.driver_connection)

    def test_rec_close_reopen(self):
        # test that _ConnectionRecord.close() allows
        # the record to be reusable
        dbapi = MockDBAPI()
        p1 = pool.Pool(creator=lambda: dbapi.connect("foo.db"))

        r1 = pool._ConnectionRecord(p1)

        c1 = r1.dbapi_connection
        c2 = r1.get_connection()
        is_(c1, c2)

        r1.close()

        assert not r1.dbapi_connection
        eq_(c1.mock_calls, [call.close()])

        c2 = r1.get_connection()

        is_not(c1, c2)
        is_(c2, r1.dbapi_connection)

        eq_(c2.mock_calls, [])

    @testing.combinations(
        (
            pool.QueuePool,
            dict(pool_size=8, max_overflow=10, timeout=25, use_lifo=True),
        ),
        (pool.QueuePool, {}),
        (pool.NullPool, {}),
        (pool.SingletonThreadPool, {}),
        (pool.StaticPool, {}),
        (pool.AssertionPool, {}),
    )
    def test_recreate_state(self, pool_cls, pool_args):
        creator = object()
        pool_args["pre_ping"] = True
        pool_args["reset_on_return"] = "commit"
        pool_args["recycle"] = 35
        pool_args["logging_name"] = "somepool"
        pool_args["dialect"] = default.DefaultDialect()
        pool_args["echo"] = "debug"

        p1 = pool_cls(creator=creator, **pool_args)

        cls_keys = dir(pool_cls)

        d1 = dict(p1.__dict__)

        p2 = p1.recreate()

        d2 = dict(p2.__dict__)

        for k in cls_keys:
            d1.pop(k, None)
            d2.pop(k, None)

        for k in (
            "_invoke_creator",
            "_pool",
            "_overflow_lock",
            "_fairy",
            "_conn",
            "logger",
        ):
            if k in d2:
                d2[k] = mock.ANY

        eq_(d1, d2)

        eq_(p1.echo, p2.echo)
        is_(p1._dialect, p2._dialect)

        if "use_lifo" in pool_args:
            eq_(p1._pool.use_lifo, p2._pool.use_lifo)

    @testing.combinations(
        (pool.QueuePool, False),
        (pool.AsyncAdaptedQueuePool, True),
        (pool.FallbackAsyncAdaptedQueuePool, True),
        (pool.NullPool, None),
        (pool.SingletonThreadPool, False),
        (pool.StaticPool, None),
        (pool.AssertionPool, None),
    )
    def test_is_asyncio_from_dialect(self, pool_cls, is_async_kind):
        p = pool_cls(creator=object())
        for is_async in (True, False):
            if is_async:
                p._dialect = _AsyncConnDialect()
            else:
                p._dialect = _ConnDialect()
            if is_async_kind is None:
                eq_(p._is_asyncio, is_async)
            else:
                eq_(p._is_asyncio, is_async_kind)

    @testing.combinations(
        (pool.QueuePool, False),
        (pool.AsyncAdaptedQueuePool, True),
        (pool.FallbackAsyncAdaptedQueuePool, True),
        (pool.NullPool, False),
        (pool.SingletonThreadPool, False),
        (pool.StaticPool, False),
        (pool.AssertionPool, False),
    )
    def test_is_asyncio_from_dialect_cls(self, pool_cls, is_async):
        eq_(pool_cls._is_asyncio, is_async)

    def test_rec_fairy_default_dialect(self):
        dbapi = MockDBAPI()
        p1 = pool.Pool(creator=lambda: dbapi.connect("foo.db"))

        rec = pool._ConnectionRecord(p1)

        is_not_none(rec.dbapi_connection)

        is_(rec.connection, rec.dbapi_connection)
        is_(rec.driver_connection, rec.dbapi_connection)

        fairy = pool._ConnectionFairy(rec.dbapi_connection, rec, False)

        is_not_none(fairy.dbapi_connection)
        is_(fairy.connection, fairy.dbapi_connection)
        is_(fairy.driver_connection, fairy.dbapi_connection)

        is_(fairy.dbapi_connection, rec.dbapi_connection)
        is_(fairy.driver_connection, rec.driver_connection)

    def test_rec_fairy_adapted_dialect(self):
        dbapi = MockDBAPI()

        mock_dc = object()

        class _AdaptedDialect(_ConnDialect):
            def get_driver_connection(self, connection):
                return mock_dc

        p1 = pool.Pool(
            creator=lambda: dbapi.connect("foo.db"), dialect=_AdaptedDialect()
        )

        rec = pool._ConnectionRecord(p1)

        is_not_none(rec.dbapi_connection)

        is_(rec.connection, rec.dbapi_connection)
        is_(rec.driver_connection, mock_dc)

        fairy = pool._ConnectionFairy(rec.dbapi_connection, rec, False)

        is_not_none(fairy.dbapi_connection)
        is_(fairy.connection, fairy.dbapi_connection)
        is_(fairy.driver_connection, mock_dc)

        is_(fairy.dbapi_connection, rec.dbapi_connection)
        is_(fairy.driver_connection, mock_dc)

    def test_connection_setter(self):
        dbapi = MockDBAPI()
        p1 = pool.Pool(creator=lambda: dbapi.connect("foo.db"))

        rec = pool._ConnectionRecord(p1)

        is_not_none(rec.dbapi_connection)

        is_(rec.connection, rec.dbapi_connection)
        rec.connection = 42
        is_(rec.connection, rec.dbapi_connection)
        rec.dbapi_connection = 99
        is_(rec.connection, rec.dbapi_connection)


class PoolDialectTest(PoolTestBase):
    def _dialect(self):
        canary = []

        class PoolDialect(object):
            is_async = False

            def do_rollback(self, dbapi_connection):
                canary.append("R")
                dbapi_connection.rollback()

            def do_commit(self, dbapi_connection):
                canary.append("C")
                dbapi_connection.commit()

            def do_close(self, dbapi_connection):
                canary.append("CL")
                dbapi_connection.close()

            def get_driver_connection(self, connection):
                return connection

        return PoolDialect(), canary

    def _do_test(self, pool_cls, assertion):
        mock_dbapi = MockDBAPI()
        dialect, canary = self._dialect()

        p = pool_cls(creator=mock_dbapi.connect)
        p._dialect = dialect
        conn = p.connect()
        conn.close()
        p.dispose()
        p.recreate()
        conn = p.connect()
        conn.close()
        eq_(canary, assertion)

    def test_queue_pool(self):
        self._do_test(pool.QueuePool, ["R", "CL", "R"])

    def test_assertion_pool(self):
        self._do_test(pool.AssertionPool, ["R", "CL", "R"])

    def test_singleton_pool(self):
        self._do_test(pool.SingletonThreadPool, ["R", "CL", "R"])

    def test_null_pool(self):
        self._do_test(pool.NullPool, ["R", "CL", "R", "CL"])

    def test_static_pool(self):
        self._do_test(pool.StaticPool, ["R", "CL", "R"])


class PoolEventsTest(PoolTestBase):
    def _first_connect_event_fixture(self):
        p = self._queuepool_fixture()
        canary = []

        def first_connect(*arg, **kw):
            canary.append("first_connect")

        event.listen(p, "first_connect", first_connect)

        return p, canary

    def _connect_event_fixture(self):
        p = self._queuepool_fixture()
        canary = []

        def connect(*arg, **kw):
            canary.append("connect")

        event.listen(p, "connect", connect)

        return p, canary

    def _checkout_event_fixture(self):
        p = self._queuepool_fixture()
        canary = []

        def checkout(*arg, **kw):
            canary.append("checkout")

        event.listen(p, "checkout", checkout)

        return p, canary

    def _checkin_event_fixture(self, _is_asyncio=False, _has_terminate=False):
        p = self._queuepool_fixture(
            _is_asyncio=_is_asyncio, _has_terminate=_has_terminate
        )
        canary = []

        @event.listens_for(p, "checkin")
        def checkin(*arg, **kw):
            canary.append("checkin")

        @event.listens_for(p, "close_detached")
        def close_detached(*arg, **kw):
            canary.append("close_detached")

        @event.listens_for(p, "detach")
        def detach(*arg, **kw):
            canary.append("detach")

        return p, canary

    def _reset_event_fixture(self):
        p = self._queuepool_fixture()
        canary = []

        def reset(*arg, **kw):
            canary.append("reset")

        event.listen(p, "reset", reset)

        return p, canary

    def _invalidate_event_fixture(self):
        p = self._queuepool_fixture()
        canary = Mock()
        event.listen(p, "invalidate", canary)

        return p, canary

    def _soft_invalidate_event_fixture(self):
        p = self._queuepool_fixture()
        canary = Mock()
        event.listen(p, "soft_invalidate", canary)

        return p, canary

    def _close_event_fixture(self):
        p = self._queuepool_fixture()
        canary = Mock()
        event.listen(p, "close", canary)

        return p, canary

    def _detach_event_fixture(self):
        p = self._queuepool_fixture()
        canary = Mock()
        event.listen(p, "detach", canary)

        return p, canary

    def _close_detached_event_fixture(self):
        p = self._queuepool_fixture()
        canary = Mock()
        event.listen(p, "close_detached", canary)

        return p, canary

    def test_close(self):
        p, canary = self._close_event_fixture()

        c1 = p.connect()

        connection = c1.dbapi_connection
        rec = c1._connection_record

        c1.close()

        eq_(canary.mock_calls, [])

        p.dispose()
        eq_(canary.mock_calls, [call(connection, rec)])

    def test_detach(self):
        p, canary = self._detach_event_fixture()

        c1 = p.connect()

        connection = c1.dbapi_connection
        rec = c1._connection_record

        c1.detach()

        eq_(canary.mock_calls, [call(connection, rec)])

    def test_detach_close(self):
        p, canary = self._close_detached_event_fixture()

        c1 = p.connect()

        connection = c1.dbapi_connection

        c1.detach()

        c1.close()
        eq_(canary.mock_calls, [call(connection)])

    def test_first_connect_event(self):
        p, canary = self._first_connect_event_fixture()

        p.connect()
        eq_(canary, ["first_connect"])

    def test_first_connect_event_fires_once(self):
        p, canary = self._first_connect_event_fixture()

        p.connect()
        p.connect()

        eq_(canary, ["first_connect"])

    def test_first_connect_on_previously_recreated(self):
        p, canary = self._first_connect_event_fixture()

        p2 = p.recreate()
        p.connect()
        p2.connect()

        eq_(canary, ["first_connect", "first_connect"])

    def test_first_connect_on_subsequently_recreated(self):
        p, canary = self._first_connect_event_fixture()

        p.connect()
        p2 = p.recreate()
        p2.connect()

        eq_(canary, ["first_connect", "first_connect"])

    def test_connect_event(self):
        p, canary = self._connect_event_fixture()

        p.connect()
        eq_(canary, ["connect"])

    def test_connect_insert_event(self):
        p = self._queuepool_fixture()
        canary = []

        def connect_one(*arg, **kw):
            canary.append("connect_one")

        def connect_two(*arg, **kw):
            canary.append("connect_two")

        def connect_three(*arg, **kw):
            canary.append("connect_three")

        event.listen(p, "connect", connect_one)
        event.listen(p, "connect", connect_two, insert=True)
        event.listen(p, "connect", connect_three)

        p.connect()
        eq_(canary, ["connect_two", "connect_one", "connect_three"])

    def test_connect_event_fires_subsequent(self):
        p, canary = self._connect_event_fixture()

        c1 = p.connect()  # noqa
        c2 = p.connect()  # noqa

        eq_(canary, ["connect", "connect"])

    def test_connect_on_previously_recreated(self):
        p, canary = self._connect_event_fixture()

        p2 = p.recreate()

        p.connect()
        p2.connect()

        eq_(canary, ["connect", "connect"])

    def test_connect_on_subsequently_recreated(self):
        p, canary = self._connect_event_fixture()

        p.connect()
        p2 = p.recreate()
        p2.connect()

        eq_(canary, ["connect", "connect"])

    def test_checkout_event(self):
        p, canary = self._checkout_event_fixture()

        p.connect()
        eq_(canary, ["checkout"])

    def test_checkout_event_fires_subsequent(self):
        p, canary = self._checkout_event_fixture()

        p.connect()
        p.connect()
        eq_(canary, ["checkout", "checkout"])

    def test_checkout_event_on_subsequently_recreated(self):
        p, canary = self._checkout_event_fixture()

        p.connect()
        p2 = p.recreate()
        p2.connect()

        eq_(canary, ["checkout", "checkout"])

    def test_checkin_event(self):
        p, canary = self._checkin_event_fixture()

        c1 = p.connect()
        eq_(canary, [])
        c1.close()
        eq_(canary, ["checkin"])

    def test_reset_event(self):
        p, canary = self._reset_event_fixture()

        c1 = p.connect()
        eq_(canary, [])
        c1.close()
        eq_(canary, ["reset"])

    def test_soft_invalidate_event_no_exception(self):
        p, canary = self._soft_invalidate_event_fixture()

        c1 = p.connect()
        c1.close()
        assert not canary.called
        c1 = p.connect()
        dbapi_con = c1.dbapi_connection
        c1.invalidate(soft=True)
        assert canary.call_args_list[0][0][0] is dbapi_con
        assert canary.call_args_list[0][0][2] is None

    def test_soft_invalidate_event_exception(self):
        p, canary = self._soft_invalidate_event_fixture()

        c1 = p.connect()
        c1.close()
        assert not canary.called
        c1 = p.connect()
        dbapi_con = c1.dbapi_connection
        exc = Exception("hi")
        c1.invalidate(exc, soft=True)
        assert canary.call_args_list[0][0][0] is dbapi_con
        assert canary.call_args_list[0][0][2] is exc

    def test_invalidate_event_no_exception(self):
        p, canary = self._invalidate_event_fixture()

        c1 = p.connect()
        c1.close()
        assert not canary.called
        c1 = p.connect()
        dbapi_con = c1.dbapi_connection
        c1.invalidate()
        assert canary.call_args_list[0][0][0] is dbapi_con
        assert canary.call_args_list[0][0][2] is None

    def test_invalidate_event_exception(self):
        p, canary = self._invalidate_event_fixture()

        c1 = p.connect()
        c1.close()
        assert not canary.called
        c1 = p.connect()
        dbapi_con = c1.dbapi_connection
        exc = Exception("hi")
        c1.invalidate(exc)
        assert canary.call_args_list[0][0][0] is dbapi_con
        assert canary.call_args_list[0][0][2] is exc

    @testing.variation("is_asyncio", [(True, testing.requires.asyncio), False])
    @testing.variation("has_terminate", [True, False])
    @testing.requires.python3
    def test_checkin_event_gc(self, is_asyncio, has_terminate):
        p, canary = self._checkin_event_fixture(
            _is_asyncio=is_asyncio, _has_terminate=has_terminate
        )

        c1 = p.connect()

        dbapi_connection = weakref.ref(c1.dbapi_connection)

        eq_(canary, [])
        del c1
        lazy_gc()

        detach_gced = is_asyncio and not has_terminate

        if detach_gced:
            # "close_detached" is not called because for asyncio the
            # connection is just lost.
            eq_(canary, ["detach"])

        else:
            eq_(canary, ["checkin"])

        gc_collect()
        if detach_gced:
            is_none(dbapi_connection())
        else:
            is_not_none(dbapi_connection())

    def test_checkin_event_on_subsequently_recreated(self):
        p, canary = self._checkin_event_fixture()

        c1 = p.connect()
        p2 = p.recreate()
        c2 = p2.connect()

        eq_(canary, [])

        c1.close()
        eq_(canary, ["checkin"])

        c2.close()
        eq_(canary, ["checkin", "checkin"])

    def test_listen_targets_scope(self):
        canary = []

        def listen_one(*args):
            canary.append("listen_one")

        def listen_two(*args):
            canary.append("listen_two")

        def listen_three(*args):
            canary.append("listen_three")

        def listen_four(*args):
            canary.append("listen_four")

        engine = testing_engine(testing.db.url)
        event.listen(pool.Pool, "connect", listen_one)
        event.listen(engine.pool, "connect", listen_two)
        event.listen(engine, "connect", listen_three)
        event.listen(engine.__class__, "connect", listen_four)

        with engine.connect() as conn:
            conn.execute(select(1))
        eq_(
            canary, ["listen_one", "listen_four", "listen_two", "listen_three"]
        )

    def test_listen_targets_per_subclass(self):
        """test that listen() called on a subclass remains specific to
        that subclass."""

        canary = []

        def listen_one(*args):
            canary.append("listen_one")

        def listen_two(*args):
            canary.append("listen_two")

        def listen_three(*args):
            canary.append("listen_three")

        event.listen(pool.Pool, "connect", listen_one)
        event.listen(pool.QueuePool, "connect", listen_two)
        event.listen(pool.SingletonThreadPool, "connect", listen_three)

        p1 = pool.QueuePool(creator=MockDBAPI().connect)
        p2 = pool.SingletonThreadPool(creator=MockDBAPI().connect)

        assert listen_one in p1.dispatch.connect
        assert listen_two in p1.dispatch.connect
        assert listen_three not in p1.dispatch.connect
        assert listen_one in p2.dispatch.connect
        assert listen_two not in p2.dispatch.connect
        assert listen_three in p2.dispatch.connect

        p1.connect()
        eq_(canary, ["listen_one", "listen_two"])
        p2.connect()
        eq_(canary, ["listen_one", "listen_two", "listen_one", "listen_three"])

    @testing.variation("exc_type", ["plain", "base_exception"])
    def test_connect_event_fails_invalidates(self, exc_type):
        fail = False

        if exc_type.plain:

            class RegularThing(Exception):
                pass

            exc_cls = RegularThing
        elif exc_type.base_exception:

            class TimeoutThing(BaseException):
                pass

            exc_cls = TimeoutThing
        else:
            exc_type.fail()

        def listen_one(conn, rec):
            if fail:
                raise exc_cls("it failed")

        def listen_two(conn, rec):
            rec.info["important_flag"] = True

        p1 = pool.QueuePool(
            creator=MockDBAPI().connect, pool_size=1, max_overflow=0, timeout=5
        )
        event.listen(p1, "connect", listen_one)
        event.listen(p1, "connect", listen_two)

        conn = p1.connect()
        eq_(conn.info["important_flag"], True)
        conn.invalidate()
        conn.close()

        fail = True

        # if the failed checkin is not reverted, the pool is blocked
        assert_raises(exc_cls, p1.connect)

        fail = False

        conn = p1.connect()
        eq_(conn.info["important_flag"], True)
        conn.close()

    def teardown_test(self):
        # TODO: need to get remove() functionality
        # going
        pool.Pool.dispatch._clear()


class PoolFirstConnectSyncTest(PoolTestBase):
    """test for :ticket:`2964`, where the pool would not mutex the
    initialization of the dialect.

    Unfortunately, as discussed in :ticket:`6337`, this test suite did not
    ensure that the ``Engine`` itself actually uses the "first_connect" event,
    so when :ticket:`5497` came along, the "first_connect" event was no longer
    used and no test detected the re-introduction of the exact same race
    condition, which was now worse as the un-initialized dialect would now
    pollute the SQL cache causing the application to not work at all.

    A new suite has therefore been added in test/engine/test_execute.py->
    OnConnectTest::test_initialize_connect_race to ensure that the engine
    in total synchronizes the "first_connect" process, which now works
    using a new events feature _exec_w_sync_on_first_run.

    """

    @testing.requires.timing_intensive
    def test_sync(self):
        pool = self._queuepool_fixture(pool_size=3, max_overflow=0)

        evt = Mock()

        @event.listens_for(pool, "first_connect")
        def slow_first_connect(dbapi_con, rec):
            time.sleep(1)
            evt.first_connect()

        @event.listens_for(pool, "connect")
        def on_connect(dbapi_con, rec):
            evt.connect()

        def checkout():
            for j in range(2):
                c1 = pool.connect()
                time.sleep(0.02)
                c1.close()
                time.sleep(0.02)

        threads = []

        # what we're trying to do here is have concurrent use of
        # all three pooled connections at once, and the thing we want
        # to test is that first_connect() finishes completely before
        # any of the connections get returned.   so first_connect()
        # sleeps for one second, then pings the mock.  the threads should
        # not have made it to the "checkout() event for that one second.
        for i in range(5):
            th = threading.Thread(target=checkout)
            th.start()
            threads.append(th)
        for th in threads:
            th.join(join_timeout)

        # there is a very unlikely condition observed in CI on windows
        # where even though we have five threads above all calling upon the
        # pool, we didn't get concurrent use of all three connections, two
        # connections were enough.  so here we purposely just check out
        # all three at once just to get a consistent test result.
        make_sure_all_three_are_connected = [pool.connect() for i in range(3)]
        for conn in make_sure_all_three_are_connected:
            conn.close()

        eq_(
            evt.mock_calls,
            [
                call.first_connect(),
                call.connect(),
                call.connect(),
                call.connect(),
            ],
        )


class QueuePoolTest(PoolTestBase):
    def test_queuepool_del(self):
        self._do_testqueuepool(useclose=False)

    def test_queuepool_close(self):
        self._do_testqueuepool(useclose=True)

    def _do_testqueuepool(self, useclose=False):
        p = self._queuepool_fixture(pool_size=3, max_overflow=-1)

        def status(pool):
            return (
                pool.size(),
                pool.checkedin(),
                pool.overflow(),
                pool.checkedout(),
            )

        c1 = p.connect()
        self.assert_(status(p) == (3, 0, -2, 1))
        c2 = p.connect()
        self.assert_(status(p) == (3, 0, -1, 2))
        c3 = p.connect()
        self.assert_(status(p) == (3, 0, 0, 3))
        c4 = p.connect()
        self.assert_(status(p) == (3, 0, 1, 4))
        c5 = p.connect()
        self.assert_(status(p) == (3, 0, 2, 5))
        c6 = p.connect()
        self.assert_(status(p) == (3, 0, 3, 6))
        if useclose:
            c4.close()
            c3.close()
            c2.close()
        else:
            c4 = c3 = c2 = None
            lazy_gc()
        eq_(status(p), (3, 3, 3, 3))
        if useclose:
            c1.close()
            c5.close()
            c6.close()
        else:
            c1 = c5 = c6 = None
            lazy_gc()
        self.assert_(status(p) == (3, 3, 0, 0))
        c1 = p.connect()
        c2 = p.connect()
        self.assert_(status(p) == (3, 1, 0, 2), status(p))
        if useclose:
            c2.close()
        else:
            c2 = None
            lazy_gc()
        self.assert_(status(p) == (3, 2, 0, 1))
        c1.close()

    def test_timeout_accessor(self):
        expected_timeout = 123
        p = self._queuepool_fixture(timeout=expected_timeout)
        eq_(p.timeout(), expected_timeout)

    @testing.requires.timing_intensive
    def test_timeout(self):
        p = self._queuepool_fixture(pool_size=3, max_overflow=0, timeout=2)
        c1 = p.connect()  # noqa
        c2 = p.connect()  # noqa
        c3 = p.connect()  # noqa
        now = time.time()

        assert_raises(tsa.exc.TimeoutError, p.connect)
        assert int(time.time() - now) == 2

    @testing.requires.timing_intensive
    def test_timeout_subsecond_precision(self):
        p = self._queuepool_fixture(pool_size=1, max_overflow=0, timeout=0.5)
        c1 = p.connect()  # noqa
        with expect_raises(tsa.exc.TimeoutError):
            now = time.time()
            c2 = p.connect()  # noqa
        # Python timing is not very accurate, the time diff should be very
        # close to 0.5s but we give 200ms of slack.
        assert 0.3 <= time.time() - now <= 0.7, "Pool timeout not respected"

    @testing.requires.threading_with_mock
    @testing.requires.timing_intensive
    def test_timeout_race(self):
        # test a race condition where the initial connecting threads all race
        # to queue.Empty, then block on the mutex.  each thread consumes a
        # connection as they go in.  when the limit is reached, the remaining
        # threads go in, and get TimeoutError; even though they never got to
        # wait for the timeout on queue.get().  the fix involves checking the
        # timeout again within the mutex, and if so, unlocking and throwing
        # them back to the start of do_get()
        dbapi = MockDBAPI()
        p = pool.QueuePool(
            creator=lambda: dbapi.connect(delay=0.05),
            pool_size=2,
            max_overflow=1,
            timeout=3,
        )
        timeouts = []

        def checkout():
            for x in range(1):
                now = time.time()
                try:
                    c1 = p.connect()
                except tsa.exc.TimeoutError:
                    timeouts.append(time.time() - now)
                    continue
                time.sleep(4)
                c1.close()

        threads = []
        for i in range(10):
            th = threading.Thread(target=checkout)
            th.start()
            threads.append(th)
        for th in threads:
            th.join(join_timeout)

        assert len(timeouts) > 0
        for t in timeouts:
            assert t >= 3, "Not all timeouts were >= 3 seconds %r" % timeouts
            # normally, the timeout should under 4 seconds,
            # but on a loaded down buildbot it can go up.
            assert t < 14, "Not all timeouts were < 14 seconds %r" % timeouts

    def _test_overflow(self, thread_count, max_overflow):
        reaper = testing.engines.ConnectionKiller()

        dbapi = MockDBAPI()
        mutex = threading.Lock()

        def creator():
            time.sleep(0.05)
            with mutex:
                return dbapi.connect()

        p = pool.QueuePool(
            creator=creator, pool_size=3, timeout=2, max_overflow=max_overflow
        )
        reaper.add_pool(p)
        peaks = []

        def whammy():
            for i in range(10):
                try:
                    con = p.connect()
                    time.sleep(0.005)
                    peaks.append(p.overflow())
                    con.close()
                    del con
                except tsa.exc.TimeoutError:
                    pass

        threads = []
        for i in range(thread_count):
            th = threading.Thread(target=whammy)
            th.start()
            threads.append(th)
        for th in threads:
            th.join(join_timeout)

        self.assert_(max(peaks) <= max_overflow)

        reaper.assert_all_closed()

    def test_overflow_reset_on_failed_connect(self):
        dbapi = Mock()

        def failing_dbapi():
            raise Exception("connection failed")

        creator = dbapi.connect

        def create():
            return creator()

        p = pool.QueuePool(creator=create, pool_size=2, max_overflow=3)
        c1 = self._with_teardown(p.connect())  # noqa
        c2 = self._with_teardown(p.connect())  # noqa
        c3 = self._with_teardown(p.connect())  # noqa
        eq_(p._overflow, 1)
        creator = failing_dbapi
        assert_raises(Exception, p.connect)
        eq_(p._overflow, 1)

    @testing.requires.threading_with_mock
    @testing.requires.timing_intensive
    def test_hanging_connect_within_overflow(self):
        """test that a single connect() call which is hanging
        does not block other connections from proceeding."""

        dbapi = Mock()
        mutex = threading.Lock()

        def hanging_dbapi():
            time.sleep(2)
            with mutex:
                return dbapi.connect()

        def fast_dbapi():
            with mutex:
                return dbapi.connect()

        creator = threading.local()

        def create():
            return creator.mock_connector()

        def run_test(name, pool, should_hang):
            if should_hang:
                creator.mock_connector = hanging_dbapi
            else:
                creator.mock_connector = fast_dbapi

            conn = pool.connect()
            conn.operation(name)
            time.sleep(1)
            conn.close()

        p = pool.QueuePool(creator=create, pool_size=2, max_overflow=3)

        threads = [
            threading.Thread(target=run_test, args=("success_one", p, False)),
            threading.Thread(target=run_test, args=("success_two", p, False)),
            threading.Thread(target=run_test, args=("overflow_one", p, True)),
            threading.Thread(target=run_test, args=("overflow_two", p, False)),
            threading.Thread(
                target=run_test, args=("overflow_three", p, False)
            ),
        ]
        for t in threads:
            t.start()
            time.sleep(0.2)

        for t in threads:
            t.join(timeout=join_timeout)
        eq_(
            dbapi.connect().operation.mock_calls,
            [
                call("success_one"),
                call("success_two"),
                call("overflow_two"),
                call("overflow_three"),
                call("overflow_one"),
            ],
        )

    @testing.requires.threading_with_mock
    @testing.requires.timing_intensive
    def test_waiters_handled(self):
        """test that threads waiting for connections are
        handled when the pool is replaced.

        """
        mutex = threading.Lock()
        dbapi = MockDBAPI()

        def creator():
            with mutex:
                return dbapi.connect()

        success = []
        for timeout in (None, 30):
            for max_overflow in (0, -1, 3):
                p = pool.QueuePool(
                    creator=creator,
                    pool_size=2,
                    timeout=timeout,
                    max_overflow=max_overflow,
                )

                def waiter(p, timeout, max_overflow):
                    success_key = (timeout, max_overflow)
                    conn = p.connect()
                    success.append(success_key)
                    time.sleep(0.1)
                    conn.close()

                c1 = p.connect()  # noqa
                c2 = p.connect()

                threads = []
                for i in range(2):
                    t = threading.Thread(
                        target=waiter, args=(p, timeout, max_overflow)
                    )
                    t.daemon = True
                    t.start()
                    threads.append(t)

                # this sleep makes sure that the
                # two waiter threads hit upon wait()
                # inside the queue, before we invalidate the other
                # two conns
                time.sleep(0.2)
                p._invalidate(c2)

                for t in threads:
                    t.join(join_timeout)

        eq_(len(success), 12, "successes: %s" % success)

    def test_connrec_invalidated_within_checkout_no_race(self):
        """Test that a concurrent ConnectionRecord.invalidate() which
        occurs after the ConnectionFairy has called
        _ConnectionRecord.checkout()
        but before the ConnectionFairy tests "fairy.dbapi_connection is None"
        will not result in an InvalidRequestError.

        This use case assumes that a listener on the checkout() event
        will be raising DisconnectionError so that a reconnect attempt
        may occur.

        """
        dbapi = MockDBAPI()

        def creator():
            return dbapi.connect()

        p = pool.QueuePool(creator=creator, pool_size=1, max_overflow=0)

        conn = p.connect()
        conn.close()

        _existing_checkout = pool._ConnectionRecord.checkout

        @classmethod
        def _decorate_existing_checkout(cls, *arg, **kw):
            fairy = _existing_checkout(*arg, **kw)
            connrec = fairy._connection_record
            connrec.invalidate()
            return fairy

        with patch(
            "sqlalchemy.pool._ConnectionRecord.checkout",
            _decorate_existing_checkout,
        ):
            conn = p.connect()
            is_(conn._connection_record.dbapi_connection, None)
        conn.close()

    @testing.requires.threading_with_mock
    @testing.requires.timing_intensive
    def test_notify_waiters(self):
        dbapi = MockDBAPI()

        canary = []

        def creator():
            canary.append(1)
            return dbapi.connect()

        p1 = pool.QueuePool(
            creator=creator, pool_size=1, timeout=None, max_overflow=0
        )

        def waiter(p):
            conn = p.connect()
            canary.append(2)
            time.sleep(0.5)
            conn.close()

        c1 = p1.connect()

        threads = []
        for i in range(5):
            t = threading.Thread(target=waiter, args=(p1,))
            t.start()
            threads.append(t)
        time.sleep(0.5)
        eq_(canary, [1])

        # this also calls invalidate()
        # on c1
        p1._invalidate(c1)

        for t in threads:
            t.join(join_timeout)

        eq_(canary, [1, 1, 2, 2, 2, 2, 2])

    def test_dispose_closes_pooled(self):
        dbapi = MockDBAPI()

        p = pool.QueuePool(
            creator=dbapi.connect, pool_size=2, timeout=None, max_overflow=0
        )
        c1 = p.connect()
        c2 = p.connect()
        c1_con = c1.dbapi_connection
        c2_con = c2.dbapi_connection

        c1.close()

        eq_(c1_con.close.call_count, 0)
        eq_(c2_con.close.call_count, 0)

        p.dispose()

        eq_(c1_con.close.call_count, 1)
        eq_(c2_con.close.call_count, 0)

        # currently, if a ConnectionFairy is closed
        # after the pool has been disposed, there's no
        # flag that states it should be invalidated
        # immediately - it just gets returned to the
        # pool normally...
        c2.close()
        eq_(c1_con.close.call_count, 1)
        eq_(c2_con.close.call_count, 0)

        # ...and that's the one we'll get back next.
        c3 = p.connect()
        assert c3.dbapi_connection is c2_con

    @testing.requires.threading_with_mock
    @testing.requires.timing_intensive
    def test_no_overflow(self):
        self._test_overflow(40, 0)

    @testing.requires.threading_with_mock
    @testing.requires.timing_intensive
    def test_max_overflow(self):
        self._test_overflow(40, 5)

    def test_overflow_no_gc(self):
        p = self._queuepool_fixture(pool_size=2, max_overflow=2)

        # disable weakref collection of the
        # underlying connections
        strong_refs = set()

        def _conn():
            c = p.connect()
            strong_refs.add(c.dbapi_connection)
            return c

        for j in range(5):
            # open 4 conns at a time.  each time this
            # will yield two pooled connections + two
            # overflow connections.
            conns = [_conn() for i in range(4)]
            for c in conns:
                c.close()

        # doing that for a total of 5 times yields
        # ten overflow connections closed plus the
        # two pooled connections unclosed.

        eq_(
            set([c.close.call_count for c in strong_refs]),
            set([1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 0]),
        )

    def test_recycle(self):
        with patch("sqlalchemy.pool.base.time.time") as mock:
            mock.return_value = 10000

            p = self._queuepool_fixture(
                pool_size=1, max_overflow=0, recycle=30
            )
            c1 = p.connect()
            c_ref = weakref.ref(c1.dbapi_connection)
            c1.close()
            mock.return_value = 10001
            c2 = p.connect()

            is_(c2.dbapi_connection, c_ref())
            c2.close()

            mock.return_value = 10035
            c3 = p.connect()
            is_not(c3.dbapi_connection, c_ref())

    @testing.requires.timing_intensive
    def test_recycle_on_invalidate(self):
        p = self._queuepool_fixture(pool_size=1, max_overflow=0)
        c1 = p.connect()
        c_ref = weakref.ref(c1.dbapi_connection)
        c1.close()
        c2 = p.connect()
        is_(c2.dbapi_connection, c_ref())

        c2_rec = c2._connection_record
        p._invalidate(c2)
        assert c2_rec.dbapi_connection is None
        c2.close()
        time.sleep(0.5)
        c3 = p.connect()

        is_not(c3.dbapi_connection, c_ref())

    @testing.requires.timing_intensive
    def test_recycle_on_soft_invalidate(self):
        p = self._queuepool_fixture(pool_size=1, max_overflow=0)
        c1 = p.connect()
        c_ref = weakref.ref(c1.dbapi_connection)
        c1.close()
        c2 = p.connect()
        is_(c2.dbapi_connection, c_ref())

        c2_rec = c2._connection_record

        # ensure pool invalidate time will be later than starttime
        # for ConnectionRecord objects above
        time.sleep(0.1)
        c2.invalidate(soft=True)

        is_(c2_rec.dbapi_connection, c2.dbapi_connection)

        c2.close()

        c3 = p.connect()
        is_not(c3.dbapi_connection, c_ref())
        is_(c3._connection_record, c2_rec)
        is_(c2_rec.dbapi_connection, c3.dbapi_connection)

    def _no_wr_finalize(self):
        finalize_fairy = pool._finalize_fairy

        def assert_no_wr_callback(
            connection, connection_record, pool, ref, echo, fairy=None
        ):
            if fairy is None:
                raise AssertionError(
                    "finalize fairy was called as a weakref callback"
                )
            return finalize_fairy(
                connection, connection_record, pool, ref, echo, fairy
            )

        return patch.object(pool, "_finalize_fairy", assert_no_wr_callback)

    def _assert_cleanup_on_pooled_reconnect(self, dbapi, p, exc_cls=Exception):
        # p is QueuePool with size=1, max_overflow=2,
        # and one connection in the pool that will need to
        # reconnect when next used (either due to recycle or invalidate)

        with self._no_wr_finalize():
            eq_(p.checkedout(), 0)
            eq_(p._overflow, 0)
            dbapi.shutdown(True)
            assert_raises_context_ok(exc_cls, p.connect)
            eq_(p._overflow, 0)

            eq_(p.checkedout(), 0)  # and not 1

            dbapi.shutdown(False)

            c1 = self._with_teardown(p.connect())  # noqa
            assert p._pool.empty()  # poolsize is one, so we're empty OK
            c2 = self._with_teardown(p.connect())  # noqa
            eq_(p._overflow, 1)  # and not 2

            # this hangs if p._overflow is 2
            c3 = self._with_teardown(p.connect())

            c3.close()

    def test_error_on_pooled_reconnect_cleanup_invalidate(self):
        dbapi, p = self._queuepool_dbapi_fixture(pool_size=1, max_overflow=2)
        c1 = p.connect()
        c1.invalidate()
        c1.close()
        self._assert_cleanup_on_pooled_reconnect(dbapi, p)

    @testing.requires.timing_intensive
    def test_error_on_pooled_reconnect_cleanup_recycle(self):
        dbapi, p = self._queuepool_dbapi_fixture(
            pool_size=1, max_overflow=2, recycle=1
        )
        c1 = p.connect()
        c1.close()
        time.sleep(1.5)
        self._assert_cleanup_on_pooled_reconnect(dbapi, p)

    @testing.requires.timing_intensive
    def test_connect_handler_not_called_for_recycled(self):
        """test [ticket:3497]"""

        dbapi, p = self._queuepool_dbapi_fixture(pool_size=2, max_overflow=2)

        canary = Mock()

        c1 = p.connect()
        c2 = p.connect()

        c1.close()
        c2.close()

        dbapi.shutdown(True)

        # ensure pool invalidate time will be later than starttime
        # for ConnectionRecord objects above
        time.sleep(0.1)

        bad = p.connect()
        p._invalidate(bad)
        bad.close()
        assert p._invalidate_time

        event.listen(p, "connect", canary.connect)
        event.listen(p, "checkout", canary.checkout)

        assert_raises(Exception, p.connect)

        p._pool.queue = collections.deque(
            [c for c in p._pool.queue if c.dbapi_connection is not None]
        )

        dbapi.shutdown(False)
        c = p.connect()
        c.close()

        eq_(
            canary.mock_calls,
            [call.connect(ANY, ANY), call.checkout(ANY, ANY, ANY)],
        )

    @testing.requires.timing_intensive
    def test_connect_checkout_handler_always_gets_info(self):
        """test [ticket:3497]"""

        dbapi, p = self._queuepool_dbapi_fixture(pool_size=2, max_overflow=2)

        c1 = p.connect()
        c2 = p.connect()

        c1.close()
        c2.close()

        dbapi.shutdown(True)

        # ensure pool invalidate time will be later than starttime
        # for ConnectionRecord objects above
        time.sleep(0.1)

        bad = p.connect()
        p._invalidate(bad)
        bad.close()
        assert p._invalidate_time

        @event.listens_for(p, "connect")
        def connect(conn, conn_rec):
            conn_rec.info["x"] = True

        @event.listens_for(p, "checkout")
        def checkout(conn, conn_rec, conn_f):
            assert "x" in conn_rec.info

        assert_raises(Exception, p.connect)

        p._pool.queue = collections.deque(
            [c for c in p._pool.queue if c.dbapi_connection is not None]
        )

        dbapi.shutdown(False)
        c = p.connect()
        c.close()

    @testing.variation("exc_type", ["plain", "base_exception"])
    def test_error_on_pooled_reconnect_cleanup_wcheckout_event(self, exc_type):
        dbapi, p = self._queuepool_dbapi_fixture(pool_size=1, max_overflow=2)

        c1 = p.connect()
        c1.close()

        if exc_type.plain:

            @event.listens_for(p, "checkout")
            def handle_checkout_event(dbapi_con, con_record, con_proxy):
                if dbapi.is_shutdown:
                    raise tsa.exc.DisconnectionError()

        elif exc_type.base_exception:

            class TimeoutThing(BaseException):
                pass

            @event.listens_for(p, "checkout")
            def handle_checkout_event(dbapi_con, con_record, con_proxy):
                if dbapi.is_shutdown:
                    raise TimeoutThing()

        else:
            exc_type.fail()

        self._assert_cleanup_on_pooled_reconnect(
            dbapi,
            p,
            exc_cls=TimeoutThing if exc_type.base_exception else Exception,
        )

    @testing.variation(
        "detach_gced",
        [("detached_gc", testing.requires.asyncio), "normal_gc"],
    )
    @testing.emits_warning("The garbage collector")
    @testing.requires.python3
    def test_userspace_disconnectionerror_weakref_finalizer(self, detach_gced):
        dbapi, pool = self._queuepool_dbapi_fixture(
            pool_size=1, max_overflow=2, _is_asyncio=detach_gced
        )

        if detach_gced:
            pool._dialect.is_async = True

        @event.listens_for(pool, "checkout")
        def handle_checkout_event(dbapi_con, con_record, con_proxy):
            if getattr(dbapi_con, "boom") == "yes":
                raise tsa.exc.DisconnectionError()

        conn = pool.connect()
        old_dbapi_conn = conn.dbapi_connection
        conn.close()

        eq_(old_dbapi_conn.mock_calls, [call.rollback()])

        old_dbapi_conn.boom = "yes"

        conn = pool.connect()
        dbapi_conn = conn.dbapi_connection
        del conn
        gc_collect()

        if detach_gced:
            # new connection was detached + abandoned on return
            eq_(dbapi_conn.mock_calls, [])
        else:
            # new connection reset and returned to pool
            eq_(dbapi_conn.mock_calls, [call.rollback()])

        # old connection was just closed - did not get an
        # erroneous reset on return
        eq_(old_dbapi_conn.mock_calls, [call.rollback(), call.close()])

    @testing.requires.timing_intensive
    def test_recycle_pool_no_race(self):
        def slow_close():
            slow_closing_connection._slow_close()
            time.sleep(0.5)

        slow_closing_connection = Mock()
        slow_closing_connection.connect.return_value.close = slow_close

        class Error(Exception):
            pass

        dialect = Mock()
        dialect.is_disconnect = lambda *arg, **kw: True
        dialect.dbapi.Error = Error

        pools = []

        class TrackQueuePool(pool.QueuePool):
            def __init__(self, *arg, **kw):
                pools.append(self)
                super(TrackQueuePool, self).__init__(*arg, **kw)

        def creator():
            return slow_closing_connection.connect()

        p1 = TrackQueuePool(creator=creator, pool_size=20)

        from sqlalchemy import create_engine

        eng = create_engine(testing.db.url, pool=p1, _initialize=False)
        eng.dialect = dialect

        # 15 total connections
        conns = [eng.connect() for i in range(15)]

        # return 8 back to the pool
        for conn in conns[3:10]:
            conn.close()

        def attempt(conn):
            time.sleep(random.random())
            try:
                conn._handle_dbapi_exception(
                    Error(), "statement", {}, Mock(), Mock()
                )
            except tsa.exc.DBAPIError:
                pass

        # run an error + invalidate operation on the remaining 7 open
        # connections
        threads = []
        for conn in conns:
            t = threading.Thread(target=attempt, args=(conn,))
            t.start()
            threads.append(t)

        for t in threads:
            t.join()

        # return all 15 connections to the pool
        for conn in conns:
            conn.close()

        # re-open 15 total connections
        conns = [eng.connect() for i in range(15)]

        # 15 connections have been fully closed due to invalidate
        assert slow_closing_connection._slow_close.call_count == 15

        # 15 initial connections + 15 reconnections
        assert slow_closing_connection.connect.call_count == 30
        assert len(pools) <= 2, len(pools)

    def test_invalidate(self):
        p = self._queuepool_fixture(pool_size=1, max_overflow=0)
        c1 = p.connect()
        c_id = c1.dbapi_connection.id
        c1.close()
        c1 = None
        c1 = p.connect()
        assert c1.dbapi_connection.id == c_id
        c1.invalidate()
        c1 = None
        c1 = p.connect()
        assert c1.dbapi_connection.id != c_id

    def test_recreate(self):
        p = self._queuepool_fixture(
            reset_on_return=None, pool_size=1, max_overflow=0
        )
        p2 = p.recreate()
        assert p2.size() == 1
        assert p2._reset_on_return is pool.reset_none
        assert p2._max_overflow == 0

    def test_reconnect(self):
        """tests reconnect operations at the pool level.  SA's
        engine/dialect includes another layer of reconnect support for
        'database was lost' errors."""

        dbapi, p = self._queuepool_dbapi_fixture(pool_size=1, max_overflow=0)
        c1 = p.connect()
        c_id = c1.dbapi_connection.id
        c1.close()
        c1 = None
        c1 = p.connect()
        assert c1.dbapi_connection.id == c_id
        dbapi.raise_error = True
        c1.invalidate()
        c1 = None
        c1 = p.connect()
        assert c1.dbapi_connection.id != c_id

    def test_detach(self):
        dbapi, p = self._queuepool_dbapi_fixture(pool_size=1, max_overflow=0)
        c1 = p.connect()
        c1.detach()
        c2 = p.connect()  # noqa
        eq_(dbapi.connect.mock_calls, [call("foo.db"), call("foo.db")])

        c1_con = c1.dbapi_connection
        assert c1_con is not None
        eq_(c1_con.close.call_count, 0)
        c1.close()
        eq_(c1_con.close.call_count, 1)

    def test_detach_via_invalidate(self):
        dbapi, p = self._queuepool_dbapi_fixture(pool_size=1, max_overflow=0)

        c1 = p.connect()
        c1_con = c1.dbapi_connection
        c1.invalidate()
        assert c1.dbapi_connection is None
        eq_(c1_con.close.call_count, 1)

        c2 = p.connect()
        assert c2.dbapi_connection is not c1_con
        c2_con = c2.dbapi_connection

        c2.close()
        eq_(c2_con.close.call_count, 0)

    def test_no_double_checkin(self):
        p = self._queuepool_fixture(pool_size=1)

        c1 = p.connect()
        rec = c1._connection_record
        c1.close()
        assert_warns_message(
            Warning, "Double checkin attempted on %s" % rec, rec.checkin
        )

    def test_lifo(self):
        c1, c2, c3 = Mock(), Mock(), Mock()
        connections = [c1, c2, c3]

        def creator():
            return connections.pop(0)

        p = pool.QueuePool(creator, use_lifo=True)

        pc1 = p.connect()
        pc2 = p.connect()
        pc3 = p.connect()

        pc1.close()
        pc2.close()
        pc3.close()

        for i in range(5):
            pc1 = p.connect()
            is_(pc1.dbapi_connection, c3)
            pc1.close()

            pc1 = p.connect()
            is_(pc1.dbapi_connection, c3)

            pc2 = p.connect()
            is_(pc2.dbapi_connection, c2)
            pc2.close()

            pc3 = p.connect()
            is_(pc3.dbapi_connection, c2)

            pc2 = p.connect()
            is_(pc2.dbapi_connection, c1)

            pc2.close()
            pc3.close()
            pc1.close()

    def test_fifo(self):
        c1, c2, c3 = Mock(), Mock(), Mock()
        connections = [c1, c2, c3]

        def creator():
            return connections.pop(0)

        p = pool.QueuePool(creator)

        pc1 = p.connect()
        pc2 = p.connect()
        pc3 = p.connect()

        pc1.close()
        pc2.close()
        pc3.close()

        pc1 = p.connect()
        is_(pc1.dbapi_connection, c1)
        pc1.close()

        pc1 = p.connect()
        is_(pc1.dbapi_connection, c2)

        pc2 = p.connect()
        is_(pc2.dbapi_connection, c3)
        pc2.close()

        pc3 = p.connect()
        is_(pc3.dbapi_connection, c1)

        pc2 = p.connect()
        is_(pc2.dbapi_connection, c3)

        pc2.close()
        pc3.close()
        pc1.close()


class ResetOnReturnTest(PoolTestBase):
    def _fixture(self, **kw):
        dbapi = Mock()
        return (
            dbapi,
            pool.QueuePool(creator=lambda: dbapi.connect("foo.db"), **kw),
        )

    def _engine_fixture(self, **kw):
        dbapi = Mock()

        return dbapi, create_engine(
            "postgresql://",
            module=dbapi,
            creator=lambda: dbapi.connect("foo.db"),
            _initialize=False,
        )

    def test_custom(self):
        dbapi, p = self._fixture(reset_on_return=None)

        @event.listens_for(p, "reset")
        def custom_reset(dbapi_conn, record):
            dbapi_conn.special_reset_method()

        c1 = p.connect()
        c1.close()

        assert dbapi.connect().special_reset_method.called
        assert not dbapi.connect().rollback.called
        assert not dbapi.connect().commit.called

    @testing.combinations(True, False, argnames="assert_w_event")
    @testing.combinations(True, False, argnames="use_engine_transaction")
    def test_custom_via_engine(self, assert_w_event, use_engine_transaction):
        dbapi, engine = self._engine_fixture(reset_on_return=None)

        if assert_w_event:

            @event.listens_for(engine, "reset")
            def custom_reset(dbapi_conn, record):
                dbapi_conn.special_reset_method()

        c1 = engine.connect()
        if use_engine_transaction:
            c1.begin()
        c1.close()
        assert dbapi.connect().rollback.called

        if assert_w_event:
            assert dbapi.connect().special_reset_method.called

    @testing.combinations(True, False, argnames="assert_w_event")
    def test_plain_rollback(self, assert_w_event):
        dbapi, p = self._fixture(reset_on_return="rollback")

        if assert_w_event:

            @event.listens_for(p, "reset")
            def custom_reset(dbapi_conn, record):
                dbapi_conn.special_reset_method()

        c1 = p.connect()
        c1.close()
        assert dbapi.connect().rollback.called
        assert not dbapi.connect().commit.called

        if assert_w_event:
            assert dbapi.connect().special_reset_method.called

    @testing.combinations(True, False, argnames="assert_w_event")
    @testing.combinations(True, False, argnames="use_engine_transaction")
    def test_plain_rollback_via_engine(
        self, assert_w_event, use_engine_transaction
    ):
        dbapi, engine = self._engine_fixture(reset_on_return="rollback")

        if assert_w_event:

            @event.listens_for(engine, "reset")
            def custom_reset(dbapi_conn, record):
                dbapi_conn.special_reset_method()

        c1 = engine.connect()
        if use_engine_transaction:
            c1.begin()
        c1.close()
        assert dbapi.connect().rollback.called

        if assert_w_event:
            assert dbapi.connect().special_reset_method.called

    def test_plain_commit(self):
        dbapi, p = self._fixture(reset_on_return="commit")

        c1 = p.connect()
        c1.close()
        assert not dbapi.connect().rollback.called
        assert dbapi.connect().commit.called

    def test_plain_none(self):
        dbapi, p = self._fixture(reset_on_return=None)

        c1 = p.connect()
        c1.close()
        assert not dbapi.connect().rollback.called
        assert not dbapi.connect().commit.called


class SingletonThreadPoolTest(PoolTestBase):
    @testing.requires.threading_with_mock
    def test_cleanup(self):
        self._test_cleanup(False)

    #   TODO: the SingletonThreadPool cleanup method
    #   has an unfixed race condition within the "cleanup" system that
    #   leads to this test being off by one connection under load; in any
    #   case, this connection will be closed once it is garbage collected.
    #   this pool is not a production-level pool and is only used for the
    #   SQLite "memory" connection, and is not very useful under actual
    #   multi-threaded conditions
    #    @testing.requires.threading_with_mock
    #    def test_cleanup_no_gc(self):
    #       self._test_cleanup(True)

    def _test_cleanup(self, strong_refs):
        """test that the pool's connections are OK after cleanup() has
        been called."""

        dbapi = MockDBAPI()

        lock = threading.Lock()

        def creator():
            # the mock iterator isn't threadsafe...
            with lock:
                return dbapi.connect()

        p = pool.SingletonThreadPool(creator=creator, pool_size=3)

        if strong_refs:
            sr = set()

            def _conn():
                c = p.connect()
                sr.add(c.dbapi_connection)
                return c

        else:

            def _conn():
                return p.connect()

        def checkout():
            for x in range(10):
                c = _conn()
                assert c
                c.cursor()
                c.close()
                time.sleep(0.01)

        threads = []
        for i in range(10):
            th = threading.Thread(target=checkout)
            th.start()
            threads.append(th)
        for th in threads:
            th.join(join_timeout)

        lp = len(p._all_conns)
        is_true(3 <= lp <= 4)

        if strong_refs:
            still_opened = len([c for c in sr if not c.close.call_count])
            eq_(still_opened, 3)

    def test_no_rollback_from_nested_connections(self):
        dbapi = MockDBAPI()

        lock = threading.Lock()

        def creator():
            # the mock iterator isn't threadsafe...
            with lock:
                return dbapi.connect()

        p = pool.SingletonThreadPool(creator=creator, pool_size=3)

        c1 = p.connect()
        mock_conn = c1.dbapi_connection

        c2 = p.connect()
        is_(c1, c2)

        c2.close()

        eq_(mock_conn.mock_calls, [])
        c1.close()

        eq_(mock_conn.mock_calls, [call.rollback()])


class AssertionPoolTest(PoolTestBase):
    def test_connect_error(self):
        dbapi = MockDBAPI()
        p = pool.AssertionPool(creator=lambda: dbapi.connect("foo.db"))
        c1 = p.connect()  # noqa
        assert_raises(AssertionError, p.connect)

    def test_connect_multiple(self):
        dbapi = MockDBAPI()
        p = pool.AssertionPool(creator=lambda: dbapi.connect("foo.db"))
        c1 = p.connect()
        c1.close()
        c2 = p.connect()
        c2.close()

        c3 = p.connect()  # noqa
        assert_raises(AssertionError, p.connect)


class NullPoolTest(PoolTestBase):
    def test_reconnect(self):
        dbapi = MockDBAPI()
        p = pool.NullPool(creator=lambda: dbapi.connect("foo.db"))
        c1 = p.connect()

        c1.close()
        c1 = None

        c1 = p.connect()
        c1.invalidate()
        c1 = None

        c1 = p.connect()
        dbapi.connect.assert_has_calls(
            [call("foo.db"), call("foo.db")], any_order=True
        )


class StaticPoolTest(PoolTestBase):
    def test_recreate(self):
        dbapi = MockDBAPI()

        def creator():
            return dbapi.connect("foo.db")

        p = pool.StaticPool(creator)
        p2 = p.recreate()
        assert p._creator is p2._creator

    def test_connect(self):
        dbapi = MockDBAPI()

        def creator():
            return dbapi.connect("foo.db")

        p = pool.StaticPool(creator)

        c1 = p.connect()
        conn = c1.dbapi_connection
        c1.close()

        c2 = p.connect()
        is_(conn, c2.dbapi_connection)


class CreatorCompatibilityTest(PoolTestBase):
    def test_creator_callable_outside_noarg(self):
        e = testing_engine()

        creator = e.pool._creator
        try:
            conn = creator()
        finally:
            conn.close()

    def test_creator_callable_outside_witharg(self):
        e = testing_engine()

        creator = e.pool._creator
        try:
            conn = creator(Mock())
        finally:
            conn.close()

    def test_creator_patching_arg_to_noarg(self):
        e = testing_engine()
        creator = e.pool._creator
        try:
            # the creator is the two-arg form
            conn = creator(Mock())
        finally:
            conn.close()

        def mock_create():
            return creator()

        conn = e.connect()
        conn.invalidate()
        conn.close()

        # test that the 'should_wrap_creator' status
        # will dynamically switch if the _creator is monkeypatched.

        # patch it with a zero-arg form
        with patch.object(e.pool, "_creator", mock_create):
            conn = e.connect()
            conn.invalidate()
            conn.close()

        conn = e.connect()
        conn.close()