Add support for newer pg8000.

Fixes #438

CHANGES.rst

@@ -11,6 +11,8 @@
 - Make more conflict errors include information about the OIDs and
   TIDs that may have been involved in the conflict.
 
+- Add support for pg8000 1.17 and newer; tested with 1.19.2. See
+  :issue:`438`.
 
 3.4.2 (2021-04-21)
 ==================

setup.py

@@ -258,8 +258,7 @@ def read_file(*path):
             # pure-python
             # pg8000 on Python 2.7 or PyPy. We get coverage from Travis, and we also
             # get Windows.
-            # 1.17 breaks us: https://github.com/zodb/relstorage/issues/438
-            'pg8000 >= 1.11.0, <1.17.0; python_version == "2.7" or platform_python_implementation == "PyPy"',
+            'pg8000 >= 1.11.0 ; python_version == "2.7" or platform_python_implementation == "PyPy"',
             # CFFI, runs on all implementations.
             # We get coverage from 3.5 on Travis and verification it works on Windows from Travis.
             # We get 2.7 testing from PyPy on Travis.

src/relstorage/adapters/postgresql/drivers/pg8000.py

@@ -92,10 +92,12 @@ class Cursor(self.driver_module.Cursor):
                 def __init__(self, conn):
                     super(Cursor, self).__init__(conn)
                     # pylint:disable=access-member-before-definition
-                    assert isinstance(self._cached_rows, deque)
-                    # Make sure rows are tuples, not lists.
-                    # BTrees don't like lists.
-                    self._cached_rows = _tuple_deque()
+                    if hasattr(self, '_cached_rows'):
+                        # This went away in 1.17
+                        assert isinstance(self._cached_rows, deque)
+                        # Make sure rows are tuples, not lists.
+                        # BTrees don't like lists.
+                        self._cached_rows = _tuple_deque()
 
                 @property
                 def connection(self):
@@ -106,6 +108,15 @@ def connection(self):
                 def copy_expert(self, sql, stream):
                     return self.execute(sql, stream=stream)
 
+                def execute(self, *args, **kwargs):
+                    result = super(Cursor, self).execute(*args, **kwargs)
+                    if hasattr(self, '_row_iter'):
+                        # pylint:disable=attribute-defined-outside-init
+                        self._row_iter = iter([
+                            tuple(row) for row in self._row_iter
+                        ])
+                    return result
+
             class Connection(LobConnectionMixin,
                              self.driver_module.Connection):
                 readonly = False
@@ -151,6 +162,19 @@ def __init__(self,
                         # 1.16.0 dropped the ``max_prepared_statements`` argument.
                         del kwargs['max_prepared_statements']
                         super(Connection, self).__init__(**kwargs)
+                    if (
+                            hasattr(self, 'py_types')
+                            and list not in self.py_types
+                            and not hasattr(self, 'make_param')
+                    ):
+                        # We're trying to detect pg8000 1.17+ to
+                        # fix https://github.com/zodb/relstorage/issues/438#issuecomment-825116452:
+                        # pg8000 can guess a the parameter type wrong for arrays
+                        # (I only directly observed this issue on pg8000 1.19.2)
+                        # pylint:disable=no-name-in-module,import-error
+                        from pg8000.converters import BIGINT_ARRAY
+                        from pg8000.converters import int_array_out
+                        self.py_types[list] = (BIGINT_ARRAY, int_array_out)
 
                 def cursor(self):
                     return Cursor(self)

src/relstorage/storage/tpc/tests/test_temporary_storage.py

@@ -0,0 +1,66 @@
+# -*- coding: utf-8 -*-
+"""
+Tests for temporary_storage.py
+
+"""
+from __future__ import absolute_import
+from __future__ import division
+from __future__ import print_function
+
+import unittest
+
+class TestTemporaryStorage(unittest.TestCase):
+
+    def _makeOne(self):
+        from ..temporary_storage import TemporaryStorage
+        return TemporaryStorage()
+
+    def setUp(self):
+        super(TestTemporaryStorage, self).setUp()
+        from .. import temporary_storage
+        temporary_storage.id = lambda _: 0xDEADBEEF
+
+    def tearDown(self):
+        from .. import temporary_storage
+        del temporary_storage.id
+        super(TestTemporaryStorage, self).tearDown()
+
+    _EMPTY_STR = '<relstorage.storage.tpc.temporary_storage.TemporaryStorage at 0xdeadbeef len: 0>'
+
+    def test_empty_str(self):
+        temp = self._makeOne()
+        s = str(temp)
+        self.assertEqual(
+            s,
+            self._EMPTY_STR
+        )
+
+    def test_closed_str(self):
+        temp = self._makeOne()
+        temp.close()
+        s = str(temp)
+        self.assertEqual(s, self._EMPTY_STR)
+
+    def test_str_with_data(self):
+        from textwrap import dedent
+        self.maxDiff = None
+        temp = self._makeOne()
+        temp.store_temp(6547, b'defghijkl', 23)
+        temp.store_temp(1, b'abc')
+        temp.store_temp(2, b'def', 42)
+
+        s = str(temp)
+
+        self.assertEqual(
+            s,
+            dedent("""\
+            <relstorage.storage.tpc.temporary_storage.TemporaryStorage at 0xdeadbeef len: 3>
+            ================================================================================
+            | OID                      | Length                   | Previous TID            |
+            ================================================================================
+                                    1  |                        3 |                        0
+                                    2  |                        3 |                       42
+                                 6547  |                        9 |                       23
+            """
+                   )
+        )