Merge "Turn off pyodbc setinputsizes() by default"

3 files changed, 38 insertions, 3 deletions

diff --git a/lib/sqlalchemy/connectors/pyodbc.py b/lib/sqlalchemy/connectors/pyodbc.py
index aa14cd9aa..ddff62db6 100644
--- a/lib/sqlalchemy/connectors/pyodbc.py
+++ b/lib/sqlalchemy/connectors/pyodbc.py
@@ -24,16 +24,19 @@ class PyODBCConnector(Connector):
     supports_native_decimal = True
     default_paramstyle = "named"
 
-    use_setinputsizes = True
+    use_setinputsizes = False
 
     # for non-DSN connections, this *may* be used to
     # hold the desired driver name
     pyodbc_driver_name = None
 
-    def __init__(self, supports_unicode_binds=None, **kw):
+    def __init__(
+        self, supports_unicode_binds=None, use_setinputsizes=False, **kw
+    ):
         super(PyODBCConnector, self).__init__(**kw)
         if supports_unicode_binds is not None:
             self.supports_unicode_binds = supports_unicode_binds
+        self.use_setinputsizes = use_setinputsizes
 
     @classmethod
     def dbapi(cls):
@@ -163,6 +166,10 @@ class PyODBCConnector(Connector):
         # for the subsequent values if you don't pass a tuple which fails
         # for types such as pyodbc.SQL_WLONGVARCHAR, which is the datatype
         # that ticket #5649 is targeting.
+
+        # NOTE: as of #6058, this won't be called if the use_setinputsizes flag
+        # is False, or if no types were specified in list_of_tuples
+
         cursor.setinputsizes(
             [
                 (dbtype, None, None)
diff --git a/lib/sqlalchemy/dialects/mssql/pyodbc.py b/lib/sqlalchemy/dialects/mssql/pyodbc.py
index 96ac2dff7..ba4fc84ec 100644
--- a/lib/sqlalchemy/dialects/mssql/pyodbc.py
+++ b/lib/sqlalchemy/dialects/mssql/pyodbc.py
@@ -56,7 +56,7 @@ Other keywords interpreted by the Pyodbc dialect to be passed to
 ``authentication``.
 Note that in order for the dialect to recognize these keywords
 (including the ``driver`` keyword above) they must be all lowercase.
-Multiple additional keyword arguments must be separated by an 
+Multiple additional keyword arguments must be separated by an
 ampersand (``&``), not a semicolon::
 
     engine = create_engine(
@@ -158,6 +158,23 @@ driver in order to use this flag::
     `fast executemany <https://github.com/mkleehammer/pyodbc/wiki/Features-beyond-the-DB-API#fast_executemany>`_
     - on github
 
+.. _mssql_pyodbc_setinputsizes:
+
+Setinputsizes Support
+-----------------------
+
+The pyodbc ``cursor.setinputsizes()`` method can be used if necessary.  To
+enable this hook, pass ``use_setinputsizes=True`` to :func:`_sa.create_engine`::
+
+    engine = create_engine("mssql+pyodbc://...", use_setinputsizes=True)
+
+The behavior of the hook can then be customized, as may be necessary
+particularly if fast_executemany is in use, via the
+:meth:`.DialectEvents.do_setinputsizes` hook. See that method for usage
+examples.
+
+.. versionchanged:: 1.4.1  The pyodbc dialects will not use setinputsizes
+   unless ``use_setinputsizes=True`` is passed.
 
 """  # noqa
 
diff --git a/lib/sqlalchemy/engine/events.py b/lib/sqlalchemy/engine/events.py
index fb8e5aeb2..c6e27c03c 100644
--- a/lib/sqlalchemy/engine/events.py
+++ b/lib/sqlalchemy/engine/events.py
@@ -796,6 +796,17 @@ class DialectEvents(event.Events):
         the flag ``use_setinputsizes=True``.  Dialects which use this
         include cx_Oracle, pg8000, asyncpg, and pyodbc dialects.
 
+        .. note::
+
+            For use with pyodbc, the ``use_setinputsizes`` flag
+            must be passed to the dialect, e.g.::
+
+                create_engine("mssql+pyodbc://...", use_setinputsizes=True)
+
+            .. seealso::
+
+                  :ref:`mssql_pyodbc_setinputsizes`
+
         .. versionadded:: 1.2.9
 
         .. seealso::