additional mypy strictness

enable type checking within untyped defs.  This allowed
some more internals to be fixed up with assertions etc.

some internals that were unnecessary or not even used
at all were removed.  BaseCursorResult was no longer
necessary since we only have one kind of CursorResult
now.  The different ResultProxy subclasses that had
alternate "strategies" dont appear to be used at all
even in 1.4.x, as there's no code that accesses the
_cursor_strategy_cls attribute, which is also removed.
As these were mostly private constructs that weren't
even functioning correctly in any case,
it's fine to remove these over the 2.0 boundary.

Change-Id: Ifd536987d104b1cd8b546cefdbd5c1e5d1801082

1 files changed, 4 insertions, 5 deletions

diff --git a/lib/sqlalchemy/sql/compiler.py b/lib/sqlalchemy/sql/compiler.py
index 09e38a5ab..423c3d446 100644
--- a/lib/sqlalchemy/sql/compiler.py
+++ b/lib/sqlalchemy/sql/compiler.py
@@ -34,6 +34,7 @@ import re
 from time import perf_counter
 import typing
 from typing import Any
+from typing import Callable
 from typing import Dict
 from typing import List
 from typing import Mapping
@@ -629,11 +630,11 @@ class SQLCompiler(Compiled):
     """list of columns that can be post-fetched after INSERT or UPDATE to
     receive server-updated values"""
 
-    insert_prefetch: Optional[List[Column[Any]]]
+    insert_prefetch: Sequence[Column[Any]] = ()
     """list of columns for which default values should be evaluated before
     an INSERT takes place"""
 
-    update_prefetch: Optional[List[Column[Any]]]
+    update_prefetch: Sequence[Column[Any]] = ()
     """list of columns for which onupdate default values should be evaluated
     before an UPDATE takes place"""
 
@@ -739,8 +740,6 @@ class SQLCompiler(Compiled):
     """if True, there are bindparam() objects that have the isoutparam
     flag set."""
 
-    insert_prefetch = update_prefetch = ()
-
     postfetch_lastrowid = False
     """if True, and this in insert, use cursor.lastrowid to populate
     result.inserted_primary_key. """
@@ -1340,7 +1339,7 @@ class SQLCompiler(Compiled):
         )
 
     @util.memoized_property
-    def _within_exec_param_key_getter(self):
+    def _within_exec_param_key_getter(self) -> Callable[[Any], str]:
         getter = self._key_getters_for_crud_column[2]
         if self.escaped_bind_names: