pep-484: the pep-484ening, SQL part three

hitting DML which is causing us to open up the
ColumnCollection structure a bit, as we do put anonymous
column expressions with None here.  However, we still want
Table /TableClause to have named column collections that
don't return None, so parametrize the "key" in this
collection also.

* rename some "immutable" elements to "readonly".  we change
  the contents of immutablecolumncollection underneath, so it's
  not "immutable"

Change-Id: I2593995a4e5c6eae874bed5bf76117198be8ae97

1 files changed, 2 insertions, 2 deletions

diff --git a/lib/sqlalchemy/engine/default.py b/lib/sqlalchemy/engine/default.py
index 65cb57e10..85ce91deb 100644
--- a/lib/sqlalchemy/engine/default.py
+++ b/lib/sqlalchemy/engine/default.py
@@ -54,7 +54,6 @@ from ..sql import expression
 from ..sql._typing import is_tuple_type
 from ..sql.compiler import DDLCompiler
 from ..sql.compiler import SQLCompiler
-from ..sql.elements import ColumnClause
 from ..sql.elements import quoted_name
 from ..sql.schema import default_is_scalar
 
@@ -88,6 +87,7 @@ if typing.TYPE_CHECKING:
     from ..sql.dml import DMLState
     from ..sql.dml import UpdateBase
     from ..sql.elements import BindParameter
+    from ..sql.roles import ColumnsClauseRole
     from ..sql.schema import Column
     from ..sql.schema import ColumnDefault
     from ..sql.type_api import _BindProcessorType
@@ -1166,7 +1166,7 @@ class DefaultExecutionContext(ExecutionContext):
             return ()
 
     @util.memoized_property
-    def returning_cols(self) -> Optional[Sequence[ColumnClause[Any]]]:
+    def returning_cols(self) -> Optional[Sequence[ColumnsClauseRole]]:
         if TYPE_CHECKING:
             assert isinstance(self.compiled, SQLCompiler)
         return self.compiled.returning