Merge "pep484 - SQL internals" into main

4 files changed, 11 insertions, 14 deletions

diff --git a/lib/sqlalchemy/engine/base.py b/lib/sqlalchemy/engine/base.py
index 6a79cdf02..db6d1ef3f 100644
--- a/lib/sqlalchemy/engine/base.py
+++ b/lib/sqlalchemy/engine/base.py
@@ -73,6 +73,7 @@ if typing.TYPE_CHECKING:
     from ..sql.functions import FunctionElement
     from ..sql.schema import ColumnDefault
     from ..sql.schema import HasSchemaAttr
+    from ..sql.schema import SchemaItem
 
 """Defines :class:`_engine.Connection` and :class:`_engine.Engine`.
 
@@ -2015,7 +2016,7 @@ class Connection(ConnectionEventsTarget, inspection.Inspectable["Inspector"]):
     def _run_ddl_visitor(
         self,
         visitorcallable: Type[Union[SchemaGenerator, SchemaDropper]],
-        element: DDLElement,
+        element: SchemaItem,
         **kwargs: Any,
     ) -> None:
         """run a DDL visitor.
@@ -2760,7 +2761,7 @@ class Engine(
     def _run_ddl_visitor(
         self,
         visitorcallable: Type[Union[SchemaGenerator, SchemaDropper]],
-        element: DDLElement,
+        element: SchemaItem,
         **kwargs: Any,
     ) -> None:
         with self.begin() as conn:
diff --git a/lib/sqlalchemy/engine/default.py b/lib/sqlalchemy/engine/default.py
index 4a833d2e5..d605af3ef 100644
--- a/lib/sqlalchemy/engine/default.py
+++ b/lib/sqlalchemy/engine/default.py
@@ -54,7 +54,9 @@ 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
 
 if typing.TYPE_CHECKING:
     from types import ModuleType
@@ -1164,7 +1166,7 @@ class DefaultExecutionContext(ExecutionContext):
             return ()
 
     @util.memoized_property
-    def returning_cols(self) -> Optional[Sequence[Column[Any]]]:
+    def returning_cols(self) -> Optional[Sequence[ColumnClause[Any]]]:
         if TYPE_CHECKING:
             assert isinstance(self.compiled, SQLCompiler)
         return self.compiled.returning
@@ -1778,15 +1780,11 @@ class DefaultExecutionContext(ExecutionContext):
         # to avoid many calls of get_insert_default()/
         # get_update_default()
         for c in insert_prefetch:
-            if c.default and not c.default.is_sequence and c.default.is_scalar:
-                if TYPE_CHECKING:
-                    assert isinstance(c.default, ColumnDefault)
+            if c.default and default_is_scalar(c.default):
                 scalar_defaults[c] = c.default.arg
 
         for c in update_prefetch:
-            if c.onupdate and c.onupdate.is_scalar:
-                if TYPE_CHECKING:
-                    assert isinstance(c.onupdate, ColumnDefault)
+            if c.onupdate and default_is_scalar(c.onupdate):
                 scalar_defaults[c] = c.onupdate.arg
 
         for param in self.compiled_parameters:
@@ -1817,9 +1815,7 @@ class DefaultExecutionContext(ExecutionContext):
         ) = self.compiled_parameters[0]
 
         for c in compiled.insert_prefetch:
-            if c.default and not c.default.is_sequence and c.default.is_scalar:
-                if TYPE_CHECKING:
-                    assert isinstance(c.default, ColumnDefault)
+            if c.default and default_is_scalar(c.default):
                 val = c.default.arg
             else:
                 val = self.get_insert_default(c)
diff --git a/lib/sqlalchemy/engine/mock.py b/lib/sqlalchemy/engine/mock.py
index a0ba96603..c94dd1032 100644
--- a/lib/sqlalchemy/engine/mock.py
+++ b/lib/sqlalchemy/engine/mock.py
@@ -32,6 +32,7 @@ if typing.TYPE_CHECKING:
     from ..sql.ddl import SchemaDropper
     from ..sql.ddl import SchemaGenerator
     from ..sql.schema import HasSchemaAttr
+    from ..sql.schema import SchemaItem
 
 
 class MockConnection:
@@ -55,7 +56,7 @@ class MockConnection:
     def _run_ddl_visitor(
         self,
         visitorcallable: Type[Union[SchemaGenerator, SchemaDropper]],
-        element: DDLElement,
+        element: SchemaItem,
         **kwargs: Any,
     ) -> None:
         kwargs["checkfirst"] = False
diff --git a/lib/sqlalchemy/engine/reflection.py b/lib/sqlalchemy/engine/reflection.py
index e1281365e..b8ece2b1d 100644
--- a/lib/sqlalchemy/engine/reflection.py
+++ b/lib/sqlalchemy/engine/reflection.py
@@ -317,7 +317,6 @@ class Inspector(inspection.Inspectable["Inspector"]):
             with an already-given :class:`_schema.MetaData`.
 
         """
-
         with self._operation_context() as conn:
             tnames = self.dialect.get_table_names(
                 conn, schema, info_cache=self.info_cache