remove a few superfluous imports

lib/sqlalchemy/orm/session.py

@@ -1616,7 +1616,6 @@ def _state_session(state):
     return None
 
 # Lazy initialization to avoid circular imports
-unitofwork.object_session = object_session
 unitofwork._state_session = _state_session
 from sqlalchemy.orm import mapper
 mapper._expire_state = _expire_state

lib/sqlalchemy/sql/expression.py

@@ -34,8 +34,8 @@ from sqlalchemy.sql import operators
 from sqlalchemy.sql.visitors import Visitable, cloned_traverse
 import operator
 
-functions, schema, sql_util, sqltypes = None, None, None, None
-DefaultDialect, ClauseAdapter, Annotated = None, None, None
+functions, sql_util, sqltypes = None, None, None
+DefaultDialect = None
 
 __all__ = [
     'Alias', 'ClauseElement',
@@ -1075,10 +1075,10 @@ class ClauseElement(Visitable):
         dictionary.
         
         """
-        global Annotated
-        if Annotated is None:
-            from sqlalchemy.sql.util import Annotated
-        return Annotated(self, values)
+        global sql_util
+        if sql_util is None:
+            from sqlalchemy.sql import util as sql_util
+        return sql_util.Annotated(self, values)
 
     def _deannotate(self):
         """return a copy of this ClauseElement with an empty annotations
@@ -1973,10 +1973,11 @@ class FromClause(Selectable):
         object, returning a copy of this :class:`FromClause`.
         
         """
-        global ClauseAdapter
-        if ClauseAdapter is None:
-            from sqlalchemy.sql.util import ClauseAdapter
-        return ClauseAdapter(alias).traverse(self)
+
+        global sql_util
+        if sql_util is None:
+            from sqlalchemy.sql import util as sql_util
+        return sql_util.ClauseAdapter(alias).traverse(self)
 
     def correspond_on_equivalents(self, column, equivalents):
         """Return corresponding_column for the given column, or if None

lib/sqlalchemy/sql/util.py

@@ -288,7 +288,6 @@ class Annotated(object):
 # so that the resulting objects are pickleable.
 annotated_classes = {}
 
-from sqlalchemy.sql import expression
 for cls in expression.__dict__.values() + [schema.Column, schema.Table]:
     if isinstance(cls, type) and issubclass(cls, expression.ClauseElement):
         exec "class Annotated%s(Annotated, cls):\n" \

lib/sqlalchemy/types.py

@@ -1285,9 +1285,8 @@ class SchemaType(object):
     def create(self, bind=None, checkfirst=False):
         """Issue CREATE ddl for this type, if applicable."""
         
-        from sqlalchemy.schema import _bind_or_error
         if bind is None:
-            bind = _bind_or_error(self)
+            bind = schema._bind_or_error(self)
         t = self.dialect_impl(bind.dialect)
         if t is not self and isinstance(t, SchemaType):
             t.create(bind=bind, checkfirst=checkfirst)
@@ -1295,9 +1294,8 @@ class SchemaType(object):
     def drop(self, bind=None, checkfirst=False):
         """Issue DROP ddl for this type, if applicable."""
 
-        from sqlalchemy.schema import _bind_or_error
         if bind is None:
-            bind = _bind_or_error(self)
+            bind = schema._bind_or_error(self)
         t = self.dialect_impl(bind.dialect)
         if t is not self and isinstance(t, SchemaType):
             t.drop(bind=bind, checkfirst=checkfirst)