ensure correlate_except is checked for empty tuple

Fixed issue where :meth:`_sql.Select.correlate_except` method, when passed
either the ``None`` value or no arguments, would not correlate any elements
when used in an ORM context (that is, passing ORM entities as FROM
clauses), rather than causing all FROM elements to be considered as
"correlated" in the same way which occurs when using Core-only constructs.

Fixes: #7514
Change-Id: Ic4a5252c8f3c1140aba6c308264948f3a91f33f5

1 files changed, 2 insertions, 2 deletions

diff --git a/lib/sqlalchemy/orm/context.py b/lib/sqlalchemy/orm/context.py
index 7c2d72954..0c1d16d0e 100644
--- a/lib/sqlalchemy/orm/context.py
+++ b/lib/sqlalchemy/orm/context.py
@@ -774,7 +774,7 @@ class ORMSelectCompileState(ORMCompileState, SelectState):
                     for s in query._correlate
                 )
             )
-        elif query._correlate_except:
+        elif query._correlate_except is not None:
             self.correlate_except = tuple(
                 util.flatten_iterator(
                     sql_util.surface_selectables(s) if s is not None else None
@@ -1192,7 +1192,7 @@ class ORMSelectCompileState(ORMCompileState, SelectState):
         if correlate:
             statement.correlate.non_generative(statement, *correlate)
 
-        if correlate_except:
+        if correlate_except is not None:
             statement.correlate_except.non_generative(
                 statement, *correlate_except
             )