Use ternary when running conditional with Query._offset

Fixed bug where using :meth:`.Query.first` or a slice expression in
conjunction with a query that has an expression based "offset" applied
would raise TypeError, due to an "or" conditional against "offset" that did
not expect it to be a SQL expression as opposed to an integer or None.

Fixes: #4803
Change-Id: I56b97a5d23cb45427a27a90ab557fa1ac5c6739e

1 files changed, 9 insertions, 0 deletions

diff --git a/lib/sqlalchemy/testing/requirements.py b/lib/sqlalchemy/testing/requirements.py
index 04537905b..62e600eaa 100644
--- a/lib/sqlalchemy/testing/requirements.py
+++ b/lib/sqlalchemy/testing/requirements.py
@@ -112,6 +112,15 @@ class SuiteRequirements(Requirements):
         return exclusions.open()
 
     @property
+    def sql_expression_limit_offset(self):
+        """target database can render LIMIT and/or OFFSET with a complete
+        SQL expression, such as one that uses the addition operator.
+        parameter
+        """
+
+        return exclusions.open()
+
+    @property
     def parens_in_union_contained_select_w_limit_offset(self):
         """Target database must support parenthesized SELECT in UNION
         when LIMIT/OFFSET is specifically present.