reject methods as lambda SQL callables

Added an informative error message when a method object is passed to a SQL
construct. Previously, when such a callable were passed, as is a common
typographical error when dealing with method-chained SQL constructs, they
were interpreted as "lambda SQL" targets to be invoked at compilation time,
which would lead to silent failures. As this feature was not intended to be
used with methods, method objects are now rejected.

Fixes: #7032
Change-Id: If714715bd8c11557ab769ee3b1a24264b0b06acc

1 files changed, 21 insertions, 0 deletions

diff --git a/test/sql/test_lambdas.py b/test/sql/test_lambdas.py
index 43aed0672..96a6ecbf4 100644
--- a/test/sql/test_lambdas.py
+++ b/test/sql/test_lambdas.py
@@ -8,6 +8,7 @@ from sqlalchemy.sql import and_
 from sqlalchemy.sql import bindparam
 from sqlalchemy.sql import coercions
 from sqlalchemy.sql import column
+from sqlalchemy.sql import func
 from sqlalchemy.sql import join
 from sqlalchemy.sql import lambda_stmt
 from sqlalchemy.sql import lambdas
@@ -38,6 +39,26 @@ class LambdaElementTest(
 ):
     __dialect__ = "default"
 
+    def test_reject_methods(self):
+        """test #7032"""
+
+        t1 = table("t1", column("q"), column("p"))
+
+        subq = select(t1).subquery
+
+        with expect_raises_message(
+            exc.ArgumentError,
+            "Method <bound method SelectBase.subquery .* may not be "
+            "passed as a SQL expression",
+        ):
+            select(func.count()).select_from(subq)
+
+        self.assert_compile(
+            select(func.count()).select_from(subq()),
+            "SELECT count(*) AS count_1 FROM "
+            "(SELECT t1.q AS q, t1.p AS p FROM t1) AS anon_1",
+        )
+
     def test_select_whereclause(self):
         t1 = table("t1", column("q"), column("p"))