Infer types in BindParameter when expanding=True

Enhanced the "expanding" feature used for :meth:`_sql.ColumnOperators.in_`
operations to infer the type of expression from the right hand list of
elements, if the left hand side does not have any explicit type set up.
This allows the expression to support stringification among other things.
In 1.3, "expanding" was not automatically used for
:meth:`_sql.ColumnOperators.in_` expressions, so in that sense this change
fixes a behavioral regression.

Fixes: #6222
Change-Id: Icdfda1e2c226a21896cafd6d8f251547794451c2

1 files changed, 37 insertions, 0 deletions

diff --git a/test/sql/test_operators.py b/test/sql/test_operators.py
index 0d7f331e0..878360b9d 100644
--- a/test/sql/test_operators.py
+++ b/test/sql/test_operators.py
@@ -1989,6 +1989,23 @@ class InTest(fixtures.TestBase, testing.AssertsCompiledSQL):
             "SELECT t.a FROM t WHERE t.a IN (SELECT scan)",
         )
 
+    def test_type_inference_one(self):
+        expr = column("q").in_([1, 2, 3])
+        is_(expr.right.type._type_affinity, Integer)
+
+        self.assert_compile(expr, "q IN (1, 2, 3)", literal_binds=True)
+
+    def test_type_inference_two(self):
+        expr = column("q").in_([])
+        is_(expr.right.type, sqltypes.NULLTYPE)
+
+        self.assert_compile(
+            expr,
+            "q IN (SELECT 1 WHERE 1!=1)",
+            literal_binds=True,
+            dialect="default_enhanced",
+        )
+
 
 class MathOperatorTest(fixtures.TestBase, testing.AssertsCompiledSQL):
     __dialect__ = "default"
@@ -3075,6 +3092,26 @@ class TupleTypingTest(fixtures.TestBase):
 
         self._assert_types(expr.right.type.types)
 
+    # since we want to infer "binary"
+    @testing.requires.python3
+    def test_tuple_type_expanding_inference(self):
+        a, b, c = column("a"), column("b"), column("c")
+
+        t1 = tuple_(a, b, c)
+        expr = t1.in_([(3, "hi", b"there"), (4, "Q", b"P")])
+
+        eq_(len(expr.right.value), 2)
+
+        self._assert_types(expr.right.type.types)
+
+    @testing.requires.python3
+    def test_tuple_type_plain_inference(self):
+        a, b, c = column("a"), column("b"), column("c")
+
+        t1 = tuple_(a, b, c)
+        expr = t1 == (3, "hi", b"there")
+        self._assert_types(expr.right.type.types)
+
 
 class InSelectableTest(fixtures.TestBase, testing.AssertsCompiledSQL):
     __dialect__ = "default"