consider truediv as truediv; support floordiv operator

Implemented full support for "truediv" and "floordiv" using the
"/" and "//" operators.  A "truediv" operation between two expressions
using :class:`_types.Integer` now considers the result to be
:class:`_types.Numeric`, and the dialect-level compilation will cast
the right operand to a numeric type on a dialect-specific basis to ensure
truediv is achieved.  For floordiv, conversion is also added for those
databases that don't already do floordiv by default (MySQL, Oracle) and
the ``FLOOR()`` function is rendered in this case, as well as for
cases where the right operand is not an integer (needed for PostgreSQL,
others).

The change resolves issues both with inconsistent behavior of the
division operator on different backends and also fixes an issue where
integer division on Oracle would fail to be able to fetch a result due
to inappropriate outputtypehandlers.

Fixes: #4926
Change-Id: Id54cc018c1fb7a49dd3ce1216d68d40f43fe2659

1 files changed, 86 insertions, 0 deletions

diff --git a/lib/sqlalchemy/testing/suite/test_types.py b/lib/sqlalchemy/testing/suite/test_types.py
index e7131ec6e..78596457e 100644
--- a/lib/sqlalchemy/testing/suite/test_types.py
+++ b/lib/sqlalchemy/testing/suite/test_types.py
@@ -26,6 +26,7 @@ from ... import Float
 from ... import Integer
 from ... import JSON
 from ... import literal
+from ... import literal_column
 from ... import MetaData
 from ... import null
 from ... import Numeric
@@ -505,6 +506,90 @@ class CastTypeDecoratorTest(_LiteralRoundTripFixture, fixtures.TestBase):
         eq_(result, {2})
 
 
+class TrueDivTest(fixtures.TestBase):
+    @testing.combinations(
+        ("15", "10", 1.5),
+        ("-15", "10", -1.5),
+        argnames="left, right, expected",
+    )
+    def test_truediv_integer(self, connection, left, right, expected):
+        """test #4926"""
+
+        eq_(
+            connection.scalar(
+                select(
+                    literal_column(left, type_=Integer())
+                    / literal_column(right, type_=Integer())
+                )
+            ),
+            expected,
+        )
+
+    @testing.combinations(
+        ("15", "10", 1), ("-15", "5", -3), argnames="left, right, expected"
+    )
+    def test_floordiv_integer(self, connection, left, right, expected):
+        """test #4926"""
+
+        eq_(
+            connection.scalar(
+                select(
+                    literal_column(left, type_=Integer())
+                    // literal_column(right, type_=Integer())
+                )
+            ),
+            expected,
+        )
+
+    @testing.combinations(
+        ("5.52", "2.4", "2.3"), argnames="left, right, expected"
+    )
+    def test_truediv_numeric(self, connection, left, right, expected):
+        """test #4926"""
+
+        eq_(
+            connection.scalar(
+                select(
+                    literal_column(left, type_=Numeric())
+                    / literal_column(right, type_=Numeric())
+                )
+            ),
+            decimal.Decimal(expected),
+        )
+
+    @testing.combinations(
+        ("5.52", "2.4", "2.0"), argnames="left, right, expected"
+    )
+    def test_floordiv_numeric(self, connection, left, right, expected):
+        """test #4926"""
+
+        eq_(
+            connection.scalar(
+                select(
+                    literal_column(left, type_=Numeric())
+                    // literal_column(right, type_=Numeric())
+                )
+            ),
+            decimal.Decimal(expected),
+        )
+
+    def test_truediv_integer_bound(self, connection):
+        """test #4926"""
+
+        eq_(
+            connection.scalar(select(literal(15) / literal(10))),
+            1.5,
+        )
+
+    def test_floordiv_integer_bound(self, connection):
+        """test #4926"""
+
+        eq_(
+            connection.scalar(select(literal(15) // literal(10))),
+            1,
+        )
+
+
 class NumericTest(_LiteralRoundTripFixture, fixtures.TestBase):
     __backend__ = True
 
@@ -1439,6 +1524,7 @@ __all__ = (
     "TimeMicrosecondsTest",
     "TimestampMicrosecondsTest",
     "TimeTest",
+    "TrueDivTest",
     "DateTimeMicrosecondsTest",
     "DateHistoricTest",
     "StringTest",