establish consistency for RETURNING column labels

The RETURNING clause now renders columns using the routine as that of the
:class:`.Select` to generate labels, which will include disambiguating
labels, as well as that a SQL function surrounding a named column will be
labeled using the column name itself. This is a more comprehensive change
than a similar one made for the 1.4 series that adjusted the function label
issue only.

includes 1.4's changelog for the backported version which also
fixes an Oracle issue independently of the 2.0 series.

Fixes: #8770
Change-Id: I2ab078a214a778ffe1720dbd864ae4c105a0691d

1 files changed, 30 insertions, 0 deletions

diff --git a/test/dialect/postgresql/test_compiler.py b/test/dialect/postgresql/test_compiler.py
index 96a8e7d5a..338d0da4e 100644
--- a/test/dialect/postgresql/test_compiler.py
+++ b/test/dialect/postgresql/test_compiler.py
@@ -61,6 +61,7 @@ from sqlalchemy.testing.assertions import AssertsCompiledSQL
 from sqlalchemy.testing.assertions import eq_ignore_whitespace
 from sqlalchemy.testing.assertions import expect_warnings
 from sqlalchemy.testing.assertions import is_
+from sqlalchemy.types import TypeEngine
 from sqlalchemy.util import OrderedDict
 
 
@@ -200,6 +201,35 @@ class CompileTest(fixtures.TestBase, AssertsCompiledSQL):
             dialect=dialect,
         )
 
+    @testing.fixture
+    def column_expression_fixture(self):
+        class MyString(TypeEngine):
+            def column_expression(self, column):
+                return func.lower(column)
+
+        return table(
+            "some_table", column("name", String), column("value", MyString)
+        )
+
+    @testing.combinations("columns", "table", argnames="use_columns")
+    def test_plain_returning_column_expression(
+        self, column_expression_fixture, use_columns
+    ):
+        """test #8770"""
+        table1 = column_expression_fixture
+
+        if use_columns == "columns":
+            stmt = insert(table1).returning(table1)
+        else:
+            stmt = insert(table1).returning(table1.c.name, table1.c.value)
+
+        self.assert_compile(
+            stmt,
+            "INSERT INTO some_table (name, value) "
+            "VALUES (%(name)s, %(value)s) RETURNING some_table.name, "
+            "lower(some_table.value) AS value",
+        )
+
     def test_create_drop_enum(self):
         # test escaping and unicode within CREATE TYPE for ENUM
         typ = postgresql.ENUM("val1", "val2", "val's 3", "méil", name="myname")