- Fixed issue where the columns from a SELECT embedded in an

INSERT, either through the values clause or as a "from select",
would pollute the column types used in the result set produced by
the RETURNING clause when columns from both statements shared the
same name, leading to potential errors or mis-adaptation when
retrieving the returning rows.
fixes #3248

4 files changed, 82 insertions, 0 deletions

diff --git a/doc/build/changelog/changelog_09.rst b/doc/build/changelog/changelog_09.rst
index 8ed2ea776..66a7da8da 100644
--- a/doc/build/changelog/changelog_09.rst
+++ b/doc/build/changelog/changelog_09.rst
@@ -14,6 +14,18 @@
     :version: 0.9.9
 
     .. change::
+        :tags: bug, sql
+        :versions: 1.0.0
+        :tickets: 3248
+
+        Fixed issue where the columns from a SELECT embedded in an
+        INSERT, either through the values clause or as a "from select",
+        would pollute the column types used in the result set produced by
+        the RETURNING clause when columns from both statements shared the
+        same name, leading to potential errors or mis-adaptation when
+        retrieving the returning rows.
+
+    .. change::
         :tags: bug, orm, sqlite
         :versions: 1.0.0
         :tickets: 3241
diff --git a/lib/sqlalchemy/sql/compiler.py b/lib/sqlalchemy/sql/compiler.py
index 5fa78ad0f..8f3ede25f 100644
--- a/lib/sqlalchemy/sql/compiler.py
+++ b/lib/sqlalchemy/sql/compiler.py
@@ -1729,6 +1729,12 @@ class SQLCompiler(Compiled):
         )
 
     def visit_insert(self, insert_stmt, **kw):
+        self.stack.append(
+            {'correlate_froms': set(),
+             "iswrapper": False,
+             "asfrom_froms": set(),
+             "selectable": insert_stmt})
+
         self.isinsert = True
         crud_params = crud._get_crud_params(self, insert_stmt, **kw)
 
@@ -1812,6 +1818,8 @@ class SQLCompiler(Compiled):
         if self.returning and not self.returning_precedes_values:
             text += " " + returning_clause
 
+        self.stack.pop(-1)
+
         return text
 
     def update_limit_clause(self, update_stmt):
diff --git a/test/sql/test_compiler.py b/test/sql/test_compiler.py
index 5d1afe616..9e99a947b 100644
--- a/test/sql/test_compiler.py
+++ b/test/sql/test_compiler.py
@@ -3437,3 +3437,32 @@ class ResultMapTest(fixtures.TestBase):
         is_(
             comp.result_map['t1_a'][1][2], t1.c.a
         )
+
+    def test_insert_with_select_values(self):
+        astring = Column('a', String)
+        aint = Column('a', Integer)
+        m = MetaData()
+        Table('t1', m, astring)
+        t2 = Table('t2', m, aint)
+
+        stmt = t2.insert().values(a=select([astring])).returning(aint)
+        comp = stmt.compile(dialect=postgresql.dialect())
+        eq_(
+            comp.result_map,
+            {'a': ('a', (aint, 'a', 'a'), aint.type)}
+        )
+
+    def test_insert_from_select(self):
+        astring = Column('a', String)
+        aint = Column('a', Integer)
+        m = MetaData()
+        Table('t1', m, astring)
+        t2 = Table('t2', m, aint)
+
+        stmt = t2.insert().from_select(['a'], select([astring])).\
+            returning(aint)
+        comp = stmt.compile(dialect=postgresql.dialect())
+        eq_(
+            comp.result_map,
+            {'a': ('a', (aint, 'a', 'a'), aint.type)}
+        )
diff --git a/test/sql/test_returning.py b/test/sql/test_returning.py
index 79a0b38a5..cd9f632b9 100644
--- a/test/sql/test_returning.py
+++ b/test/sql/test_returning.py
@@ -160,6 +160,39 @@ class ReturningTest(fixtures.TestBase, AssertsExecutionResults):
         eq_(result2.fetchall(), [(2, False), ])
 
 
+class CompositeStatementTest(fixtures.TestBase):
+    __requires__ = 'returning',
+    __backend__ = True
+
+    @testing.provide_metadata
+    def test_select_doesnt_pollute_result(self):
+        class MyType(TypeDecorator):
+            impl = Integer
+
+            def process_result_value(self, value, dialect):
+                raise Exception("I have not been selected")
+
+        t1 = Table(
+            't1', self.metadata,
+            Column('x', MyType())
+        )
+
+        t2 = Table(
+            't2', self.metadata,
+            Column('x', Integer)
+        )
+
+        self.metadata.create_all(testing.db)
+        with testing.db.connect() as conn:
+            conn.execute(t1.insert().values(x=5))
+
+            stmt = t2.insert().values(
+                x=select([t1.c.x]).as_scalar()).returning(t2.c.x)
+
+            result = conn.execute(stmt)
+            eq_(result.scalar(), 5)
+
+
 class SequenceReturningTest(fixtures.TestBase):
     __requires__ = 'returning', 'sequences'
     __backend__ = True