- Fixed regression where new methods on :class:`.ResultProxy` used

by the ORM :class:`.Query` object (part of the performance
enhancements of :ticket:`3175`) would not raise the "this result
does not return rows" exception in the case where the driver
(typically MySQL) fails to generate cursor.description correctly;
an AttributeError against NoneType would be raised instead.
fixes #3481

3 files changed, 33 insertions, 4 deletions

diff --git a/doc/build/changelog/changelog_10.rst b/doc/build/changelog/changelog_10.rst
index 1e00ddcd4..a2b4273bf 100644
--- a/doc/build/changelog/changelog_10.rst
+++ b/doc/build/changelog/changelog_10.rst
@@ -20,6 +20,17 @@
 
     .. change::
         :tags: bug, engine
+        :tickets: 3481
+
+        Fixed regression where new methods on :class:`.ResultProxy` used
+        by the ORM :class:`.Query` object (part of the performance
+        enhancements of :ticket:`3175`) would not raise the "this result
+        does not return rows" exception in the case where the driver
+        (typically MySQL) fails to generate cursor.description correctly;
+        an AttributeError against NoneType would be raised instead.
+
+    .. change::
+        :tags: bug, engine
         :tickets: 3483
 
         Fixed regression where :meth:`.ResultProxy.keys` would return
diff --git a/lib/sqlalchemy/engine/result.py b/lib/sqlalchemy/engine/result.py
index 3fcab873b..74a0fce77 100644
--- a/lib/sqlalchemy/engine/result.py
+++ b/lib/sqlalchemy/engine/result.py
@@ -495,10 +495,20 @@ class ResultProxy(object):
         self._init_metadata()
 
     def _getter(self, key):
-        return self._metadata._getter(key)
+        try:
+            getter = self._metadata._getter
+        except AttributeError:
+            return self._non_result(None)
+        else:
+            return getter(key)
 
     def _has_key(self, key):
-        return self._metadata._has_key(key)
+        try:
+            has_key = self._metadata._has_key
+        except AttributeError:
+            return self._non_result(None)
+        else:
+            return has_key(key)
 
     def _init_metadata(self):
         metadata = self._cursor_description()
diff --git a/test/sql/test_query.py b/test/sql/test_query.py
index 16ba285b2..0313a9cd0 100644
--- a/test/sql/test_query.py
+++ b/test/sql/test_query.py
@@ -976,14 +976,22 @@ class QueryTest(fixtures.TestBase):
         # result.BufferedColumnResultProxy
 
         conn = testing.db.connect()
-        for meth in ('fetchone', 'fetchall', 'first', 'scalar', 'fetchmany'):
+        for meth in [
+            lambda r: r.fetchone(),
+            lambda r: r.fetchall(),
+            lambda r: r.first(),
+            lambda r: r.scalar(),
+            lambda r: r.fetchmany(),
+            lambda r: r._getter('user'),
+            lambda r: r._has_key('user'),
+        ]:
             trans = conn.begin()
             result = conn.execute(users.insert(), user_id=1)
             assert_raises_message(
                 exc.ResourceClosedError,
                 "This result object does not return rows. "
                 "It has been closed automatically.",
-                getattr(result, meth),
+                meth, result,
             )
             trans.rollback()