Allow Table._reset_exported to silently pass

Fixed bug in :class:`.Table` where the internal method
``_reset_exported()`` would corrupt the state of the object.  This
method is intended for selectable objects and is called by the ORM
in some cases; an erroneous mapper configuration would could lead the
ORM to call this on on a :class:`.Table` object.

Change-Id: I63fa34ee0cdf16358bb125c556390df79758bcbc
Fixes: #3755

1 files changed, 15 insertions, 0 deletions

diff --git a/test/sql/test_metadata.py b/test/sql/test_metadata.py
index 92d35e6e5..846e70589 100644
--- a/test/sql/test_metadata.py
+++ b/test/sql/test_metadata.py
@@ -1231,6 +1231,21 @@ class TableTest(fixtures.TestBase, AssertsCompiledSQL):
             t.info['bar'] = 'zip'
             assert t.info['bar'] == 'zip'
 
+    def test_reset_exported_passes(self):
+
+        m = MetaData()
+
+        t = Table('t', m, Column('foo', Integer))
+        eq_(
+            list(t.c), [t.c.foo]
+        )
+
+        t._reset_exported()
+
+        eq_(
+            list(t.c), [t.c.foo]
+        )
+
     def test_foreign_key_constraints_collection(self):
         metadata = MetaData()
         t1 = Table('foo', metadata, Column('a', Integer))