Merge lp:~cjwatson/storm/fix-wrapped-exception-caching into lp:storm

[Colin Watson]

Fix incorrect caching of wrapped DB-API exceptions.

[Simon Poirier (simpoir)]

+1 It took some time and fiddling to wrap my head around the issue, but the change looks sane.

review: Approve

=== modified file 'NEWS'
--- NEWS	2019-09-20 07:15:20 +0000
+++ NEWS	2019-09-27 19:24:08 +0000
@@ -1,3 +1,11 @@
+0.21.1 (XXXX-XX-XX)
+===================
+
+Bug fixes
+---------
+
+- Fix incorrect caching of wrapped DB-API exceptions (bug 1845702).
+
 0.21 (2019-09-20)
 =================
 

=== modified file 'storm/database.py'
--- storm/database.py	2019-08-11 16:57:24 +0000
+++ storm/database.py	2019-09-27 19:24:08 +0000
@@ -622,10 +622,10 @@
 
         @return: The combined exception type.
         """
-        if wrapper_type not in self._exception_types:
-            self._exception_types[wrapper_type] = type(
+        if dbapi_type.__name__ not in self._exception_types:
+            self._exception_types[dbapi_type.__name__] = type(
                 dbapi_type.__name__, (dbapi_type, wrapper_type), {})
-        return self._exception_types[wrapper_type]
+        return self._exception_types[dbapi_type.__name__]
 
     def _wrap_exception(self, wrapper_type, exception):
         """Wrap a DB-API exception as a StormError instance.

=== modified file 'storm/tests/databases/base.py'
--- storm/tests/databases/base.py	2019-09-17 09:35:10 +0000
+++ storm/tests/databases/base.py	2019-09-27 19:24:08 +0000
@@ -445,6 +445,21 @@
         self.connection.unblock_access()
         self.connection.execute("SELECT 1")
 
+    def test_wrap_exception_subclasses(self):
+        """Subclasses of the generic DB-API exception types are wrapped."""
+        db_api_operational_error = getattr(
+            self.database._exception_module, 'OperationalError')
+        operational_error_types = [
+            type(name, (db_api_operational_error,), {})
+            for name in ('A', 'B')]
+        for error_type in operational_error_types:
+            error = error_type('error message')
+            wrapped = self.database._wrap_exception(OperationalError, error)
+            self.assertTrue(isinstance(wrapped, error_type))
+            self.assertTrue(isinstance(wrapped, OperationalError))
+            self.assertEqual(error_type.__name__, wrapped.__class__.__name__)
+            self.assertEqual(('error message',), wrapped.args)
+
 
 class TwoPhaseCommitTest(object):