[1.1.X] Fixed #11900 -- Corrected an edge case of transaction handling in the commit_on_success decorator. Thanks to guettli for the report, and Gabriel Hurley for the initial test case.

Backport of r12764 from trunk.

git-svn-id: http://code.djangoproject.com/svn/django/branches/releases/1.1.X@12765 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/db/transaction.py

@@ -245,7 +245,11 @@ def commit_on_success(func):
                 raise
             else:
                 if is_dirty():
+                    try:
                         commit()
+                    except:
+                        rollback()
+                        raise
             return res
         finally:
             leave_transaction_management()

tests/modeltests/transactions/models.py

@@ -100,3 +100,23 @@ Traceback (most recent call last):
     ...
 TransactionManagementError: Transaction managed block ended with pending COMMIT/ROLLBACK
 """
+
+# Regression for #11900: If a function wrapped by commit_on_success writes a
+# transaction that can't be committed, that transaction should be rolled back.
+# The bug is only visible using the psycopg2 backend, though
+# the fix is generally a good idea.
+if building_docs or settings.DATABASE_ENGINE == 'postgresql_psycopg2':
+    __test__['API_TESTS'] += """
+>>> def execute_bad_sql():
+...     cursor = connection.cursor()
+...     cursor.execute("INSERT INTO transactions_reporter (first_name, last_name) VALUES ('Douglas', 'Adams');")
+...     transaction.set_dirty()
+...
+>>> execute_bad_sql = transaction.commit_on_success(execute_bad_sql)
+>>> execute_bad_sql()
+Traceback (most recent call last):
+    ...
+IntegrityError: null value in column "email" violates not-null constraint
+<BLANKLINE>
+
+"""