Add debug message showing the self.__transaction count.

rhc/database/db.py

@@ -22,9 +22,13 @@
 THE SOFTWARE.
 '''
 import pymysql
+import logging
 import threading
 
 
+log = logging.getLogger(__name__)
+
+
 class _DB(object):
 
     def __init__(self):
@@ -86,6 +90,10 @@ def start_transaction(self):
         self.__transaction += 1
 
     def stop_transaction(self, commit=True):
+        log.debug(
+            'starting `stop_transaction`, self.__transaction=%s',
+            self.__transaction,
+        )
         if self.__transaction == 0:
             raise Exception('attempting to stop transaction when none is started')
         self.__transaction -= 1
@@ -96,6 +104,10 @@ def stop_transaction(self, commit=True):
                 self._rollback()
             if self.__close:
                 self.close()
+        log.debug(
+            'finishing `stop_transaction`, self.__transaction=%s',
+            self.__transaction,
+        )
 
     def database_map(self, tablename):
         return self.__database_map.get(tablename, tablename)

rhc/database/test/test_basic.py

@@ -1,5 +1,6 @@
 from __future__ import absolute_import
 import pytest
+import weakref
 
 from rhc.database.dao import DAO
 
@@ -103,3 +104,22 @@ def test_join(data):
     assert len(names) == 2
     assert 'fred' in names
     assert 'sally' in names
+
+
+def test_dao_cleanup_from_save(db):
+    obj = Parent(foo=1, bar=2).save()
+    ref = weakref.ref(obj)
+    assert obj is ref()
+    obj = 0  # dereference
+    assert ref() is None
+
+
+def test_dao_cleanup_from_load(db):
+    # save object and remember id
+    obj_id = Parent(foo=1, bar=2).save().id
+    assert obj_id
+    obj = Parent.load(obj_id)
+    ref = weakref.ref(obj)
+    assert ref() is obj
+    obj = 0
+    assert ref() is None