Test case and proposed fix for Debian bug #497049

2 files changed, 34 insertions, 10 deletions

diff --git a/python/cache.cc b/python/cache.cc
index bd280dec..523444b5 100644
--- a/python/cache.cc
+++ b/python/cache.cc
@@ -936,14 +936,25 @@ PyObject *TmpGetCache(PyObject *Self,PyObject *Args)
    pkgCacheFile *Cache = new pkgCacheFile();
 
    if(pyCallbackInst != 0) {
+      if (PyObject_HasAttrString(pyCallbackInst, "done") != 1) {
+        PyErr_SetString(PyExc_ValueError,
+                        "progress object must implement done()");
+        return 0;
+      }
+      if (PyObject_HasAttrString(pyCallbackInst, "update") != 1) {
+        PyErr_SetString(PyExc_ValueError,
+                        "progress object must implement update()");
+        return 0;
+      }
       PyOpProgress progress;
       progress.setCallbackInst(pyCallbackInst);
       if (Cache->Open(progress,false) == false)
-	 return HandleErrors();
-   }  else {
+         return HandleErrors();
+   }  
+   else {
       OpTextProgress Prog;
       if (Cache->Open(Prog,false) == false)
-	 return HandleErrors();
+	     return HandleErrors();
    }
 
    CppOwnedPyObject<pkgCacheFile*> *CacheFileObj =
diff --git a/tests/getcache_mem_corruption.py b/tests/getcache_mem_corruption.py
index e127f66e..42e9af00 100644
--- a/tests/getcache_mem_corruption.py
+++ b/tests/getcache_mem_corruption.py
@@ -1,11 +1,24 @@
 #!/usr/bin/python
+import apt
 import apt_pkg
 import re
 
-apt_pkg.InitConfig()
-apt_pkg.InitSystem()
-apt_cache = apt_pkg.GetCache()
-# wrong
-apt_depcache = apt_pkg.GetCache(apt_cache)
-# correct: apt_depcache = apt_pkg.GetDepCache(apt_cache)
-re.compile('a')
+import unittest
+
+class TestGetCache(unittest.TestCase):
+    
+    def setUp(self):
+        apt_pkg.InitConfig()
+        apt_pkg.InitSystem()
+    
+    def testWrongInvocation(self):
+        # wrongly invoke GetCache() rather than GetDepCache()
+        apt_cache = apt_pkg.GetCache()
+        self.assertRaises(ValueError, apt_pkg.GetCache, apt_cache)
+    
+    def testProperInvocation(self):
+        apt_cache = apt_pkg.GetCache(apt.progress.OpTextProgress())
+        apt_depcache = apt_pkg.GetDepCache(apt_cache)
+
+if __name__ == "__main__":
+    unittest.main()