[Python-checkins] r52841 - in python/trunk: Lib/ctypes/test/test_structures.py Misc/NEWS Modules/_ctypes/stgdict.c

Fri Nov 24 19:45:40 CET 2006

Author: thomas.heller
Date: Fri Nov 24 19:45:39 2006
New Revision: 52841
Modified:
 python/trunk/Lib/ctypes/test/test_structures.py
 python/trunk/Misc/NEWS
 python/trunk/Modules/_ctypes/stgdict.c
Log:
Fix bug #1598620: A ctypes structure cannot contain itself.
Modified: python/trunk/Lib/ctypes/test/test_structures.py
==============================================================================

--- python/trunk/Lib/ctypes/test/test_structures.py	(original)
+++ python/trunk/Lib/ctypes/test/test_structures.py	Fri Nov 24 19:45:39 2006
@@ -381,5 +381,35 @@
 s.p = None
 self.failUnlessEqual(s.x, 12345678)
 
+class TestRecursiveStructure(unittest.TestCase):
+ def test_contains_itself(self):
+ class Recursive(Structure):
+ pass
+
+ try:
+ Recursive._fields_ = [("next", Recursive)]
+ except AttributeError, details:
+ self.failUnless("Structure or union cannot contain itself" in
+ str(details))
+ else:
+ self.fail("Structure or union cannot contain itself")
+
+
+ def test_vice_versa(self):
+ class First(Structure):
+ pass
+ class Second(Structure):
+ pass
+
+ First._fields_ = [("second", Second)]
+
+ try:
+ Second._fields_ = [("first", First)]
+ except AttributeError, details:
+ self.failUnless("_fields_ is final" in
+ str(details))
+ else:
+ self.fail("AttributeError not raised")
+
 if __name__ == '__main__':
 unittest.main()
Modified: python/trunk/Misc/NEWS
==============================================================================
--- python/trunk/Misc/NEWS	(original)
+++ python/trunk/Misc/NEWS	Fri Nov 24 19:45:39 2006
@@ -101,6 +101,8 @@
 Library
 -------
 
+- Bug #1598620: A ctypes Structure cannot contain itself.
+
 - Patch #1362975: Rework CodeContext indentation algorithm to
 avoid hard-coding pixel widths.
 
Modified: python/trunk/Modules/_ctypes/stgdict.c
==============================================================================
--- python/trunk/Modules/_ctypes/stgdict.c	(original)
+++ python/trunk/Modules/_ctypes/stgdict.c	Fri Nov 24 19:45:39 2006
@@ -339,14 +339,14 @@
 	stgdict = PyType_stgdict(type);
 	if (!stgdict)
 		return -1;
+	/* If this structure/union is already marked final we cannot assign
+	 _fields_ anymore. */
+
 	if (stgdict->flags & DICTFLAG_FINAL) {/* is final ? */
 		PyErr_SetString(PyExc_AttributeError,
 				"_fields_ is final");
 		return -1;
 	}
-	/* XXX This should probably be moved to a point when all this
-	 stuff is sucessfully finished. */
-	stgdict->flags |= DICTFLAG_FINAL;	/* set final */
 
 	if (stgdict->ffi_type_pointer.elements)
 		PyMem_Free(stgdict->ffi_type_pointer.elements);
@@ -480,5 +480,15 @@
 	stgdict->size = size;
 	stgdict->align = total_align;
 	stgdict->length = len;	/* ADD ffi_ofs? */
+
+	/* We did check that this flag was NOT set above, it must not
+	 have been set until now. */
+	if (stgdict->flags & DICTFLAG_FINAL) {
+		PyErr_SetString(PyExc_AttributeError,
+				"Structure or union cannot contain itself");
+		return -1;
+	}
+	stgdict->flags |= DICTFLAG_FINAL;
+
 	return MakeAnonFields(type);
 }
