Fix bug #1598620: A ctypes structure cannot contain itself.
diff --git a/Lib/ctypes/test/test_structures.py b/Lib/ctypes/test/test_structures.py
index 8a4531d..613163d 100644
--- a/Lib/ctypes/test/test_structures.py
+++ b/Lib/ctypes/test/test_structures.py
@@ -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()
diff --git a/Misc/NEWS b/Misc/NEWS
index 0153ac7..2017092 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -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.
diff --git a/Modules/_ctypes/stgdict.c b/Modules/_ctypes/stgdict.c
index d701f9e..8fd9a1e 100644
--- a/Modules/_ctypes/stgdict.c
+++ b/Modules/_ctypes/stgdict.c
@@ -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);
}