issue 2045: Infinite recursion when printing a subclass of defaultdict,
if default_factory is set to a bound method.
Will backport.
diff --git a/Lib/test/test_defaultdict.py b/Lib/test/test_defaultdict.py
index 6108840..5935e05 100644
--- a/Lib/test/test_defaultdict.py
+++ b/Lib/test/test_defaultdict.py
@@ -141,6 +141,29 @@
else:
self.fail("expected KeyError")
+ def test_recursive_repr(self):
+ # Issue2045: stack overflow when default_factory is a bound method
+ class sub(defaultdict):
+ def __init__(self):
+ self.default_factory = self._factory
+ def _factory(self):
+ return []
+ d = sub()
+ self.assert_(repr(d).startswith(
+ "defaultdict(<bound method sub._factory of defaultdict(..."))
+
+ # NOTE: printing a subclass of a builtin type does not call its
+ # tp_print slot. So this part is essentially the same test as above.
+ tfn = tempfile.mktemp()
+ try:
+ f = open(tfn, "w+")
+ try:
+ print >>f, d
+ finally:
+ f.close()
+ finally:
+ os.remove(tfn)
+
def test_main():
test_support.run_unittest(TestDefaultDict)
diff --git a/Misc/NEWS b/Misc/NEWS
index af9f364..7975cbb 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -12,6 +12,9 @@
Core and builtins
-----------------
+- Issue #2045: Fix an infinite recursion triggered when printing a subclass of
+ collections.defaultdict, if its default_factory is set to a bound method.
+
- Fixed a minor memory leak in dictobject.c. The content of the free
list was not freed on interpreter shutdown.
diff --git a/Modules/_collectionsmodule.c b/Modules/_collectionsmodule.c
index 05b03b7..67700de 100644
--- a/Modules/_collectionsmodule.c
+++ b/Modules/_collectionsmodule.c
@@ -1300,7 +1300,17 @@
if (dd->default_factory == NULL)
defrepr = PyString_FromString("None");
else
- defrepr = PyObject_Repr(dd->default_factory);
+ {
+ int status = Py_ReprEnter(dd->default_factory);
+ if (status != 0) {
+ if (status < 0)
+ return NULL;
+ defrepr = PyString_FromString("...");
+ }
+ else
+ defrepr = PyObject_Repr(dd->default_factory);
+ Py_ReprLeave(dd->default_factory);
+ }
if (defrepr == NULL) {
Py_DECREF(baserepr);
return NULL;