bpo-36473: add maximum iteration check for dict .values() and .items() (GH-12619)
diff --git a/Lib/test/test_dict.py b/Lib/test/test_dict.py
index eecdc8b..13be857 100644
--- a/Lib/test/test_dict.py
+++ b/Lib/test/test_dict.py
@@ -477,7 +477,25 @@
with self.assertRaises(RuntimeError):
for i in d:
del d[0]
- d[1] = 1
+ d[0] = 0
+
+ def test_mutating_iteration_delete_over_values(self):
+ # change dict content during iteration
+ d = {}
+ d[0] = 0
+ with self.assertRaises(RuntimeError):
+ for i in d.values():
+ del d[0]
+ d[0] = 0
+
+ def test_mutating_iteration_delete_over_items(self):
+ # change dict content during iteration
+ d = {}
+ d[0] = 0
+ with self.assertRaises(RuntimeError):
+ for i in d.items():
+ del d[0]
+ d[0] = 0
def test_mutating_lookup(self):
# changing dict during a lookup (issue #14417)
diff --git a/Misc/NEWS.d/next/Core and Builtins/2019-03-27-23-53-00.bpo-36452.xhK2lT.rst b/Misc/NEWS.d/next/Core and Builtins/2019-03-27-23-53-00.bpo-36452.xhK2lT.rst
index 37c0c50..26d8568 100644
--- a/Misc/NEWS.d/next/Core and Builtins/2019-03-27-23-53-00.bpo-36452.xhK2lT.rst
+++ b/Misc/NEWS.d/next/Core and Builtins/2019-03-27-23-53-00.bpo-36452.xhK2lT.rst
@@ -1 +1,5 @@
-Changing `dict` keys during iteration will now be detected in certain corner cases where the number of keys isn't changed (but they keys themselves are), and a `RuntimeError` will be raised.
\ No newline at end of file
+Changing ``dict`` keys during iteration of the dict itself, ``keys()``,
+``values()``, or ``items()`` will now be detected in certain corner cases where
+keys are deleted/added so that the number of keys isn't changed.
+A `RuntimeError` will be raised after ``len(dict)`` iterations.
+Contributed by Thomas Perl.
diff --git a/Objects/dictobject.c b/Objects/dictobject.c
index 7ea979c..bba27dd 100644
--- a/Objects/dictobject.c
+++ b/Objects/dictobject.c
@@ -3630,6 +3630,12 @@
goto fail;
value = entry_ptr->me_value;
}
+ // We found an element, but did not expect it
+ if (di->len == 0) {
+ PyErr_SetString(PyExc_RuntimeError,
+ "dictionary keys changed during iteration");
+ goto fail;
+ }
di->di_pos = i+1;
di->len--;
Py_INCREF(value);
@@ -3713,6 +3719,12 @@
key = entry_ptr->me_key;
value = entry_ptr->me_value;
}
+ // We found an element, but did not expect it
+ if (di->len == 0) {
+ PyErr_SetString(PyExc_RuntimeError,
+ "dictionary keys changed during iteration");
+ goto fail;
+ }
di->di_pos = i+1;
di->len--;
Py_INCREF(key);