Merge with ongoing work in 3.5 branch.

Lib/test/test_dict.py

@@ -937,6 +937,20 @@ class DictTest(unittest.TestCase):
                 d.popitem()
         self.check_reentrant_insertion(mutate)
 
+    def test_merge_and_mutate(self):
+        class X:
+            def __hash__(self):
+                return 0
+
+            def __eq__(self, o):
+                other.clear()
+                return False
+
+        l = [(i,0) for i in range(1, 1337)]
+        other = dict(l)
+        other[X()] = 0
+        d = {X(): 0, 1: 1}
+        self.assertRaises(RuntimeError, d.update, other)
 
 from test import mapping_tests
 

Lib/test/test_unpack_ex.py

@@ -128,6 +128,9 @@ Dict display element unpacking
     ...                          for i in range(1000)) + "}"))
     1000
 
+    >>> {0:1, **{0:2}, 0:3, 0:4}
+    {0: 4}
+
 List comprehension element unpacking
 
     >>> a, b, c = [0, 1, 2], 3, 4

Misc/NEWS

@@ -10,6 +10,10 @@ Release date: 2015-07-26
 Core and Builtins
 -----------------
 
+- Issue #24569: Make PEP 448 dictionary evaluation more consistent.
+
+- Issue #24407: Fix crash when dict is mutated while being updated.
+
 Library
 -------
 

Objects/dictobject.c

@@ -2039,23 +2039,35 @@ PyDict_Merge(PyObject *a, PyObject *b, int override)
             if (dictresize(mp, (mp->ma_used + other->ma_used)*2) != 0)
                return -1;
         for (i = 0, n = DK_SIZE(other->ma_keys); i < n; i++) {
-            PyObject *value;
+            PyObject *key, *value;
+            Py_hash_t hash;
             entry = &other->ma_keys->dk_entries[i];
+            key = entry->me_key;
+            hash = entry->me_hash;
             if (other->ma_values)
                 value = other->ma_values[i];
             else
                 value = entry->me_value;
 
-            if (value != NULL &&
-                (override ||
-                 PyDict_GetItem(a, entry->me_key) == NULL)) {
-                if (insertdict(mp, entry->me_key,
-                               entry->me_hash,
-                               value) != 0)
+            if (value != NULL) {
+                int err = 0;
+                Py_INCREF(key);
+                Py_INCREF(value);
+                if (override || PyDict_GetItem(a, key) == NULL)
+                    err = insertdict(mp, key, hash, value);
+                Py_DECREF(value);
+                Py_DECREF(key);
+                if (err != 0)
+                    return -1;
+
+                if (n != DK_SIZE(other->ma_keys)) {
+                    PyErr_SetString(PyExc_RuntimeError,
+                                    "dict mutated during update");
                     return -1;
                 }
             }
         }
+    }
     else {
         /* Do it the generic, slower way */
         PyObject *keys = PyMapping_Keys(b);

Python/ceval.c

@@ -2561,22 +2561,25 @@ PyEval_EvalFrameEx(PyFrameObject *f, int throwflag)
         }
 
         TARGET(BUILD_MAP) {
+            int i;
             PyObject *map = _PyDict_NewPresized((Py_ssize_t)oparg);
             if (map == NULL)
                 goto error;
-            while (--oparg >= 0) {
+            for (i = oparg; i > 0; i--) {
                 int err;
-                PyObject *value = TOP();
-                PyObject *key = SECOND();
-                STACKADJ(-2);
+                PyObject *key = PEEK(2*i);
+                PyObject *value = PEEK(2*i - 1);
                 err = PyDict_SetItem(map, key, value);
-                Py_DECREF(value);
-                Py_DECREF(key);
                 if (err != 0) {
                     Py_DECREF(map);
                     goto error;
                 }
             }
+
+            while (oparg--) {
+                Py_DECREF(POP());
+                Py_DECREF(POP());
+            }
             PUSH(map);
             DISPATCH();
         }

Tools/msi/msi.targets

@@ -24,7 +24,7 @@
         </ItemGroup>
     </Target>
 
-    <Target Name="_TransformWxlTemplates" AfterTargets="PrepareForBuild">
+    <Target Name="_TransformWxlTemplates" AfterTargets="PrepareForBuild" Inputs="@(WxlTemplate);$(PySourcePath)include\patchlevel.h" Outputs="$(IntermediateOutputPath)%(Filename).wxl">
         <PropertyGroup>
             <_Content>$([System.IO.File]::ReadAllText(%(WxlTemplate.FullPath)).Replace(`{{ShortVersion}}`, `$(MajorVersionNumber).$(MinorVersionNumber)`).Replace(`{{LongVersion}}`, `$(PythonVersion)`).Replace(`{{Bitness}}`, `$(Bitness)`))</_Content>
             <_ExistingContent Condition="Exists('$(IntermediateOutputPath)%(WxlTemplate.Filename).wxl')">$([System.IO.File]::ReadAllText($(IntermediateOutputPath)%(WxlTemplate.Filename).wxl))</_ExistingContent>