bpo-31428: Prevent raising a SystemError in case the memo arg of ElementTree.Element.__deepcopy__() isn't a dictionary. (#3512)

orenmn · serhiy-storchaka · commit d056818ed2ad · 2017-09-12T17:39:15.000+03:00
diff --git a/Modules/_elementtree.c b/Modules/_elementtree.c
@@ -733,14 +733,14 @@ LOCAL(PyObject *) deepcopy(PyObject *, PyObject *);
 /*[clinic input]
 _elementtree.Element.__deepcopy__
 
-    memo: object
+    memo: object(subclass_of="&PyDict_Type")
     /
 
 [clinic start generated code]*/
 
 static PyObject *
-_elementtree_Element___deepcopy__(ElementObject *self, PyObject *memo)
-/*[clinic end generated code: output=d1f19851d17bf239 input=df24c2b602430b77]*/
+_elementtree_Element___deepcopy___impl(ElementObject *self, PyObject *memo)
+/*[clinic end generated code: output=eefc3df50465b642 input=a2d40348c0aade10]*/
 {
     Py_ssize_t i;
     ElementObject* element;
@@ -849,7 +849,8 @@ deepcopy(PyObject *object, PyObject *memo)
             /* Fall through to general case */
         }
         else if (Element_CheckExact(object)) {
-            return _elementtree_Element___deepcopy__((ElementObject *)object, memo);
+            return _elementtree_Element___deepcopy___impl(
+                (ElementObject *)object, memo);
         }
     }
 
diff --git a/Modules/clinic/_elementtree.c.h b/Modules/clinic/_elementtree.c.h
@@ -70,6 +70,24 @@ PyDoc_STRVAR(_elementtree_Element___deepcopy____doc__,
 #define _ELEMENTTREE_ELEMENT___DEEPCOPY___METHODDEF    \
     {"__deepcopy__", (PyCFunction)_elementtree_Element___deepcopy__, METH_O, _elementtree_Element___deepcopy____doc__},
 
+static PyObject *
+_elementtree_Element___deepcopy___impl(ElementObject *self, PyObject *memo);
+
+static PyObject *
+_elementtree_Element___deepcopy__(ElementObject *self, PyObject *arg)
+{
+    PyObject *return_value = NULL;
+    PyObject *memo;
+
+    if (!PyArg_Parse(arg, "O!:__deepcopy__", &PyDict_Type, &memo)) {
+        goto exit;
+    }
+    return_value = _elementtree_Element___deepcopy___impl(self, memo);
+
+exit:
+    return return_value;
+}
+
 PyDoc_STRVAR(_elementtree_Element___sizeof____doc__,
 "__sizeof__($self, /)\n"
 "--\n"
@@ -731,4 +749,4 @@ _elementtree_XMLParser__setevents(XMLParserObject *self, PyObject **args, Py_ssi
 exit:
     return return_value;
 }
-/*[clinic end generated code: output=75d0ff80e20b830f input=a9049054013a1b77]*/
+/*[clinic end generated code: output=ed55bd5209c12364 input=a9049054013a1b77]*/

Original file line number	Diff line number	Diff line change
`@@ -733,14 +733,14 @@ LOCAL(PyObject ) deepcopy(PyObject , PyObject *);`
`733`	`733`	`/*[clinic input]`
`734`	`734`	`_elementtree.Element.__deepcopy__`
`735`	`735`
`736`		`- memo: object`
	`736`	`+ memo: object(subclass_of="&PyDict_Type")`
`737`	`737`	`/`
`738`	`738`
`739`	`739`	`[clinic start generated code]*/`
`740`	`740`
`741`	`741`	`static PyObject *`
`742`		`-_elementtree_Element___deepcopy__(ElementObject self, PyObject memo)`
`743`		`-/[clinic end generated code: output=d1f19851d17bf239 input=df24c2b602430b77]/`
	`742`	`+_elementtree_Element___deepcopy___impl(ElementObject self, PyObject memo)`
	`743`	`+/[clinic end generated code: output=eefc3df50465b642 input=a2d40348c0aade10]/`
`744`	`744`	`{`
`745`	`745`	`Py_ssize_t i;`
`746`	`746`	`ElementObject* element;`
`@@ -849,7 +849,8 @@ deepcopy(PyObject object, PyObject memo)`
`849`	`849`	`/* Fall through to general case */`
`850`	`850`	`}`
`851`	`851`	`else if (Element_CheckExact(object)) {`
`852`		`- return _elementtree_Element___deepcopy__((ElementObject *)object, memo);`
	`852`	`+ return _elementtree_Element___deepcopy___impl(`
	`853`	`+ (ElementObject *)object, memo);`
`853`	`854`	`}`
`854`	`855`	`}`
`855`	`856`