Index: Objects/unicodeobject.c
===================================================================
--- Objects/unicodeobject.c	(révision 68646)
+++ Objects/unicodeobject.c	(copie de travail)
@@ -565,6 +565,11 @@
 				 Py_ssize_t size)
 {
     PyUnicodeObject *unicode;
+    register Py_ssize_t i;
+    Py_ssize_t alloc;
+#ifndef Py_UNICODE_WIDE
+    const wchar_t *orig_w;
+#endif
 
     if (w == NULL) {
         if (size == 0)
@@ -577,7 +582,17 @@
         size = wcslen(w);
     }
 
-    unicode = _PyUnicode_New(size);
+    alloc = size;
+#ifndef Py_UNICODE_WIDE
+    orig_w = w;
+    for (i = size; i > 0; i--) {
+        if (0xffff < *w)
+            alloc++;
+        w++;
+    }
+    w = orig_w;
+#endif
+    unicode = _PyUnicode_New(alloc);
     if (!unicode)
         return NULL;
 
@@ -587,11 +602,20 @@
 #else
     {
 	register Py_UNICODE *u;
-	register Py_ssize_t i;
 	u = PyUnicode_AS_UNICODE(unicode);
-	for (i = size; i > 0; i--)
+        for (i = size; i > 0; i--) {
+#ifndef Py_UNICODE_WIDE
+            if (0xffff < *w) {
+                wchar_t ordinal = *w++;
+                ordinal -= 0x10000;
+                *u++ = 0xD800 | (ordinal >> 10);
+                *u++ = 0xDC00 | (ordinal & 0x3FF);
+                continue;
+            }
+#endif
 	    *u++ = *w++;
     }
+    }
 #endif
 
     return (PyObject *)unicode;
Index: Modules/_testcapimodule.c
===================================================================
--- Modules/_testcapimodule.c	(révision 68646)
+++ Modules/_testcapimodule.c	(copie de travail)
@@ -708,6 +708,48 @@
 }
 
 static PyObject *
+test_widechar(PyObject *self)
+{
+#if SIZEOF_WCHAR_T == 4
+	const wchar_t wtext[2] = {(wchar_t)0x10ABCDu};
+	size_t wtextlen = 1;
+#else
+	const wchar_t wtext[3] = {(wchar_t)0xDBEAu, (wchar_t)0xDFCDu};
+	size_t wtextlen = 2;
+#endif
+	PyObject *wide, *utf8;
+
+	wide = PyUnicode_FromWideChar(wtext, wtextlen);
+	if (wide == NULL)
+		return NULL;
+
+	utf8 = PyUnicode_FromString("\xf4\x8a\xaf\x8d");
+	if (utf8 == NULL) {
+		Py_DECREF(wide);
+		return NULL;
+	}
+
+	if (PyUnicode_GET_SIZE(wide) != PyUnicode_GET_SIZE(utf8)) {
+		Py_DECREF(wide);
+		Py_DECREF(utf8);
+		return raiseTestError("test_widechar",
+				"wide string and utf8 string have different length");
+	}
+	if (PyUnicode_Compare(wide, utf8)) {
+		Py_DECREF(wide);
+		Py_DECREF(utf8);
+		if (PyErr_Occurred())
+			return NULL;
+		return raiseTestError("test_widechar",
+				"wide string and utf8 string are differents");
+	}
+
+	Py_DECREF(wide);
+	Py_DECREF(utf8);
+	Py_RETURN_NONE;
+}
+
+static PyObject *
 test_empty_argparse(PyObject *self)
 {
 	/* Test that formats can begin with '|'. See issue #4720. */
@@ -1206,6 +1248,7 @@
 	{"test_s_code",		(PyCFunction)test_s_code,	 METH_NOARGS},
 	{"test_u_code",		(PyCFunction)test_u_code,	 METH_NOARGS},
 	{"test_Z_code",		(PyCFunction)test_Z_code,	 METH_NOARGS},
+ 	{"test_widechar",	(PyCFunction)test_widechar,	 METH_NOARGS},
 #ifdef WITH_THREAD
 	{"_test_thread_state",  test_thread_state, 		 METH_VARARGS},
 	{"_pending_threadfunc",	pending_threadfunc,		 METH_VARARGS},