Patch #1071: Improve unicode.translate() so that you can pass unicode

characters as mapping keys and invalid mapping keys are recognized
and raise an error.

Doc/library/stdtypes.rst

@@ -931,7 +931,7 @@ functions based on regular expressions.
    Return a copy of the *s* where all characters have been mapped through the
    *map* which must be a dictionary of characters (strings of length 1) or
    Unicode ordinals (integers) to Unicode ordinals, strings or ``None``.
-   Unmapped characters are left untouched. Characters mapped to ``None`` are
+   Unmapped characters are left untouched.  Characters mapped to ``None`` are
    deleted.
 
    .. note::

Lib/test/test_unicode.py

@@ -160,12 +160,14 @@ class UnicodeTest(
         self.checkequalnofix('bbbc', 'abababc', 'translate', {ord('a'):None})
         self.checkequalnofix('iiic', 'abababc', 'translate', {ord('a'):None, ord('b'):ord('i')})
         self.checkequalnofix('iiix', 'abababc', 'translate', {ord('a'):None, ord('b'):ord('i'), ord('c'):'x'})
-        self.checkequalnofix('<i><i><i>c', 'abababc', 'translate', {ord('a'):None, ord('b'):'<i>'})
+        self.checkequalnofix('<i><i><i>c', 'abababc', 'translate', {'a':None, 'b':'<i>'})
         self.checkequalnofix('c', 'abababc', 'translate', {ord('a'):None, ord('b'):''})
         self.checkequalnofix('xyyx', 'xzx', 'translate', {ord('z'):'yy'})
 
         self.assertRaises(TypeError, 'hello'.translate)
         self.assertRaises(TypeError, 'abababc'.translate, 'abc', 'xyz')
+        self.assertRaises(ValueError, 'abababc'.translate, {'xy':2})
+        self.assertRaises(TypeError, 'abababc'.translate, {(1,):2})
 
     def test_split(self):
         string_tests.CommonTest.test_split(self)

Objects/unicodeobject.c

@@ -7810,10 +7810,54 @@ are deleted.");
 static PyObject*
 unicode_translate(PyUnicodeObject *self, PyObject *table)
 {
-    return PyUnicode_TranslateCharmap(self->str,
-				      self->length,
-				      table,
-				      "ignore");
+    PyObject *newtable = NULL;
+    Py_ssize_t i = 0;
+    PyObject *key, *value, *result;
+
+    if (!PyDict_Check(table)) {
+        PyErr_SetString(PyExc_TypeError, "translate argument must be a dict");
+        return NULL;
+    }
+    /* fixup the table -- allow size-1 string keys instead of only int keys */
+    newtable = PyDict_Copy(table);
+    if (!newtable) return NULL;
+    while (PyDict_Next(table, &i, &key, &value)) {
+        if (PyUnicode_Check(key)) {
+            /* convert string keys to integer keys */
+            PyObject *newkey;
+            int res;
+            if (PyUnicode_GET_SIZE(key) != 1) {
+                PyErr_SetString(PyExc_ValueError, "string items in translate "
+                                "table must be 1 element long");
+                goto err;
+            }
+            newkey = PyInt_FromLong(PyUnicode_AS_UNICODE(key)[0]);
+            if (!newkey)
+                goto err;
+            res = PyDict_SetItem(newtable, newkey, value);
+            Py_DECREF(newkey);
+            if (res < 0)
+                goto err;
+        } else if (PyInt_Check(key)) {
+            /* just keep integer keys */
+            if (PyDict_SetItem(newtable, key, value) < 0)
+                goto err;
+        } else {
+            PyErr_SetString(PyExc_TypeError, "items in translate table must be "
+                            "strings or integers");
+            goto err;
+        }
+    }
+
+    result = PyUnicode_TranslateCharmap(self->str,
+                                        self->length,
+                                        newtable,
+                                        "ignore");
+    Py_DECREF(newtable);
+    return result;
+  err:
+    Py_DECREF(newtable);
+    return NULL;
 }
 
 PyDoc_STRVAR(upper__doc__,