Merge pull request #509 from python/main

Sync Fork from Upstream Repo

Author: sthagen

Doc/library/dis.rst

@@ -936,7 +936,7 @@ All of the following opcodes use their arguments.
    .. versionadded:: 3.9
 
 
-.. opcode:: DICT_MERGE
+.. opcode:: DICT_MERGE (i)
 
    Like :opcode:`DICT_UPDATE` but raises an exception for duplicate keys.
 

Lib/test/string_tests.py

@@ -80,12 +80,14 @@ class subtype(self.__class__.type2test):
                 self.assertIsNot(obj, realresult)
 
     # check that obj.method(*args) raises exc
-    def checkraises(self, exc, obj, methodname, *args):
+    def checkraises(self, exc, obj, methodname, *args, expected_msg=None):
         obj = self.fixtype(obj)
         args = self.fixtype(args)
         with self.assertRaises(exc) as cm:
             getattr(obj, methodname)(*args)
         self.assertNotEqual(str(cm.exception), '')
+        if expected_msg is not None:
+            self.assertEqual(str(cm.exception), expected_msg)
 
     # call obj.method(*args) without any checks
     def checkcall(self, obj, methodname, *args):
@@ -1195,6 +1197,10 @@ def test_subscript(self):
 
         self.checkraises(TypeError, 'abc', '__getitem__', 'def')
 
+        for idx_type in ('def', object()):
+            expected_msg = "string indices must be integers, not '{}'".format(type(idx_type).__name__)
+            self.checkraises(TypeError, 'abc', '__getitem__', idx_type, expected_msg=expected_msg)
+
     def test_slice(self):
         self.checkequal('abc', 'abc', '__getitem__', slice(0, 1000))
         self.checkequal('abc', 'abc', '__getitem__', slice(0, 3))

Lib/test/test_userstring.py

@@ -27,12 +27,14 @@ def checkequal(self, result, object, methodname, *args, **kwargs):
             realresult
         )
 
-    def checkraises(self, exc, obj, methodname, *args):
+    def checkraises(self, exc, obj, methodname, *args, expected_msg=None):
         obj = self.fixtype(obj)
         # we don't fix the arguments, because UserString can't cope with it
         with self.assertRaises(exc) as cm:
             getattr(obj, methodname)(*args)
         self.assertNotEqual(str(cm.exception), '')
+        if expected_msg is not None:
+            self.assertEqual(str(cm.exception), expected_msg)
 
     def checkcall(self, object, methodname, *args):
         object = self.fixtype(object)

Misc/NEWS.d/next/Core and Builtins/2021-05-11-21-52-44.bpo-44110.VqbAsB.rst

@@ -0,0 +1 @@
+Improve :func:`str.__getitem__` error message

Misc/NEWS.d/next/Library/2021-06-23-01-33-01.bpo-44491.tiOlr5.rst

@@ -1,3 +1,3 @@
 Allow clearing the :mod:`sqlite3` authorizer callback by passing
-:const:``None`` to :meth:`~sqlite3.Connection.set_authorizer`. Patch by
+:const:`None` to :meth:`~sqlite3.Connection.set_authorizer`. Patch by
 Erlend E. Aasland.

Objects/unicodeobject.c

@@ -14279,7 +14279,8 @@ unicode_subscript(PyObject* self, PyObject* item)
         assert(_PyUnicode_CheckConsistency(result, 1));
         return result;
     } else {
-        PyErr_SetString(PyExc_TypeError, "string indices must be integers");
+        PyErr_Format(PyExc_TypeError, "string indices must be integers, not '%.200s'",
+                     Py_TYPE(item)->tp_name);
         return NULL;
     }
 }

Parser/asdl_c.py

@@ -71,16 +71,20 @@ def reflow_lines(s, depth):
 def reflow_c_string(s, depth):
     return '"%s"' % s.replace('\n', '\\n"\n%s"' % (' ' * depth * TABSIZE))
 
-def is_simple(sum):
+def is_simple(sum_type):
     """Return True if a sum is a simple.
 
-    A sum is simple if its types have no fields, e.g.
+    A sum is simple if it's types have no fields and itself
+    doesn't have any attributes. Instances of these types are
+    cached at C level, and they act like singletons when propagating
+    parser generated nodes into Python level, e.g.
     unaryop = Invert | Not | UAdd | USub
     """
-    for t in sum.types:
-        if t.fields:
-            return False
-    return True
+
+    return not (
+        sum_type.attributes or
+        any(constructor.fields for constructor in sum_type.types)
+    )
 
 def asdl_of(name, obj):
     if isinstance(obj, asdl.Product) or isinstance(obj, asdl.Constructor):