gh-71682: Make pprint.pformat always order sets

Lib/pprint.py

@@ -556,17 +556,29 @@ def _safe_repr(self, object, context, maxlevels, level):
             return "{%s}" % ", ".join(components), readable, recursive
 
         if (issubclass(typ, list) and r is list.__repr__) or \
-           (issubclass(typ, tuple) and r is tuple.__repr__):
+           (issubclass(typ, tuple) and r is tuple.__repr__) or \
+           (issubclass(typ, set) and r is set.__repr__) or \
+           (issubclass(typ, frozenset) and r is frozenset.__repr__):
             if issubclass(typ, list):
                 if not object:
                     return "[]", True, False
                 format = "[%s]"
-            elif len(object) == 1:
-                format = "(%s,)"
+            elif issubclass(typ, tuple):
+                if len(object) == 1:
+                    format = "(%s,)"
+                else:
+                    if not object:
+                        return "()", True, False
+                    format = "(%s)"
             else:
                 if not object:
-                    return "()", True, False
-                format = "(%s)"
+                    return repr(object), True, False
+                if typ is set:
+                    format = "{%s}"
+                else:
+                    format = typ.__name__ + "({%s})"
+                object = sorted(object, key=_safe_key)
+
             objid = id(object)
             if maxlevels and level >= maxlevels:
                 return format % "...", False, objid in context

Lib/test/test_pprint.py

@@ -474,6 +474,9 @@ def test_subclassing(self):
     def test_set_reprs(self):
         self.assertEqual(pprint.pformat(set()), 'set()')
         self.assertEqual(pprint.pformat(set(range(3))), '{0, 1, 2}')
+        self.assertEqual(pprint.pformat(set([-1, 0, 1])), "{-1, 0, 1}")
+        self.assertEqual(pprint.pformat(set("0123")), "{'0', '1', '2', '3'}")
+        self.assertEqual(pprint.pformat(set("abcd")), "{'a', 'b', 'c', 'd'}")
         self.assertEqual(pprint.pformat(set(range(7)), width=20), '''\
 {0,
  1,
@@ -482,6 +485,11 @@ def test_set_reprs(self):
  4,
  5,
  6}''')
+        self.assertEqual(pprint.pformat(set2([-1, 0, 1])), "set2({-1, 0, 1})")
+        self.assertEqual(pprint.pformat(set2("0123")),
+                         "set2({'0', '1', '2', '3'})")
+        self.assertEqual(pprint.pformat(set2("abcd")),
+                         "set2({'a', 'b', 'c', 'd'})")
         self.assertEqual(pprint.pformat(set2(range(7)), width=20), '''\
 set2({0,
       1,
@@ -496,6 +504,12 @@ def test_set_reprs(self):
         self.assertEqual(pprint.pformat(frozenset()), 'frozenset()')
         self.assertEqual(pprint.pformat(frozenset(range(3))),
                          'frozenset({0, 1, 2})')
+        self.assertEqual(pprint.pformat(frozenset([-1, 0, 1])),
+                         "frozenset({-1, 0, 1})")
+        self.assertEqual(pprint.pformat(frozenset("0123")),
+                         "frozenset({'0', '1', '2', '3'})")
+        self.assertEqual(pprint.pformat(frozenset("abcd")),
+                         "frozenset({'a', 'b', 'c', 'd'})")
         self.assertEqual(pprint.pformat(frozenset(range(7)), width=20), '''\
 frozenset({0,
            1,
@@ -504,6 +518,12 @@ def test_set_reprs(self):
            4,
            5,
            6})''')
+        self.assertEqual(pprint.pformat(frozenset2([-1, 0, 1])),
+                         "frozenset2({-1, 0, 1})")
+        self.assertEqual(pprint.pformat(frozenset2("0123")),
+                         "frozenset2({'0', '1', '2', '3'})")
+        self.assertEqual(pprint.pformat(frozenset2("abcd")),
+                         "frozenset2({'a', 'b', 'c', 'd'})")
         self.assertEqual(pprint.pformat(frozenset2(range(7)), width=20), '''\
 frozenset2({0,
             1,

Misc/ACKS

@@ -193,6 +193,7 @@ Gawain Bolton
 Carl Friedrich Bolz-Tereick
 Forest Bond
 Gregory Bond
+Ben Bonenfant
 Angelin Booz
 Médéric Boquien
 Matias Bordese

Misc/NEWS.d/next/Library/2020-10-26-14-20-58.bpo-27495.OWavSt.rst

@@ -0,0 +1,2 @@
+Update the :mod:`pprint` module to always order the contents of :class:`set`
+and :class:`frozenset` objects.