bpo-41546: make pprint (like print) not write to stdout when it is None (GH-26810)

2 files changed, 11 insertions, 2 deletions

diff --git a/Lib/pprint.py b/Lib/pprint.py
index 13819f3..60ce57e 100644
--- a/Lib/pprint.py
+++ b/Lib/pprint.py
@@ -148,8 +148,9 @@ class PrettyPrinter:
         self._underscore_numbers = underscore_numbers
 
     def pprint(self, object):
-        self._format(object, self._stream, 0, 0, {}, 0)
-        self._stream.write("\n")
+        if self._stream is not None:
+            self._format(object, self._stream, 0, 0, {}, 0)
+            self._stream.write("\n")
 
     def pformat(self, object):
         sio = _StringIO()
diff --git a/Lib/test/test_pprint.py b/Lib/test/test_pprint.py
index 6c714fd..c7b9893 100644
--- a/Lib/test/test_pprint.py
+++ b/Lib/test/test_pprint.py
@@ -1,6 +1,7 @@
 # -*- coding: utf-8 -*-
 
 import collections
+import contextlib
 import dataclasses
 import io
 import itertools
@@ -159,6 +160,13 @@ class QueryTestCase(unittest.TestCase):
             self.assertTrue(pp.isreadable(safe),
                             "expected isreadable for %r" % (safe,))
 
+    def test_stdout_is_None(self):
+        with contextlib.redirect_stdout(None):
+            # smoke test - there is no output to check
+            value = 'this should not fail'
+            pprint.pprint(value)
+            pprint.PrettyPrinter().pprint(value)
+
     def test_knotted(self):
         # Verify .isrecursive() and .isreadable() w/ recursion
         # Tie a knot.