diff --git a/mercurial/util.py b/mercurial/util.py
--- a/mercurial/util.py
+++ b/mercurial/util.py
@@ -25,6 +25,7 @@
 import locale
 import mmap
 import os
+import pickle  # provides util.pickle symbol
 import re as remod
 import shutil
 import stat
diff --git a/tests/test-check-pyflakes.t b/tests/test-check-pyflakes.t
--- a/tests/test-check-pyflakes.t
+++ b/tests/test-check-pyflakes.t
@@ -24,4 +24,5 @@
   mercurial/util.py:*:* undefined name 'file' (glob) (?)
   mercurial/encoding.py:*:* undefined name 'localstr' (glob) (?)
   tests/run-tests.py:*:* undefined name 'PermissionError' (glob) (?)
+  mercurial/util.py:*:* 'pickle' imported but unused (glob)