# HG changeset patch
# User Pulkit Goyal <7895pulkit@gmail.com>
# Date 2020-06-19 15:12:14
# Node ID 7af5c1f5b3a0c3b90dbace991edbf06bebc1432e
# Parent  fa151f7af2756f0c7be4bcfb13881c5411bce8ac

util: flush stderr explicitly after using warnings.warn()

Due to some unknown reasons, when using chg with python3, the warnings.warn()
output is not flushed.

Fixes test-devel-warnings.t on py3 with chg.

diff --git a/mercurial/util.py b/mercurial/util.py
--- a/mercurial/util.py
+++ b/mercurial/util.py
@@ -204,6 +204,8 @@ def nouideprecwarn(msg, version, stackle
             b" update your code.)"
         ) % version
         warnings.warn(pycompat.sysstr(msg), DeprecationWarning, stacklevel + 1)
+        # on python 3 with chg, we will need to explicitly flush the output
+        sys.stderr.flush()
 
 
 DIGESTS = {