# HG changeset patch
# User Augie Fackler <augie@google.com>
# Date 2016-08-05 18:00:46
# Node ID 4d23cd6e2219493be62dfb91f69c3c8104252b17
# Parent  44ea12756fef874dd07c7dbbeca64ed10789dd48

util: use `iter(callable, sentinel)` instead of while True

This is functionally equivalent, but is a little more concise.

diff --git a/mercurial/util.py b/mercurial/util.py
--- a/mercurial/util.py
+++ b/mercurial/util.py
@@ -1012,10 +1012,7 @@ def system(cmd, environ=None, cwd=None, 
             proc = subprocess.Popen(cmd, shell=True, close_fds=closefds,
                                     env=env, cwd=cwd, stdout=subprocess.PIPE,
                                     stderr=subprocess.STDOUT)
-            while True:
-                line = proc.stdout.readline()
-                if not line:
-                    break
+            for line in iter(proc.stdout.readline, ''):
                 out.write(line)
             proc.wait()
             rc = proc.returncode