# HG changeset patch
# User FUJIWARA Katsunori <foozy@lares.dti.ne.jp>
# Date 1467671151 -32400
# Node ID 4533f5b47949a4d0544bda9bc65c34622c560928
# Parent  d2361999016002bf008afccf142af4715dbd7df0
perf: add historical portability policy for future reference

diff -r d23619990160 -r 4533f5b47949 contrib/perf.py
--- a/contrib/perf.py	Sat Jul 09 14:01:55 2016 +0800
+++ b/contrib/perf.py	Tue Jul 05 07:25:51 2016 +0900
@@ -1,6 +1,23 @@
 # perf.py - performance test routines
 '''helper extension to measure performance'''
 
+# "historical portability" policy of perf.py:
+#
+# We have to do:
+# - make perf.py "loadable" with as wide Mercurial version as possible
+#   This doesn't mean that perf commands work correctly with that Mercurial.
+#   BTW, perf.py itself has been available since 1.1 (or eb240755386d).
+# - make historical perf command work correctly with as wide Mercurial
+#   version as possible
+#
+# We have to do, if possible with reasonable cost:
+# - make recent perf command for historical feature work correctly
+#   with early Mercurial
+#
+# We don't have to do:
+# - make perf command for recent feature work correctly with early
+#   Mercurial
+
 from __future__ import absolute_import
 import functools
 import os