[PATCH] check-code: suggest policy.importmod

[Jun Wu]

# HG changeset patch
# User Jun Wu <quark at fb.com>
# Date 1496256114 25200
#      Wed May 31 11:41:54 2017 -0700
# Node ID 7827171727234eac61bc993b8f85ef5eee45c945
# Parent  5313d98089f569efffaca25de60e73be04156713
# Available At https://bitbucket.org/quark-zju/hg-draft
#              hg pull https://bitbucket.org/quark-zju/hg-draft -r 782717172723
check-code: suggest policy.importmod

This forbids patterns like `from mercurial.cext import parsers` which breaks
pure.

diff --git a/contrib/check-code.py b/contrib/check-code.py
--- a/contrib/check-code.py
+++ b/contrib/check-code.py
@@ -341,4 +341,6 @@ pypats = [
     (r'^import httplib', "don't use httplib, use util.httplib"),
     (r'^import BaseHTTPServer', "use util.httpserver instead"),
+    (r'^(from|import) mercurial\.(cext|pure|cffi)',
+     "use mercurial.policy.importmod instead"),
     (r'\.next\(\)', "don't use .next(), use next(...)"),
     (r'([a-z]*).revision\(\1\.node\(',