hgweb: use importlib.reload() if available

reload() was nuked in Python 3. We need to use importlib.reload()
instead.

But pyflakes isn't smart enough to detect our conditional usage, so
we allow this error.

Differential Revision: https://phab.mercurial-scm.org/D6992

mercurial/hgweb/server.py

@@ -9,6 +9,7 b''
 from __future__ import absolute_import
 
 import errno
+import importlib
 import os
 import socket
 import sys
@@ -370,7 +371,11 b' def create_server(ui, app):'
         # codec is hardcoded as ascii.
 
         sys.argv # unwrap demand-loader so that reload() works
-        reload(sys) # resurrect sys.setdefaultencoding()
+        # resurrect sys.setdefaultencoding()
+        try:
+            importlib.reload(sys)
+        except AttributeError:
+            reload(sys)
         oldenc = sys.getdefaultencoding()
         sys.setdefaultencoding("latin1") # or any full 8-bit encoding
         mimetypes.init()

tests/test-check-pyflakes.t

@@ -22,4 +22,5 b' run pyflakes on all tracked files ending'
   > 2>/dev/null \
   > | xargs pyflakes 2>/dev/null | "$TESTDIR/filterpyflakes.py"
   contrib/perf.py:*: undefined name 'xrange' (glob) (?)
+  mercurial/hgweb/server.py:*: undefined name 'reload' (glob) (?)