[PATCH 1 of 7] py3: make util.datapath a bytes variable

[Pulkit Goyal]

# HG changeset patch
# User Pulkit Goyal <7895pulkit at gmail.com>
# Date 1478113113 -19800
#      Thu Nov 03 00:28:33 2016 +0530
# Node ID e541b0e5839988f63446c88509db68772a55775b
# Parent  bb586966818986131068280bfd95fc96fbdaaa0d
py3: make util.datapath a bytes variable

Fixing things when a warning or error comes up was a good approach, but that
won't work in long time, because we will be having all the errors fixed
but no idea where we set which variable to bytes and which to unicodes.
Which function is returning bytes and which is returning unicodes.
We have to make sure if some variable is changed then its effects throughout
the repository are taken care.

In this patch we make util.datapath a bytes variables.

The line containing i18n.setdatapath is skipped for a reason.
i18n.setdatapath looks something like this.

def setdatapath(datapath):
    localedir = os.path.join(datapath, pycompat.sysstr('locale'))
    t = gettextmod.translation('hg', localedir, _languages, fallback=True)
    ....

Here we can't pass gettextmod.translation() bytes when we have _languages as
None in Python 3.5. But yeah we can pass 'hg' as bytes because the code which
returns TypeError deals with localedir variable only. So we need localedir to
be unicode to make gettextmod.translation() happy. If we pass the bytes
version of datapath we will have to convert localedir back to unicode.
So skipped that line of code before converting util.datapath to bytes to
use in rest of the code.

diff -r bb5869668189 -r e541b0e58399 mercurial/util.py
--- a/mercurial/util.py	Tue Nov 01 15:40:21 2016 -0400
+++ b/mercurial/util.py	Thu Nov 03 00:28:33 2016 +0530
@@ -940,6 +940,9 @@
 
 i18n.setdatapath(datapath)
 
+if not isinstance(datapath, bytes):
+    datapath = datapath.encode('utf-8')
+
 _hgexecutable = None
 
 def hgexecutable():