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

[Yuya Nishihara]

On Thu, 03 Nov 2016 03:53:06 +0530, Pulkit Goyal wrote:
> # 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.

i18n.setdatapath() can decode bytes to unicode by fsdecode() for consistency
of API.

> 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')

Perhaps we can use pycompat.fsencode(), which would be what Python 2 does
on Windows.