[PATCH windows] windows: add an experimental option for long paths support

[Matt Harbison]

On Mon, 09 Oct 2017 05:38:04 -0400, Kostia Balytskyi <ikostia at fb.com>  
wrote:

> # HG changeset patch
> # User Kostia Balytskyi <ikostia at fb.com>
> # Date 1507541423 25200
> #      Mon Oct 09 02:30:23 2017 -0700
> # Node ID aa5c7de6a86ba8bbc7d46bb414ac7ee6fbde3a4a
> # Parent  a57c938e7ac8f391a62de6c7c4d5cf0e81b2dcf4
> windows: add an experimental option for long paths support
>
> +
> +    def addlongpathsmanifest(self):
> +        """Add manifest pieces so that hg.exe understands long paths
> +
> +        This is an EXPERIMENTAL feature, use with care.
> +        To enable long paths support, one needs to do two things:
> +        - build Mercurial with --long-paths-support option
> +        - change HKLM\SYSTEM\CurrentControlSet\Control\FileSystem\
> +                 LongPathsEnabled to have value 1.

The way I read the documentation[1], it seems like either one alone is  
sufficient.  Did you find different in testing?

[1] https://msdn.microsoft.com/en-us/library/aa365247(v=vs.85).aspx#maxpath