[PATCH] util: add length argument to util.buffer()

[Yuya Nishihara]

On Sun, 15 Jan 2017 17:04:24 +0530, Pulkit Goyal wrote:
> # HG changeset patch
> # User Pulkit Goyal <7895pulkit at gmail.com>
> # Date 1484404515 -19800
> #      Sat Jan 14 20:05:15 2017 +0530
> # Node ID 087be8a1c7a0452beee36ca23d7978d107b72315
> # Parent  9dc4d056d85a041b2b28587b3b84608b1f0903a5
> util: add length argument to util.buffer()

Queued, thanks.

> --- a/mercurial/util.py	Sat Jan 14 01:23:07 2017 +0530
> +++ b/mercurial/util.py	Sat Jan 14 20:05:15 2017 +0530
> @@ -238,10 +238,14 @@
>      buffer = buffer
>  except NameError:
>      if not pycompat.ispy3:
> -        def buffer(sliceable, offset=0):
> +        def buffer(sliceable, offset=0, length=None):
> +            if not length is None:
> +                return sliceable[offset:offset + length]
>              return sliceable[offset:]
>      else:
> -        def buffer(sliceable, offset=0):
> +        def buffer(sliceable, offset=0, length=None):
> +            if not length is None:

I've updated them to use "is not" operator, which seems more common.