[PATCH 09 of 11] wireproto: advertise supported compression formats in capabilities

[Augie Fackler]

On Sun, Nov 20, 2016 at 02:23:46PM -0800, Gregory Szorc wrote:
> # HG changeset patch
> # User Gregory Szorc <gregory.szorc at gmail.com>
> # Date 1479667112 28800
> #      Sun Nov 20 10:38:32 2016 -0800
> # Node ID f3f2bb7d66a45f16856ad890a8892b3dbafa480e
> # Parent  9e0c42d347fd8bcba87561c92fc93b3ba597ec6f
> wireproto: advertise supported compression formats in capabilities

[...]

>
> diff --git a/mercurial/wireproto.py b/mercurial/wireproto.py
> --- a/mercurial/wireproto.py
> +++ b/mercurial/wireproto.py
> @@ -608,6 +608,59 @@ def bundle1allowed(repo, action):
>
>      return ui.configbool('server', 'bundle1', True)
>
> +def supportedcompengines(ui, proto, role):
> +    """Obtain the list of supported compression engines for a request."""
> +    assert role in ('client', 'server')

Yeah, I think the more I see this the more I want some
constants. Maybe also COMPRESSSION_ROLES or something that can be a
set() of valid roles for this assertion.

> +
> +    if not proto.supportscompression:
> +        return []
> +
> +    compengines = util.compengines.supportedwireengines(role,
> +                                                        onlyavailable=True)
> +
> +    # Allow config to override default list and ordering.
> +    if role == 'server':
> +        configengines = ui.configlist('server', 'compressionengines')
> +        config = 'server.compressionengines'

[...]

Overall this looked fine, modulo my feelings about constants instead
of magic strings.