[PATCH python-hglib] Add the abilty to trace the protocol between the client and server

[Yuya Nishihara]

On Thu, 06 Oct 2016 18:04:47 +0100, Barry A. Scott wrote:
> # HG changeset patch
> # User Barry A. Scott <barry at barrys-emacs.org>
> # Date 1475770955 -3600
> #      Thu Oct 06 17:22:35 2016 +0100
> # Branch hglib-protocol-trace
> # Node ID efc527cc43d7394a5bd0deb1d29c4307592f7528
> # Parent  6f15cb7cc9cb4427f35c60080f85dbf4ca5abd10
> Add the abilty to trace the protocol between the client and server.
> This is useful when debugging issues with driving hg via hglib
> where output and error messages can be lost.
> 
> call setprotocoltrace with the name of a trace function or None.
> If the trace function is None no tracing is done.
> The trace function is called with the channel and its data.

This generally looks good to me. Can you update the commit message and
coding style?

https://www.mercurial-scm.org/wiki/ContributingChanges

> diff -r 6f15cb7cc9cb -r efc527cc43d7 hglib/client.py
> --- a/hglib/client.py	Mon Jul 18 23:40:45 2016 -0500
> +++ b/hglib/client.py	Thu Oct 06 17:22:35 2016 +0100
> @@ -62,6 +62,15 @@
>          if connect:
>              self.open()
>  
> +        self._protocoltracefn = None
> +
> +    def setprotocoltrace( self, tracefn=None ):
> +        """
> +        if tracefn is None no trace calls will be made.
> +        Otherwise tracefn is call as tracefn( channel, data )
> +        """
> +        self._protocoltracefn = tracefn
> +
>      def __enter__(self):
>          if self.server is None:
>              self.open()
> @@ -119,6 +128,7 @@
>  
>      def runcommand(self, args, inchannels, outchannels):
>          def writeblock(data):
> +            if self._protocoltracefn is not None: self._protocoltracefn( b'i', data )

Using a fake channel name seems a bit unfortunate. I slightly prefer b'' or
None.s