wireprotov2: decode responses to their expected types
Callers of established wire protocol commands expect the
response from that command to be decoded into a data structure.
It's not very useful if callers get back a stream of bytes and
don't know how they should be interpreted - especially since that
stream of bytes varies by wire protocol and even the transport
within that protocol version.
This commit establishes decoding functions for various command
responses so callers of those commands get the response type
they expect.
In theory, this should make the version 2 HTTP peer usable for
various operations. But I haven't tested to confirm.
Differential Revision: https://phab.mercurial-scm.org/D3381
wireprotov2: establish a type for representing command response
It will be desirable to have a higher-level type for representing
command responses. This will allow us to do nicer things.
For now, the instance encapsulates existing logic. It is still
a bit primitive. But we're slowly making things better.
Version 1 protocols have a wrapping layer that decodes the raw
string data into a data structure and that data structure is
sent to the future. Version 2 doesn't yet have this layer and
the future is receiving the raw wire response. Hence why
debugcommands needed to be taught about the response type.
Differential Revision: https://phab.mercurial-scm.org/D3380