[PATCH 2 of 2] chgserver: handle ParseError during validate

[Yuya Nishihara]

On Fri, 11 Mar 2016 12:48:59 +0000, Jun Wu wrote:
> # HG changeset patch
> # User Jun Wu <quark at fb.com>
> # Date 1457698875 0
> #      Fri Mar 11 12:21:15 2016 +0000
> # Node ID 57ce1dae166bcfcaae191e2077b0dff21f7efc42
> # Parent  b39cdec1d4e8817cf096474642ad8337d218d126
> chgserver: handle ParseError during validate
> 
> Currently the validate command in chgserver expects config can be loaded
> without issues but that's not true if the config file is ill-formed. The
> current code does not catch ParseError. The server will print a stacktrace
> then abort, while the client will abort with "failed to read channel".
> 
> This patch add handler for ParseError during validate and makes getpager,
> runcommand no-ops, returning the correct exit code without crashing the
> server.
> 
> diff --git a/hgext/chgserver.py b/hgext/chgserver.py
> --- a/hgext/chgserver.py
> +++ b/hgext/chgserver.py
> @@ -340,6 +340,7 @@
>          self._oldios = []  # original (self.ch, ui.fp, fd) before "attachio"
>          self.hashstate = hashstate
>          self.baseaddress = baseaddress
> +        self._exitcode = None
>          if hashstate is not None:
>              self.capabilities = self.capabilities.copy()
>              self.capabilities['validate'] = chgcmdserver.validate
> @@ -428,7 +429,16 @@
>                server instead.
>          """
>          args = self._readlist()
> -        self.ui = _renewui(self.ui, args)
> +        try:
> +            self.ui = _renewui(self.ui, args)
> +        except error.ParseError as inst:
> +            # same behavior with dispatch.py
> +            dispatch._formatparse(self.ui.warn, inst)
> +            if inst.hint:
> +                self.ui.warn(_("(%s)\n") % inst.hint)
> +            self._exitcode = -1
> +            self.cresult.write('\0')
> +            return

Can it return an instruction such as "unlink" to forcibly retry connection?
It seems ugly to keep exitcode until "runcommand" and simulate the behavior of
dispatch().