Re: [PATCH v3 2/2] transport-helper: check if remote helper is alive

From: Junio C Hamano <gitster@pobox.com>
Date: Apr 8, 2013, 21:08 UTC
Message-ID: <7vy5csvih8.fsf@alter.siamese.dyndns.org>
In-Reply-To: <CAMP44s0DjJL44uavM44sxgSyrgbTLpUarEPB6=-imvw1rewOOA@mail.gmail.com>

Felipe Contreras <felipe.contreras@gmail.com> writes:

Show 20 quoted lines

> On Mon, Apr 8, 2013 at 1:46 PM, Junio C Hamano <gitster@pobox.com> wrote:
>
>>>> ...  But if we keep
>>>> helper running, who will be communicating with it via these open
>>>> pipes?  The process that is calling finish_command() on fast-import
>>>> and disconnecting from the helper won't be, as read/write to the
>>>> pipe, even if we do not disconnect from here, will result in errors
>>>> if the helper has already exited at this point.
>>>
>>> Nobody will send any further input, but in theory we could redirect
>>> the pipe and send more commands. That's how it was designed.
>>
>> Who does the redirection to whom?
>
> The one that is doing all the redirections, transport-helper.
>
>> How would the process tree and
>> piping constructed around the current system?
>
> I cannot parse that correctly,

Sorry, s/the current system/& look like/;

> but transport-helper is already
> receiving the output from the remote-helper.

OK, so you are envisioning that transport-helper would read from the helper after importer is done? If so, perhaps it is a prudent solution to disconnect in this version (to fix), and then in a separate patch that adds such an extension (I imagine it would involve that the helper advertising a capability or being invoked with an option to let transport-helper somehow know that it should continue the conversation once fast-import is done) to disable the disconnect here when that extension is in use?