Thread (10 messages) flat view 10 messages, 3 authors, 2016-07-08

Re: [PATCH 2/4] receive-pack: implement advertising and receiving push options

From: Junio C Hamano <hidden>
Date: 2016-07-08 18:40:30

Jonathan Nieder [off-list ref] writes:
Hi,

Junio C Hamano wrote:
quoted
Stefan Beller [off-list ref] writes:
quoted
quoted
quoted
More importantly, if we plan to make this configurable and not make
the limit a hardwired constant of the wire protocol, it may be
better to advertise push-options capability with the limit, e.g.
"push-options=32" (or even "push-options=1024/32"), so that the
client side can count and abort early?
Sorry to butt into the conversation late, but: I am not yet convinced.

Is the idea that if the push options were very large, this would save
the client from the cost of sending them?  
Not really.  I have no strong opinion on the benefit of limiting
number/size.  Stefan limited the number/size at the receiving end
and made receiving end die with its message.  I was merely trying to
tweak the arrangement so that the sending end can complain with its
own message, possibly in its own language, especially because it was
unclear to me if the die() message on the receiving end would always
go back to the sending end correctly.
But this comes with a
downside: the server doesn't get to send an error message about
where 
the maximum number of push options can come from (e.g., with a link to
a page where the limit can be adjusted, or with an explanation of when
clients tend to run into this problem and what they should do
instead).
Hmm, interesting point.  That would be better told by the receiving
end, as the way to configure it (if offered) would be different from
installation to installation.
So I'd like to propose an alternative. What if the client tells the
server the number of push options early on (and possibly also a cap on
the length of those push options)?  That way, the client doesn't have
to waste bit sending the push options but the server gets an
opportunity to send a helpful error message on sideband 3.

	server> HEAD\0push-options ...
	client> ... commands ...
	client> push-options 2
	client> my-first-option
	client> my-second-option
  
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