From: Robin Jarry <robin.jarry@6wind.com>
Date: Thu, 27 Jan 2022 08:38:47 GMT
Subject: Re: [PATCH v2] receive-pack: add option to interrupt pre-receive when client exits
Message-ID: <CHGBKD7TF1S5.3VUMATFQPY9TE@diabtop>
In-Reply-To: <CANYiYbGME-=w4raiwW3w1_gHzVpsvdStz7xVpKqAwx2r_Vezzw@mail.gmail.com>

Jiang Xin, Jan 27, 2022 at 04:21:
> Can we use a flag instead of hook_pid to distinguish the source of the
> SIGPIPE signal?
> 1. "pre-receive" hook exits early without consuming stdin.
> 2. "pre-receive" hook hangs after receiving commands from stdin, until
> client quits by receiving a "ctrl-c".

Also there is:

3. the client has exited and receive-pack got SIGPIPE while forwarding
   pre-receive output in the socket.

I don't think we can differentiate from these three situations from the
receive-pack point of view.

However, using a flag in the signal handler to note that SIGPIPE was
received (for whatever reason) may be better than my current
implementation.

> Can we let the signal handler in "pre-receive" to do it job? And we
> can show some user friendly error message here. E.g.:
>
>     die("broken pipe: seems like the pre-receive hook exits early
> without consuming its stdin");

If that flag is set after pre-receive has exited, we can indeed:

    die("broken pipe: ...").

Of course, if 3. the error message will never reach the client.