bug#22344: 25.0.50 (and 24.5.1, 24.4); Sending 4097 bytes to a subprocess hangs Emacs on Windows 8 and 10

[Clément Pit--Claudel]

On 01/14/2016 01:01 PM, Eli Zaretskii wrote:
>> Cc: 22344@debbugs.gnu.org
>> From: Clément Pit--Claudel <clement.pit@gmail.com>
>> Date: Wed, 13 Jan 2016 19:48:38 -0500
>>
>> Eli, there's something magical about your debugging abilities.
>> I downloaded and compiled the latest master on Windows 8; I could reproduce 
>> the bug there. Then I checked out emacs-25 and recompiled, and the bug seems 
>> to be gone! Amazing.
> 
> I wish I had such magic, but I don't.  It's just a lot of hard work,
> that's all.  But thank you for your kind words.
> 
>> This is only for my personal curiosity, but would you mind expanding a bit 
>> on what the issue was (and how you found out)? I read the commit message and 
>> looked at the diff, but I don't think I understood everything from there. 
>> Did you have to look at node.js' source code? Would it be helpful for me to 
>> file a bug with node.js?
> 
> I'm not entirely sure what caused the issue.  From the Emacs side, it
> looked like the other end of the pipe wasn't read at all: each time
> Emacs called _write, it got the return value of -1 with errno set to
> ENOSPC, which means the pipe's buffer is full.  No other program with
> which I tried the same test case did this.  With those other programs,
> after a few first attempts which returned -1, _write started to return
> positive values, meaning that it succeeded to write some part of the
> stuff.
> (...)

Thanks a lot for the explanations! I've raised an issue with the Node.js 
people, inviting them to join this discussion if there was interest about 
fixing this on their side.

Cheers,
Clément.

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