From: Jeff King <peff@peff.net>
Date: Sat, 01 Dec 2018 19:50:37 GMT
Subject: Re: [PATCH] t5562: skip if NO_CURL is enabled
Message-ID: <20181201195037.GA29120@sigill.intra.peff.net>
In-Reply-To: <20181128132708.GE30222@szeder.dev>

On Wed, Nov 28, 2018 at 02:27:08PM +0100, SZEDER Gábor wrote:

> > Curiously, the act.err file also has 54 NUL bytes before the "fatal:"
> > message.
> 
> I think those NUL bytes come from the file system.
> 
> The contents of 'act.err' from the previous test ('fetch gzipped
> empty') is usually:
> 
>   fatal: request ended in the middle of the gzip stream
>   fatal: the remote end hung up unexpectedly
> 
> Notice that the length of the first line is 54 bytes (including the
> trailing newline).  So I suspect that the following is happening:
> 
>   - http-backend in the previous test writes the first line,
>   - that test finishes and this one starts,
>   - this test truncates 'act.err',
>   - and then the still-running http-backend from the previous test
>     finally writes the second line.
> 
> So at this point 'act.err' is empty, but the offset of the fd of the
> redirection still open from the previous test is at 54, so the file
> system fills those bytes with NULs.

Right, good thinking. Thanks for the explanation!

-Peff