Re: [Quilt-dev] [patch 6/7] Exit with an error when diffs retcode=2 (error) on patch

[Jean Delvare]

Hi Martin,

Le Saturday 18 January 2014 à 01:38 +0100, Martin Quinson a écrit :
> On Fri, Jan 17, 2014 at 10:11:47PM +0100, Jean Delvare wrote:
>> Hmm. We incorrectly assumed that portability of this construct wasn't an
> > issue because we were using bash. We aren't. The tester is written in
> > perl, and except for a few special cases, it blindly execs the commands
> > in the test cases. So we get /usr/bin/printf called here, not bash's
> > printf.
> >
> > I am using GNU coreutils 8.12 and 8.21 on my machine. I suppose you are
> > using something else on your system.
> 
> Nope, I'm the same. But /bin/sh is an alias to dash here. That might
> be why, as the runner script seems to use /bin/sh to start the
> commands that need a shell (such as the ones with a redirection).

That would indeed explain it.

I installed dash and checked its manual page and it claims that its
built-in printf implementation supports octal escapes. I tested it and
it indeed works. As dash is a POSIX-compliant shell, this approach
should be portable.

So we could just use:

$  printf "\\002\\000\\001" > test.bin

> > $ bash -c "printf '\\x02\\x00\\x01'" > test.bin
> > 
> > Performance-wise it's suboptimal but I suppose we don't really care.
> 
> I did that, and it works. Yeah, the performance drop is not noticable
> on this test file ;)

OK. My idea to special-case printf and map it to perl's printf was silly
(and I failed to implement it), so let's not do that. If any
optimisation shall be implemented, it should be on "bash -c", so that we
call bash directly instead of calling /bin/sh which in turn calls bash.
I'll look into that...

-- 
Jean Delvare
Suse L3 Support