Re: interrupt causes parse error in configure script

[Jim Meyering]

Ralf Wildenhues <address@hidden> wrote:
> Hello again,
>
> first, sorry for being a bit blunt earlier.

No apology needed ;-)

...
>> It appears that what Jim is seeing is that the shell (which one?)
>> catches the Ctrl-C, aborts the subshell, but then proceeds with
>> execution of the builtin test before quitting the script.  In other
>> words, the Ctrl-C is not properly affecting the parent shell.
>
> ACK.  I've tried some shells with your example:
>
>> I think we can factor it into a simpler testcase.  I just tried this:
>>
>> $ sh -c 'if test `sleep 5; echo hi` = hi ; then echo yes; fi'
>
> and found only pdksh and OpenBSD sh (which is a pdksh descendant) to
> have this issue.

I'm pretty sure this happened with recent bash on my primary desktop
system.  You can reproduce it with any shell like this:

    if test `sleep 5 && echo f` = f; then echo yes; fi

Then kill the sleep process in under 5 seconds.  I get parse
errors from the latest versions of bash, dash, and zsh.
So this *can* happen with other shells, if either the eval or
the $as_echo from the expansion of AS_VAR_GET fails.
Admittedly, this isn't the same as a simple ^C, so maybe
there's a race condition somewhere in there and the signal
has to hit a small window... or maybe it did happen on
some other type of system.

>> So it looks like my copy of ksh (pdksh 5.2.14) suffers from the bug.
>
>> > Beside, the AS_VAR_YES interface is ugly, but that's orthogonal.
>>
>> And based on the usage pattern, maybe an interface like this would be nicer:
>>
>> AS_VAR_IFELSE(var, [value = yes], if-true, if-false)
>
> Very good idea.  Proposed patch below, for this and the documentation
> issue.

Nice!  I prefer AS_VAR_IFELSE, too.

> What do you think about this patch (putting Eric and me in ChangeLog as
> co authors)?

Thanks for doing that.
You're welcome to push that, assuming there is no new test failure.
"make check" did pass for my patch.