Re: [FYI] {master} maint: assume 'test -x' is portable

[Eric Blake]

On 02/23/2012 04:39 PM, Stefano Lattarini wrote:
>> Using the M4sh language of autoconf already has _AS_DETECT_BETTER_SHELL;
>> we've used it for sanity probes in the past, and doing a sanity probe
>> for a working 'test -x' and 'rm -f' now would be reasonable.
>>
> Still, this is not 100% correct, as, e.g., a probe on 'rm' does not truly
> pertain to a macro that, judging from its name, should check the features
> of the shell.

It would be checking the features of the 'shell scripting environment',
not just the shell.  But you are right - choosing a different shell
won't fix a broken rm, so the best we can do is:

>> For 'test -x', that's usually a shell builtin; so we can require it of
>> the shell.  For 'rm -f', that's a separate executable, so I'm leaning
>> more towards a probe, and see what feedback we get, while still using
>> the workarounds for now.
>>
> Sounds good to me...  but what is the "rm -f" workaround you are referring
> to exactly? (and sorry if this is a dumb question).

Instead of 'rm -f $list', you have to use 'test -n "$list" || rm -f $list'.

>> We still have to set as_test_x for libtool; but I'm thinking we should
>> go one step further, and rewrite AS_TEST_X to just blindly call 'test
>> -x' rather than '$as_test_x', if we go with the minimum shell requirement.
>>
> That's fine by me; I just took the "path of least modification" out of
> laziness :-)  Do you want me to tweak and re-submit my patch, or will
> you take care of it?

I'll take it from here, if you'd like, since I've done probes before, so
I know where to edit.

-- 
Eric Blake   address@hidden    +1-919-301-3266
Libvirt virtualization library http://libvirt.org

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