Re: [PATCH] bootstrap: handle perl-5.11's changed --version output

[Pádraig Brady]

Jim Meyering wrote:
> Pádraig Brady wrote:
>> Jim Meyering wrote:
>>> I've built and have been experimenting with perl 5.11.2+
>>> and hit a little snag: bootstrap was unable to extract
>>> the version number from its new --version output.
>>> To address that, I've changed bootstrap to special-case perl:
>> That looks good, the caveat being that all projects
>> with specifications of perl in bootstrap.conf must be
>> updated to the new format.
>>
>> Note I just noticed there was an issue with the perl-5.5 dependency
>> specification in coreutils::bootstrap.conf as on perl 5.5.x
>> systems one would have got:
>>
>> Error: 'perl' version == 5.005 is too old
>>        'perl' version >= 5.5 is required
>>
>> One could also handle both of these issues with
>> this updated get_version(), the advantage being that
>> no bootstrap.conf files need to be updated. Also all
>> version specs would be of a consistent format.
> ...
>>           #the following essentially does s/5.005/5.5/
>>           s/\.0*\([1-9]\)/.\1/g
> ...
> 
> good catch!
> 
> However, performing that substitution on a string like 5.010000
> would give 5.10000.  Not what we want.

Note no `perl --version` I know outputs 5.005002, it outputs
5.005_002 which will be truncated to 5.005 by our regex.
So in general we would just be treating the version as ints delimited with '.'

> Using $^V appears to be the solution:
> 
>     $ perl -le '($v = $^V) =~ s/^v//; print $v'
>     5.10.0
> 
> Generally, I prefer to avoid using $_, but here it might be worthwhile
> for the slight overall decrease in syntax:
> 
>     $ perl -le '$_ = $^V; s/^v//; print'
> 
> Opinions?

I looked at $^V first but was dissuaded as
I thought $^V was not available until perl 5.6?
Also I thought it changed format recently
(it doesn't work on 5.8 on solaris at least).

cheers,
Pádraig