Eric Wilhelm wrote:
> I'm very troubled by any inclusion of underscores in the META.yml spec
> because they behave differently between perl v-strings and version.pm.
>
> Example: v1.0.2_3 gt v1.0.3, but qv(v1.0.2_3) < v1.0.3
You aren't using version.pm comparisons in both cases, so it shouldn't be all
that surprising that it doesn't work the way you'd expect it. Look here:
$ perl -Mversion -MDevel::Peek -e 'Dump(v1.0.2_3)'
SV = PVMG(0x830658c) at 0x82a8984
REFCNT = 1
FLAGS = (PADTMP,RMG,POK,READONLY,pPOK)
IV = 0
NV = 0
PV = 0x82cacac "\1\0\27"\0
CUR = 3
LEN = 8
MAGIC = 0x82caf24
MG_VIRTUAL = 0
MG_TYPE = PERL_MAGIC_vstring(V)
MG_LEN = 8
MG_PTR = 0x82cc464 "v1.0.2_3"
When constructing the PV, the underscore is ignored (as in any bare number), but
the PERL_MAGIC_vstring(V) has the original text as written. If you do this
instead:
$ perl -Mversion -e 'print (v1.0.2_3 < version->new(v1.0.3))'
1
you'll see that correct version object comparisons work as designed. If your
code is comparing versions with version.pm, liberally sprinkle version->new() on
at least one of your terms and you will always be safe. Don't use qv() because
it is _not_ a generic version object creator; it forces extended version
notation, even where it would otherwise parse as numeric:
> ยท qv()
> An alternate way to create a new version object is through the
> exported qv() sub. This is not strictly like other q? operators
> (like qq, qw), in that the only delimiters supported are parenthe-
> ses (or spaces). It is the best way to initialize a short version
> without triggering the floating point interpretation. For example:
>
> $v1 = qv(1.2); # 1.2.0
> $v2 = qv("1.2"); # also 1.2.0
>
> As you can see, either a bare number or a quoted string can usually
> be used interchangably, except in the case of a trailing zero,
> which must be quoted to be converted properly. For this reason, it
> is strongly recommended that all initializers to qv() be quoted
> strings instead of bare numbers.
This was one of my big failings when writing version.pm; I originally intended
this to be useful to CVS users (where $Revision$ is a sequence of integers
separated by one or more decimal points). However, a lot of people assumed
because it was 'qv' (quoted version) that must mean it was a generic version
creation operator.
John
