Re: BUG #5339: Version of Perl detected incorrectly

Jonathan Leto <jonathan@leto.net> writes:
> On Mon, Feb 22, 2010 at 12:07 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>>> This is perl 5, version 11, subversion 4 (v5.11.4-114-ga4cc961*) built for
>>> x86_64-linux
>>
>> Ugh.  Can't they manage to keep that message reasonably consistent?

> The form of the version string is the closest release version
> (5.11.4), the number of commits ahead of that (114) and the SHA1 of
> the actual commit. What flavor of consistency are you looking for?

The output format of "perl -v" has been reasonably consistent for well
over a decade, eg (examples captured from various machines around my
house)

    This is perl, version 4.0
    This is perl, v5.8.7 built for PA-RISC2.0
    This is perl, v5.10.0 built for darwin-thread-multi-2level

Why did 5.11 feel a need to go off in a new direction?  They haven't
added any actual new information AFAICS, just made it harder to parse.

>> This is not a path towards an acceptable solution, as it effectively
>> assumes what we are setting out to prove, namely that we have found
>> a reasonably modern version of perl.  Try it in perl 4...

> These words don't seem to make sense. Can you translate?

Which part of "it doesn't work in perl 4" is not clear to you?
Yes, I'm aware that it *fails* in perl 4, but it doesn't produce
an error message that would be helpful to a non Perl hacker:

$ /usr/local/bin/perl4 -e 'use 5.008001;'
syntax error in file /tmp/perl-ea01429 at line 1, next 2 tokens "use 5.008001"
Execution of /tmp/perl-ea01429 aborted due to compilation errors.

That isn't going to lead to people realizing that they need a newer
Perl, it's just going to lead to bug reports --- sent to *us*.
I am not prepared to compromise one inch on the clarity of the error
message put out by configure.

            regards, tom lane