Re: [PATCH 00/16] git-send-email cleanups

From: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Date: Sep 30, 2010, 15:11 UTC
Message-ID: <AANLkTikDFJ8jWnuSc9U3hZCRSA971h5Zc2FfJmNiqTUN@mail.gmail.com>
In-Reply-To: <18E0A903-D625-4C7A-A575-AC5C5EF448C9@gernhardtsoftware.com>

On Thu, Sep 30, 2010 at 14:30, Brian Gernhardt <brian@gernhardtsoftware.com> wrote:

> None of these subroutines strictly need the prototype, but it does
> allow Perl to warn us if we send incorrect arguments.  Why remove
> them?  Are they causing problems somewhere?

As Jeff pointed out prototypes are troublesome. If you want to be warned about too many arguments a better way is:

    sub foo {
        warn sprintf "You gave me %d arguments", scalar @_ if @_ != 1;

Or something like that, but there's no reason to do that for these subs in particular. There are 32 subroutines in git-send-email.perl, these weren't in any way more special than the rest.

They probably had prototypes in the first place because they were added by someone who was under the mistaken impression that Perl prototypes were remotely similar to C-like prototypes, they're not.

The purpose of Perl prototypes is to rewrite the *caller* code, so that e.g. if you have:

    sub blah ($$) { ... }

Perl will rewrite this call:

    blah @foo, @bar;

As:

    blah(scalar(@foo), scalar(@bar))

While a blah without prototypes would just be:

    blah(@foo, @bar);

Using prototypes superfluously like this makes it harder to read the code, because you end up checking every call site for every subroutine call that uses prototypes to see if rewriting the argument list like this is producing some unexpected logic error.