Mailing-List: contact dev-help@perl.apache.org; run by ezmlm
Precedence: bulk
Received-SPF: neutral (athena.apache.org: local policy)
Message-ID: <b26611240811061239l2ad37dqcfdec3ef38b80254@mail.gmail.com>
Date: Thu, 6 Nov 2008 15:39:56 -0500
From: "Casey West" <casey@geeknest.com>
Sender: casey@onewestway.com
To: dev@perl.apache.org
Subject: [PATCH] prototypes/constant redefinition warnings from ModPerl::Util
MIME-Version: 1.0
Content-Type: multipart/mixed;
	boundary="----=_Part_30116_22096032.1226003996319"

------=_Part_30116_22096032.1226003996319
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: 7bit
Content-Disposition: inline

Hi,

Apache2::Reload relies on ModPerl::Util::unload_package_pp to
disassemble a stash entry before importing the code again. I like how
it does this with two exceptions.

First, prototypes. unload_package_pp() takes care to retain the
prototype when redefining a code stash entry. That's a good thing
because it (typically) avoids a warning. Then it removes the
subroutine from the stash using undef(). That's not so hot because
undef takes the liberty to explicitly undefine the prototype of that
subroutine. In the case of Apache2::Reload, what happens next is we
remake a prototyped subroutine - lets use try() from Error.pm for
illustration - and get warnings about mismatched prototypes. perl
believes the prototype for this subroutine is not defined, Error tries
to define it as (&;$), and perl warns about "none vs. (&;$)" prototype
mismatch.

This can be avoided by explicitly deleting the CODE slot in the stash
entry, like this: "delete ${$fullname}{CODE};" This will remove the
body of the coderef but leave the prototype in tact.

Second, constant redefinitions. In this case the assignment of an
empty subroutine (with proper prototype) throws a warning, only in the
case of constant subroutines. Take something created by "use constant"
as an example, and combine that with Apache2::Reload.
unload_package_pp() makes every attempt to turn off warnings but
can't, for whatever reason, make it work for this one. The reason, I
found through copious trial and error and a pairing session with Adam
Foxson, is to turn off the warning directly in the eval, like this:

  *{$fullname} = eval "no warmings 'redefine'; sub ($p) {}";

I am not sure why the redefinition warning is thrown from this lexical
scope. Nevertheless, a solution is found.

Attached is a patch which accounts for these two problems. Please consider it.

Cheers,

-- 
Casey West

------=_Part_30116_22096032.1226003996319
Content-Type: text/x-patch; name=mp-ap2-reload-warnings-stfu.patch
Content-Transfer-Encoding: base64
X-Attachment-Id: f_fn7v2rul0
Content-Disposition: attachment; filename=mp-ap2-reload-warnings-stfu.patch
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------=_Part_30116_22096032.1226003996319
Content-Type: text/plain; charset=us-ascii

---------------------------------------------------------------------
To unsubscribe, e-mail: dev-unsubscribe@perl.apache.org
For additional commands, e-mail: dev-help@perl.apache.org
------=_Part_30116_22096032.1226003996319--