This Week on perl5-porters - 24-30 October 2005
Mathoms, fixes, hobbits, speedups, all of them together advancing the
development of Perl.
A *maint* Snapshot
Nicholas Clark rolled out a maint snapshot towards 5.8.8. He called
for reports of success and failure while stuff integration from blead
to maint goes on. In the followups, OS X Tiger and Mandriva Linux
seemed to be quite happy with the current state of maint. Nicholas'
plan hopes to see another snapshot about a week later and probably
5.8.8 RC1 one week after this.
Nicholas' announcement
http://xrl.us/h896
The snapshot
http://opensource.fotango.com/~nclark/perl-25817.tar.bz2
Cut-and-Paste Findings
Jarkko Hietaniemi posted the findings of cut-and-paste code on
[EMAIL PROTECTED] That triggered a discussion on how to deal with repeated
code, why it is worthy and when it could be desirable.
http://xrl.us/h897
Getting "sort()" Right
Robin Houston had no rest this week fighting battles with recursive
sorts and issues on fiddling with active subs.
Robin started wondering about the rationale behind the "Can't redefine
active sort sub" thing and found a number of bugs in the way. These
bugs were related to oversights in doing multiple calls to subroutines
and affected "sort()" as well "List::Util". To solve the issue, Robin
thought of a set of macros *MULTICALL* for repeatedly calling the same
sub and intented to make easier to get right code like the "sort"
implementation.
http://xrl.us/h898
Robin showed yet another subtle bug when you call "sort()" with a sort
sub that's already active.
http://xrl.us/h899
Ben Tilly, the requestor of RT ticket #36430, explained Robin what
exactly made the ticket issue unlike the one of bug #7063.
http://xrl.us/h9aa
Then, Robin prepared drafts of his so-called sort/multicall patch.
Yitzchak Scott-Thoennes prodded for tests and Graham Barr (the
maintainer of "List::Util") asked for description of what really
changes and how compatibility may be preserved/restored.
First draft
http://xrl.us/h9ab
Second draft
http://xrl.us/h9ac
Getting there
http://xrl.us/h9ad
"pp_push()" Gets Faster
Tassilo von Parseval stumbled at a comment at pp.c and found a good
opportunity to speed up "pp_push()" for the case of pushing multiple
elements. Yitzchak Scott-Thoennes had comments and suggestions that
led Tassilo to write a more effective patch, illustrated by benchmarks
hinted by H.Merijn Brand. Rafael applied it as change #25854.
http://xrl.us/h9ae
Mathoms Held Together
Back in June, Nicholas Clark suggested the name mathoms.c, for a file
holding C functions still kept around for binary compatibility
reasons. (For the record, mathoms will be yet another Tolkien's
reference in Perl source code.) This week, Steve Peters made it happen
with a patch to create the new file and a configure switch to turn
on/off the inclusion of the file in the build. Ronald J. Kimball and
Philip M. Gollucci played the part of the ones who don't like the
name. Rafael Garcia-Suarez thought Steve's patch would break build on
everything but Unix. Steve asked for pointers on what files would need
editing in other environments and, confronted with golden silence,
found those files and made what was necessary, applying change #25866.
Nicholas coins the file name
http://xrl.us/h9af
Steve Peters gets mathoms together
http://xrl.us/h9ag
Ken and PerlIO
* Panic with Multiple Encodings * Ken Hirsch reported bug #37526 which
shows how using multiple encodings at once may cause panic (more
exactly, "panic: sv_setpvn called with negative strlen").
http://xrl.us/h9ah
* Reconciled 3-arg Opens * Ken Hirsch reported yet another problem
with PerlIO encoding layers. This time, in RT ticket #37533, he
noticed that three-arg opens seem to always ignore default layer
settings by the "open" pragma. Furthermore, he pointed an issue that
Rafael Garcia-Suarez considered a contradiction between the "open"
pragma documentation and perlfunc. Rafael produced a patch to
reconcile the 3-arg opens with the "open" pragma settings and
suggested to settle the "perlfunc" behavior as the correct one.
http://xrl.us/h9ai
Gory Quoted Constructs
Bas van Sisseren in bug #37527 reported the parser was having trouble
with regexes delimited with "[]" and backslashes. Jeff 'japhy' Pinyan
elucidated the gory details which Rafael Garcia-Suarez believed to be
documented in perlop, although not very clearly. Bas proceeded to
patch "B::Deparse" which he was using when he met the problem.
http://xrl.us/h9aj
Pre-loaded Perl executables
Joseph Thames exposed a maintenance issue at his actual work
environment using Perl, Apache, mod_perl and various CPAN modules with
very demanding requirements. He was looking for a scalable solution
minimizing configuration, preferably with native executables and
wondered if there was a standard way of using early-bound Perls rather
than the dynamic traditional way. Yitzchak Scott-Thoennes advised
about the highly experimental nature of "B::C" or "B::CC" approaches
and about "PAR" as a candidate for the job. He also referred Joseph
could reach a wider audience by asking at perlmonks.org. John Peacock
suggested him to also evaluate "perl2exe" in his context.
http://xrl.us/h9ak
Fast "IO::File" Once Again
Pratik noticed that a recent change at "IO::File" introduced a call to
"File::Spec->rel2abs()" which uses "Cwd" that in turn forks a new
process to determine the working directory. This led to a major
performance hit. Gisle Aas explained the change was due to fixing a
failure in Windows and soon found a way to fix the situation with a
3-arg open instead of munging with file names. Steve Peters applied
and that made Pratik happy and eager to see the fix in 5.8.x branch as
well.
http://xrl.us/h9am
Multi-threaded "IO::Socket"
Peter Millington had a multi-threaded application and found some
trouble when using "IO::Socket" and "Net::FTP" in such environment. He
asked whether the corresponding objects are believed to be thread-safe
and explained how he worked around the issue with a change to
"IO::Socket::Net::configure()". Rafael Garcia-Suarez confirmed there
may be problems with "IO::Socket" and threads, called for a patch in
unified diff format and greeted opinions on other points raised by
Peter.
http://xrl.us/h9an
"utime"'s Turn
In July, Gisle Aas set a trend on taking advantage of the
corresponding C "fxxx()" functions to implement builtins like "chmod",
"fchown", and "fchdir". This time, Yitzchak Scott-Thoennes proposed to
make "utime" use "futimes" where available. Gisle Aas backed it up and
waits for somebody to add Configure probes for "futimes".
Gisle's start
http://xrl.us/h9ao
Yitzchak's turn
http://xrl.us/h9ap
Extending Left Bit-shifts
Tassilo von Parseval wondered whether perl could try to use the
biggest available native integer type for left bit-shift operations.
Adriano Ferreira believed perl would better stick to its
configure/build-time integer types and "bigint" pragma would be there
for arbitrary precision integer arithmetic. Tassilo and Tels pointed
the inconvenience of the performance hit when using "Math::BigInt".
Yitzchak Scott-Thoennes foresaw trouble in upgrading IV to NV types
for integer-type operations like shifts.
http://xrl.us/h9aq
John and VMS
*VMS failure summary* After a failure summary of blead on VMS by John
E. Malmberg, Rafael Garcia-Suarez thanked John (in the name of all
perl5 porters and lovers, I dare to say) and gave a clue on making
tests more portable.
http://xrl.us/h9ar
*VMS exit handling* After sorting out most of the issues in exit
handling in VMS, John E. Malmberg asked for help to make it right once
and for all. In fact, he did work out his own way and regretted not
being able to change the default behavior due to the compatibility
burden, which was commented by Rafael Garcia-Suarez. And then John
posted what he expects to be the last VMS exit/error fixes that were
needed.
Call for help
http://xrl.us/h9as
Hopefully the last fixes
http://xrl.us/h9at
* vms.c improvements and fixes * John E. Malmberg introduced in vms.c
a new "do_mp_rmsexpand()" to support longer filenames for
platforms/versions where it makes sense. While on this, he fixed
memory leaks in old "do_mp_rmsexpand()" and made code safer with
"memmove()" replacing "memcpy()".
http://xrl.us/h9au
* "sprintf" on VMS * John E. Malmberg posted a minor change to reflect
the fact that "sprintf" in VMS returns the length of the buffer.
http://xrl.us/h9av
Jarkko and Symbian
This week, Nicholas Clark and Jarkko Hietaniemi discussed what changes
would be needed to make "Encode" work with the constraint of
non-writeable data on Symbian. The issue at stage was how changes in
underlying structure types would break compatibility among "Encode"
and older format encode tables.
http://xrl.us/h9aw
Jarkko also announced better support for Series 80 devices and some
handy utilities for Perl on Symbian.
http://xrl.us/h9ax
More Platform Specific Issues
* Cygwin, "unlink", Win32 * Sébastien Aperghis-Tramoni noticed how
weird Perl on Cygwin can be when issuing code like this:
open FILE, '>', $file;
unlink $file or warn $!;
opendir DIR, '.';
print "here yet" if grep { $_ eq $file } readdir(DIR)
"unlink()" succeeds but the file can be seen yet with "readdir()",
even though it is gone when the script ends or when the file is
closed. To Sébastien, it does not feel like Unix or Windows. Yitzchak
Scott-Thoennes quoted perlport: "Don't "unlink" or "rename" an open
file" for portable code. Some discussion ensued with Yitzchak
Scott-Thoennes unveiling the relevant Perl source code and Yves Orton
explaining oddities in Win32 API. Very instructive and scary.
http://xrl.us/h9ay
*AIX Woes* David Favor had some trouble building blead on AIX. Rafael
Garcia-Suarez pointed it was probably due to the Makefile failing to
use makedef.pl to generate perl.exp where that matters. And then it
worked.
http://xrl.us/h9az
* EBCDIC, Unicode, "unpack" * Sadahiro Tomoyuki explained the results
Rajarshi Das was seing using "unpack" with formats 'U' and 'C' on
EBCDIC platforms: a UTF-8 versus UTF-EBCDIC issue.
http://xrl.us/h9a2
* A Linux Issue * Jason Vas Dias found perl.h to incorrectly guess the
"IOPARM_LEN" on Linux to be constant 256 and posted a patch to use the
"_IOC_SIZE" as it should. Rafael tweaked the change to avoid
misterious side-effects on some other random platform and applied it.
http://xrl.us/h9a3
Perl5 Bug Summary
The open tickets count was at 1519 in Oct 24 13:00.
Robert Spier and the Bug summary
http://xrl.us/h2ze
Perl RT just now
http://rt.perl.org/rt3/NoAuth/perl5/Overview.html
In Brief
* Exit Code in 5.8.8? * Nicholas Clark, after seeing a lot of patching
in exit code, asked whether it just had to do with VMS or if it
affects Unix and Windows sides. He wondered about the convenience of
integrating this to maint now or in a couple of months. No answer so
far.
http://xrl.us/h9a4
* Revisited cc/cppsymbols * Yitzchak Scott-Thoennes posted a patch to
fix a long-standing bug on Configure's test for cppsymbols with values
which contain spaces, such as Cygwin's "_LONG_DOUBLE=long double".
http://xrl.us/h9a5
* mv-if-diff Days are Counted * Rafael Garcia-Suarez posted a patch to
remove mv-if-diff from the main makefile and asked for people to try
it. Nicholas did and found the need for a tweak.
The "remove mv-if-diff" campaign summarized
http://xrl.us/h9a6
This week
http://xrl.us/h9a7
* White Smokes for "Compress::Zlib" * Without much ado, Paul Marquess
filed a fix for the "Compress::Zlib"'s smoke failures seen on Win32,
which was applied by H.Merijn Brand with great expectations.
http://xrl.us/h9a8
* warnings.pm Works as It Should * Rafael Garcia-Suarez dismissed bug
#36781 which claimed functions "enabled", "warn", "warnif" in
warnings.pm were buggy. He explained how the reported behavior was the
intented one according to the docs and Paul Marquess noted it is all
there in perllexwarn.pod.
http://xrl.us/h9a9
* Named Escapes in Eval * Peter Scott noticed an oddity when using
named escapes in evals and thought a POD fix could be in order.
Sadahiro Tomoyuki suggested the issue could be slightly different as
well as the appropriate doc fix.
http://xrl.us/h9ba
* Misleading Closures in Regexes * William L. Devanney opened RT
ticket #37543 after being surprised with how $^N worked with respect
to global and lexical variables. Jeff 'japhy' Pinyan explained the
point was the use of regex construction "?{}" which creates a closure
around the lexical environment and a known bug that makes it refer to
the first time the regex is compiled, giving wrong results for
subsequent calls.
http://xrl.us/h9bb
* perl5db.pl Fix * Brendan O'Dea sent a patch for fixing an incorrect
instruction in termination message emitted by perl5db.pl.
http://xrl.us/h9bc
*Free the Tries* Jarkko Hietaniemi spotted and patched a bug in
"regcomp.c" that prevented tries to be freed.
http://xrl.us/h9bd
"ExtUtils::Constant" and Perl 5.004 Sébastien Aperghis-Tramoni posted
a small patch to restore "ExtUtils::Constant" compatibility with Perl
5.004.
http://xrl.us/h9be
About this summary
This summary was written by Adriano Ferreira. I would like to
acknowledge a mistake and apologize myself to H.Merijn Brand for
spelling wrong his name in the last summaries. Please correct me and
send comments.
Information concerning bugs referenced in this summary (as #nnnnn) may
be viewed at http://rt.perl.org/rt3/Ticket/Display.html?id=nnnnn
Information concerning patches to maint or blead referenced in this
summary (as #nnnnn) may be viewed at
http://public.activestate.com/cgi-bin/perlbrowse?patch=nnnnn
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