This Week on perl5-porters - 13-19 October 2008
"It's far from being a critical issue, and I'm not saying that magic
shouldn't be enabled there. But I'd really like to see magic behave in
the most predictable possible way." -- Vincent Pit, inventing a new
meaning for "predictable".
Topics of Interest
use bytes pragma
Karl Williamson, in his ongoing overhaul of Unicode handling,
discovered some inconsistencies between the documentation for and
implementation of the "bytes" pragma. As such, he wasn't willing to
hazard a change, but wondered how often it was used in real life.
http://xrl.us/ovbq2
PATL/autorequire-0.08.tar.gz broken since [EMAIL PROTECTED]
Slaven Rezic noted that refactoring in DynaLoader had caused this
module to fail, and traced it down to some hairy .PL template code.
Vadim Konovalov admitted guilt over the template syntax and offered to
atone for his sins by writing the machinery that would allow nicer
templating during the build.
http://xrl.us/ovbq4
ties and other filehandle bondage
Ricardo Signes uncovered an ugly problem with opening a file handle to
a reference of a tied scalar. And while this was probably not the
wisest thing to do in the first place, any error message would be
better than none.
Vincent Pit reasoned that the best way to solve this would be to have
magic triggered on every "print" argument, but that might be woefully
expensive. Nicholas Clark thought that correctness was better than
speed, and if you're into magic you probably don't care about
efficiency.
http://xrl.us/ovbq6
blead and Glib's lazy-loader
Torsten Schönfeld reported a problem with "av_clear" on @ISA not doing
the right thing, and having to call "av_shift" repeatedly instead. (I
seem to remember summarising a similar issue a couple of weeks ago).
http://xrl.us/ovbq8
Change 32016 breaks a test in "MPEG::Audio::Frame"
Slaven Rezic uncovered a bug in "MPEG::Audio::Frame". Nicholas Clark
noted that this was because Yuval Kogman was a wicked man who peeked,
and relied upon the implementation. Yuval admitted that the module
ought to be fixed up (rather than perl), but confessed to low amounts
of tuits.
Nicholas was also in awe of the amount of testing Slaven was doing in
tracking the changes for 5.8.9.
http://xrl.us/ovbra
TODO of the week
Add a code coverage target to the Makefile
Make it easy for anyone to run "Devel::Cover" on the core's tests. The
steps to do this manually are roughly
* do a normal "Configure", but include "Devel::Cover" as a module to
install (see INSTALL for how to do this)
* make perl
* cd t; HARNESS_PERL_SWITCHES=-MDevel::Cover ./perl -I../lib
harness
* Process the resulting Devel::Cover database
This just give you the coverage of the .pms. To also get the C level
coverage you need to
* Additionally tell "Configure" to use the appropriate C compiler
flags for "gcov"
* make perl.gcov
(instead of "make perl")
* After running the tests run "gcov" to generate all the .gcov
files. (Including down in the subdirectories of ext/
* (From the top level perl directory) run "gcov2perl" on all the
".gcov" files to get their stats into the cover_db directory.
* Then process the Devel::Cover database.
It would be good to add a single switch to "Configure" to specify that
you wanted to perform perl level coverage, and another to specify C
level coverage, and have "Configure" and the Makefile do all the right
things automatically.
New and old bugs from RT
"File::Copy" module (#32135)
Nicholas Clark disagreed with Adriano Ferreira's comment of what was
the underlying problem in this bug report. He wondered if the real
problem did not in fact lie with "IO::Scalar".
http://xrl.us/ovbrc
In a related report ("File::Copy" does not handle file objects sanely
(bug #59650)), a rabbit supplied a patch to deal with "IO::Scalar"
objects (which is probably why Nicholas revived the preceding bug.
Nicholas had a minor quibble over the use of "xor" rather than "ne",
and wondered if there were any corner cases where they would behave
differently.
http://xrl.us/ovbre
Unicode problem (#58182)
Karl Williamson reported back on his progress in dealing with Unicode
in Perl. He now has a good idea of what he wants to do, but had some
questions of a practical nature regarding C coding standards. He asked
a very interesting question: what is the feeling regarding the use of
lookup table to push design decisions into data, rather than code.
Another crucial design assumption was that "uc" tries to convert in
place if possible. Karl wondered if it would reasonable to always
return a new SV regardless of whether the original container would
fit, as it would simplify the code. To this latter point, Rafaël
Garcia-Suarez told him to go ahead with whatever was easiest; there
would always be time to optimise it later on, should the need arise.
In another subthread, Karl pointed people at the bikeshed and asked
for colour schemes. That is, this new Unicode functionality will be
enabled via a pragma in 5.10 (becoming the default behaviour in 5.12).
What, then, should be the name of the pragma? Karl had a number of
ideas, but was dissatisfied with all of them.
http://xrl.us/ovbrg
Memory leak with regex in 5.10.0 (#59516)
Marcus Holland-Moritz plugged the leak with a well-placed
"SvREFCNT_dec".
http://xrl.us/ovbri
bun in perl 5.8.8 on AIX 5.3 (#59866)
Rainer Tammer noted a perfect 64-bit build on AIX 5.2, but *ceteris
paribus* a failure AIX 5.3. A 32-bit build was fine. H.Merijn Brand
was able to repeat the failure.
http://xrl.us/ovbrk
Variable falls out of scope but is not garbage-collected (#59882)
Frédéric Brière reported a problem of a variable with no remaining
references not being garbage collected. Dave Mitchell explained that
method lookup caching was interfering with things and suggested an
alternate syntax to Do The Right Thing.
Nicholas Clark thought that caching should only improve performance,
not require people to jump through hoops to avoid side effects. He
proposed a change to the implementation but wondered if there were any
corner cases that might be affected. Dave Mitchell was reluctant to
entertain any changes, since the GV implementation has not been widely
studied.
the cold light of day
http://xrl.us/ovbrn
"x" forces scalar context on array variables (#59884)
James Schneider stumbled over an edge case with "x", the replication
operator. Much discussion about context, parentheses and "qw()"
followed.
http://xrl.us/ovbrp
"\x", "\0", and "\N{}" not ok in double-quotish when followed by > \x100
(#59908)
Karl Williamson needs someone to tell him where to look in the source
to track down the problem he summarised in this bug report.
help, I need somebody
http://xrl.us/ovbrr
tainted values in ternary conditional (#59916)
Dean wanted the propagation of tainted values with ternary expressions
to change, and wrote some tests to describe the behaviour he sought.
http://xrl.us/ovbrt
Errors in compilation (#59922)
Rajini S was encountering difficulties in testing a 32-bit build on
HP-UX. H.Merijn Brand and Andy Dougherty thought that the new build
was getting mixed up with parts of the system perl.
http://xrl.us/ovbrv
Memory leak when accessing "%+" (#59942)
Marc Lehmann reported a problem with "%+", but Renée Bäcker thought it
had already been solved in blead by change #34151, and suggested
looking at bug #57024.
http://xrl.us/ovbrx
"Modification of read-only value" in grep (#59956)
Ed Avis set up a construct that produced a misleading error message.
Eric Brine explained that the so-called modification error was due to
autovivification, and suggested that it would be nice to have a better
error message.
http://xrl.us/ovbrz
Bug in threads / perl 5.8.8 on AIX 5.2 / 5.3 (#59960)
Rainer Tammer found, and solved, a bug in threads on AIX. H.Merijn
Brand suggested that at the very least, a maintainer for README.aix
would be a great idea, should Rainer feel like volunteering.
http://xrl.us/ovbr3
Memory leak when using the "qr" operator (#59994)
Roland Illig independently (re-)discovered the "qr//" leak, only to
learn it had been fixed. Marcus Holland-Moritz suggested what he hoped
was an appropriate patch for Roland's 5.10.0 installation since 5.10.1
is not yet shipping.
http://xrl.us/ovbr5
"crypt()" returns tainted data even when input strings are detainted
(#59998)
Frédéric Buclin uncovered some inconsistencies with tainted data when
"crypt" is involved.
http://xrl.us/ovbr7
Perl5 Bug Summary
279 new + 1054 open = 1333 (+15 -5)
http://xrl.us/oudz6
http://rt.perl.org/rt3/NoAuth/perl5/Overview.html
New Core Modules
Archive::Tar 1.40
http://xrl.us/ovbr9
CPAN.pm 1.9301
http://xrl.us/ovbsb
ExtUtils::MakeMaker 6.47_01
http://xrl.us/ovbsd
ExtUtils::MakeMaker 6.47_02
http://xrl.us/ovbsf
Test::More/Simple/Builder 0.82
http://xrl.us/ovbsh
Test::More/Simple/Builder 0.84
http://xrl.us/ovbsj
In Brief
Yamashina Hio found that "Storable::thaw" segfaults on blessed
reference to overloaded object and supplied a patch that Nicholas
Clark was happy to apply.
http://xrl.us/ovbsm
Jerry D. Hedden saw some problems arising following change #33119 that
integrated some consting goodness to cygwin.c.
http://xrl.us/ovbso
Jerry then suggested a small lib/DB.t fix, and Nicholas Clark fixed
the problem with change #34554.
applied
http://xrl.us/ovbsq
Karl Williamson wondered if there was a document that helped porters
come to grips with the use of git. The answer was to note things on
the wiki. This could then be folded into perlhack at a later date.
http://xrl.us/ovbss
http://xrl.us/ovbsu
Niko Tyni pushed a Debian patch to fix "h2xs" enum handling with C++
comments
unapplied
http://xrl.us/ovbsw
Niko also posted a patch because "h2xs" incorrectly treats enum values
like macros.
also unapplied
http://xrl.us/ovbsy
While discussing the (im?)possibility of prototype-based polymorphism,
Michael G. Schwern thought that "Method::Signatures" was probably the
way to go.
just a smop
http://xrl.us/ovbs2
Last week's summary
This Fortnight on perl5-porters - 28 September-12 October 2008
http://xrl.us/ovbs4
About this summary
This summary was written by David Landgren.
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