This Week on perl5-porters - 1-8 March 2008

This Week on perl5-porters - 1-8 March 2008

   "I personally think that the git tools have far too many ways to do
   the same thing (a complaint levelled against Perl itself at times) for
   the normal human to comprehend, let alone remember." -- John Peacock,
   gitting used to the idea of a new code repository.

Topics of Interest

ExtUtils::Install updates

   Michael G. Schwern released a new version of the venerable
   "ExtUtils::MakeMaker" distribution, partly to include
   "ExtUtils::Install" version 1.45. Unfortunately Yves Orton had, in the
   meantime, pushed out version 1.46 which closed out a number of bug
   reports which had been quietly gathering dust in the RT queue.

   The changes caused a ripple of failures to show up in smoke tests.
   Yves had everything squared up again as of version 1.50.

     http://xrl.us/bhpt9

   A side thread on the same issue was started by Jerry D. Hedden
   concerning problems with the module on Cygwin. One of the problems
   encountered was the broken behaviour of "Archive::Tar" with respect to
   the WinZip archive tool on Windows. Apparently due to concerns with
   Solaris interoperability, "Archive::Tar" will construct a tar file for
   which WinZip is unable to discern the directory structure, thus
   causing everything to be extracted into the current directory.

     bit of a hassle, that
     http://xrl.us/bhpub

Interesting self contained task

   In the follow-up to the discussion of getting fresh blood hacking on
   the core, Joshua ben Jore pointed to his perlguts talk with a focus on
   the op-tree. Eric Wilhelm reminded people of the importance of the
   Google Summer of Code with respect to getting new people hacking on
   perl.

     http://xrl.us/bhpud

   This lead to further discussion of the Summer of Code, with cross-pver
   from the pm_groups mailing list, about how similar the effort required
   is to herding cats.

     don't be eval
     http://xrl.us/bhpuf

   Eric put out a formal call for an official p5p cat-herder to
   coordinate the issues between the SoC and the perl5 porters. I hope he
   received a flood of off-list replies.

     http://xrl.us/bhpuh

"List::Util::sum()" doesn't handle overloading

   Jan Dubois uncovered a glaring inconsistency between the XS and
   pure-Perl implementations of the "sum" routine: the XS version doesn't
   deal with objects that overload "+" correctly.

   Yves Orton recalled previous discussions on the matter and the
   concensus was that the XS version was built for speed, which leads to
   things like overloading being ignored. Michael G. Schwern thought that
   he'd rather settle for slightly slower and always right, rather than
   slightly faster and sometimes subtly wrong. Nicholas Clark wanted to
   know how much slower an XS version that handles overloading would turn
   out to be.

     premature evil
     http://xrl.us/bhpuj

ext/Time/Piece/Piece.xs use of "strptime"

   The FreeBSD copyright statement in "Time::Piece" went from Matt
   Sergeant to blead. A patch from blead to silence a warning on Windows
   with the Borland C compiler was sent back in return to Matt.

     two-way street
     http://xrl.us/bhpum

"glob()" implementation

   Peter Dintelmann wondered why he kept winding up with csh semantics
   for "glob" rather than bsd semantics, as the documentation suggested.
   Adriano Ferreira pointed out that "csh_glob" is implemented in terms
   of "bsd_glob" anyway.

     http://xrl.us/bhpuo

"PL_destroyhook" race condition

   Dave Mitchell had identified a potential race condition where two
   threads try to destroy an object and in an "After you", "No, after
   you" scenario and the object would be freed but no-one would call its
   destructor.

   Jerry D. Hedden thought this was an ugly state of affairs, and after
   mulling a long time over the code, could not see how to resolve the
   issue. He finally began to wonder whether the race condition could
   actually be provoked. So he wrote a program to try and exercise it,
   but didn't encounter the failure.

   Jerry wasn't sure whether this was because there was truly no was no
   race condition, or that his program was not subtle enough to coax it
   to the surface.

     http://xrl.us/bhpuq

   Jerry also wondered whether this patch could be backported to the 5.8
   track, or whether it broke binary compatibility.

     http://xrl.us/bhpus

POSIX::access(...) returns "0 but true"

   Jerry D. Hedden was having trouble with "POSIX::access" returning the
   magic value '0 but true' for both writable and non-writable
   directories, so a test was failing when it shouldn't be on Cygwin and
   Win32.

     http://xrl.us/bhpuu

Perl @ 33218 (continued)

   The current maintenance snapshot that will lead to 5.8.9 is currently
   stuck on Stratus VOS, since the test suite of "Module::Pluggable" has
   a file that begins with '-' (dash, hyphen, minus...) and this is a
   no-go on that platform.

   Nicholas Clark couldn't remember what the other issues were.
   Consulting previous summaries would lead one to conclude that there is
   an unresolved issue concerning "POSIX::strftime" as well.

     http://xrl.us/bhpuw

   A long back-and-forth between Nicholas and Steve Hay finished up with
   a warnings-free build on Win32. The main issue was one of casts
   causing warnings.

     http://xrl.us/bhpuy

   In another thread, Jerry D. Hedden coordinated with Nicholas to quash
   the remaining 5.8.x build warnings under Cygwin.

     http://xrl.us/bhpu2

 From Perforce to git

   Sam Vilain reported that he had achieved a complete Perforce-to-git
   migration, and it was now being updated (albeit with a slight lag)
   with changes in real time. He asked for people to have a hard look to
   see if they could find any conversion errors.

   Nicholas enquired as to whether there would be an easy way to map a
   Perforce change number to a git commit (answer: yes, a couple). He was
   also wondering how he would be able to cherry pick patches from blead
   for application to the various maint tracks.

     git along
     http://xrl.us/bhpu4

   Shortly afterwards, Rafael announced the switch to git. John Peacock
   deeply regretted not having been able to complete the Perforce to
   Subversion project, but a new job in Real Life had eaten all his
   tuits.

   One of the main issues that needs to be sorted out is a simple "git
   for perl5 porters" cheat sheet, that supply a minimum list of commands
   one needs to know. The other point for early adopters to remember is
   that the repository is likely to be torn down and rebuilt, this time
   encoded in UTF-8 rather than Latin-1.

   (Note to non-native English speakers: the "g" in "git" is pronounced
   with a voiced velar plosive (a hard G), like "give" or "get").

     http://xrl.us/bhpu6

More TLC for opcode.pl

   Jim Cromie continued to tweak opcode.pl this week, by adding comments
   to explain its behaviour and deobfuscating the syntax a bit. He
   reasoned that because it is so rarely used by people outside the inner
   circle that it needs to be able to stand on its own two feet a bit
   better. But the patch got a bit messed up and he'll probably have to
   do it again, since no-one actually applied it.

     http://xrl.us/bhpu8

5.10.0 and "Math::Pari" (and Fedora)

   Tom "spot" Callaway wondered if there was a fix for "Math::Pari" on
   5.10, since it was broken, but it is also a dependency for a couple of
   "Crypt::*" modules. Nicholas Clark wondered what the authors had to
   say for themselves, having encountered comments like

     int numargs = ((CV*)cv)->sv_any->xof_off; /* XXXX Nasty of us... */

   Nicholas Clark was slightly miffed by the corners cut in the XS code.
   The extensive restructuring of the internals that went into the 5.10
   release was theoretically "off limits" to client XS code, but it turns
   out that the Pari code was running around stuffing pointers and ints
   in all sorts of places that weren't expected to hold them. This caused
   a variety of failures that Nicholas wasn't really inclined to fix.

     http://xrl.us/bhpva

   In his race against time, Tom also reported that Data::Structure::Util
   was also failing its tests on 5.10.0. Nicholas Clark saw that this
   (and other) module(s) are authored by Fotango, and since Fotango no
   longer officially exists, they are thus all orphan modules.

   Ævar Arnfjörð Bjarmason wondered what else was on Fedora's list of
   modules from hell, to which Tom replied that "perlbal" (A Perl-based
   proxy balancer) was also blowing black smoke, but felt that it was not
   a show-stopper.

   Also problematic was "Sys::Virt", "PDL" and "Test::AutoBuild".

   Yves Orton suggested Tom run with the slow @_ parameter passing
   speed-up patch, slated for 5.10.1 (and that Tom should make sure that
   it is clear in the output from "perl -v" that it is in there, to help
   with future bug reports from Fedora users).

     http://xrl.us/bhpvc

   Nicholas Clark did a fine piece of sleuthing work on PDL and
   discovered that a random number generator part of the code was not
   calling a function like "drand48", which led to predictable results.

     Not good if you want unpredictable results
     http://xrl.us/bhpve

   He also solved the "Devel::Profiler" 5.10.0 failure that Tom
   uncovered. As for "B::TerseSize", Nicholas suggested Tom get in touch
   with Philip Gollucci.

     http://xrl.us/bhpvg

Perl @ 33444

   Nicholas made another snapshot for 5.8.9 and asked what else was
   broken apart from the Stratus VOS issues. Craig A. Berry reported that
   a smoke test from a patchlevel a few changes earlier was having
   problems with threads and ExtUtils. The latter he suggested could be
   marked TODO if necessary, mainly because a certain amount of test
   failures are for tests that weren't around in 5.8.8 in the first
   place.

   Jerry D. Hedden listed a number of dual-life CPAN modules that were
   out of date with respect to maint. Nicholas gave them a 50/50 chance.

   Reini Urban summarised the problems on Cygwin. The work Jan Dubois
   made on the compiler switches, to allow gcc to be binary compatible
   with VC probably won't make it in until 5.12.

     http://xrl.us/bhpvi

   Problems occurred on Mac OS X 10.5, and the resolution was made harder
   by the lack of "strace"/"truss" tool to analyse system calls. I think
   Nicholas had it all sorted out in the end.

     http://xrl.us/bhpvk

File/Glob/t/basic.t intermittently fails test 6

   Dominic Dunlop noted that this test would fail from time to time on
   darwin 9.2.0 and he couldn't see why. Nor could Nicholas. Dominic and
   Steve Peters had suspicions about the C implementation of "glob", as
   some parts of it remain unchanged since the day the code was
   originally checked in.

     http://xrl.us/bhpvn

Patches of Interest

make "Archive::Extract"'s x.lzma test file be lzma'd, not uupacktool'd

   Yitzchak Scott-Thoennes noticed that a data file that was supposed to
   be encoded with lzma was in fact encoded with uupack instead. So he
   encoded it the right way, and Rafael applied the patch.

     http://xrl.us/bhpvp

count-only transliteration needlessly makes copy-on-write scalars normal

   Yitzchak also made "tr" behave cleanly in the face of copy-on-write
   strings.

     moo
     http://xrl.us/bhpvr

Pushing parent.pm

   Yitzchak also thought that now that the issue of the API of "parent"
   has been settled, then "base" could be marked as discouraged

     not yet deprecated
     http://xrl.us/bhpvt

New and old bugs from RT

"/^.../m" is slower than logical alternatives (#33051)

   Rob Kinyon (dragonchild on Perlmonks) reported a problem where one
   regexp was logically equivalent to another... but two orders of
   magnitude slower.

   This was on perl 5.8.4. Steve Peters noted that the difference was
   lost in the noise on 5.10, and 5.8.8 did not appear to be affected
   either.

     not any more
     http://xrl.us/bhpvv

pod2usage(-verbose => 0) & pod2usage(-verbose => 1) (#39775)

   Steve Peters also saw that the patch in this bug report had been
   applied to a version of Pod::Parser (version 1.35).

     http://xrl.us/bhpvx

Counting bug in "Test::Harness" with unexpected early exit (#43267)

   Steve Peters thought that this bug could be marked resolved, since its
   twin sister on the CPAN RT queue was marked as resolved over there.
   Andy Dougherty regretfully informed Steve that the solution given for
   resolving it was "upgrade to "Test::Harness" version 3".

   Alas, in the code freeze during the push to 5.10, Test::Harness 3 was
   considered too raw for inclusion, and the bug in the RT ticket
   concerns version 2. Andy, having taken a stab at fixing the bug in
   Test::Harness 2.64, suggested that if the problem was sufficiently
   annoying to people, then they should upgrade to "Test::Harness" 3
   (which appears to be settling down nicely).

   Rafael hinted that "Test::Harness" 3 will probably be released during
   the 5.10 maintenance track. One of the reasons being, as Michael G.
   Schwern points out, it's so much nicer to work with than screen
   scraping test output.

     http://xrl.us/bhpvz

make "Devel::Peek::mstat" always available (#46957)

   Slaven Rezic had filed a bug report with a patch. Steve took the
   patch, applied it, and closed the report. The fix will be of interest
   to people who like compiling perl with "PERL_DEBUGGING_MSTATS".

   Slaven had also noted in the report that compiling with "PLAIN_MALLOC"
   no longer works. This was not addressed (but I imagine it's not
   serious).

     http://xrl.us/bhpv3

5.9.5 fails make test on AIX 5.3 (#47415)

   Continuing his trawl through the 1700+ unresolved bugs in the RT
   queue, Steve asked for "Config" information to help him understand
   what the problem was.

     http://xrl.us/bhpv5

Use of uninitialized value in die at /opt/perl/lib/perl5/File/Copy.pm 
line 224. (#49660)

   Steve Peters tried to close this one as well, but Marc Lehmann replied
   that the problem remained, although it was very tricky to provoke the
   bug on demand. And the trouble is that the symptom is the removal of
   the source file.

     http://xrl.us/bhpv7

Not OK: perl 5.11.0 +DEVEL on i686-linux 2.6.22-3-486 (#50080)

   No-one begrudged Steve closing this one with some vague waving of
   hands, citing that patch or patches unknown had conspired to fix the
   issue.

     http://xrl.us/bhpv9

prototypes sneakily break lvalue subs (#51408)

   L. Mai filed the only new bug this week, showing how prototypes
   interact with lvalue subs in unexpected ways.

     http://xrl.us/bhpwb

Perl5 Bug Summary

     288 new + 1501 open = 1789 (+4 -2)
     http://xrl.us/bhpwd
     http://rt.perl.org/rt3/NoAuth/perl5/Overview.html

In Brief

   The Google summer of code mentoring thread was wrapped up this week,
   with Eric Wilhelm explaining a mentor for a GSoC project had to do,
   and what they received in return (a T-shirt).

     what mentoring meant
     http://xrl.us/bhpwf

   Jesse Vincent announce the release of the rt.cpan.org source code.

     http://xrl.us/bhpwh

   Back in November 2007, Marcel Grünauer wrote a patch to fix the
   "NEXT.pm" bug within overloaded stringification. This week Nicholas
   Clark applied it.

     http://xrl.us/bhpwj

   In regards to the op/sprintf.t and op/write.t failures with
   mingw-runtime-3.14, Nicholas Clark commented that if Sisyphus (or
   anyone) was able to figure out a test probe to identify if the local
   environment was running with the buggy library, that they would be
   able to work around it during build configuration.

     http://xrl.us/bhpwm

   The "checkpods" program is going to face the sound of the chain-saw
   and/or be subsumed into "podchecker".

     cruft culler
     http://xrl.us/bhpwo

   H.Merijn Brand went digging around in "Devel::PPPort" and "perlguts"
   to get "Text::CVS_XS" to run on everything from 5.005 to 5.10. Tim
   Bunce thought a "newSVpv" needed to be wrapped in a "sv_2mortal", but
   that led to an attempt to free unreferenced scalar.

     DDTT
     http://xrl.us/bhpwq

   No, the list is not blocking inline patches in messages.

     at least, not on purpose
     http://xrl.us/bhpws

   Jarkko Hietaniemi wondered if he was having an attack of the 64-bit
   perls. Three modules of his, quite different internally, were popping
   up with test failures on 64-bit systems.

     the 64-bit question
     http://xrl.us/bhpwu

Last week's summary

   Juerd Waalboer clarified a couple of points in the Unicode debate, and
   asked a couple of questions. Notably whether it was true that Perl on
   EBCDIC was broken.

   Nicholas Clark replied that it was false to state that it doesn't, as
   in actual fact we don't have any information to confirm or refute the
   hypothesis that Perl runs on EBCDIC.

     24-29 February 2008
     http://xrl.us/bhpww

About this summary

   This summary was written by David Landgren.

   Weekly summaries are published on http://use.perl.org/ and posted on a
   mailing list, (subscription: perl5-summary-subscribe@perl.org). The
   archive is at http://dev.perl.org/perl5/list-summaries/. Corrections
   and comments are welcome.

   If you found this summary useful, please consider contributing to the
   Perl Foundation to help support the development of Perl.

• This Week on perl5-porters - 1-8 March 2008 by David Landgren
• Re: This Week on perl5-porters - 1-8 March 2008 by Aristotle Pagaltzis