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
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