"But having it match what perl6 will do is even more important than having it make perfect sense, IMO.", Yitzchak Scott-Thoennes, thinking about forwards compatibility.
exit and die in threads Following on from the threads 1.33 conversation last week that was
given short shrift in last week's summary (sorry Jerry), Jerry D.
Hedden put forward a proposal to nail down the semantics of what
happens when a thread calls exit (and more to the point, what
to do about everything that might want to clean up after itself).
Throw in a __WARN__ and/or __DIE__ handler or two, and you're
starting to talk about some serious fun.
Jan Dubois and Rafael Garcia-Suarez commented on a number of points that Jerry raised, and while Rafael didn't agree with a few things, he was quick to point out that he didn't have any definite opinions one way or another, only that he wanted the best possible solution to come out the discussion.
Dave Mitchell wondered whether it wouldn't be possible to add an
exit method to the threads class, which would apply only to the
thread, leaving the core exit to behave as usual.
In through the out door http://xrl.us/ot6z
Jerry the checked with the porters to see whether everyone agreed to what he thought threads should do. Jan and Liz Mattijsen gave their assent.
http://xrl.us/ot63
Just to be really certain, Jerry then posted a consensuality
matrix, to get people who had made suggestions to sign off, or
explain what they disagreed about. The moral of the story is
that calling exit() as a thread method ends the thread, but
calling exit() ends everything, modulo some differences in
opinion over how much to warn about and when.
fluid neon origami trick http://xrl.us/ot65
Jerry went about modifying the threads module to do all this and
ran into problems with too many ENTERs and not enough LEAVEs
and the like. Jan said that he had no time to look closely, but
eyeballed Jerry's code, sketched out a brief idea of what needed
to be done. Jerry picked it up and ran with it, and straightened
out all the problems.
Balancing act http://xrl.us/ot68
By the end of the week, Jerry had the new implementation up and
running to his satisfaction, except for a nagging problem of
die messages not being captured by the test harness, thus
polluting the output.
Weaving in and out http://xrl.us/ot7b
Dave Mitchell listed the available possibilities:
New month, new thread http://xrl.us/ot7e
After having looked over the stellar achievements of Dave Mitchell
in removing eval leaks (caused when the eval'ed code fails),
Nicholas Clark listed the remaining known leaks and asked for help
in trying to identify the code paths taken (which would help in
figuring out how to plug them).
Dr. Ruud suggested taking a look at a tool called MemProf.
Dominic Dunlop answered the question with a question, and offered
another leak to add to the list.
Lost property http://xrl.us/ot7g
chromatic posted a short, sharp snippet of C, showing how easy it is to insert your own XS code into an existing op code, which opens up all sorts of interesting possibilities.
http://xrl.us/ot7j
$A::::B::C a bug or feature? Continuing in the I-didn't-know-Perl-could-do-that vein, Chip Salzenberg
discovered that this meant that C is inside package ::B:: which
in turn is inside A, and thought it was all rather evil.
Sadahiro Tomoyuki traced the change down to somewhere between 5.004_04
and 5.004_05, when scan_words in toke.c was modified to permit
this, some time back in 2003. No-one appeared to remember the reason.
http://xrl.us/ot7m
Steve Peters was going over the new smart match (~~) operator
from Perl 6, that Robin Houston added to blead last year, and
making sure it was well tested. He wrote a couple of tests, was
puzzled by the results, and wondered whether the problem lay with
the implementation, or with the documentation.
Yitzchak Scott-Thoennes analysed Steve's reasoning, but no firm conclusions were made.
http://xrl.us/ot7o
Win32API::File now in core Steve Hay announced that he had set things up to make Win32API::File
a first-class dual-lifed module, in blead and on CPAN. He called on
Jan Dubois to see whether Jan needed or wanted to do anything about
libwin32. There was discussion of moving files from win32/ext/Win32
to ext/Win32, which would ease the building of perl on Cygwin.
It just got bigger http://xrl.us/ot7q
Some discussion followed as to whether or not it would make it in time for 5.8.9.
http://xrl.us/ot7r
John E. Malmberg offered a short patch to correct a function that failed to append a null character to strings, which gave the underlying C library indigestion since it was expecting one. Rafael applied.
Overshooting yourself in the foot http://xrl.us/ot7s
Similarly, Jarkko Hietaniemi taught cflags.SH to scan the gcc
warning flags only once:
http://xrl.us/ot7t
splint support Andy Lester set about adding splint (a lint-like tool) support
for the porters. First off he created some embed.pl enhancements:
http://xrl.us/ot7u
And then followed with some Makefile splint support. It doesn't
quite do everything that it should, and Andy called upon other people
(hi Jarkko!) for help.
http://xrl.us/ot7w
consting front Elsewhere in the code base, Andy tweaked DProf.xs to only compile a small static function if in fact it was actually required in the current configuration.
http://xrl.us/ot7z
He then turned his attention to ye cruftey olde mathoms.c. Just because they're obsolete doesn't mean they can't be squeaky clean.
http://xrl.us/ot73
And for dessert, Andy tidied up mg.c, by localising a variable
here and there, and encapsulating Perl_* calls in macros.
http://xrl.us/ot76
close $fh Vadim Konovalov wanted to clean up win32/buildext.pl by removing an
explicit close, since just nearby is a similar open that also omits
the close.
Yves Orton that a better idea was to rewrite the code, because it's a complete mess. (Amd it isn't particularly big, either).
Innovations in brace placement http://xrl.us/ot78
FAIL(FMm) OSF1 V5.1 (EV6/4 cpu)] Jarkko noted some failures had been cropping up in recent smokes, but didn't feel they were specific to the platform (Tru64) he was running.
Nicholas Clark explained what the issues were. One was a simple test design issue that anybody with a reasonable grasp of designing tests should be able to figure out. Alas, no-one had volunteered to have a look. Jarkko asked for more background.
Background check http://xrl.us/nf28
The other issue was one of eval leaks, and Jarkko courageously
deferred to Dave Mitchell as the likely fixer of that.
Snot funny http://xrl.us/ot8b
FAIL(F) MSWin32 WinXP/.Net SP2 (x86/2 cpu) Anno Siegel looked at one of Steve Hay's smokes, and wondered how one was supposed to interpret the results. H. Merijn Brand explained the general case, and Steve explained what was going wrong in this particular case.
Inconsistent test results (between TEST and harness) http://xrl.us/ot8d
FAIL(c) Solaris 2.10 (i386/1 cpu) H.Merijn looked at one of Abe Timmerman's failing Solaris smokes and
traced it down to a change he'd made to Configure following on
from a suggestion from Andy Dougherty. Andy thanked H.Merijn for the
catch and noted that the entire hack was no longer needed anyway,
since the original problem (one of 64-bit tests) has since been
fixed.
http://xrl.us/ot8g
Jan Dubois wrote to say that it is possible to install DBD::Oracle
for ActiveState, at the price of also downloading many megabytes
of Oracle libraries.
But alas, only for 5.6 http://xrl.us/ot8j
The code was corrected to handle this problem, and Yves folded the original bug report into the test suite. Yves then went on to rewrite the regexp display code, since, up until now, control characters have always been invisible, which makes it much harder to understand bug reports when control characters are present.
She's lost control http://xrl.us/ot8m
Jaymax was having problems upgrading 5.8.2 to 5.8.8. miniperl
was dying with a Undefined symbol "nl_langinfo" error. No
takers as yet.
http://xrl.us/ot8p
%SIG should generate a warning (#39630) Nik thought that he would have saved a lot of time if perl complained
about trying to use keys in %SIG that don't refer to valid signal
handlers. Rafael thought that the problem might be because that the
code in question was not, in fact, running with warnings enabled.
Ask no questions, tell no lies http://xrl.us/ot8s
@ISA is not mentioned in perlvar (#39633) Sebastian Schmidt kicked off a long thread about whether or not
@ISA should be referenced in perlvar or not. The main
dissent was due to the fact that @ISA isn't particularly
special as far as perl is concerned, it merely has lots of
cultural conventions associated with it.
Nevertheless, it was agreed that perlvar should in fact list
all extraordinary variables, with L<> references
to the appropriate pages if a better definition already existed
elsewhere.
http://xrl.us/ot8u
__attribute__((unused)) (#39634) John Gardiner Myers was having some trouble compiling Encode::Detect
with the GNU C++ compiler. Andy Dougherty realised that blead had
already solved this problem and proposed a couple of patches to get
things going. John, however, had another patch that he thought was
better. After looking at it, Andy did too. He tidied it up slightly,
and suggested that it was fit for inclusion to both blead and
maint.
http://xrl.us/ot8y
Marc Esser was having trouble configuring perl on Solaris 10. After a getting Marc to try a few things, Andy Dougherty believed that he had isolated the problem in some incorrect hints for Solaris.
http://xrl.us/ot82
STDIN/STDOUT on Windows (#39637) Paul Marquess reported that he had had some problems with not being
able to apply -r to \*STDIN and get a sensible result back on
Windows.
Par for the course http://xrl.us/ot84
perldoc -f waitpid has wrong code example (#39639) Alexander Gernler mentioned that he thought the snippet explaining
waitpid was wrong, and that it should use a do/while loop and
not a do/until loop. Rafael agreed, and Salvador Fandiño and
Dr. Ruud made a few suggestion about making the snippet truly
cross platform (well, and least Unix and Windows).
Zombie-free zone http://xrl.us/ot87
Jon V. had a weird compilation error. Rafael suspected that some errant header was defining a symbol standing in for a function or something, as a number.
http://xrl.us/ot9a
DynaLoader corrupts %ENV (#39647) Daniel Pfeiffer as having trouble with a Solaris 2.10 box coming to grief with environment variables eating all available memory. Rafael had trouble reproducing it. So did Daniel for that matter. Unfortunately, there's not much to go on.
http://xrl.us/ot9c
require and List::MoreUtils seg fault (#39650) Darin McBride had some code worked if List::MoreUtils
was used, but dumped core if it was required. Rafael saw that the
problem lay in the module building an iterator as a closure to traverse
an array, but couldn't see off-hand why it should fail.
http://xrl.us/ot9f
Another back-tracking stack-blowing pattern.
FITNR http://xrl.us/ot9h
Peter J.Holzer discovered that taking a simple byte string and upgrading it to UTF-8 makes the match go three times slower when the target remains byte-encoded. Or, to put it another way, if the polarity of the target and regexp are reversed, performance is awful.
Even Yves admitted to being scared at the amount of effort required to make the engine do the right thing. It's doable, and he's thought about it on occasion. Sadahiro Tomoyuki gave Peter a tip that helped in improve the performance in his particular case.
Fruit at the top of the tree http://xrl.us/ot9k
Yves went onto to explain far more than you ever wanted to know about UTF-8, and just how much effort it takes to move to the next character in a string. Juerd suggested a number of optimisations that, if implemented, may improve performance. Yves went down the list and pointed out that nearly all of Juerd's ideas are already implemented in the engine in some way or another.
In other sub-thread, Sadahiro caught a naughty macro that lacked a parenthesised argument, which Rafael fixed in blead.
It ain't easy http://xrl.us/ot9n
+ 13 - 7 = 1499 http://xrl.us/ot9q
Ooh, nice RT upgrade http://rt.perl.org/rt3/NoAuth/perl5/Overview.html
ExtUtils::Install version 1.41 released by Yves Orton. No change
in functionality, merely a tweak to the versions to get blead
and CPAN in sync.
Do the bump http://xrl.us/ot9r
Rafael announced that he was removing references to 5005threads
in the perlguts documentation.
The end of the line http://xrl.us/ot9t
Steve Hay showed the best settings to get the most out of malloc
on the Win32 platform.
http://xrl.us/ot9v
Andy Lester noted that the Coverity defect scan of the codebase had risen from 35 to 40 in two weeks.
Misfeature creep http://xrl.us/ot9y
Alan Burlison pointed to Data Race Detection Tool (or DRDT) from Sun, which is a tool designed to help track down data race issues with threads.
Might be handy http://xrl.us/ot93
Sébastien Aperghis-Tramoni posted a small precision about \Q \E
inside m//x , after having spent too much time trying to figure out
why his code wasn't doing what he expected.
DWIM or RTFM http://xrl.us/ot95
Brendan O'Dea put forward a modest proposal remove x2p/* , that is, the
awk-to-perl and sed-to-perl scripts, arguing that no-one uses them anymore.
Neither Rafael nor H.Merijn were in favour of such a move.
http://xrl.us/ot98
Craig A. Berry tidied up some POD typos.
http://xrl.us/ouaa
This summary was written by David Landgren.
Last week's unfinished opus attracted a comment from Nicholas Clark asking how other open-source languages deal with the day to day housekeeping, and he even received an answer!
http://xrl.us/ouad
If you want a bookmarklet approach to viewing bugs and change reports, there are a couple of bookmarklets that you might find useful on my page of Perl stuff:
http://www.landgren.net/perl/
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.
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