Another week of business as usual. The 5.8.8 progesses steadily,
bugs are found in POD, people post ways of making perl do the
wrong thing, and Test::More is released.
John Malmberg continued his journey making bleadperl work on VMS.
This time he noticed that ExtUtils::MM_Unix can use the command
'false' to indicate falsehood, but that there is no such beast in
VMS.
Michael Schwern suggested solving the problem by adding a layer of
indirection, that is, a scalar that hold the command fragment to
use, such as perl -e 'exit 1'. Peter Prymmer suggested that
exit 44 would be a superior choice. John then struck back with
some killer DCL to teach us far more than we ever wanted to know
about exit codes on VMS (and admitted that it is a bit ugly) and
promised to look at perlport, as he suspects that it is probably
out of date.
The main thing to remember is that VMS exit codes are like signals. They can propagate all the way back to top unless the shell script takes care in trapping them.
It's quite an interesting thread, even if VMS is not your cup of tea.
http://xrl.us/hqx4
John also noticed that the t/io/fs.t triply-linked file test does
not do what the comments says it does. It's actually more about
Unix's uname behaviour. Which makes it a bit tricky to figure
out what to do on VMS. One idea was to make the test test what it
claimed to test.
http://xrl.us/hqx5
He ended on a high note of proposed VMSish changes, which appeared to be well received by Craig Berry and Peter Prymmer.
http://xrl.us/hqx6
Yitzchak Scott-Thoennes pulled down a copy of 5.8.8 to be and ran
the test suite on cygwin. Things went well, except for a failure
in op/layers.t which should be fixed as soon as patch 24767 is
landed in maint.
What went less well is Yitzchak installed it over 5.8.7 by mistake and expressed desire at seeing the version number being bumped soon to 5.8.8 to prevent this happening to someone else.
Nicholas was reluctant to do so, until such time as the version numbering scheme makes it exceedingly clear what the official maintenance releases are, as opposed to a release in the buildup to a maintenance release. He pointed out that it is the first task on the TODO "that need a little C knowledge." John Peacock suggested a patch.
The discussion http://xrl.us/hqx7
The TODO as she stands http://public.activestate.com/cgi-bin/perlbrowse?file=pod%2Fperltodo.pod&rev=
The blead version of Perl supports the DOR (defined-or) operator
// (shamelessly pinched from Perl 6), implemented by Brent Dax.
DOR being so nice to have, H.Merijn Brand backported this patch to
maint, and offers a patch to every version of maint perl (5.8.x)
to support it too. Andy Lester's ongoing consting of blead (and
Nicholas's integration of those patches into maint for 5.8.8) has
made H.Merijn's job more difficult than usual to keep his patch
applying cleanly.
As a result of this, H.Merijn spotted some smelly code in the
S_new_logop function, and discussed it with Nicholas Clark. It
has been there since 5.8.0 so it must be working, but it seems
wrong, especially when compared to the same code in blead. Jan
Dubois thought the two fragments were semantically equivalent
although the blead version was more robust.
The oddity http://xrl.us/hqx8
The Cygwin status http://xrl.us/hqx9
DOR patches for maint http://search.cpan.org/CPAN/authors/id/H/HM/HMBRAND/
H.Merijn's perl for HP-UX and the DOR repository http://mirrors.develooper.com/hpux/
Michael Schwern wants the latest version of ExtUtils::MakeMaker
in maint. Or at least any version which is not two years old.
(Michael has been dragging EU::MM into the 21st century for some
time now -- in another thread on perl-qa he even mentioned that
the latest alpha now emits proper license information into the
META.yml file).
John Malmberg gave it a clean bill of health on VMS. Nicholas Clark recalled some problems with distclean and SDBM_File
http://xrl.us/hqya
perlglossary.pod is
Based on the Glossary of Programming Perl, Third Edition, by Larry Wall, Tom Christiansen & Jon Orwant. Copyright (c) 2000, 1996, 1991 O'Reilly Media, Inc. Used with permission.
Well, it used to be. Yitzchak Scott-Thoennes wrote to say that Tim O'Reilly said that the last sentence can be changed to
This document may be distributed under the same terms as Perl itself.
And there was much rejoicing.
The patch http://xrl.us/hqyb
The forwarded message from Allison http://xrl.us/hqyc
Alan Olsen had problems building 64-bit Perl 5.8.7 on AIX 5.2.
Campo Weijerman asked for some information, Alan replied and then
nothing else was heard, so apparently he fixed it. Alan then sent
another message saying that he was having more problems on 5.3 and
again Campo Weijerman came to the rescue. Apparently AIX just won't
let you build perl with -Duse64bitall and -Duseithreads. AIX
is strange.
http://xrl.us/hqyd
Steve Hay reported in bug #37223 that it doesn't work, and that
follow and follow_fast should be no-ops on Win32, since the
file system doesn't support symbolic links.
Rafael Garcia-Suarez couldn't believe nobody had noticed it until now. Steve Peters guiltily raised his hand and pointed to patch #23510.
http://xrl.us/hqye
Merijn sent in a patch for pod/pod2usage2.t but the attachment
was eaten by a grue. Nicholas pointed out that the perl.org MTA
eats anything that looks like /\.t$/. Newsflash: apparently
now fixed.
Merijn resent the patch with a .txt extension, but it still
contains a Unixism (open(IN, "-|") that doesn't work quite right
on Win32. He remembered that t/op/write.t has a workaround for
this.
http://xrl.us/hqyf
Brian Candler reported bug #37230 where ^"(?:[^"\\]|\\.)*"\s+\d+\s+(\d+)
(used to munge Apache log files) bombed out with deep recursion,
and he couldn't see why the engine would want to backtrack (notably,
over the (?:[^"\\]|\\.) bit - "anything except a double quote
or backslash, or a backslash followed by anything.")
Hugo van der Sanden explained that the engine lacks the capacity to analyse the alternations and see that they are mutually exclusive.
Abigail suggested using /"[^"\\]*(?:\\.[^"\\]*)*"/s instead,
since it removes all alternations. Brian reported that with a
sufficiently long target string, this expression will still cause
perl to dump core. Yitzchak suggested
/"[^"\\]*(?>\\.[^"\\]*)*"/s as an alternative (The rarely
used, rarely understood (?>...) assertion).
Brian said that that one dumped core too. Abigail concluded that sometimes, core dumps happen.
http://xrl.us/hqyg
Hugo wondered why perl refuses to run INIT blocks, simply because a
module has been loaded via require rather than use, and thought it
an odd wart. Rafael suggested adding a UNITCHECK code block, that
would be run regardless of how the module was loaded.
The thread http://xrl.us/hqyh
Possible source of Hugo's question, from Perlmonks http://www.perlmonks.org/index.pl?node_id=494439
Ilya Zakharevich wrote in to say that he thought it must be easier to rewrite the PerlIO layer from scratch rather than attempt to fix bugs in it.
unix2dos .tcshrc | \
perl -we 'binmode STDIN, ":crlf" or die;
print while read STDIN, $_, 32000'
Looks simple, but it doesn't work. He truss'ed the program and observed
two seeks and read for each converted line ending, which of course does
wonders for performance. Nick Ing-Simmons replied, saying that what was
needed is an efficient version of :crlf.
http://xrl.us/hqyi
Nicholas Clark raised the issue of mv-if-diff, a little shell script
hack used by make to avoid damaging the timestamps on auto-generated
files, if the contents haven't actually changed.
He noted that on a clean rebuild, lib/unicore/mktables is run 7 times
(when only once would suffice). It gets much worse after editing a file
and rebuilding. Cascading effects cause a merry-go-round of files being
rebuilt.
And parallel makes are also broken. (The summariser, having access to a
six-CPU box, can confirm that a make -j 18 causes spectacular
fireworks). Nicholas wonders if these two observations are related, and
that things might be a whole lot better if mv-if-diff was simply
thrown away.
Steve Peters thought it was a symptom of insufficient targets and
dependencies to keep track of the build. Russ Allbery thought it was
mv-if-diff that was lacking in capability, because otherwise it would
do The Right Thing. Vadim Konovalov suggested a heavy engineering
approach with additional helper files.
Joshua Juran identified the problem as being the issue of attempting to
manage two pieces of information (the date a file was changed, and the
date it was confirmed up-to-date) in the same slot. The Macintosh
filesystem has a backup date field on files which could be pressed into
service for this, but that is non-portable. His second suggestion was
to throw away the broken optimisation that is mv-if-diff.
Yves Orton brought patches 24004, 24056 and 24320 back up on the radar, saying that all this business is probably the cause of those patches.
http://xrl.us/hqyj
Michael Schwern announced Test::Simple/More/Builder version 0.61.
Lots of new goodies and fixes.
http://xrl.us/hqyk
Jarkko Hietaniemi wanted a pair of fresh eyes to take t/Complex.t
from Math::Complex and rewrite it using Test::More. Michael
Schwern sketched out briefly how it might be done. Since the data
for the tests are stored in a __DATA__ section of the script,
Jarkko wanted a test failure to display something like:
not ok 123 # Failed test in Complex.t at line 56, <DATA> line 1234. # got: '1+2i' # expected: '1+i'
Michael showed how this could be approximated to a first degree
using diag(), but that the real solution would be to override
Test::Builder's diagnostics, but that it's not yet quite
flexible enough to do that.
http://xrl.us/hqym
Smylers filed bug #37199 relating to mangled POD in File::Basename
and Steve Hay replied that the problem had already been fixed in blead.
Dan "Unstorable" Kogai noted that $Storable::drop_utf8 seems ineffective on Perl 5.8.x, and went on to say why, supported by code fragments in Perl and C. He wondered whether the code or documentation should be fixed. He was Warnocked.
http://xrl.us/hqyn
Yitzchak sent in a patch to silence a couple of compiler warnings (three out of seven). Rafael fell asleep at the wheel and had to be pinged to apply it two days later.
http://xrl.us/hqyo
Paul Marquess supplied a patch to sync Compress::Zlib 1.40 with core.
Patch applied with alacrity by Rafael.
http://xrl.us/hqyp
Alex Davies reported a memory leak in #37231 when eval'ing syntactically incorrect code.
while (1) {
eval "sub { \$foo = "; # closing } missing
}
... the above will rapidly consume all available memory (don't try this at home). No takers yet; Dave Mitchell must be busy doing something else.
"lace" reported in #37250 that pod2html does not produce XHTML-conformant
code.
http://xrl.us/hqyq
Jan Hudec posted more ways of making perl panic, but cheated by using UTF-8 in the PerlIO layer.
http://xrl.us/hqyr
Taro Kawagishi found a problem with perlfaq3 "How do I find which
modules are installed on my system?", and supplied code to deal with the
case when a directory path listed in @INC is a symbolic link.
http://xrl.us/hqys
Steve Peters posted a patch (#25571) to get PERL_DEBUG_COW (Copy On
Write) working correctly on the smoke tests.
http://xrl.us/hqyt
This summary was written by David Landgren.
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
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 or enjoyable, please consider contributing to the Perl Foundation to help support the development of Perl.