This Week on perl5-porters - 21-27 November 2005
A quiet week with a bit of action at many corners of Perl development,
including some shiny new ones like Lamp. Improvement to docs and
threads on "Switch", "Module::Build" modules are among the discussion
themes.
No Brute Force Anymore
The last summary mentioned bug #37710 about a failed "require"
succeeding in a second time. Rafael Garcia-Suarez pointed this is
fixed in bleadperl and Yitzchak Scott-Thoennes noticed the bug goes
back to 5.6.1 through current maint. Rick Delaney entered the
discussion to say the fix never made into maint because of the
introduction of the new semantic that an "undef" value for an entry in
%INC means the module failed to compile. Rick mumbled on the
unfortunate passing of the corresponding change to
"L<perlfunc/require>" which actually shows implementation details in
blead but not in 5.8.
http://xrl.us/izox
Save Safe.pm
Andreas Koenig opened RT ticket #37713 to warn about Safe.pm, which
fails miserably with modules like "POSIX", "version", and others. Even
when no opcode restriction is made, examples like the one below fails
with blead and even worse with 5.8.7.
perl -le '
use Safe;
use Opcode;
my $comp = Safe->new;
my $opset = Opcode::full_opset;
$comp->permit($opset);
$comp->reval("use version; \$VERSION = qv(q{1.0.3}); print \$VERSION");
print $@ if $@;
'
Undefined subroutine &version::qv called at (eval 2) line 1.
Yves Orton remembered Tim Bunce declared "Safe.pm" to be a failed
experiment and wondered which is the current status of the module now
that Raphael owns it. Rafael answered he continues to fix things,
backport the changes to CPAN and thought this issue should be fixed.
http://xrl.us/izoy
Linked List of Arenas
Jim Cromie came back this week to polish its previous RFC patch based
on Nicholas Clark's feedback. Jim concentrated on the idea of having
arena-size per sv-type and included comments/docs for posterity, say,
posterior maintenance. Later, Nicholas Clark pointed some confusion in
the patch and kept waiting for Jim's answers.
http://xrl.us/izo2
"Pod::Perldoc" and Localized Docs
Enrico Sorcinelli, one of the authors of "POD2::IT", a project to
translate Perl man pages into Italian, proposed again a patch against
"Pod::Perldoc" to support viewing translated pods. Rafael
Garcia-Suarez applied to bleadperl the patch. Enrico noticed
"POD2::FR" just started, Portuguese fellows announced "POD2::PT"
shortly, and there is also a little "POD2::LT" for Lithuanian. This
may become a trend.
http://xrl.us/izo3
Documentation Conventions
Sébastien Aperghis-Tramoni triggered a discussion asking about the
convenience of a patch to POD files setting up a consistent pattern in
the formatting of functions, modules, variables, and others. Andy
Lester suggested Sébastien to have a go, see the reaction and go from
there. Rafael Garcia-Suarez and others remembered it could be a good
idea taking into account the differences in rendering in POD
formatters, since pod2text (via perldoc), pod2html to the custom
formatters in sites like search.cpan.org and perldoc.perl.org. After a
suggestion by David Landgren, Sébastien's patch which touched
perlstyle.pod adopted the use of "F<>" for files, "C<>" for generally
anything that can be considered part of code and "B<>" for command
names. I think it basically sums up to being simple as POD already is,
which doesn't preclude POD formatters to be clever and improved. The
patch was applied after a few minor fixes.
http://xrl.us/izo4
*concat* Misbehavior with Magic
Michele Dondi opened ticket #37722 to report how weird can be the
interaction of concat and magic in "tie()"d variables. Robin Houston
summed it up to the bit of code
sub TIESCALAR { bless {} }
sub FETCH { shift()->{i} ++ }
tie $h, "main";
print $h.$h;
which may output "00" rather than "01" and posted a patch. Rafael
Garcia-Suarez noticed the patch broke the warning test case
$ ./perl -we '$x.=$x'
which should report a use of uninitialized value error. On the grounds
of a comment by Dave Mitchell on Michele's finding, Rafael conceded
the behavior was not really a bug but the undefined result of
execution order in expressions involving side-effects. Robin Houston
insisted it could not be that difficult to fix, and tweaked the patch
that now provides a left-to-right order on evaluation of
subexpressions. The change has been applied as #26192.
Michele's finding
http://xrl.us/izo5
Robin's approach
http://xrl.us/izo6
Perl on Lamp
Joshua Juran started a thread by posting some test results from the
starting Lamp port for perl 5.6.1. Nicholas Clark curiously asked what
led Joshua to elect 5.6.1 as a departing point rather than 5.6.2 or
even better 5.8.something. Joshua explained he started working from
Chris Nandor's MacPerl codebase, which is at 5.6.1 and promised to
leave 5.6 behind as soon as he gets tests passing, approaching 5.8.x
or blead. Rafael Garcia-Suarez suggested that, by starting at 5.6.2,
Joshua's changes could be incorporated in this or in MacPerl branch.
Joshua pointed that Lamp, a project for a Mac-hosted unix-like
environment is similar in spirit to Cygwin and will hopefully have
more in common with standard Perl than with MacPerl.
Joshua's test results
http://xrl.us/izo7
The Lamp project URL
http://sourceforge.net/projects/lamp/
Win32 Lean and Mean
Jan Dubois appreciated the analysis by Thomas Kratz (in ticket #37708)
about issues with socket-related declarations on Win32 whether
winsock2.h or winsock.h is included. The problem being that Perl
compiles using "winsock2.h" but perl.h includes winsock.h leading to
wrong winsock 1.1 constants and errors due to redefined structs. Jan
considered the best way to do it, avoiding the breakage of existing
modules, which may not need to know about this and neither want it.
H.Merijn Brand applied Jan's patch as change #26189.
http://xrl.us/izo8
"Module::Build" Issues on Win32
A long thread started with a RT report on problems building
"PathTools" on Win2K which was forwarded by Ken Williams to the list.
Yves Orton spotted that it was a "Module::Build" thing, related to the
fact that you can't unlink a DLL that is loaded into the memory.
"ExtUtils::MakeMaker" works around the issue because it does the
install via make so it doesn't need to load anything that it might be
installing over. Yves suggested "Module::Build" on Win32 should
produce a Build.bat rather than a Build perl script, which would allow
a more Unixy behavior. Yves, Ken and Randy Sims discussed some issues
involving what should force the user to rerun "Build.PL" and, while on
this, Randy produced a patch to "ExtUtils::CBuilder" to fix an
encountered issue. The original case was made to work and more
permanent solutions to "Module::Build" on Win32 should be near
(besides the recommendation to use another OS).
http://xrl.us/izo9
Fast Unicode with "SWASHGET" in XS
This week, Sadahiro Tomoyuki thought it would be a good idea to
speedup the retrieval of Unicode properties and transliterations
mappings, which was done by the pure perl method SWASHGET. He rewrote
SWASHGET in XS, which was welcome and commented by Dave Mitchell, Tels
and Steve Peters. By the end of the week, an improved patch was
already commited to blead.
http://xrl.us/izpa
Bad "Switch" Boy
Offer Kaye opened a can of worms when he did the simple question of
whether the bug #5607 in "Switch" had any chance to be fixed. Ronald
J. Kimball explained how the issue of an unbalanced "/" causing a
fatal error under "use Switch" is due to the source filter nature of
the module and the small probability of a fix due to technical
constraints. David Landgren pointed Damian's module was always meant
to be an experiment and not for production purposes. There ensued some
discussion about the unpredictibility of source-filtered modules, the
requirements for a module to enter the core and the possibilities of
doing the opposite, removing a module from core. Ah, and there were
some advertisement on the DOR operator.
http://xrl.us/izpb
Upgrade to "PathTools" 3.14 in *maint*
Ken Williams reflected with Nicholas Clark about the alternatives to
merge "PathTools" 3.14 to maint, after the change that fixed
"absrel($x, $x)" to return "curdir()" and which is backwards
incompatible from the point of view of who risked to depend on this
buggy behavior.
http://xrl.us/izpc
Pipes + Threads Broken in *blead* on VMS
Craig Berry wrote to say how the simplest command line piping in a
threaded build of bleadperl on VMS now emits errors:
$ perl -e "print 'ok';" | exit
panic: free from wrong pool.
panic: free from wrong pool during global destruction.
%C-F-EBADF, bad file number
On VMS, command-line piping is implemented by Perl itself, and such
pipe is opened before any thread context has been initialized. The
problem is a check to yelp when deallocating from a different thread
than the one which did the allocation and the no context case actually
falls into this trap. To Rafael Garcia-Suarez, it looks like this
check should be bypassed, which can help also applications that embed
a perl interpreter.
http://xrl.us/izpd
Switch in the Core
Robin Houston started an effort to implement the "switch" construct in
core (in manner which is as-compatible-as-possible with Switch.pm by
Damian Conway) and called for feedback on his initial proposal, with
replies by Rafael Garcia-Suarez, Dave Mitchel, Nicholas Clark and
Damian Conway.
http://xrl.us/izpe
Perl5 Bug Summary
This week started with the count of 1517 open RT tickets.
Robert Spier and the Bug summary
http://xrl.us/izpf
Perl RT just now
http://rt.perl.org/rt3/NoAuth/perl5/Overview.html
In Brief
*valgrind finding from blead* Following on Steve Peters trying to
guess the source of the leak in a sympathetic bit of code Jarkko
Hietaniemi posted, Jarkko delved into the gory combination that was
causing the problem: His latest conclusions point to problems with the
approach of determining whether $`, $&, $' were found , the
corresponding "PL_sawampersand" and the eluding problem of how we can
foresee what eval is going to do to us. With a bit more of
investigation, Jarkko is yet not convinced he really found the guilty
part.
http://xrl.us/izpg
*Fighting Compilers Again* Steve Hay reported how change #26152 ("All
that can be in the first switch statement ofsv_upgrade is now") broke
the windows build using VC++ 6. Steve and Nicholas Clark worked out a
fixing change (concerning the use of unary minus to unsigned types),
which, despite Nicholas' hopes, produces no errors but a bunch of
warnings in VC++ 6, 7 and Borland.
http://xrl.us/izph
*Thread Failures due to Interleaved Output* H.Merijn Brand got fixed a
problem causing thread failures on AIX (and others) caused by
interleaved output.
http://xrl.us/izpi
* "libnet" 1.19 on HP-UX on Perl 5.6.0 * Yves Orton reported how he
has met with core dumps while building "libnet" 1.19 on HP-UX on Perl
5.6.0 and asked for any recommendations. H.Merijn Brand brought some
clues and made a lot of questions to help diagnosing the problem,
which basically pointed to the non-root status of Yves, missing
installed patches, and issues with trusted HP-UX systems, the
beginning of perl 5.6 and outdated software.
Yves Orton's woes
http://xrl.us/izpj
Recent perl builds for HP-UX can be found here
http://mirrors.develooper.com/hpux/
* "GDBM_file" realloc failures * On a threads-enabled perl, Rafael
Garcia-Suarez noticed the tests ext/GDBM_File/t/gdbm.t and
lib/Memoize/t/tie_gdbm.t were failing with the message:
panic: realloc from wrong pool
Rafael proposed a patch which reconciled the trouble due to memory
alloc'd by libgdbm and realloc'd by perl. It was applied as change
#26193 to bleadperl.
http://xrl.us/izpk
* Where is "Perl_do_open"? * Stas Bekman noticed blead @ 26185 broke
mod_perl2 after a problem to find out "Perl_do_open" function. Rafael
Garcia-Suarez explained "Perl_do_open" now lives in mathoms.c and the
"do_open" macro in perl.h is the way to go. Stas' issues revealed a
bug in that "Perl_do_open" should be visible anyway unless
"-DNO_MATHOMS" were used. Stas did it by dropping the "Perl_" prefix
on "do_open"/"do_close".
http://xrl.us/izpm
* Can't reset %ENV on VMS * John Malmberg noticed t/op/array.t and
t/op/pat.t failed on VMS because the test scripts call "reset 'X'",
and perl can not reset %ENV hash values on VMS.
http://xrl.us/izpn
http://xrl.us/izpo
* Trouble with "for (reverse @array)" * Chris Duryee opened RT ticket
#37725 to tell about a segfault on a script using a "for (reverse
@array)" construction. Dave Mitchell found the bug to be due to an
optimization error to handle this very construction and fixed the
problem. After this, the one-liner
perl -e '$a[3] = 1; $i = 3; for my $x (reverse @a) { $x = $i--
}; print "@a"'
prints "0 1 2 3" instead of "1 0".
http://xrl.us/izpp
* Sort subs can now be recursive * Robin Houston fixed perlfunc.pod
raising the limitation that sort subs may not be recursive, thanks to
the sort/multicall patch worked out in the last weeks.
http://xrl.us/izpq
* Version Check Failures due to "locale" * In ticket #37714, "dakkar"
showed how version checks can made to fail when a locale is in effect
due to conversions of float to strings. John Peacock explained how it
is happening in maint and blead and will do some research to make
version comparisons independent of locales.
http://xrl.us/izpr
* VMS Issues with "__FILE__" assuming UNIX Pathnames * John E.
Malmberg pointed ext/List/Util/t/p_tainted.t assumes "__FILE__"
returns a Unix pathname, which called for a fix on VMS. On John's
question about where "__FILE__" is set, Rafael Garcia-Suarez disclosed
the relevant points in code. There remained some uncertainty about the
adequacy of John's fix, which should be hammered by the discussion
among Rafael, John and Craig A. Berry.
http://xrl.us/izps
* "Tk" Compatibility * Gisle Aas pointed how "Tk" programs segfault
when tried with blead and wondered when it happened. Gisle also
reminded of changes needed to be applied for compiling and running
"Tk" in the perl-5.8.x branch.
http://xrl.us/izpt
* perlce Touches * Vadim Konovalov keeps on with the work on the WinCE
port of Perl. This time, his patch touches some compilation bits and
update explanations, renaming ./wince/README.perlce to ./README.ce.
http://xrl.us/izpu
* perlpod.pod and "=encoding" * Yves Orton noticed perlpod.pod omits
the new "=encoding" directive from its "currently supported directive
list" and made it right.
http://xrl.us/izpv
* Fast "IS_UTF8_CHAR()" for EBCDIC * A couple of weeks ago, it was
noticed EBCDIC platforms UTF8 handling was broken, which Sadahiro
Tomoyuki promptly fixed - the guilty part was found to be on a change
to speedup "IS_UTF8_CHAR". This week, Jarkko Hietaniemi tried to
redeem himself with a patch to bring the "IS_UTF8_CHAR()" speedup to
(UTF-)EBCDIC platforms and called for feedback from people which have
access to EBCDIC platforms.
http://xrl.us/izpw
*char (un)signedness in Tru64* Jarkko Hietaniemi grew bored of the
wrong guesses of Configure in Tru64 about the stdio char signedness,
showed how funky Tru64 can be and implemented a workaround.
http://xrl.us/izpx
*Cygwin Wrong Pools* Yitzchak Scott-Thoennes found in cygwin/cygwin.c
the bug which caused messages like the one below in Cygwin builds and
fixed it.
panic: free from wrong pool at lib/lib_pm.PL line 6.
http://xrl.us/izpy
About this summary
Where's the summary?, you may have asked, or worse you didn't even
missed it. "What happened to professionalism? What about deadlines?
I've had a cold. The cats ate my homework." And before you say I stole
Piers Cawley's line, I just borrowed him the cats. Anyway, here's
another better-late-than-never summary brought to you by Adriano
Ferreira.
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: [EMAIL PROTECTED]). 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
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