"May I remind everybody my personal opinion, which is that I see little to null utility to style patches to C or perl code, but that they clobber version control history, waste my time, and that in most I cases will not apply them." — Rafaël Garcia-Suarez, current pumpking, on why people should not fiddle with the bloody whitespace.
Last week, Dr. Ruud and Yves Orton worked on bringing makepatch up to
speed on the Windows platform. For some reason it sparked a long discussion
about the merits of writing code compatible with ancient versions of Perl
and $_ topicalisation.
http://xrl.us/sm5z
free() in Perl_do_exec3 Alexey Tourbin spotted a problem with the current 5.8 snapshot that doesn't show up in the 5.8.8 release. Dave Mitchell thanked him for picking it up, and fixed it.
Alexey went on to mention that he runs a git repository that tracks the 5.8 and 5.9 sources, and lamented that he could not quite figure out to which change corresponded the 5.9.0 release.
ah say git down http://xrl.us/sm52
Adam Kennedy uses only.pm to lock down the versions of modules
used in the code he delivers to clients, and noticed that only
doesn't work correctly with changes that have taken place since in
version, and development on only appears to have dragged to
a halt.
John Peacock took a look at only's code, saw what was wrong with
it, and at the same time asked Adam wither version::Limit might
do the trick instead.
http://xrl.us/sm53
After weeks of patching and tweaking the source, Jarkko Hietaniemi announced
that he had succeeded in performing a C++ compilation of the perl source,
and a completely successful test suite run. Rafaël Garcia-Suarez noted
that NDBM_File still had trouble. Jarkko didn't notice that because it
wasn't configured to be built on his platform. Robin Barker provided a
patch to fix it up.
Paul Marquess, Steve Peters and Jesse Vincent reported successes with other C++ compilers and platforms. H.Merijn Brand found a problem on Suse Linux, as did Dominic Dunlop on Mac OS/X.
http://xrl.us/sm54
Robin's patches http://xrl.us/sm55 http://xrl.us/sm56 http://xrl.us/sm57
Yves Orton surfaced briefly to discuss some oddities he had found in the regular expression concerning how opening and closing capturing parentheses are managed. An optimisation in the engine consists of throwing the regop codes that denote the parentheses, and tracks them itself... but doesn't track them all that well.
Over time, this has manifested itself through a variety of bugs, all of which have been solved in ad hoc ways, as no one really understood the big picture.
Yves thinks that his hypothesis is right, and wanted to know what
Dave Mitchell thought of it. Ilya Zakharevich remembered that Yves's
two variables, PL_reglastparen and PL_reglastcloseparen were
once upon a time a single variable, but were split into two, probably
when non-capturing parentheses were introduced. As such, it's quite
possible that the code was not correctly updated in all the required
places. In a patch elsewhere this week, Yves dropped some comment
markers here and there, where he thought the variables should be
updated.
http://xrl.us/sm58
Perl_reg_named_buff_sv please stand up? Craig A. Berry was having trouble building the re extension on VMS,
since the VMS linker didn't like the fact that the Perl_reg_named_buff_sv
symbol was defined twice, in two different object files.
Yves explained that one was derived from the other, in order to generate the debugging version. His linker, being slightly more lax, did not complain about this issue, and fixed it up in a subsequent patch.
http://xrl.us/sm59
Yves then looked at the TODO list for 5.10 and counted four issues
outstanding. He wanted to know that their status was, and what
needs to be done. Rafaël said three of them were issues he planned
to deal with, and one was less important (lexical encoding pragmas).
He also mentioned that aliases were probably important enough to
be taken on board, as were UNITCHECK blocks.
Juerd was very keen to see work done on the encoding pragma. He
as released a work-around encoding::split to get things to work
to his satisfaction, but would like to see the functionality appear
in the core.
Adriano Ferreira reminded the porters of bug #38945, which notes that
Configure is not x.10 version aware. Andreas König mentioned
that DBI doesn't compile on blead (and someone needs to open a
ticket on that).
http://xrl.us/sm6a
Philip M. Gollucci, almost left behind, pointed out that there was an icky attribute/printf problem that needed to be sorted out as well.
http://xrl.us/sm6b
SVpvs vs SVpvn Jim Cromie was looking through the source when he noticed that there
were a number of places where the newSVpvn call could be more
profitably replaced by a newSVpvs, the reason being that this
removes the need to keep hard-coded lengths of strings lying
around (as this can allow bit-rot to creep in).
Nicholas Clark went ahead and made the change. Aaron Sherman pointed out that the hard-coded length might be a slightly sick way of taking a substring of a constant, such as
SV *s = newSVpvn("pear",3);
Nicholas had already looked for such cases in the code, and the only occurrences he found were deliberate tests.
Vadim Konovalov wondered whether the real reason that hard-coded lengths were used was to avoid possibly costly length computations. Jim Cromie believed that this was not a problem, since the constructs tended to be evaluated when the C source is compiled, and boil down to a constant in the resulting object code.
http://xrl.us/sm6c
Michael G. Schwern wished to register his disgruntledness at the
fact that a diagnostic change caused a number of his modules
(Exporter::Lite, UNIVERSAL::exports and UNIVERSAL::require
for starters), and wondered how many other modules were in the
same boat.
John Peacock was loathe to give up the more informative new error message. He could get close to matching the old message if certain conditions were met, but not completely. Michael remarked that future-proofing the checking of perl error messages is hard.
Never mind localisation http://xrl.us/sm6d
Nicholas Clark wrote a psychotic regular expression to provoke a leak that was picked up by valgrind, and he wondered if there was an off-by-one error. Yves promised to have a look at it later.
http://xrl.us/sm6e
Jarkko tweaked some of Yves's code to get it to compile cleanly with the more fussy compilers that he has at his disposal.
Do not cross the initialisation boundary, do not collect $200 http://xrl.us/sm6f
Jarkko transformed Digest::SHA from K&R C to ANSI, and described
the delicate footwork required to ensure that blead and CPAN
play nicely together.
Mark Shelor, Digest::SHA's author, thanked Jarkko for the patch,
and planned to integrate it for the upcoming 5.44 release, so with
luck no one will have to take extra care for very long.
http://xrl.us/sm6g
Jarkko performed similar tweaks for Encode.xs, with a eye on C++.
http://xrl.us/sm6h http://xrl.us/sm6i
He then gave a few hints to Linux and Solaris to tell C++ how to
deal with dlerror, noting that if a third platform needs this
trickery then it will be time to push it off into Configure.
http://xrl.us/sm6j
Moving on through the modules, he then performed a classy act
on ExtUtils::ParseXS.
http://xrl.us/sm6k
And then ANSIfied the Text::Soundex module.
A530 T500 A521 T000 T232 M340 http://xrl.us/sm6m
And an EXTERN_C wrapper for something in re.pm
http://xrl.us/sm6n
Yves Orton, the unstoppable feature-adder to the regular expression
engine, added named recursion this week, whereby <(?&NAME)>
recurses to the capture buffer defined by (?<NAME>...).
No, my brane hurts http://xrl.us/sm6o
He landed another patch to fix bugs, test code and add more functionality to deal with conditionals in regular expressions.
http://xrl.us/sm6p
He then added even more documentation, of note is an update to perlreguts.
http://xrl.us/sm6q
And last but not least, Yves announced that he had added possessive quantifiers to the engine. He also put floated the idea of removing the dire warnings about the experimental status of the existing extensions, since they have been around for a long time and have been well documented and well explored by large numbers of people.
http://xrl.us/sm6r
Sadahiro-san delivered a patch to remove leaveit from
toke.c:scan_const, which deals with escaped characters in patterns.
There were a number of short-comings with the current code, not to
mention breakage. Now it's better.
http://xrl.us/sm6s
sprintf width+precision fails on wide chars (#40473) Anatoly Vorobey found a bug in the way sprintf handles UTF-8 characters
and supplied a patch against blead to correct it. Applied by Rafaël.
Why aren't all bug reports like this? http://xrl.us/sm6t
Matthias Urlichs demonstrated a bug in the regular expression engine. It
failed with x{2} but went away when replaced by xx. Dave Mitchell
explained that sometimes the optimiser fails to recognise such transforms.
In any event, with the latest work to the engine in blead, the
offending pattern works just fine.
Even if it does consume quite a bit of memory http://xrl.us/sm6u
Can't locate Foo/Bar.pm isn't a helpful message (#40516) Tina thought that this message exposed too much of how things are
implemented, and a beginner might not necessarily realise that there
was a problem loading the Foo::Bar module. She thought that
adding a "perhaps Foo::Bar is not installed" to the end of the message
would help improve matters.
Juerd wondered whether this would encourage newbies to
hunt down the Foo/Bar.pm file and dump it in an @INC directory.
People already tend to do this, which leads to problems when modules
have XS components and the result is traffic on mailing lists and
other fora.
http://xrl.us/sm6v
1525, bugometric pressure steady http://xrl.us/sm6w
http://rt.perl.org/rt3/NoAuth/perl5/Overview.html
version 0.67_03 from John Peacock,
http://xrl.us/sm6x
ExtUtils::MakeMaker 6.31 from Michael G. Schwern,
http://xrl.us/sm6y
CPANPLUS 0.076 (although not part of core) from Jos I. Boumans,
http://xrl.us/sm6z
and XSLoader 0.07 from Sébastien Aperghis-Tramoni.
http://xrl.us/sm62
Tels made a few suggestions about the code in makepatch that received
a work-over last week.
http://xrl.us/sm63
Dave Nicol suggested that the source code be formatted according to a fixed set of rules.
http://xrl.us/sm64
Johan Vromans looked at Carp::Clan and thought that its functionality
was so useful that it should be subsumed into the core Carp module,
arguing that it is better to extend an existing module than to introduce
a new one that duplicates a lot of the functionality of the previous one.
http://xrl.us/sm65
Gabor Szabo asked about running Devel::Cover on core modules in blead
and Paul Johnson set him straight.
http://xrl.us/sm66
Andreas König found that change #28976 breaks YAML, but Rafaël
was unable to reproduce the problem. Andreas later discovered that #28997
resolved the problem in any event.
http://xrl.us/sm67
Similarly, David Landgren compiled Template Toolkit on a recent
build of blead (change #28998) and watched in blow up. Rafaël
noted that the code in Template.xs relied on a macro producing
a parenthesised result, which was used directly in a C switch
statement, and at some point the blead version of the macro lost
the parenthesis wrapper. So Template.xs needs to add in the
parentheses itself.
relying on the core to do it for you http://xrl.us/sm68
Jerry D. Hedden raised threads to version 1.44, and threads::shared
to version 1.04.
http://xrl.us/sm69 http://xrl.us/sm7a
Juerd Waalboer wondered if he had hit a B::Deparse bug, since
a nested hashref/listref structure deparses into a different structure
that in turn deparses to something else...
... and so on to viscosity http://xrl.us/sm7b
Yves shed some light on why he chose \k<...> over \k{...}
for named captures in regular expressions.
Because http://xrl.us/sm7c
Jos I. Boumans proposed adding Log::Message and
Log::Message::Simple to the core.
http://xrl.us/sm7d
Mark J. Reed sought more information on the way File::Find
orders directories and files, since he could not see a way to
process directories first and then files.
lots of "HACK:" comments http://xrl.us/sm7e
Jim Cromie wanted to know how does Configure -O work.
delete config.sh and Policy.sh beforehand http://xrl.us/sm7f
Leopold Tötsch was encountering some ambiguous behaviour with sprintf
and wondered who was right. Sadahiro Tomoyuki straightened it out with
a sharp patch to the right.
http://xrl.us/sm7g
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.
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