Welcome to this week's P5P summary, with all sorts of interesting new stuff on regular expressions, threads and other improvements.
Yitzchak Scott-Thoennes suggested that Yves Orton send in a patch
to pull out some of the ancillary functions in Data::Dump::Streamer
in order to make them available in the core distribution.
http://xrl.us/k2x7
So Yves did just that. The first addition is to add reftype_name(), that
behaves like reftype except that it returns false rather than undef
on non-references. This removes the need for fussy make-work code on the
client side to avoid warnings.
The second addition is a regex() function, which makes it easier to
deal with patterns, whether they have been blessed into other namespaces
or not.
Graham Barr admitted that the return value of reftype() was a mistake,
and reftype_name() was acceptable, but felt that the regex()
function was better off in the Regexp module.
Yves didn't like the fact that Scalar::Util::reftype returns SCALAR
instead of something like REGEX. Nick Ing-Simmons liked the idea, but
thought that it was too dangerous for maint.
Another sub-thread in the discussion revolved around whether a qr// thing is an object or a type. It is, in fact, an object, but Yves argued that it is much more useful to treat it as a type. Graham agreed to disagree.
Adam Kennedy admitted to using Regexps as objects quite a bit and
would be happy to see the Regexp module receive a dose of
spring-cleaning (which I suppose means fixing up the reblessing
inconsistency that Yves was getting at).
Another hassle Yves pointed out was the non-reversibility of stringifying regexps:
my $qr=qr/foo/; my $str="$qr"; print qr/$str/; # equivalent but not equal
Dave Mitchell pointed out that a regular expression currently is a scalar, it just happens to have a bit of magic attached...
Shouldering the weight of history http://xrl.us/k2x8
Hugo van der Sanden returned to the super-linear cache bug (a ||
logical or instead of a | bitwise or) in the regular expression
engine, and came up with a suitable test case:
("a" x 31) =~ /^(a*?)(?!(a{6}|a{5})*$)/;
print length($1);
This prompted Yitzchak Scott-Thoennes to come up with another bug
that showed how blead broke existing behaviour. Since no-one
should ever have come to rely on this behaviour, it was all quietly
swept under the rug. Dave Mitchell hinted that he was working on
New Stuff in the engine.
http://xrl.us/k2x9
threads into the third millenium Jerry D. Hedden continued to send patches to sync CPAN's threads with
blead, first by removing a superfluous counter.
http://xrl.us/k2ya
and again http://xrl.us/k2yb
and reworked the threads destruct call http://xrl.us/k2yc
He vented his frustration at the slow pace with which the patches were getting applied, believing that he was playing by the rules as much as possible. Rafael was very apologetic, explaining that he understands so little about threads that he's barely qualified to apply them. And apart from Rafael, there aren't too many alternatives.
http://xrl.us/k2yd
blead RE improvements to maint Nicholas Clark posted a proof-of-concept update to re.pm to deliver Dave Mitchell's iterative (as opposed to recursive) implementation of the regular expression to perl 5.8.1 and beyond. A few show-stoppers need to be cleaned up: some coredumps in the test suite need to be sorted out and some tweaks to ppport.h are needed. As a bonus, Yves Orton's trie work comes along for the ride.
More songs about building regexps http://xrl.us/k2ye
valgrind and Perl 5 Nicholas Clark wondered what would happen, as in, how many bugs
would be uncovered, if one were to run the test suite under
valgrind. So Rafael Garcia-Suarez did just that, and discovered
that 41 test files produce errors.
Nicholas and Rafael then set about fixing up the problems that were uncovered.
There's always something to do http://xrl.us/k2yf
Nicholas Clark looked at the unexpurgated version of the output from the test suite and noticed that six tests were marked as unexpectedly succeeding. In test parlance, these tests are called TODO tests, since they show what there is to do. This state of affairs is usually due to a test case that is expected to fail when run, since it exercised a bug in perl that needed to be fixed, and at some point, a source code change caused the failing test to succeed.
Nicholas saw that many of the really old regexp bugs that have been fixed, had no TODO tests, and in any event, the default, summarised, output of the test test suite makes no mention of them anyway, so it is not as if anyone would have noticed the improvement.
So firstly, the test harness had to be upgraded to report the summary of TODO tests that succeed, and (much more work) all the open bugs need test cases written for them, so that it becomes easier to see when they have been fixed.
Yves Orton hacked up his copy of Test::Harness to do this. Andy
Lester took the idea and applied it to his development version
of Test::Harness (see the "New Modules" section below).
Abe Timmerman updated the test smoke kit, in order to get all this new goodness into the hands of the smokers.
Much ado about todo http://xrl.us/k2yg
Up in smoke rsync -avz source.test-smoke.org::ts-current .
After having read the traffic on p5p concerning the errors that Coverity uncovered, Alan Olsen what the possibilities were for having the tests extended to cover CPAN modules with XS components.
Johnathon Stowe realised that it was the output of xsubpp
that needs to be tested, rather than the .xs files themselves,
and wondered whether all the possible constructs it is possible
to have xsubpp emit ere in fact being covered, and whether
one ought to create a dummy XS module that simply causes
xsubpp to emit everything it knows how to.
Tim Jenness thought that that issue should be covered by
XS::Typemap. Johnathon did some quick coverage calculations
and was surprised to learn that it wasn't too shabby.
Andy Lester volunteered to liaise with the Coverity people to have XS-based modules analysed, should the authors in question care to know the results. Randy W. Sims was concerned that some authors might think of it as a ratings system. Be that as it may, a couple of authors asked for analysis to be applied to their modules.
http://xrl.us/k2yh
This week, Andy Lester performed some more op_type shrinking in
sv.c and dump.c,
http://xrl.us/k2yi
and hauled some variables down into tighter scopes in util.c.
http://xrl.us/k2yj
Marcus Holland-Moritz grew tired of watching an endless list of
warnings spew from compiling perl with a recent copy of gcc,
so he patched things to get rid of the problems that gave rise to
them.
Andy Lester was pleased to hear of the work, since it had been something of an annoyance for him too. He asked for a slightly less monolithic patch, so that different classes of errors could be fixed a bit at a time. Rafael eventually applied all the changes.
Understanding error messages http://xrl.us/k2yk
Nicholas Clark looked at a NetBSD smoke report, and wondered what it was that was being tested in ext/B/t/bytecode.t that was failing. Whatever it was, he fixed it with change #27874.
Smoke [5.9.4] 27855 FAIL(F) netbsd 3.0 (i386/1 cpu) http://xrl.us/k2ym
Steve Peters wondered why a test run was failing, simply because TEST was seeing test results being delivered out of order, where as harness didn't care.
Smoke [5.9.4] 27939 FAIL(F) MSWin32 WinXP/.Net SP2 (x86/2 cpu) http://xrl.us/k2yn
Steve Peters and Johnathon Stowe kicked this bug around, but as neither of them have access to the platform in question it shall have to remain open for the time being.
OpenServer anyone? http://xrl.us/k2yo
Rafael fixed this bug by accident while working on something else. No-one minded.
http://xrl.us/k2yp
In fact, Steve Peters continued his thankless task of trawling through old, open tickets and noticed that a certain number of bugs had been solved by changes committed recently and not so recently.
Fixed in previous millenium http://xrl.us/k2yq
Sys::Syslog) requires \0 terminator in syslog messages (#28019) Julian Mehnle called in from Debian-land to see what the status on this bug was, explaining that some comments or documentation would help avoid bugs being filed in the future.
http://xrl.us/k2yr
threads and require IO causes segmentation fault (#37076) Nicholas Clark jotted down a couple of notes on how to fix this problem.
Add it to the TODO http://xrl.us/k2ys
Steve Peters wondered why Dave's excellent example shouldn't be used to close this ticket.
http://xrl.us/k2yt
Text::ParseWords doesn't always handle backslashes correctly (#38904) John Vromans argued that the following equivalency was incorrect:
is_deeply([shellwords("aa bb cc\\ ")], ["aa", "bb", "cc "])
Alexey Toptygin delved into the code to find out why and offered a patch to make the behaviour a little more intuitive. Applied by Rafael.
http://xrl.us/k2yu
map sometimes uses only the last mapped value (#38935) Someone on Perlmonks posted an innocuous question about some strange
behaviour with map, that turned out to be a caused by a change that
was applied in 1998. People were surprised at that such a bug had
remained unnoticed for so long.
http://xrl.us/k2yv
The original thread http://www.perlmonks.org/index.pl?node_id=543989
Configure won't handle versions 5.10.0 or 5.8.10. (#38945) Andy Dougherty filed a bug on this problem so that people remember to do something about it in time.
http://xrl.us/k2yw
system 1 foo repeatedly (#38946) An interesting discussion arose from this report. It turns out that
system 1, ... does something interesting under Windows.
http://xrl.us/k2yx
$TMP is not writable (#38947) Gabor Szabo noted that certain tests lib/Memoize/t/tie_ndbm.t fail if
the directory pointed to by $TMP was not writable. He felt that a
diagnostic should explain more clearly what the problem is rather than
failing out of hand.
http://xrl.us/k2yy
Karuppiah Subramaniam has a migration problem. If you have any advice to offer, I'm sure it will be appreciated.
http://xrl.us/k2yz
exists error message on wrong argument type is incorrect (#38955) Jeremy Hetzler wished to clarify the error message received when
exists use incorrectly, and bring it into line with the documentation.
http://xrl.us/k2y2
File::Find documentation - is "Don't modify these variables" still valid? (#38965) Steve Peters tweaked the documentation for File::Find to specify more
clearly what happens to $_ in the callback routine.
http://xrl.us/k2y3
9 created and 4 closed = 1543 http://xrl.us/kw9y
Steady as she goes http://rt.perl.org/rt3/NoAuth/perl5/Overview.html
Test-Harness version 2.57_06, by Andy Lester. This enhances the summary result to indicate clearly the number of TODO test that have unexpectedly begun to succeed, (usually due to underlying bugs being fixed).
http://xrl.us/k2y4
Nicholas Clark carried out his threat to document code references in
@INC and source filters and also added a new feature at the same time.
http://xrl.us/k2y5
Paul Johnson read about the is_list_assignment speedup patch from
Andy Lester, and pointed the porters to a two year old thread on a
similar issue.
http://xrl.us/k2y6
Nick Ing-Simmons followed up on the issue of leaking file handles in XS code.
http://xrl.us/k2y7
Jan Dubois removed some cruft from makedef.pl
http://xrl.us/k2y8
Jarkko Hietaniemi tried a patch to regcomp.c to see if it would silence an error from Coverity. It didn't. This led Jarkko to conclude that if Coverity was too clever, or too stupid, to figure out what was really happening, then maybe it's Red-flag-for-Refactoring time.
It would help us, frail humans http://xrl.us/k2y9
He then nailed another leak that Coverity found in doop.c .
http://xrl.us/k2za
Nicholas Clark saw that Coverity dislikes PerlIO_findFILE . The logic
seems a bit tortuous, so maybe that's not so surprising,
http://xrl.us/k2zb
Nicholas looked at the last two unreviewed Coverity issues, in regexec.c and wondered whether Coverity was getting confused. Dave Mitchell explained that both issues were false positives.
http://xrl.us/k2zc
Alex Waugh provided the required information to support compiling perl on RISC OS.
http://xrl.us/k2zd
Andy Lester posted a short script to prune Jarkko's cpd output,
to show more clearly where Cut-And-Paste code was happening in areas
that interested him.
http://xrl.us/k2ze
Yitzchak Scott-Thoennes fixed building perl on Cygwin .
http://xrl.us/k2zf
Joshua Juran uploaded an experimental release of Lamp on SourceForge.
Lamp Ain't Mac POSIX http://xrl.us/k2zg
Andy Lester refactored the excessive use of PM_GETRE() in pp_ctl.c .
http://xrl.us/k2zh
Jan Dubois and Steve Hay coordinated the ActiveState changes to
win32/Makefile in blead, clearing up an issue concerning
64-bit environments at the same time
http://xrl.us/k2zi
Nicholas Clark explained what he understood Larry's MAD patch to be doing.
http://xrl.us/k2zj
The UTF-8 caching code that Nicholas Clark worked on a few months
back wound up being exposed on the command-line via the -Ca switch.
Unless someone has a better idea http://xrl.us/k2zk
Nicholas Clark unearthed what is in hindsight a blindingly obvious
memory leak on unthreaded builds between Perl_newCONSTSUB and
cv_undef .
Nobody else knew what to do about it, either. http://xrl.us/k2zm
Andy Lester thought that GvUNIQUE() and its ilk could be
removed from the source. Rafael commented that the macros had
to remain, since at least Data::Alias on CPAN refer to them.
http://xrl.us/k2zn
Ashish Agarwal was having problems with weird characters displayed in the debugger. Joe McGuire thought it was probably one of the thirteen so-called variant characters in EBCDIC.
\ [ ] { } ^ ~ ! # | $ @ `
http://xrl.us/k2zo
Andy Lester cleaned up regexec.c following on from the recent changes.
http://xrl.us/k2zp
Rick Delaney had discovered that fields.pm lost their compile-time benefit,
dating back to when pseudo-hashes were removed from blead.
http://xrl.us/k2zq
Ken Williams asked for advice on some proposed File::Spec changes for VMS,
John E. Malmberg supplied what information he could. Ken lamented how
difficult it was to test VMS code if you didn't have access to a VMS box.
http://xrl.us/k2zr
Joshua ben Jore thought that the terribly cryptic
select((select(OUTPUT_HANDLE), $| = 1)[0]) idiom should be banished
from the documentation. Rafael bowed to reason.
Just because you can http://xrl.us/k2zs
The cynics scoffed at the effort expended to clear the Coverity issues,
and Rafael pointed out that state variables are almost but not quite
yet in blead.
http://xrl.us/k2zt
This summary was written by David Landgren.
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:
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