This week, your P5P summary is featuring phases of the moon, and other funny things that always make the day of the average perl hacker.
Bug #29585 describes how the Shell module fails to handle filenames
with spaces in them. Tassilo provided a patch, but Slaven Rezic pointed
out that one could argue that rm("my file") should remove two files,
my and file: rm("*") does globbing, after all. Moreover,
Shell escapes some characters and not some others.
Therefore Tassilo concluded that there are many possible ways of fixing
Shell.pm, but each of them leaves quite a lot to be desired, and Rafael
commented that Shell was mostly a toy module.
http://groups.google.com/groups?selm=rt-3.0.9-29585-87427.8.22064370668613%40per l.org
Jason Rhinelander found a semantic oddity related to scoping of the <
$<digit >> variables (#29701): in the condition of an if() block, the
$1 which is set by a regexp match is still seen after the following
block; the $1 which is set by a match in the condition of a while()
block isn't seen after the said block.
Rafael comments that this may not be a bug, but doesn't remember why exactly. (Thinking about it, probably because if(), unlike while(), can be followed by two blocks).
http://groups.google.com/groups?selm=rt-3.0.9-29701-87741.16.8398876872253%40per l.org
Roger Yager proposed a patch to File::Find to allow to pass arguments to
the callback subroutine. Gisle Aas mentioned the classical alternative
solution, to use a closure as a callback; but, as Mark-Jason Dominus
pointed out, this solution isn't always convenient. Thus, a documentation
patch to File::Find seems to be appropriate.
http://groups.google.com/groups?selm=auto-000000152005%40eyestreet.com
Jamie Lokier remarked submitted a detailed bug report (#29637) about the
factors that might influence the creation time of a new thread. It appears
that it's highly sensitive to conditions that shouldn't affect the
time: for example, changing the name of a subroutine, or even a space in
a comment. This seems to be related to the number of mprotect(2) system
calls issued during memory allocation. Those calls come from the malloc()
implementation used on the system. Jamie provided enough clues to make
Dave Mitchell find a solution: the bug was in the function used to clone
pointer tables. Thread cloning time is now apparently faster by a 10%
factor.
http://groups.google.com/groups?selm=rt-3.0.9-29637-87553.11.6565004757339%40per l.org
Stas Bekman and Rob Mueller found a situation where turning taintedness on
a scalar removes its UTF-8 flag. Sadahiro Tomoyuki proposed a patch, that
makes the internal routine sv_utf8_upgrade_flags() understand a sufficient
amount of magic to handle taintedness. As a side-effect, his patch makes
utf8::upgrade() less tolerant to read-only arguments.
http://groups.google.com/groups?selm=40AC475F.4010208%40stason.org
Shinya Hayakawa proposed a patch to allow lexicals just declared via my
to be autovivified, as in
(my $x)->{foo} # creates a hash
Rafael doesn't have a strong opinion about this language feature. Hugo isn't opposed to, but remarks that the patch lacks regression tests.
http://groups.google.com/groups?selm=200405211244.31291.tetryl%40tokyoprogrammer .com
Steve Hay found a way to make perl crash with two files, using the
autouse module. Nobody commented. (Bug #29708.)
http://groups.google.com/groups?selm=rt-3.0.9-29708-87779.17.2965328304932%40per l.org
Chip Salzenberg found a bug in the @a = sort(@a) in-place optimization,
which was promptly fixed by Dave Mitchell.
http://groups.google.com/groups?selm=rt-3.0.9-29790-87979.16.2445637115601%40per l.org
Rafiq Ismael found a regular expression and a string against which it should match, that makes a threaded perl segfault, but not a non-threaded perl. (Bug #29650.)
http://groups.google.com/groups?selm=rt-3.0.9-29650-87589.10.6574674663369%40per l.org
Dave Mitchell fixed a parsing error in the Switch module (bug #28966)
by adding case as a keyword in Text::Balanced.
This summary was written by Rafael Garcia-Suarez. Weekly summaries are published on http://use.perl.org/ and posted on a mailing list, which subscription address is perl5-summary-subscribe@perl.org . Comments and corrections welcome.