This week's summary features UTF8 and locale incompatibility problems,
discovered on RedHat 8, but pertaining to UTF8 locales ; various bugs fixed ;
various bugs discovered ; the// operator reappearing shortly ; and a
new way to consider goto harmful.
Paul Marquess reported that the test suite for Compress::Zlib fails on the newest RedHat 8.0. This problem is due to a string holding binary data which, once written to a file, gets apparently corrupted.
Gurusamy Sarathy pointed out that marking the output filehandle with
binmode() solves the problem. In fact, RedHat 8's default configuration
apparently use UTF-8 locales, which are recognized by perl 5.8.0. Gurusamy
quoted the appropriate
paragraph from the perldelta manpage for perl 5.8.0
Note for code authors: if you want to enable your users to use UTF-8 as their default encoding but in your code still have eight-bit I/O streams (such as images or zip files), you need to explicitlyopen()orbinmode()with:bytes(see perlfunc/open and perlfunc/binmode), or you can just usebinmode(FH)(nice for pre-5.8.0 backward compatibility).
Tom Horsley added that there are probably additional bugs in RedHat 8.0 Unicode handling, judging from mysterious coredumps from system libraries.
Finally, Jarkko Hietaniemi proposed a patch to fix UTF-8 enabling via locales. The LANGUAGE environment variable should not be used (as it is in 5.8.0) to enable UTF-8.
Jan Dubois reported a bug on AUTOLOADed subroutines (bug #18113, also reported previously as #17967) : AUTOLOAD is not called on packages that haven't been encountered by perl before. This used to work with perl 5.6.1, but is broken with perl 5.8.0. Gurusamy Sarathy provided a fix.
Peter Scott reported an interesting
behavior : when using a magical
goto to exit from a __DIE__ handler, one could generate an infinite
loop
$SIG{__DIE__} = sub { goto &foo };
sub foo { print "foo\n"; die "rethrow" }
die "throw";
Whether it's actually a bug is open to discussion.
Yitzchak Scott-Thoennes remarked that B::Concise doesn't handle well the
new// and//= operators (bug #18175). Stephen McCamant sent a fix,
but a similar problem on other B:: modules (at least B::Terse) should be
fixed as well.
Bug #18186 was already reported as #17718 : one can't test the emptyness of a tied hash by using it in scalar context. Yitzchak points out that it's difficult to fix, and explains why. Mark-Jason Dominus proposed an alternative solution (a HASHSIZE method), which was already suggested a while back by Rick Delaney, and rejected at this time.
Autrijus Tang reported that uc(), lc() and ucfirst() don't appear to work
correctly on the right side of s///e expressions, applied on UTF-8
strings. Strangely, this bug (#18107) doesn't affect lcfirst().
Mark Pease found a problem on offset calculations in regular expressions (bug #18154) and offered a patch.
Nicholas Clark proposed to replace the current implementation of the
makefile target regen_headers by a perl script, which he provided.
Rafael Garcia-Suarez asked why DESTROY is called in scalar context (and proposed a patch to have it called in void context), and faced Warnock's dilemma.
Abhijit Menon-Sen and Slaven Rezic fixed a problem with the..
operator, that didn't handle well some cases where the operands were
strings ("-4".."0" and "-4\n".."0\n"). (bugs #18114 and #18165.)
This summary brought to you by Rafael Garcia-Suarez. It's also available via a mailing list, which subscription address is perl5-summary-subscribe@perl.org . Comments and corrections are, as always, welcome.