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B::Hooks::OP::Check::StashChange causes split to disappear

by kroach (Pilgrim)
on Aug 13, 2020 at 23:49 UTC ( #11120698=perlquestion: print w/replies, xml ) Need Help??

kroach has asked for the wisdom of the Perl Monks concerning the following question:

B::Hooks::OP::Check::StashChange allows one to run a callback whenever the current package changes during compilation. If a hook is installed, all subsequent calls to split appear to be removed. How is this possible?

Here's some code without a hook being installed:
INSTALL_HOOK=0 perl -MO=Deparse -MB::Hooks::OP::Check::StashChange -e +'BEGIN { my $id = B::Hooks::OP::Check::StashChange::register(sub {}) +if $ENV{INSTALL_HOOK}; } print split "x", "1x2"' use B::Hooks::OP::Check::StashChange; sub BEGIN { my $id = B::Hooks::OP::Check::StashChange::register(sub { } ) if $ENV{'INSTALL_HOOK'}; } print split(/x/, '1x2', 0); -e syntax OK
and here's the same code with the hook enabled:
INSTALL_HOOK=1 perl -MO=Deparse -MB::Hooks::OP::Check::StashChange -e +'BEGIN { my $id = B::Hooks::OP::Check::StashChange::register(sub {}) +if $ENV{INSTALL_HOOK}; } print split "x", "1x2"' use B::Hooks::OP::Check::StashChange; sub BEGIN { my $id = B::Hooks::OP::Check::StashChange::register(sub { } ) if $ENV{'INSTALL_HOOK'}; } print 'x', '1x2'; -e syntax OK

As you can see, "split" disappeared and it's arguments are simply being printed. The module code itself is pretty short but given my lack of experience with XS I can't pinpoint the issue. How can a builtin get disabled like this?

Replies are listed 'Best First'.
Re: B::Hooks::OP::Check::StashChange causes split to disappear
by jcb (Vicar) on Aug 14, 2020 at 01:18 UTC

    The split builtin is not being disabled. XS modules are in (augmented) C; the perl core is in C. XS modules can do anything.

    You have an XS module that modifies the compilation process. Either you are misusing B::Hooks::OP::Chec≠k::StashChange somehow or that module has a bug that prevents split from being properly compiled when a hook is in place.

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