23 lines
1.5 KiB
Text
23 lines
1.5 KiB
Text
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Perl by default just ignores cycles in require statements - if Foo.pm does
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use Bar and Bar.pm does use Foo, doing use Foo elsewhere will start loading
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Foo.pm, then hit the use statement, start loading Bar.pm, hit the use
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statement, notice that Foo.pm has already started loading and ignore it,
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and continue loading Bar.pm. But Foo.pm hasn't finished loading yet, so if
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Bar.pm uses anything from Foo.pm (which it likely does, if it's loading it),
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those won't be accessible while the body of Bar.pm is being executed. This
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can lead to some very confusing errors, especially if introspection is
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happening at load time (make_immutable in Moose classes, for example). This
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module generates a warning whenever a module is skipped due to being loaded,
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if that module has not finished executing.
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This module works as a pragma, and typically pragmas have lexical scope.
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Lexical scope doesn't make a whole lot of sense for this case though,
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because the effect it's tracking isn't lexical (what does it mean to disable
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the pragma inside of a cycle vs. outside of a cycle? does disabling it
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within a cycle cause it to always be disabled for that cycle, or only if
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it's disabled at the point where the warning would otherwise be generated?
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etc.), but dynamic scope (the scope that, for instance, local uses) does,
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and that's how this module works. Saying no circular::require enables the
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module for the current dynamic scope, and use circular::require disables
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it for the current dynamic scope. Hopefully, this will just do what you mean.
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