Should the XS implementation give the (overridable) isa method the precedence?

Only if you want Perl's OO to keep working. In all other cases -- every one -- Perl calls overridden methods which optionally call super methods.

(Modern versions of UNIVERSAL explicitly recommend against calling UNIVERSAL::isa directly.)

In reply to Re: sv_derived_from vs. sub ISA by chromatic
in thread sv_derived_from vs. sub ISA by rehsack

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