local $_ could be used to localize $_, but that doesn't remove any magic associated with it on some versions of Perl.

$ perl -wE'for ($|) { local $_; $_ = "abc"; say; }'
Argument "abc" isn't numeric in scalar assignment at -e line 1.
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local *_ would do the trick by forcing an entirely new $_ to be created, but that also gets rid of @_, %_, etc.

$ perl -E'$_="x"; @_=(4,5); say $_,@_; local *_; say $_,@_;'
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Assigning to a glob is weird, though. It only assigns to the relevant slot. So that means assigning a reference to a scalar to *_ only replaces $_

$ perl -E'$_="x"; @_=(4,5); say $_,@_; local *_ = \my $a; say $_,@_;'
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Any fresh scalar would have worked.

Note that this aliases $_ to the scalar, but File::Find does not take advantage of that feature.

Awesome, thanks for the explanation.

What do you mean though by

Note that this aliases $_ to the scalar, but File::Find does not take advantage of that feature.

Specifically the part about not taking advantage of the feature. What features could be taken advantage of? Thanks

EDIT:

Oh wait are you saying that $a could be used like $_ (they become equivalent?). Or is there something else?

$ perl -E'local *_ = \my $s;  $_ = 123;  say $s;  $s = 456;  say $_;'
123
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