For years, I have been using defined %hash to check for the existence of %hash without creating it. As of Perl 5.11.x this is deprecated for some reason, and causes an annoying deprecation warning. The warning suggests just using %hash, but this auto-vivifies. Unfortunately, I haven't been able to figure out another way to do what I want: check if a hash exists without auto-vivifying its stash slot. Here are things I've tried so far: 
    main @> keys %test::
    undef
    main @> %{"test::h"} ? 1 : 0
    0
    main @> keys %test::
    'h'
    main @> defined %{"test::h2"} ? 1 : 0
    0
    main @> keys %test::
    'h'
    main @> *{"test::h3"}{HASH} ? 1 : 0
    0
    main @> keys %test::
    h  h3
    main @> defined *{"test::h4"}{HASH} ? 1 : 0
    0
    main @> keys %test::
    h  h3 h4

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Any suggestions?

Edit: After some experimentation, this test seems to do the trick: 

exists $test::{"h"} && *{"test::h"}{HASH}

[download]
Not too bad.

In reply to Check for variable without leaving a trace by educated_foo

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