Is there any truth to the rumor about bare keys?

For Perl 5 - no.

Perl 6 will, of course, be different - but that shouldn't be an issue for people developing Perl 5.

Note that this is not a question about whether one can use bare strings as keys, but about whether one should.

I think you should personally.

Yes, I think the comment was targeted at Perl 6, but five years ago it seemed that Perl 6 might be coming soon, and that we would want to use it.

At this point, we have so much existing code that I'm not sure we have the resources to refactor all of it. Perl 6 is supposed to be back compatible with perl 5, but if it is successful I assume we will eventually move our major codes over. When we do this, not having to catch all the unquoted keys would be helpful. Supposedly there will be a converter. I hope someone is clever enough to write one that actually works; this is the achilles heel of TMTOWTDI perhaps.

When will all this happen? three years? five years?

Perl 6 is supposed to be back compatible with perl 5

No it isn't. Perl 6 is substantially different from Perl 5. You will likely be able to run Perl 5 code under Perl 6 in some way, but new Perl 6 code is going to look very different from Perl 5 code. Worrying about Perl 6 conventions is you are writing Perl 5 is a waste of time :-)

When will all this happen? three years? five years?

When the people doing the work have the time available to make it happen :-)

$name->{__PACKAGE__} $name->{__PACKAGE__.''} ;

$name->{ 'PI()'} $name->{ PI() }

As other posts have said, it doesn't look like barewords as hash keys are going away any time soon.
As long as everyone knows when they must quote hash keys, then I wouldn't make a big deal out of it.

If you can persuade everyone to use/agree on a set of coding standards and style, that's a good thing. It isn't always easy though.
It my experience, things like quoting hash keys, bracketing/brace styles and the like aren't worth worrying about - concentrate on hassling/convincing your colleagues to build well engineered, robust, easily maintained code and let trival style issues slide.

It sounds like you've already established a habit of using quotes. Since it might become an issue in the future, it does no harm to use them, and might possibly cause problems if you don't - so go ahead and use them. Chances are you're not going to be able to convince others to use quotes, if they're already in the habit of using barewords.

The closest he comes to explicitly covering this is under "Fat Commas" in the "Reserve => for pairs" section on pages 66 - 68. This quote particulalry stands out " [ The Fat Comma ] also removes the need to quote the key string . . . ." This is recommended because it reduces screen clutter and thus increases the readability of your code (see the "bad" example on page 67).

So, if you like the guidlines set forth in Perl Best Practices then the answer is to only quote hash keys when necessary.