Perfect, thanks choroba!

That makes sense, and I completely overlooked that in the docs. Thankfully the couple of private functions I want to share are quasi-public anyway, so I'll just put them into @EXPORT_OK and make sure my documentation is clear on it.

I made me a loophole:

our @EXPORT_OK qw(
    func_one
    func_two
);
our @EXPORT_PRIVATE = qw(
    _private_one
    _private_two
);
our %EXPORT_TAGS = (
    all     => \@EXPORT_OK,
    private => _add_private(),
);

sub _add_private {
    push @EXPORT_OK, @EXPORT_PRIVATE;
    return \@EXPORT_OK;
[download]

Then in the script, use MyModule qw(:private);.

If I read that correctly, you might want to check your namespace after importing :all...

The _add_private sub will be called while initializing %EXPORT_TAGS, and it modifies @EXPORT_OK, which is also used to define (by reference) the :all tag. Data::Dumper should illustrate this if asked to dump the %EXPORT_TAGS hash.

If you still want this, I suggest: (untested)

# ...
our %EXPORT_TAGS = (
    all => [@EXPORT_OK],
);
$EXPORT_TAGS{private} = _add_private();
# ...
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The %EXPORT_TAGS initialization is split into two statements to ensure a sequence point and avoid a possible undefined evaluation order. This ensures that the initial @EXPORT_OK is copied into a new array before _add_private modifies its contents.

Great catch!

However, the separation isn't needed. As soon as I saw you put the EXPORT_OK into an anonymous array, changed from the taking of the reference as I had it, I realized that's all that was needed. So all now instead of being a reference to the array, it's a reference to a copy of it:

our %EXPORT_TAGS = (
    all     => [ @EXPORT_OK ],
    private => _export_private(),
);

sub _export_private {
    push @EXPORT_OK, @EXPORT_PRIVATE;
    return \@EXPORT_OK;
}
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Output:

$VAR1 = {
          'private' => [
                         'add_bugtracker',
                         'add_repository',
                         'changes',
                         'changes_bump',
                         'changes_date',
                         'ci_badges',
                         'ci_github',
                         'git_ignore',
                         'init',
                         'make_test',
                         'manifest_skip',
                         'move_distribution_files',
                         'remove_unwanted_files',
                         'version_bump',
                         'version_info',
                         '_git_commit',
                         '_git_push',
                         '_validate_git'
                       ],
          'all' => [
                     'add_bugtracker',
                     'add_repository',
                     'changes',
                     'changes_bump',
                     'changes_date',
                     'ci_badges',
                     'ci_github',
                     'git_ignore',
                     'init',
                     'make_test',
                     'manifest_skip',
                     'move_distribution_files',
                     'remove_unwanted_files',
                     'version_bump'
                     'version_info',
                   ]
        };
[download]