I'm converting a small (~200 SLOC) OO module to use Mouse, for some comparative benchmarking and other educational tomfoolery. I wrote it originally with manual OO. Nothing fancy. But I'm not sure how to implement my existing error handling mechanism with Mouse::Util::TypeConstraints. My error handler is configurable to either carp(), or set $obj->error string, or both. As far as I can tell, M::U::TypeConstraints croak()s on everything and that's it. So, going from this:

# Previous (manual OO) code:
sub error_mode {                                                      
+          
    my ($s, $mode) = @_;                                              
+          
    if ($mode) {                                                      
+          
        $s->_err('Invalid error_mode', $s->{error_mode})              
+          
            unless $mode =~ /^(carp|error|both)$/;                    
+          
        $s->{error_mode} = $mode;                                     
+          
    }                                                                 
+          
                                                                      
+          
    $s->{error_mode};                                                 
+          
}
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... to this:

# Converted to Mouse:
enum 'ErrorMode' => qw<carp error both>;
has 'error_mode' => ( is => 'rw', isa => 'ErrorMode', default => 'erro
+r' );
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... this works in the sense that $obj->error_mode($new_mode) correctly sets the mode, but if $new_mode is invalid, it outputs a fatal mess like this:

Attribute (error_mode) does not pass the type constraint because: Vali
+dation failed for 'ErrorMode' with value  at /usr/local/lib/x86_64-li
+nux-gnu/perl/5.26.1/Mouse/Util.pm line 395.
        Mouse::Util::throw_error(Mouse::Meta::Attribute=HASH(0x56165c0
+b5528), "Attribute (error_mode) does not pass the type constraint bec
+a"..., "data", "", "depth", -1) called at ./t/05-errors.t line 16
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I know I can use message to have a slightly more readable error message, but the main problem is of course the fatal exceptions with no way that I can see to implement any other kind of error handling. Of course I know I don't have to use Mouse::Util::TypeConstraints, but then it starts to look identical to my manual OO code. That or I guess I could wrap the accessor/mutator with a method that does eval { $self->_error_mode(@_) } and handles the errors from there, but that's, well, gross, especially given there are half a dozen methods to do this with. Is there a middle ground?