Question

I am updating a few records in database. And all the processing is done in eval block.
The problem is that even if the records are successfully updated , I still see a exception being raised.

To debug the exception, I tried printing it using Data Dumper but the exception is blank.

Can any one please help me identify what is this error and why is it thrown every time ?

Environment Details (Perl 5.8 and Unix SUSE)

Dump from Data Dumper:

$VAR1 = '
';

I am using various internal APIs, to update these records.. so I have modified my code to look similar:

      sub main{
        eval{
         DB->updateRecord($value)
        };
        if($@){
             Mail->SendMail(__PACKAGE__,$@):
        }
       }

       package DB;
       sub updateRecord{
             my ($self , $value) = @_;
             my $query = "update set column_value = $value ..<update query> ";
            API->processQuery($query );
        }

Answer 1

Does your code use warnings;?

The symptom your describing indicated that in your code you are passing die the string "\n". My guess would be that in your source you have a line that is trying to die with an error message but your error message was not initialized. It could be something like

my $error;
if (some_test()) {
    $error = 'Some String';
}
if (some_other_test()) {
    die "$error\n";
}

If some_test() passes but some_other_test() fails the die will report an error containing only a new line. It would also emit an warning if warnings are enabled.

Another possibility is a typo. If you don’t use strict; the error variable might not be correct.

my $error = 'Some String';
if ($error) {
    #note the typo (transposed ro to or)
    die "$erorr\n";
}

Without use strict; this can be an easy mistake to miss.