Type of argument to keys on reference must be unblessed

Question

I am very new to perl and I have been given the task of maintaining a webpage. I have found a bug that I do not know how to fix.

The perl script stops on the following code.

my @failedTests = (sort(keys ($TestResultsData{$currPlatform}{$currDate}{failedtests})));
while ( @failedTests )
{
 ...

The error message is:

Type of argument to keys on reference must be unblessed hashref or arrayref.

Can that line of code be re-written so that it works?

Its defined like this `my %TestResultsData;` outside of the function — AlexN, Oct 17 '14 at 13:51

score 3 · Accepted Answer · answered Oct 17 '14 at 13:35

3

The value of $TestResultsData{$currPlatform}{$currDate}{failedtests} is a blessed hashref. keys cowardly refuses to operate on blessed hashrefs because it would break the illusion of encapsulation and overloading.

(Older versions of Perl wouldn't accept a hashref at all - you needed to pass it a proper hash.)

Try manually dereferencing the hashref into a hash using:

my @failedtests = sort keys %{ $TestResultsData{$currPlatform}{$currDate}{failedtests} };

answered Oct 17 '14 at 13:35

tobyink

13,478
1
23
35

This worked! ... time to do some more reading on hashes. Thank you! – AlexN Oct 17 '14 at 13:56
Also, because it means the object could have overridden `@{}` or `%{}`. – ikegami Oct 17 '14 at 14:24
3

Note that `keys $ref` is experimental, so `keys %{ $ref }` is a good idea either way. – ikegami Oct 17 '14 at 14:25

Type of argument to keys on reference must be unblessed

1 Answers1