The most-peculiar thing is that... again, without any code changes that I can see... set-cookie requests are no longer being offered by the site. There are no proxies in the way. My browser is not refusing cookies. (An examination of the HTML response header in Firebug confirms that a set-cookie request is not present.)

The code is this, and I have verified that it is running:

sub _build_session {
    my $self = shift;
    
    my $store;
    my $schema = $self->_session_schema;  # LAZY...
    $schema->storage->dbh_do (        
        sub {
            my ($storage, $dbh) = @_;
            
            $store   = MojoX::Session::Store::DBI->new( 
                dbh         => $dbh,
                table        => 'blah',
                sid_column    => 'sid',
                expires_column    => 'expires',
                data_column    => 'data',
                );
        }  
    );
    croak "SPE::Context: BUG, failed to make session"
        unless defined $store;
        
        instance($self->tx, 'Mojo::Transaction');   # Data::Util...

    # So far so good... create the transport and the session-object.
    
    my $transport = 
          MojoX::Session::Transport::Cookie->new ( tx => $self->tx );
    my $session = 
          MojoX::Session->new(
            store            => $store,
            transport        => $transport,
            ip_match        => 0,
            );

    $session->load();
    if ( defined($session->sid()) ) {
        if ($session->is_expired()) {
            $session->flush();
            $session->create();
print STDERR "MyMojo::Context: session expired(1) and was re-created\n
+";
        } else {
print STDERR "MyMojo::Context: resuming session '".$session->sid()."'\
+n";    
        };
    } else {
print STDERR "MyMojo::Context: new session created\n";
        $session->create();
    };

    if ($session->is_expired()) {
print STDERR "MyMojo::Context: session expired(2) and was re-created\n
+";
        $session->flush;
        $session->create;
    } else {
print STDERR "MyMojo::Context: session extended\n";
        $session->extend_expires;
    };
    
    return $session;
}
[download]

The observed symptoms are these:

• This is all code that used to work perfectly. I have no reason to think that the root cause of the problem is actually here. (But... that is why I am humbly asking the Monks.)
• The site's HTML headers no longer offer to set a cookie. (There are no proxies in the way.)
• A session-record is created in the database, but since there is no cookie, there is no SID and therefore the session is never used.
• The sequence of STDERR debugging-messages in the above code-path is always:   new session created then session extended.
• The instance() calls are from Data::Util and are used to assert that the variable is, in fact, a (non-undef) instance of a variable of, or descended from, the specified class. Since the code does not die, the assertion must be true.

I am, needless to say, quite baffled.