Broken eval in _hdlr_field_link_group

[jayallen]

Using ConfigAssistant 2.3.13 under MT 4.37, I'm getting the following warnings when I try to republish an entire blog:

String found where operator expected at (eval 838) line 1, near "]""" at (eval 838) line 1.
    eval '$value = ""[]""
;' called at addons/ConfigAssistant.pack/lib/ConfigAssistant/Plugin.pm line 738
    ConfigAssistant::Plugin::_hdlr_field_link_group(MT::Component=HASH(0x7fb33499d870), MT::Template::Context=HASH(0x7fb3381b3d50), HASH(0x7fb334f1eba0), HASH(0x7fb3381c8830)) called at addons/ConfigAssistant.pack/lib/ConfigAssistant/Init.pm line 589
    ConfigAssistant::Init::runner("_hdlr_field_link_group", "ConfigAssistant::Plugin", MT::Template::Context=HASH(0x7fb3381b3d50), HASH(0x7fb334f1eba0), HASH(0x7fb3381c8830)) called at addons/ConfigAssistant.pack/lib/ConfigAssistant/Init.pm line 328
    ConfigAssistant::Init::__ANON__(MT::Template::Context=HASH(0x7fb3381b3d50), HASH(0x7fb334f1eba0), HASH(0x7fb3381c8830)) called at lib/MT/Builder.pm line 396
    MT::Builder::build(MT::Builder=HASH(0x7fb333a169c8), MT::Template::Context=HASH(0x7fb3381b3d50), MT::Template::Tokens=ARRAY(0x7fb3381d4d60), undef) called at lib/MT/Template.pm line 269
    MT::Template::build(MT::Template=HASH(0x7fb3339d4ea8), MT::Template::Context=HASH(0x7fb3381b3d50)) called at lib/MT/WeblogPublisher.pm line 1574
    MT::WeblogPublisher::rebuild_indexes(MT::WeblogPublisher=HASH(0x7fb33817a3c0), "BlogID", 1) called at lib/MT.pm line 1509
    MT::rebuild_indexes(MT::App::CMS=HASH(0x7fb333802140), "BlogID", 1) called at lib/MT/CMS/Blog.pm line 662
    MT::CMS::Blog::rebuild_pages(MT::App::CMS=HASH(0x7fb333802140)) called at lib/MT.pm line 2974
    MT::__ANON__(MT::App::CMS=HASH(0x7fb333802140)) called at lib/MT/App.pm line 2715
    eval {...} called at lib/MT/App.pm line 2582
    MT::App::run(MT::App::CMS=HASH(0x7fb333802140)) called at lib/MT/Bootstrap.pm line 135
    eval {...} called at lib/MT/Bootstrap.pm line 76
    MT::Bootstrap::import("MT::Bootstrap", "App", "MT::App::CMS") called at mt.cgi line 11
    main::BEGIN() called at (eval 838) line 1
    eval {...} called at (eval 838) line 1

Line 738 of ConfigAssistant::Plugin is marked below:

sub _hdlr_field_link_group {
    my $plugin = shift;
    my ( $ctx, $args, $cond ) = @_;
    my $field = $ctx->stash('field') or return _no_field($ctx);
    my $value = _get_field_value($ctx);
    $value = '"[]"' if ( !$value || $value eq '' );
    eval "\$value = \"$value\"";            #<------- line 738
    if ($@) { $value = '[]'; }
    my $list = JSON::from_json($value);

Unfortunately, I have no clue what that little piece of Perl gymnastics is intended to accomplish but certainly it should be done differently. Any ideas?

[rujudan]

danwolfgang, and jayallen, has anyone looked at the stash('field') method call? I read up on two good documentations herehttp://template-toolkit.org/docs/modules/Template/Stash/index.html
and herehttp://search.cpan.org/dist/Template-Toolkit/lib/Template/Stash.pm which are both about the stash::* module

[jayallen]

@rujudan I haven't seen this particular issue in a long time so there's a good chance that it was being caused by a bug in Movable Type or (more likely) elsewhere in ConfigAssistant and has been subsequently fixed. Are you experiencing it currently?

The $ctx object is not a Template::Toolkit object (MT doesn't use Template::Toolkit) but an MT::Template::Context object (documented here; latest code is here). In any case, the stash method is one of its most widely used and it's very, very simple so I highly doubt that's causing any problems.

Far more likely is the _get_field_value method and the crazy looking handling of a non-true(!?) or empty string value:

$value = '"[]"' if ( !$value || $value eq '' );
eval "\$value = \"$value\"";
if ($@) { $value = '[]'; }

That makes no sense to me why the original author chose to do that (which is why I posted this ticket asking if Dan had any clue). In any case, that piece of code above is definitely a piece of work that needs to be refactored out. And it would have been by now if either of us had seen this error in the time since I posted this but we haven't. If you have, let us know.

[danwolfgang]

I haven't seen this error before and we do use the link group field with at least one client, FWIW.