singleton can't be dumped

[newbray]

I am getting the following issue:

Started GET "/" for 127.0.0.1 at 2011-04-12 15:38:32 +0100
Processing by ApplicationController#index as HTML
Guessed service url: "http://localhost:3002/"
Generated login url: http://localhost:3000/login?service=http%3A%2F%2Flocalhost%3A3002%2F
Redirecting to "http://localhost:3000/login?service=http%3A%2F%2Flocalhost%3A3002%2F"
Redirected to http://localhost:3000/login?service=http%3A%2F%2Flocalhost%3A3002%2F
Completed 302 Found in 1ms

Started GET "/?ticket=ST-1302619113r5FBE2774BCA3684F53" for 127.0.0.1 at 2011-04-12 15:38:33 +0100
Processing by ApplicationController#index as HTML
Parameters: {"ticket"=>"ST-1302619113r5FBE2774BCA3684F53"}
Request contains ticket "ST-1302619113r5FBE2774BCA3684F53".
Guessed service url: "http://localhost:3002/"
Requesting CAS response for URI http://localhost:3000/proxyValidate?service=http%3A%2F%2Flocalhost%3A3002%2F&ticket=ST-1302619113r5FBE2774BCA3684F53
CAS server responded with #<Net::HTTPOK 200 OK readbody=true>:

<cas:serviceResponse xmlns:cas="http://www.yale.edu/tp/cas">
cas:authenticationSuccess
cas:usersomeone@newbray.co.uk/cas:user
cas:firstnamedsfgg/cas:firstname
cas:surnamedsf/cas:surname
/cas:authenticationSuccess
/cas:serviceResponse
Ticket "ST-1302619113r5FBE2774BCA3684F53" for service "http://localhost:3002/" belonging to user "someone@newbray.co.uk" is VALID.
Extra user attributes provided along with ticket "ST-1302619113r5FBE2774BCA3684F53": {}.
Rendered application/index.html.erb within layouts/application (1.5ms)
Completed 200 OK in 121ms (Views: 4.3ms | ActiveRecord: 0.0ms)

TypeError (singleton can't be dumped):

Rendered /Users/newbray/.rvm/gems/ruby-1.9.2-p136/gems/actionpack-3.0.6/lib/action_dispatch/middleware/templates/rescues/_trace.erb (0.8ms)
Rendered /Users/newbray/.rvm/gems/ruby-1.9.2-p136/gems/actionpack-3.0.6/lib/action_dispatch/middleware/templates/rescues/_request_and_response.erb (3.9ms)
Rendered /Users/newbray/.rvm/gems/ruby-1.9.2-p136/gems/actionpack-3.0.6/lib/action_dispatch/middleware/templates/rescues/diagnostics.erb within rescues/layout (9.0ms)

Any ideas? i'm at a loss as to how to solve this.

Thanks

[craigmonson]

I get this problem as well. I believe this is happening because there's a singleton in the sessions hash, and it's trying to get marshalled. The offending key is ':cas_last_valid_ticket' If I do: sessions[:cas_last_valid_ticket] = nil, that error is cleared (but I do not know other side affects.)

[AnuragMishra]

Having the same issue. Digging deeper into the object that can't be dumped, it seems it is cas_last_valid_ticket.response.xml. All other objects are getting dumped using Mashal.dump(..). The xml attribute is of type REXML::Element. The actual singleton could be either this object, or one of its child attributes.

[AnuragMishra]

It seems to be related to this issue when trying to dump REXML::Document.

[newbray]

Here's a 'patch' that solved it for me
file: lib/casclient/responses.rb

def check_and_parse_xml(raw_xml)
# Horrible patch to stop the REXML parser triggering a 'singleton could not be dumped'
# error when source document starts with a declaration.
raw_xml.sub!(/<?xml[^\?]?>\s/, '')
... rest of method