Error in services (Yahoo Transport chatrooms)

[sander]

can't read "attr(category)": no such element in array
can't read "attr(category)": no such element in array
    while executing
"set category $attr(category)"
    ("identity" arm line 14)
    invoked from within
"switch -- [wrapper::gettag $c] {
     identity {

  # Each <identity/> element MUST possess 'category' and
  # 'type' attributes. (category/type)
 ..."
    (procedure "parse_get_info" line 18)
    invoked from within
"parse_get_info $jlibname $from $queryE"
    ("info" arm line 2)
    invoked from within
"switch -- $ditype {
     items {
  parse_get_items $jlibname $from $queryE
     }
     info {
  parse_get_info $jlibname $from $queryE
     }
 }"
    (procedure "::jlib::disco::send_get_cb" line 22)
    invoked from within
"::jlib::disco::send_get_cb info chat.yahoo.jaim.at {::Disco::InfoCB {}} ::jlib::jlib1 result {query {node 1600000002 xmlns http://jabber.org/protocol/..."
    ("uplevel" body line 1)
    invoked from within
"uplevel #0 $cmd [list $jlibname $type $subiq]"
    (procedure "::jlib::invoke_iq_callback" line 5)
    invoked from within
"::jlib::invoke_iq_callback ::jlib::jlib1 {::jlib::disco::send_get_cb info chat.yahoo.jaim.at {::Disco::InfoCB {}}} result {query {node 1600000002 xmln..."
    ("uplevel" body line 1)
    invoked from within
"uplevel #0 $iqcmd($id) [list result $subiq]"
    ("result" arm line 11)
    invoked from within
"switch -- $type {
 result {

     # Protect us from our own 'set' calls when we are awaiting
     # 'result' or 'error'.
     set setus 0
     i..."
    (procedure "iq_handler" line 56)
    invoked from within
"iq_handler $jlibname $xmldata"
    ("iq" arm line 2)
    invoked from within
"switch -- $tag {
 iq {
     iq_handler $jlibname $xmldata
 }
 message {
     message_handler $jlibname $xmldata
 }
 presence {
     presence_hand..."
    (procedure "::jlib::dispatcher" line 7)
    invoked from within
"::jlib::dispatcher ::jlib::jlib1 {iq {from chat.yahoo.jaim.at id 1044 type result to [e-mail]/Coccinella@computer-van-sander-devrieze}..."
    ("uplevel" body line 1)
    invoked from within
"uplevel #0 $wrapper($id,parsecmd) [list $wrapper($id,tree,2)]"
    (procedure "::wrapper::elementend" line 40)
    invoked from within
"::wrapper::elementend wrap1 iq -namespace http://jabber.org/protocol/disco#info"
    ("uplevel" body line 1)
    invoked from within
"uplevel #0 $options(-elementendcommand) [list $tag] $empty $ns"
    invoked from within
"ParseEvent:ElementClose $tag [array get options]"
    invoked from within
"::sgml::parseEvent {{} {} {} {} iq {} { from='chat.yahoo.jaim.at' to='[e-mail]/Coccinella@computer-van-sander-devrieze' id='1044' type..."
    ("eval" body line 1)
    invoked from within
"eval ::sgml::parseEvent [list $tokenised] $parseOptions"
    (procedure "parse" line 60)
    invoked from within
"parse xmlparser12 {<iq from='chat.yahoo.jaim.at' to='[e-mail]/Coccinella@computer-van-sander-devrieze' id='1044' type='result'><query ..."
    (in namespace inscope "::xml::tclparser" script line 1)
    invoked from within
"::namespace inscope ::xml::tclparser parse xmlparser12 {<iq from='chat.yahoo.jaim.at' to='[e-mail]/Coccinella@computer-van-sander-devr..."
    ("eval" body line 1)
    invoked from within
"eval $classinfo(-parsecommand) [list $name] $args"
    ("parse" arm line 5)
    invoked from within
"switch -- $method {

 configure {
     # BUG: We're not checking for legal options
     array set data $args
     eval $classinfo(-configurecommand) [..."
    (procedure "::xml::ParserCmd" line 7)
    invoked from within
"::xml::ParserCmd xmlparser12 parse {<iq from='chat.yahoo.jaim.at' to='[e-mail]/Coccinella@computer-van-sander-devrieze' id='1044' type..."
    ("eval" body line 1)
    invoked from within
"eval ::xml::ParserCmd xmlparser12 [list $method] $args"
    (procedure "xmlparser12" line 1)
    invoked from within
"$p parse $xml"
    (procedure "parsereentrant" line 10)
    invoked from within
"parsereentrant $id $xml"
    (procedure "wrapper::parse" line 6)
    invoked from within
"wrapper::parse $lib(wrap) $data"
    (procedure "::jlib::recvsocket" line 24)
    invoked from within
"::jlib::recvsocket ::jlib::jlib1"

[Mats (matsben)]

Apparently a component which doesn't follow the rules since from XEP-0030: "Each <identity/> element MUST possess 'category' and 'type' attributes specifying the category and type for the entity, ..."
In any case I need to protect for this:

  # Protect for entities which don't follow the rules.
  if {![info exists attr(category)] || ![info exists attr(type)]} {
      continue
  }