Invalid reference for suggester

[gnandre <ar...@gmail.com>]

I am using solr 8.5.2. I am trying to configure multiple suggester
definition in Solr search component and got error information like:

{
  "responseHeader":{
    "status":500,
    "QTime":1718343},
  "error":{
    "msg":"Invalid reference 'link_score'",
    "trace":"java.lang.IllegalArgumentException: Invalid reference
'link_score'\n\tat
org.apache.lucene.expressions.SimpleBindings.getDoubleValuesSource(SimpleBindings.java:80)\n\tat
org.apache.lucene.expressions.ExpressionValueSource.<init>(ExpressionValueSource.java:46)\n\tat
org.apache.lucene.expressions.Expression.getDoubleValuesSource(Expression.java:97)\n\tat
org.apache.solr.spelling.suggest.DocumentExpressionDictionaryFactory.fromExpression(DocumentExpressionDictionaryFactory.java:94)\n\tat
org.apache.solr.spelling.suggest.DocumentExpressionDictionaryFactory.create(DocumentExpressionDictionaryFactory.java:79)\n\tat
org.apache.solr.spelling.suggest.SolrSuggester.build(SolrSuggester.java:179)\n\tat
org.apache.solr.handler.component.SuggestComponent.prepare(SuggestComponent.java:184)\n\tat
org.apache.solr.handler.component.SearchHandler.handleRequestBody(SearchHandler.java:302)\n\tat
org.apache.solr.handler.RequestHandlerBase.handleRequest(RequestHandlerBase.java:211)\n\tat
org.apache.solr.core.SolrCore.execute(SolrCore.java:2596)\n\tat
org.apache.solr.servlet.HttpSolrCall.execute(HttpSolrCall.java:802)\n\tat
org.apache.solr.servlet.HttpSolrCall.call(HttpSolrCall.java:579)\n\tat
org.apache.solr.servlet.SolrDispatchFilter.doFilter(SolrDispatchFilter.java:420)\n\tat
org.apache.solr.servlet.SolrDispatchFilter.doFilter(SolrDispatchFilter.java:352)\n\tat
org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1596)\n\tat
org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:545)\n\tat
org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:143)\n\tat
org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:590)\n\tat
org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:127)\n\tat
org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:235)\n\tat
org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:1607)\n\tat
org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:233)\n\tat
org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1297)\n\tat
org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:188)\n\tat
org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:485)\n\tat
org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:1577)\n\tat
org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:186)\n\tat
org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1212)\n\tat
org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:141)\n\tat
org.eclipse.jetty.server.handler.ContextHandlerCollection.handle(ContextHandlerCollection.java:221)\n\tat
org.eclipse.jetty.server.handler.InetAccessHandler.handle(InetAccessHandler.java:177)\n\tat
org.eclipse.jetty.server.handler.HandlerCollection.handle(HandlerCollection.java:146)\n\tat
org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:127)\n\tat
org.eclipse.jetty.rewrite.handler.RewriteHandler.handle(RewriteHandler.java:322)\n\tat
org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:127)\n\tat
org.eclipse.jetty.server.Server.handle(Server.java:500)\n\tat
org.eclipse.jetty.server.HttpChannel.lambda$handle$1(HttpChannel.java:383)\n\tat
org.eclipse.jetty.server.HttpChannel.dispatch(HttpChannel.java:547)\n\tat
org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:375)\n\tat
org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:270)\n\tat
org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded(AbstractConnection.java:311)\n\tat
org.eclipse.jetty.io.FillInterest.fillable(FillInterest.java:103)\n\tat
org.eclipse.jetty.io.ChannelEndPoint$2.run(ChannelEndPoint.java:117)\n\tat
org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.runTask(EatWhatYouKill.java:336)\n\tat
org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.doProduce(EatWhatYouKill.java:313)\n\tat
org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.tryProduce(EatWhatYouKill.java:171)\n\tat
org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.run(EatWhatYouKill.java:129)\n\tat
org.eclipse.jetty.util.thread.ReservedThreadExecutor$ReservedThread.run(ReservedThreadExecutor.java:388)\n\tat
org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:806)\n\tat
org.eclipse.jetty.util.thread.QueuedThreadPool$Runner.run(QueuedThreadPool.java:938)\n\tat
java.lang.Thread.run(Thread.java:748)\n",
    "code":500}}

Field link_score exists in the schema file and Solr is restarted.

<field name="link_score" type="float" stored="true" indexed="true" default="
0.00000001"/>

Here is the definition of suggester in solrconfig.xml file

  <lst name="suggester">
    <str name="name">answerSuggesterLinkPopularity_en</str>
    <str name="dictionaryImpl">DocumentExpressionDictionaryFactory</str>
    <str name="lookupImpl">FuzzyLookupFactory</str>
    <str name="field">answer_suggestions_en</str>
    <str name="weightExpression">ln(link_score)</str>
    <str name="storeDir">answer_suggester_link_popularity_en_dir</str>
    <str name="suggestAnalyzerFieldType">suggestion_text_en</str>
    <str name="buildOnCommit">false</str>
    <str name="buildOnStartup">false</str>
  </lst>