Finally I found the solution:
Looks like even if you build the suggestion dictionary from a file but not from an index field, you have to specify an index field in the solrconfig. Thus in the schema.xml
create a dummy field from the text_suggest
fieldtype which we had already created:
<field name="text_suggest" type="text_suggest" indexed="false" stored="false" />
Then in the solrconfig.xml
add <str name="field">text_suggest</str>
line to the searchComponent
:
<searchComponent class="solr.SpellCheckComponent" name="suggest">
<lst name="spellchecker">
<str name="name">suggest</str>
<str name="classname">org.apache.solr.spelling.suggest.Suggester</str>
<str name="lookupImpl">org.apache.solr.spelling.suggest.fst.AnalyzingInfixLookupFactory</str>
<str name="buildOnCommit">true</str>
<str name="suggestAnalyzerFieldType">text_suggest</str>
<str name="field">text_suggest</str>
<str name="sourceLocation">suggestionsFull.txt</str>
</lst>
</searchComponent>
Restart the solr and you're done!