[SOLR-4304] Coupling between SpellCheckComponent(s) and QueryConverter(s) is a mess and makes no sense

• Type: Bug
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Affects Version/s: 4.0
• Component/s: spellchecker
• Assignee: Unassigned
• Reporter: Jack Krupansky
• Created: 14/Jan/13 18:07
• Updated: 19/Aug/13 20:17

Description

The initial report here (from jkrupan) was that if you configured multiple <queryConvertor> instances you would get an NPE because the SpellCheckComponent's inform() method assumes there will be at most 1.

Looking into this more deeply, it's actually just a surface symptom of a much more significant problem...

• QueryConverters can be configured as "first order" type plugins in solrconfig.xml using the <queryConverter> syntax, with the ability to have multiple instances each with their own names
• QueryConvertors don't seem to actually be instantiated/initialized unless there is a SpellCheckComponent – but if there are more then one SpellCheckComponent instances, then the QueryConverters will all be initialzed again and again.
• SpellCheckComponent expects there to be 0 or 1 QueryConvertors, throwing an NPE if multiple QueryConvertors are configured – there is no spellcheck request param to request a QueryConvertor by name.
• even if we tried to add a request param to pick a QueryConvertor by name – the SpellCheckComponent has a "queryAnalyzerFieldType" init param that is used to get an Analyzer which is passed to QueryConverter.setAnalyzer() on init – making it impossible to use multiple QueryConverter's with a single SpellCheckComponent, or a single (custom) QueryConvertor with multiple SpellCheckComponents with differnet queryAnalyzerFieldType init params
  • NOTE: if 0 QueryConverters are configured then each SpellCheckComponent creates it's own private instance of "SpellingQueryConverter" – so there is no serious problem in this (default) situation with the SpellCheckComponent's being configured to use different queryAnalyzerFieldTypes

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Initial steps reported to reproduce the NPE...

1. Add to 4.0 example solrconfig.xml:

<queryConverter name="myQueryConverter-1" class="solr.SpellingQueryConverter"/>
<queryConverter name="myQueryConverter-2" class="solr.SuggestQueryConverter"/>

2. Perform a spellcheck request:

curl "http://localhost:8983/solr/spell?q=test&indent=true"

Issue Links

• is related to: SOLR-5108 plugin loading should fail if mor then one instance of a singleton plugin is found