Details
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Improvement
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Status: Open
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Minor
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Resolution: Unresolved
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None
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None
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Description
I noticed a WARN error in my Solr logs after enabling the .system collection:
WARN - 2017-12-14 15:29:55.025; [ ] org.apache.solr.core.Config; You should not use LATEST as luceneMatchVersion property: if you use this setting, and then Solr upgrades to a newer release of Lucene, sizable changes may happen. If precise back compatibility is important then you should instead explicitly specify an actual Lucene version.
I traced this back to the default solrconfig.xml for the .system collection, which comes from solr/core/src/resources/SystemCollectionSolrConfig.xml and sets the luceneMatchVersion to "LATEST" at line 3.
I can't think of a specific case where this has caused a problem, but if we're warning for it we know it's at least theoretically possible that it could cause a problem in the future. Plus it's a poor user experience to do something by default that causes WARN errors that could cause confusion that something is mis-configured.
The addVersion.py script could be modified to include updating this file when it's run as part of the release process. Then users wouldn't see this warning and we would avoid unintentional trouble in the future.