[ https://issues.apache.org/jira/browse/SOLR-5526?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Hoss Man updated SOLR-5526: --------------------------- Attachment: SOLR-5526.patch fixed a javadoc mistake caught by "ant precommit" Going to commit & backport now > Query parser extends standard cause NPE on Solr startup > ------------------------------------------------------- > > Key: SOLR-5526 > URL: https://issues.apache.org/jira/browse/SOLR-5526 > Project: Solr > Issue Type: Bug > Components: query parsers > Affects Versions: 4.5.1, 4.6, 5.0 > Environment: Linux, Java 1.7.0_45 > Reporter: Nikolay Khitrin > Priority: Blocker > Attachments: NPE_load_trace, SOLR-5526-final-names.patch, > SOLR-5526-final-names.patch, SOLR-5526-tests.patch, SOLR-5526.patch, > SOLR-5526.patch, SOLR-5526.patch, SOLR-5526.patch, SOLR-5526.patch > > > Adding any custom query parser extending standard one with non-final field > {{NAME}} lead to messy {{NullPointerException}} during Solr startup. > Definition of standard parsers is located in > {{QParserPlugin.standardPlugins}} static array. The array contains names from > static {{NAME}} fields and classes for each plugin. > But all of listed parsers are derived from {{QParserPlugin}}, so we have > circular dependency of static fields. > Normally, class loader start initializing {{QParserPlugin}} before all listed > plugins in {{SolrCore.initQParsers}}, and array elements referenced to > {{NAME}} plugins' fields are filled properly. > Custom parsers are instantiated before standard parsers. And when we subclass > plugin with non-final {{NAME}} field and add it to Solr via > {{solrconfig.xml}}, class loader start loading our class before > {{QParserPlugin}}. Because {{QParserPlugin}} is a superclass for plugin, it > must be initialized before subclasses, and static dereferencing cause null > elements in {{standardPlugins}} array because it filled before {{NAME}} field > of loading plugin's superclass. > How to reproduce: > # Checkout Solr (trunk or stable) > # Add the following line to solr/example/solr/collection1/conf/solrconfig.xml > {{<queryParser name="fail" class="solr.search.LuceneQParserPlugin"/>}} > # Call ant run-example in solr folder > Possible workarounds: > * dev-workaround: add {{int workaround = > QParserPlugin.standardPlugins.length;}} as a first line to > {{SolrCore.initQParsers}} > * user-workaround: add plugin with final {{NAME}} field (edismax) to > solrconfig.xml before subclasses of standard plugins. > {{<queryParser name="workaround" > class="solr.search.ExtendedDismaxQParserPlugin"/>}} > > Possible fix: > Move {{standardPlugins}} to new final class to break circular dependency. -- This message was sent by Atlassian JIRA (v6.1.5#6160) --------------------------------------------------------------------- To unsubscribe, e-mail: dev-unsubscr...@lucene.apache.org For additional commands, e-mail: dev-h...@lucene.apache.org