Remove the _all metadata field (#26356)

* Remove the _all metadata field

This change removes the `_all` metadata field. This field is deprecated in 6
and cannot be activated for indices created in 6 so it can be safely removed in
the next major version (e.g. 7).

Author: jimczi

core/src/main/java/org/apache/lucene/search/uhighlight/CustomUnifiedHighlighter.java

@@ -35,7 +35,6 @@
 import org.apache.lucene.util.BytesRef;
 import org.apache.lucene.util.automaton.CharacterRunAutomaton;
 import org.elasticsearch.common.Nullable;
-import org.elasticsearch.common.lucene.all.AllTermQuery;
 import org.elasticsearch.common.lucene.search.MultiPhrasePrefixQuery;
 import org.elasticsearch.common.lucene.search.function.FunctionScoreQuery;
 import org.elasticsearch.index.search.ESToParentBlockJoinQuery;
@@ -206,9 +205,6 @@ private Collection<Query> rewriteCustomQuery(Query query) {
                 tqs.add(new TermQuery(term));
             }
             return tqs;
-        } else if (query instanceof AllTermQuery) {
-            AllTermQuery atq = (AllTermQuery) query;
-            return Collections.singletonList(new TermQuery(atq.getTerm()));
         } else if (query instanceof FunctionScoreQuery) {
             return Collections.singletonList(((FunctionScoreQuery) query).getSubQuery());
         } else if (query instanceof ESToParentBlockJoinQuery) {

core/src/main/java/org/elasticsearch/action/admin/indices/analyze/TransportAnalyzeAction.java

@@ -55,7 +55,6 @@
 import org.elasticsearch.index.analysis.NamedAnalyzer;
 import org.elasticsearch.index.analysis.TokenFilterFactory;
 import org.elasticsearch.index.analysis.TokenizerFactory;
-import org.elasticsearch.index.mapper.AllFieldMapper;
 import org.elasticsearch.index.mapper.KeywordFieldMapper;
 import org.elasticsearch.index.mapper.MappedFieldType;
 import org.elasticsearch.index.shard.ShardId;
@@ -151,13 +150,11 @@ protected AnalyzeResponse shardOperation(AnalyzeRequest request, ShardId shardId
             }
             if (field == null) {
                 /**
-                 * TODO: _all is disabled by default and index.query.default_field can define multiple fields or pattterns so we should
+                 * TODO: _all is disabled by default and index.query.default_field can define multiple fields or patterns so we should
                  * probably makes the field name mandatory in analyze query.
                  **/
                 if (indexService != null) {
                     field = indexService.getIndexSettings().getDefaultFields().get(0);
-                } else {
-                    field = AllFieldMapper.NAME;
                 }
             }
             final AnalysisRegistry analysisRegistry = indicesService.getAnalysis();