Ensure that index_prefixes settings cannot be changed (#30967)

Author: romseygeek

server/src/main/java/org/elasticsearch/index/mapper/TextFieldMapper.java

@@ -289,22 +289,6 @@ public String toString() {
             return super.toString() + ",prefixChars=" + minChars + ":" + maxChars;
         }
 
-        @Override
-        public void checkCompatibility(MappedFieldType other, List<String> conflicts, boolean strict) {
-            super.checkCompatibility(other, conflicts, strict);
-            if (strict) {
-                PrefixFieldType otherFieldType = (PrefixFieldType) other;
-                if (otherFieldType.minChars != this.minChars) {
-                    conflicts.add("mapper [" + name() + "] is used by multiple types. Set update_all_types to true to update "
-                        + "[index_prefixes.min_chars] across all types.");
-                }
-                if (otherFieldType.maxChars != this.maxChars) {
-                    conflicts.add("mapper [" + name() + "] is used by multiple types. Set update_all_types to true to update "
-                        + "[index_prefixes.max_chars] across all types.");
-                }
-            }
-        }
-
         @Override
         public Query existsQuery(QueryShardContext context) {
             throw new UnsupportedOperationException();
@@ -408,6 +392,19 @@ public void checkCompatibility(MappedFieldType other,
                 List<String> conflicts, boolean strict) {
             super.checkCompatibility(other, conflicts, strict);
             TextFieldType otherType = (TextFieldType) other;
+            if (Objects.equals(this.prefixFieldType, otherType.prefixFieldType) == false) {
+                if (this.prefixFieldType == null) {
+                    conflicts.add("mapper [" + name()
+                        + "] has different [index_prefixes] settings, cannot change from disabled to enabled");
+                }
+                else if (otherType.prefixFieldType == null) {
+                    conflicts.add("mapper [" + name()
+                        + "] has different [index_prefixes] settings, cannot change from enabled to disabled");
+                }
+                else {
+                    conflicts.add("mapper [" + name() + "] has different [index_prefixes] settings");
+                }
+            }
             if (strict) {
                 if (fielddata() != otherType.fielddata()) {
                     conflicts.add("mapper [" + name() + "] is used by multiple types. Set update_all_types to true to update [fielddata] "
@@ -425,10 +422,6 @@ public void checkCompatibility(MappedFieldType other,
                     conflicts.add("mapper [" + name() + "] is used by multiple types. Set update_all_types to true to update "
                             + "[fielddata_frequency_filter.min_segment_size] across all types.");
                 }
-                if (Objects.equals(this.prefixFieldType, ((TextFieldType) other).prefixFieldType) == false) {
-                    conflicts.add("mapper [" + name() + "] is used by multiple types. Set update_all_types to true to update "
-                        + "[index_prefixes] across all types.");
-                }
             }
         }
 
@@ -521,6 +514,7 @@ public IndexFieldData.Builder fielddataBuilder(String fullyQualifiedIndexName) {
             }
             return new PagedBytesIndexFieldData.Builder(fielddataMinFrequency, fielddataMaxFrequency, fielddataMinSegmentSize);
         }
+
     }
 
     private Boolean includeInAll;

server/src/test/java/org/elasticsearch/index/mapper/TextFieldTypeTests.java

@@ -18,23 +18,20 @@
  */
 package org.elasticsearch.index.mapper;
 
-import java.util.ArrayList;
-import java.util.Arrays;
-import java.util.List;
-
-import org.apache.lucene.document.LongPoint;
 import org.apache.lucene.index.IndexOptions;
 import org.apache.lucene.index.Term;
-import org.apache.lucene.search.TermInSetQuery;
 import org.apache.lucene.search.FuzzyQuery;
 import org.apache.lucene.search.RegexpQuery;
+import org.apache.lucene.search.TermInSetQuery;
 import org.apache.lucene.search.TermQuery;
 import org.apache.lucene.util.BytesRef;
 import org.elasticsearch.common.unit.Fuzziness;
-import org.elasticsearch.index.mapper.MappedFieldType;
-import org.elasticsearch.index.mapper.TextFieldMapper;
 import org.junit.Before;
 
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+
 public class TextFieldTypeTests extends FieldTypeTestCase {
     @Override
     protected MappedFieldType createDefaultFieldType() {
@@ -71,7 +68,7 @@ public void modify(MappedFieldType ft) {
                 tft.setFielddataMinSegmentSize(1000);
             }
         });
-        addModifier(new Modifier("index_prefixes", true) {
+        addModifier(new Modifier("index_prefixes", false) {
             @Override
             public void modify(MappedFieldType ft) {
                 TextFieldMapper.TextFieldType tft = (TextFieldMapper.TextFieldType)ft;