Lower default mappings parsing compatibility to MINIMUM_READONLY_COMPATIBLE (#119017)

Legacy indices check what minimum compatibility version the type parser supports,
for every field type found in the mappings. Only some of the basic fields are
supported, otherwise a placeholder mapper is created in place of the real field.

The minimum supported version is v5 for the supported field mappers. For all the
others, we can lower that from MINIMUM_COMPATIBLE to MINIMUM_READONLY_COMPATIBLE.

This commit also centralizes the creation of type parsers that declare support
for archive indices, as they all declare the same version.

Author: javanna

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

@@ -182,11 +182,8 @@ private FieldValues<Boolean> scriptValues() {
         }
     }
 
-    private static final IndexVersion MINIMUM_COMPATIBILITY_VERSION = IndexVersion.fromId(5000099);
-
-    public static final TypeParser PARSER = new TypeParser(
-        (n, c) -> new Builder(n, c.scriptCompiler(), IGNORE_MALFORMED_SETTING.get(c.getSettings()), c.indexVersionCreated()),
-        MINIMUM_COMPATIBILITY_VERSION
+    public static final TypeParser PARSER = createTypeParserWithLegacySupport(
+        (n, c) -> new Builder(n, c.scriptCompiler(), IGNORE_MALFORMED_SETTING.get(c.getSettings()), c.indexVersionCreated())
     );
 
     public static final class BooleanFieldType extends TermBasedFieldType {

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

@@ -398,9 +398,7 @@ public DateFieldMapper build(MapperBuilderContext context) {
         }
     }
 
-    private static final IndexVersion MINIMUM_COMPATIBILITY_VERSION = IndexVersion.fromId(5000099);
-
-    public static final TypeParser MILLIS_PARSER = new TypeParser((n, c) -> {
+    public static final TypeParser MILLIS_PARSER = createTypeParserWithLegacySupport((n, c) -> {
         boolean ignoreMalformedByDefault = IGNORE_MALFORMED_SETTING.get(c.getSettings());
         return new Builder(
             n,
@@ -410,9 +408,9 @@ public DateFieldMapper build(MapperBuilderContext context) {
             ignoreMalformedByDefault,
             c.indexVersionCreated()
         );
-    }, MINIMUM_COMPATIBILITY_VERSION);
+    });
 
-    public static final TypeParser NANOS_PARSER = new TypeParser((n, c) -> {
+    public static final TypeParser NANOS_PARSER = createTypeParserWithLegacySupport((n, c) -> {
         boolean ignoreMalformedByDefault = IGNORE_MALFORMED_SETTING.get(c.getSettings());
         return new Builder(
             n,
@@ -422,7 +420,7 @@ public DateFieldMapper build(MapperBuilderContext context) {
             ignoreMalformedByDefault,
             c.indexVersionCreated()
         );
-    }, MINIMUM_COMPATIBILITY_VERSION);
+    });
 
     public static final class DateFieldType extends MappedFieldType {
         final DateFormatter dateTimeFormatter;

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

@@ -1618,6 +1618,12 @@ public static BiConsumer<String, MappingParserContext> notFromDynamicTemplates(S
         };
     }
 
+    private static final IndexVersion MINIMUM_LEGACY_COMPATIBILITY_VERSION = IndexVersion.fromId(5000099);
+
+    public static TypeParser createTypeParserWithLegacySupport(BiFunction<String, MappingParserContext, Builder> builderFunction) {
+        return new TypeParser(builderFunction, MINIMUM_LEGACY_COMPATIBILITY_VERSION);
+    }
+
     /**
      * TypeParser implementation that automatically handles parsing
      */
@@ -1632,29 +1638,29 @@ public static final class TypeParser implements Mapper.TypeParser {
          * @param builderFunction a function that produces a Builder from a name and parsercontext
          */
         public TypeParser(BiFunction<String, MappingParserContext, Builder> builderFunction) {
-            this(builderFunction, (n, c) -> {}, IndexVersions.MINIMUM_COMPATIBLE);
+            this(builderFunction, (n, c) -> {}, IndexVersions.MINIMUM_READONLY_COMPATIBLE);
         }
 
         /**
-         * Variant of {@link #TypeParser(BiFunction)} that allows to defining a minimumCompatibilityVersion to
+         * Variant of {@link #TypeParser(BiFunction)} that allows to define a minimumCompatibilityVersion to
          * allow parsing mapping definitions of legacy indices (see {@link Mapper.TypeParser#supportsVersion(IndexVersion)}).
          */
-        public TypeParser(BiFunction<String, MappingParserContext, Builder> builderFunction, IndexVersion minimumCompatibilityVersion) {
+        private TypeParser(BiFunction<String, MappingParserContext, Builder> builderFunction, IndexVersion minimumCompatibilityVersion) {
             this(builderFunction, (n, c) -> {}, minimumCompatibilityVersion);
         }
 
         public TypeParser(
             BiFunction<String, MappingParserContext, Builder> builderFunction,
             BiConsumer<String, MappingParserContext> contextValidator
         ) {
-            this(builderFunction, contextValidator, IndexVersions.MINIMUM_COMPATIBLE);
+            this(builderFunction, contextValidator, IndexVersions.MINIMUM_READONLY_COMPATIBLE);
         }
 
         public TypeParser(
             BiFunction<String, MappingParserContext, Builder> builderFunction,
             List<BiConsumer<String, MappingParserContext>> contextValidator
         ) {
-            this(builderFunction, (n, c) -> contextValidator.forEach(v -> v.accept(n, c)), IndexVersions.MINIMUM_COMPATIBLE);
+            this(builderFunction, (n, c) -> contextValidator.forEach(v -> v.accept(n, c)), IndexVersions.MINIMUM_READONLY_COMPATIBLE);
         }
 
         private TypeParser(

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

@@ -228,17 +228,14 @@ public FieldMapper build(MapperBuilderContext context) {
 
     }
 
-    private static final IndexVersion MINIMUM_COMPATIBILITY_VERSION = IndexVersion.fromId(5000099);
-
-    public static TypeParser PARSER = new TypeParser(
+    public static TypeParser PARSER = createTypeParserWithLegacySupport(
         (n, c) -> new Builder(
             n,
             c.scriptCompiler(),
             IGNORE_MALFORMED_SETTING.get(c.getSettings()),
             c.indexVersionCreated(),
             c.getIndexSettings().getMode()
-        ),
-        MINIMUM_COMPATIBILITY_VERSION
+        )
     );
 
     private final Builder builder;

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

@@ -204,12 +204,10 @@ public IpFieldMapper build(MapperBuilderContext context) {
 
     }
 
-    private static final IndexVersion MINIMUM_COMPATIBILITY_VERSION = IndexVersion.fromId(5000099);
-
-    public static final TypeParser PARSER = new TypeParser((n, c) -> {
+    public static final TypeParser PARSER = createTypeParserWithLegacySupport((n, c) -> {
         boolean ignoreMalformedByDefault = IGNORE_MALFORMED_SETTING.get(c.getSettings());
         return new Builder(n, c.scriptCompiler(), ignoreMalformedByDefault, c.indexVersionCreated());
-    }, MINIMUM_COMPATIBILITY_VERSION);
+    });
 
     public static final class IpFieldType extends SimpleMappedFieldType {
 

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

@@ -385,9 +385,7 @@ public KeywordFieldMapper build(MapperBuilderContext context) {
         }
     }
 
-    private static final IndexVersion MINIMUM_COMPATIBILITY_VERSION = IndexVersion.fromId(5000099);
-
-    public static final TypeParser PARSER = new TypeParser(Builder::new, MINIMUM_COMPATIBILITY_VERSION);
+    public static final TypeParser PARSER = createTypeParserWithLegacySupport(Builder::new);
 
     public static final class KeywordFieldType extends StringFieldType {
 

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

@@ -131,7 +131,7 @@ public interface TypeParser {
          * Whether we can parse this type on indices with the given index created version.
          */
         default boolean supportsVersion(IndexVersion indexCreatedVersion) {
-            return indexCreatedVersion.onOrAfter(IndexVersions.MINIMUM_COMPATIBLE);
+            return indexCreatedVersion.onOrAfter(IndexVersions.MINIMUM_READONLY_COMPATIBLE);
         }
     }
 

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

@@ -57,9 +57,13 @@ public MapperRegistry(
      */
     public Mapper.TypeParser getMapperParser(String type, IndexVersion indexVersionCreated) {
         Mapper.TypeParser parser = mapperParsers.get(type);
-        if (indexVersionCreated.isLegacyIndexVersion() && (parser == null || parser.supportsVersion(indexVersionCreated) == false)) {
-            return PlaceHolderFieldMapper.PARSER.apply(type);
+        if (indexVersionCreated.isLegacyIndexVersion()) {
+            if (parser == null || parser.supportsVersion(indexVersionCreated) == false) {
+                return PlaceHolderFieldMapper.PARSER.apply(type);
+            }
+            return parser;
         } else {
+            assert parser == null || parser.supportsVersion(indexVersionCreated);
             return parser;
         }
     }

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

@@ -89,8 +89,6 @@ private static NumberFieldMapper toType(FieldMapper in) {
         return (NumberFieldMapper) in;
     }
 
-    private static final IndexVersion MINIMUM_COMPATIBILITY_VERSION = IndexVersion.fromId(5000099);
-
     public static final class Builder extends FieldMapper.DimensionBuilder {
 
         private final Parameter<Boolean> indexed;
@@ -1378,16 +1376,8 @@ private boolean isOutOfRange(Object value) {
         NumberType(String name, NumericType numericType) {
             this.name = name;
             this.numericType = numericType;
-            this.parser = new TypeParser(
-                (n, c) -> new Builder(
-                    n,
-                    this,
-                    c.scriptCompiler(),
-                    c.getSettings(),
-                    c.indexVersionCreated(),
-                    c.getIndexSettings().getMode()
-                ),
-                MINIMUM_COMPATIBILITY_VERSION
+            this.parser = createTypeParserWithLegacySupport(
+                (n, c) -> new Builder(n, this, c.scriptCompiler(), c.getSettings(), c.indexVersionCreated(), c.getIndexSettings().getMode())
             );
         }
 

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

@@ -480,11 +480,8 @@ public TextFieldMapper build(MapperBuilderContext context) {
         }
     }
 
-    private static final IndexVersion MINIMUM_COMPATIBILITY_VERSION = IndexVersion.fromId(5000099);
-
-    public static final TypeParser PARSER = new TypeParser(
-        (n, c) -> new Builder(n, c.indexVersionCreated(), c.getIndexAnalyzers(), SourceFieldMapper.isSynthetic(c.getIndexSettings())),
-        MINIMUM_COMPATIBILITY_VERSION
+    public static final TypeParser PARSER = createTypeParserWithLegacySupport(
+        (n, c) -> new Builder(n, c.indexVersionCreated(), c.getIndexAnalyzers(), SourceFieldMapper.isSynthetic(c.getIndexSettings()))
     );
 
     private static class PhraseWrappedAnalyzer extends AnalyzerWrapper {