[Rest Api Compatibility] Ignore use_field_mapping option for docvalue (#74435)

previously removed in #55622 use_field_mapping option can be used on doc
value format under rest api compatibility.
The value itself is ignored (replaced with null) as it is a default
behaviour to use field mapping format.

relates #51816

Author: pgomulka

rest-api-spec/build.gradle

@@ -104,7 +104,6 @@ tasks.named("yamlRestCompatTest").configure {
     'mtermvectors/11_basic_with_types/Basic tests for multi termvector get',
     'mtermvectors/21_deprecated_with_types/Deprecated camel case and _ parameters should fail in Term Vectors query',
     'mtermvectors/30_mix_typeless_typeful/mtermvectors without types on an index that has types',
-    'search/10_source_filtering/docvalue_fields with default format', //use_field_mapping change
     'search/150_rewrite_on_coordinator/Ensure that we fetch the document only once', //terms_lookup
     'search/171_terms_query_with_types/Terms Query with No.of terms exceeding index.max_terms_count should FAIL', //bulk
     'search/260_parameter_validation/test size=-1 is deprecated', //size=-1 change

server/src/main/java/org/elasticsearch/search/fetch/subphase/FieldAndFormat.java

@@ -9,25 +9,35 @@
 package org.elasticsearch.search.fetch.subphase;
 
 import org.elasticsearch.Version;
-import org.elasticsearch.core.Nullable;
-import org.elasticsearch.common.xcontent.ParseField;
 import org.elasticsearch.common.io.stream.StreamInput;
 import org.elasticsearch.common.io.stream.StreamOutput;
 import org.elasticsearch.common.io.stream.Writeable;
+import org.elasticsearch.common.logging.DeprecationLogger;
 import org.elasticsearch.common.xcontent.ConstructingObjectParser;
+import org.elasticsearch.common.xcontent.ObjectParser;
+import org.elasticsearch.common.xcontent.ParseField;
 import org.elasticsearch.common.xcontent.ToXContentObject;
 import org.elasticsearch.common.xcontent.XContent;
 import org.elasticsearch.common.xcontent.XContentBuilder;
 import org.elasticsearch.common.xcontent.XContentParser;
+import org.elasticsearch.core.CheckedFunction;
+import org.elasticsearch.core.Nullable;
+import org.elasticsearch.core.RestApiVersion;
 
 import java.io.IOException;
 import java.util.Objects;
 
+import static org.elasticsearch.core.RestApiVersion.equalTo;
+import static org.elasticsearch.core.RestApiVersion.onOrAfter;
+
 /**
  * Wrapper around a field name and the format that should be used to
  * display values of this field.
  */
 public final class FieldAndFormat implements Writeable, ToXContentObject {
+    private static final String USE_DEFAULT_FORMAT = "use_field_mapping";
+    private static final DeprecationLogger DEPRECATION_LOGGER =  DeprecationLogger.getLogger(FetchDocValuesPhase.class);
+
     private static final ParseField FIELD_FIELD = new ParseField("field");
     private static final ParseField FORMAT_FIELD = new ParseField("format");
     private static final ParseField INCLUDE_UNMAPPED_FIELD = new ParseField("include_unmapped");
@@ -38,10 +48,33 @@ public final class FieldAndFormat implements Writeable, ToXContentObject {
 
     static {
         PARSER.declareString(ConstructingObjectParser.constructorArg(), FIELD_FIELD);
-        PARSER.declareStringOrNull(ConstructingObjectParser.optionalConstructorArg(), FORMAT_FIELD);
+        PARSER.declareStringOrNull(ConstructingObjectParser.optionalConstructorArg(),
+            FORMAT_FIELD.forRestApiVersion(onOrAfter(RestApiVersion.V_8)));
+        PARSER.declareField(ConstructingObjectParser.optionalConstructorArg(),
+            ignoreUseFieldMappingStringParser(),
+            FORMAT_FIELD.forRestApiVersion(equalTo(RestApiVersion.V_7)),
+            ObjectParser.ValueType.STRING_OR_NULL);
         PARSER.declareBoolean(ConstructingObjectParser.optionalConstructorArg(), INCLUDE_UNMAPPED_FIELD);
     }
 
+    private static CheckedFunction<XContentParser, String, IOException> ignoreUseFieldMappingStringParser() {
+        return (p) -> {
+            if (p.currentToken() == XContentParser.Token.VALUE_NULL) {
+                return null;
+            } else {
+                String text = p.text();
+                if (text.equals(USE_DEFAULT_FORMAT)) {
+                    DEPRECATION_LOGGER.compatibleApiWarning("explicit_default_format",
+                        "[" + USE_DEFAULT_FORMAT + "] is a special format that was only used to " +
+                            "ease the transition to 7.x. It has become the default and shouldn't be set explicitly anymore.");
+                    return null;
+                } else {
+                    return text;
+                }
+            }
+        };
+    }
+
     /**
      * Parse a {@link FieldAndFormat} from some {@link XContent}.
      */