Avoid using external values in parent-join and percolator mappers (#71834)

We would like to remove the use of 'external values' in document parsing.
This commit simplifies two of the four places it is currently used, by adding
direct indexValue methods to BinaryFieldMapper and ParentIdFieldMapper.

Relates to #56063

Author: romseygeek

modules/parent-join/src/main/java/org/elasticsearch/join/mapper/ParentIdFieldMapper.java

@@ -92,10 +92,10 @@ protected ParentIdFieldMapper(String name, boolean eagerGlobalOrdinals) {
 
     @Override
     protected void parseCreateField(ParseContext context) {
-        if (context.externalValueSet() == false) {
-            throw new IllegalStateException("external value not set");
-        }
-        String refId = (String) context.externalValue();
+        throw new UnsupportedOperationException("Cannot directly call parse() on a ParentIdFieldMapper");
+    }
+
+    public void indexValue(ParseContext context, String refId) {
         BytesRef binaryValue = new BytesRef(refId);
         Field field = new Field(fieldType().name(), binaryValue, Defaults.FIELD_TYPE);
         context.doc().add(field);

modules/parent-join/src/main/java/org/elasticsearch/join/mapper/ParentJoinFieldMapper.java

@@ -254,15 +254,13 @@ public void parse(ParseContext context) throws IOException {
             if (context.sourceToParse().routing() == null) {
                 throw new IllegalArgumentException("[routing] is missing for join field [" + name() + "]");
             }
-            ParseContext externalContext = context.createExternalValueContext(parent);
             String fieldName = fieldType().joiner.parentJoinField(name);
-            parentIdFields.get(fieldName).parse(externalContext);
+            parentIdFields.get(fieldName).indexValue(context, parent);
         }
         if (fieldType().joiner.parentTypeExists(name)) {
             // Index the document as a parent
-            ParseContext externalContext = context.createExternalValueContext(context.sourceToParse().id());
             String fieldName = fieldType().joiner.childJoinField(name);
-            parentIdFields.get(fieldName).parse(externalContext);
+            parentIdFields.get(fieldName).indexValue(context, context.sourceToParse().id());
         }
 
         BytesRef binaryValue = new BytesRef(name);

modules/percolator/src/main/java/org/elasticsearch/percolator/PercolatorFieldMapper.java

@@ -376,8 +376,7 @@ static void createQueryBuilderField(Version indexVersion, BinaryFieldMapper qbFi
                 try (OutputStreamStreamOutput out  = new OutputStreamStreamOutput(stream)) {
                     out.setVersion(indexVersion);
                     out.writeNamedWriteable(queryBuilder);
-                    byte[] queryBuilderAsBytes = stream.toByteArray();
-                    qbField.parse(context.createExternalValueContext(queryBuilderAsBytes));
+                    qbField.indexValue(context, stream.toByteArray());
                 }
             }
         } else {

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

@@ -150,6 +150,10 @@ protected void parseCreateField(ParseContext context) throws IOException {
                 value = context.parser().binaryValue();
             }
         }
+        indexValue(context, value);
+    }
+
+    public void indexValue(ParseContext context, byte[] value) {
         if (value == null) {
             return;
         }