From 05aa06f88bc2741ee886a9e67fd744e976170812 Mon Sep 17 00:00:00 2001
From: carlosdelest <carlos.delgado@elastic.co>
Date: Thu, 21 Mar 2024 13:54:50 +0100
Subject: [PATCH] Add getMapper(field) to Mapper, so both field with
 multifields and object mappers can provide underlying field mappers

---
 .../elasticsearch/index/mapper/FieldAliasMapper.java  |  5 +++++
 .../org/elasticsearch/index/mapper/FieldMapper.java   | 11 +++++++++++
 .../java/org/elasticsearch/index/mapper/Mapper.java   |  8 ++++++++
 3 files changed, 24 insertions(+)

diff --git a/server/src/main/java/org/elasticsearch/index/mapper/FieldAliasMapper.java b/server/src/main/java/org/elasticsearch/index/mapper/FieldAliasMapper.java
index 8aa29e6317d51..2cbdb79c4ce45 100644
--- a/server/src/main/java/org/elasticsearch/index/mapper/FieldAliasMapper.java
+++ b/server/src/main/java/org/elasticsearch/index/mapper/FieldAliasMapper.java
@@ -69,6 +69,11 @@ public Iterator<Mapper> iterator() {
         return Collections.emptyIterator();
     }
 
+    @Override
+    public Mapper getMapper(String field) {
+        return null;
+    }
+
     @Override
     public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
         return builder.startObject(simpleName()).field("type", CONTENT_TYPE).field(Names.PATH, path).endObject();
diff --git a/server/src/main/java/org/elasticsearch/index/mapper/FieldMapper.java b/server/src/main/java/org/elasticsearch/index/mapper/FieldMapper.java
index 71fd9edd49903..53985393aa42f 100644
--- a/server/src/main/java/org/elasticsearch/index/mapper/FieldMapper.java
+++ b/server/src/main/java/org/elasticsearch/index/mapper/FieldMapper.java
@@ -306,6 +306,17 @@ public Iterator<Mapper> iterator() {
         return multiFieldsIterator();
     }
 
+    @Override
+    public Mapper getMapper(String field) {
+        while (iterator().hasNext()) {
+            Mapper mapper = iterator().next();
+            if (mapper.simpleName().equals(field)) {
+               return mapper;
+            }
+        }
+        return null;
+    }
+
     protected Iterator<Mapper> multiFieldsIterator() {
         return Iterators.forArray(multiFields.mappers);
     }
diff --git a/server/src/main/java/org/elasticsearch/index/mapper/Mapper.java b/server/src/main/java/org/elasticsearch/index/mapper/Mapper.java
index 7c047125a80d3..64d36c1928499 100644
--- a/server/src/main/java/org/elasticsearch/index/mapper/Mapper.java
+++ b/server/src/main/java/org/elasticsearch/index/mapper/Mapper.java
@@ -145,4 +145,12 @@ public static FieldType freezeAndDeduplicateFieldType(FieldType fieldType) {
      * Defines how this mapper counts towards {@link MapperService#INDEX_MAPPING_TOTAL_FIELDS_LIMIT_SETTING}.
      */
     public abstract int getTotalFieldsCount();
+
+    /**
+     * Returns a submapper for this mapper, if it exists.
+     *
+     * @param field field name from which to obtain the mapper
+     * @return submapper
+     */
+    public abstract Mapper getMapper(String field);
 }