Flip order of ignored and non ignored values in keyword field

Author: Kubik42

test/framework/src/main/java/org/elasticsearch/index/mapper/KeywordFieldSyntheticSourceSupport.java

@@ -49,10 +49,10 @@ public boolean preservesExactSource() {
 
     @Override
     public MapperTestCase.SyntheticSourceExample example(int maxValues) {
-        return example(maxValues, false);
+        return example(maxValues, false, false);
     }
 
-    public MapperTestCase.SyntheticSourceExample example(int maxValues, boolean loadBlockFromSource) {
+    public MapperTestCase.SyntheticSourceExample example(int maxValues, boolean loadBlockFromSource, boolean flipOrder) {
         if (ESTestCase.randomBoolean()) {
             Tuple<String, String> v = generateValue();
             Object sourceValue = preservesExactSource() ? v.v1() : v.v2();
@@ -77,7 +77,11 @@ public MapperTestCase.SyntheticSourceExample example(int maxValues, boolean load
             out = in;
         } else {
             var validValuesInCorrectOrder = store ? validValues : outputFromDocValues;
-            var syntheticSourceOutputList = Stream.concat(validValuesInCorrectOrder.stream(), ignoredValues.stream()).toList();
+            // this is an ugly little hack that flips the order of ignored values, which is important for the text-family fields where the
+            // ordering of produced synthetic source values can be different from what was supplied
+            var syntheticSourceOutputList = flipOrder
+                    ? Stream.concat(ignoredValues.stream(), validValuesInCorrectOrder.stream()).toList()
+                    : Stream.concat(validValuesInCorrectOrder.stream(), ignoredValues.stream()).toList();
             out = syntheticSourceOutputList.size() == 1 ? syntheticSourceOutputList.get(0) : syntheticSourceOutputList;
         }
 

test/framework/src/main/java/org/elasticsearch/index/mapper/TextFieldFamilySyntheticSourceTestSetup.java

@@ -81,7 +81,7 @@ public MapperTestCase.SyntheticSourceExample example(int maxValues) {
             // Block loader will not use keyword multi-field if it has ignore_above configured.
             // And in this case it will use values from source.
             boolean loadingFromSource = ignoreAbove != null;
-            MapperTestCase.SyntheticSourceExample delegate = keywordMultiFieldSyntheticSourceSupport.example(maxValues, loadingFromSource);
+            MapperTestCase.SyntheticSourceExample delegate = keywordMultiFieldSyntheticSourceSupport.example(maxValues, loadingFromSource, true);
 
             return new MapperTestCase.SyntheticSourceExample(delegate.inputValue(), delegate.expectedForSyntheticSource(), b -> {
                 b.field("type", fieldType);