multi-type fields

Author: not-napoleon

x-pack/plugin/esql-core/src/main/java/org/elasticsearch/xpack/esql/core/type/EsField.java

@@ -124,10 +124,6 @@ public static Reader<? extends EsField> getReader(String name) {
     private final boolean isAlias;
     private final TimeSeriesFieldType timeSeriesFieldType;
 
-    public EsField(String name, DataType esDataType, Map<String, EsField> properties, boolean aggregatable) {
-        this(name, esDataType, properties, aggregatable, false, TimeSeriesFieldType.UNKNOWN);
-    }
-
     public EsField(
         String name,
         DataType esDataType,

x-pack/plugin/esql-core/src/main/java/org/elasticsearch/xpack/esql/core/type/MultiTypeEsField.java

@@ -33,11 +33,6 @@ public class MultiTypeEsField extends EsField {
 
     private final Map<String, Expression> indexToConversionExpressions;
 
-    public MultiTypeEsField(String name, DataType dataType, boolean aggregatable, Map<String, Expression> indexToConversionExpressions) {
-        super(name, dataType, Map.of(), aggregatable);
-        this.indexToConversionExpressions = indexToConversionExpressions;
-    }
-
     public MultiTypeEsField(
         String name,
         DataType dataType,
@@ -99,7 +94,13 @@ public static MultiTypeEsField resolveFrom(
                 indexToConversionExpressions.put(indexName, convertExpr);
             }
         }
-        return new MultiTypeEsField(invalidMappedField.getName(), resolvedDataType, false, indexToConversionExpressions);
+        return new MultiTypeEsField(
+            invalidMappedField.getName(),
+            resolvedDataType,
+            false,
+            indexToConversionExpressions,
+            invalidMappedField.getTimeSeriesFieldType()
+        );
     }
 
     @Override

x-pack/plugin/esql/src/main/java/org/elasticsearch/xpack/esql/analysis/Analyzer.java

@@ -1768,7 +1768,8 @@ private Expression resolveConvertFunction(ConvertFunction convert, List<FieldAtt
                             fa.fieldName().string(),
                             convertExpression.dataType(),
                             false,
-                            indexToConversionExpressions
+                            indexToConversionExpressions,
+                            fa.field().getTimeSeriesFieldType()
                         );
                         return createIfDoesNotAlreadyExist(fa, multiTypeEsField, unionFieldAttributes);
                     }

x-pack/plugin/esql/src/test/java/org/elasticsearch/xpack/esql/type/MultiTypeEsFieldTests.java

@@ -72,21 +72,24 @@ protected MultiTypeEsField createTestInstance() {
         DataType dataType = randomFrom(types());
         DataType toType = toString ? DataType.KEYWORD : dataType;
         Map<String, Expression> indexToConvertExpressions = randomConvertExpressions(name, toString, dataType);
-        return new MultiTypeEsField(name, toType, false, indexToConvertExpressions);
+        EsField.TimeSeriesFieldType tsType = randomFrom(EsField.TimeSeriesFieldType.values());
+        return new MultiTypeEsField(name, toType, false, indexToConvertExpressions, tsType);
     }
 
     @Override
     protected MultiTypeEsField mutateInstance(MultiTypeEsField instance) throws IOException {
         String name = instance.getName();
         DataType dataType = instance.getDataType();
         Map<String, Expression> indexToConvertExpressions = instance.getIndexToConversionExpressions();
-        switch (between(0, 2)) {
+        EsField.TimeSeriesFieldType tsType = instance.getTimeSeriesFieldType();
+        switch (between(0, 3)) {
             case 0 -> name = randomAlphaOfLength(name.length() + 1);
             case 1 -> dataType = randomValueOtherThan(dataType, () -> randomFrom(DataType.types()));
             case 2 -> indexToConvertExpressions = mutateConvertExpressions(name, dataType, indexToConvertExpressions);
+            case 3 -> tsType = randomValueOtherThan(tsType, () -> randomFrom(EsField.TimeSeriesFieldType.values()));
             default -> throw new IllegalArgumentException();
         }
-        return new MultiTypeEsField(name, dataType, false, indexToConvertExpressions);
+        return new MultiTypeEsField(name, dataType, false, indexToConvertExpressions, tsType);
     }
 
     @Override