Fix .toString()

Author: svilen-mihaylov-elastic

x-pack/plugin/esql/src/main/java/org/elasticsearch/xpack/esql/querydsl/query/MultiMatchQuery.java

@@ -16,6 +16,7 @@
 
 import java.util.Map;
 import java.util.Objects;
+import java.util.TreeMap;
 import java.util.function.BiConsumer;
 
 import static java.util.Map.entry;
@@ -103,6 +104,7 @@ public boolean equals(Object obj) {
 
     @Override
     protected String innerToString() {
-        return fields + ":" + query;
+        // Use a TreeMap so we get the fields in a predictable order.
+        return new TreeMap<>(fields) + ":" + query;
     }
 }

x-pack/plugin/esql/src/test/java/org/elasticsearch/xpack/esql/querydsl/query/MultiMatchQueryTests.java

@@ -41,6 +41,6 @@ private static MultiMatchQueryBuilder getBuilder(Map<String, Object> options) {
     public void testToString() {
         final Source source = new Source(1, 1, StringUtils.EMPTY);
         final MultiMatchQuery mmq = new MultiMatchQuery(source, "eggplant", Map.of("bar", 1.0f, "foo", 1.0f), null);
-        assertEquals("MultiMatchQuery@1:2[{foo=1.0, bar=1.0}:eggplant]", mmq.toString());
+        assertEquals("MultiMatchQuery@1:2[{bar=1.0, foo=1.0}:eggplant]", mmq.toString());
     }
 }