$dateToString aggregation with timezone outputs invalid ISO8601 string (mongodb#1768)

JAVA-5044

---------

Co-authored-by: Viacheslav Babanin <slav.babanin@mongodb.com>
Co-authored-by: Maxim Katcharov <maxim.katcharov@mongodb.com>

Author: 3 people

driver-core/src/main/com/mongodb/client/model/mql/MqlExpression.java

@@ -28,6 +28,7 @@
 import java.util.function.BinaryOperator;
 import java.util.function.Function;
 
+import static com.mongodb.assertions.Assertions.fail;
 import static com.mongodb.client.model.mql.MqlValues.of;
 import static com.mongodb.client.model.mql.MqlValues.ofNull;
 import static com.mongodb.client.model.mql.MqlValues.ofStringArray;
@@ -953,6 +954,12 @@ public MqlString asString(final MqlString timezone, final MqlString format) {
                 .append("timezone", toBsonValue(cr, timezone))));
     }
 
+    public MqlString asString(final MqlString timezone) {
+        // Given that server versions < 7.1 return a wrong format, not implementing this method helps prevent users
+        // from encountering the bug, described in DRIVERS-2620, by avoiding the method that requires a format as a parameter.
+        throw fail();
+    }
+
     @Override
     public MqlDate parseDate(final MqlString timezone, final MqlString format) {
         Assertions.notNull("timezone", timezone);