[GR-65269] Dates with missing UTC offset should be interpreted (in nashorn-compat mode) as UTC time when they are "strict" only.

PullRequest: js/3520

Author: iamstolis

graal-js/src/com.oracle.truffle.js.parser/src/com/oracle/truffle/js/parser/date/DateParser.java

@@ -750,7 +750,8 @@ private boolean patchResult(final boolean strict) {
     }
 
     private boolean isUTCDefaultTimezone(boolean dateOnly, boolean strict) {
-        return (strict || realm.getContext().getLanguageOptions().useUTCForLegacyDates()) && dateOnly;
+        return realm.getContext().isOptionNashornCompatibilityMode() ? strict :
+                (dateOnly && (strict || realm.getContext().getLanguageOptions().useUTCForLegacyDates()));
     }
 
     private static void addName(final String str, final int type, final int value) {

graal-js/src/com.oracle.truffle.js.test/js/date_parse.js

@@ -0,0 +1,27 @@
+/*
+ * Copyright (c) 2025, 2025, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * Licensed under the Universal Permissive License v 1.0 as shown at http://oss.oracle.com/licenses/upl.
+ */
+
+/*
+ * Test of the interpretation of parsed dates (in the default mode).
+ *
+ * @option timezone=IST
+ */
+
+load('assert.js');
+load('date_parse_common.js');
+
+assertSame(dateOnlyUTC, zDateOnlyEcma.toString());
+assertSame(dateOnlyUTC, zDateOnlyLegacy.toString());
+
+assertSame(dateTimeUTC, zDateTimeEcma.toString());
+assertSame(dateTimeUTC, zDateTimeLegacy.toString());
+
+assertSame(dateOnlyUTC, dateOnlyEcma.toString());
+assertSame(dateOnlyUTC, dateOnlyLegacy.toString());
+
+assertSame(dateTimeLocal, dateTimeEcma.toString());
+assertSame(dateTimeLocal, dateTimeLegacy.toString());

graal-js/src/com.oracle.truffle.js.test/js/date_parse_common.js

@@ -0,0 +1,30 @@
+/*
+ * Copyright (c) 2025, 2025, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * Licensed under the Universal Permissive License v 1.0 as shown at http://oss.oracle.com/licenses/upl.
+ */
+
+/*
+ * Common definitions for tests of the interpretation of parsed dates.
+ * 
+ * @option timezone IST
+ */
+
+var zDateOnlyEcma = new Date("2023-09-28Z");
+var zDateOnlyLegacy = new Date("2023 09 28Z");
+
+var zDateTimeEcma = new Date("2023-09-28T00:31:25Z");
+var zDateTimeLegacy = new Date("2023 09 28 00:31:25Z");
+
+var dateOnlyEcma = new Date("2023-09-28");
+var dateOnlyLegacy = new Date("2023 09 28");
+
+var dateTimeEcma = new Date("2023-09-28T00:31:25");
+var dateTimeLegacy = new Date("2023 09 28 00:31:25");
+
+// Possible results
+var dateOnlyUTC = "Thu Sep 28 2023 05:30:00 GMT+0530 (IST)";
+var dateTimeUTC = "Thu Sep 28 2023 06:01:25 GMT+0530 (IST)";
+var dateOnlyLocal = "Thu Sep 28 2023 00:00:00 GMT+0530 (IST)";
+var dateTimeLocal = "Thu Sep 28 2023 00:31:25 GMT+0530 (IST)";

graal-js/src/com.oracle.truffle.js.test/js/date_parse_local_for_legacy.js

@@ -0,0 +1,28 @@
+/*
+ * Copyright (c) 2025, 2025, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * Licensed under the Universal Permissive License v 1.0 as shown at http://oss.oracle.com/licenses/upl.
+ */
+
+/*
+ * Test of the interpretation of parsed dates (with use-utc-for-legacy-dates=false).
+ *
+ * @option timezone=IST
+ * @option use-utc-for-legacy-dates=false
+ */
+
+load('assert.js');
+load('date_parse_common.js');
+
+assertSame(dateOnlyUTC, zDateOnlyEcma.toString());
+assertSame(dateOnlyUTC, zDateOnlyLegacy.toString());
+
+assertSame(dateTimeUTC, zDateTimeEcma.toString());
+assertSame(dateTimeUTC, zDateTimeLegacy.toString());
+
+assertSame(dateOnlyUTC, dateOnlyEcma.toString());
+assertSame(dateOnlyLocal, dateOnlyLegacy.toString());
+
+assertSame(dateTimeLocal, dateTimeEcma.toString());
+assertSame(dateTimeLocal, dateTimeLegacy.toString());

graal-js/src/com.oracle.truffle.js.test/js/date_parse_nashorn.js

@@ -0,0 +1,28 @@
+/*
+ * Copyright (c) 2025, 2025, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * Licensed under the Universal Permissive License v 1.0 as shown at http://oss.oracle.com/licenses/upl.
+ */
+
+/*
+ * Test of the interpretation of parsed dates (in nashorn-compat mode).
+ *
+ * @option timezone=IST
+ * @option nashorn-compat
+ */
+
+load('assert.js');
+load('date_parse_common.js');
+
+assertSame(dateOnlyUTC, zDateOnlyEcma.toString());
+assertSame(dateOnlyUTC, zDateOnlyLegacy.toString());
+
+assertSame(dateTimeUTC, zDateTimeEcma.toString());
+assertSame(dateTimeUTC, zDateTimeLegacy.toString());
+
+assertSame(dateOnlyUTC, dateOnlyEcma.toString());
+assertSame(dateOnlyLocal, dateOnlyLegacy.toString());
+
+assertSame(dateTimeUTC, dateTimeEcma.toString());
+assertSame(dateTimeLocal, dateTimeLegacy.toString());

graal-js/src/com.oracle.truffle.js.test/js/date_parse_utc_for_legacy.js

@@ -0,0 +1,21 @@
+/*
+ * Copyright (c) 2025, 2025, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * Licensed under the Universal Permissive License v 1.0 as shown at http://oss.oracle.com/licenses/upl.
+ */
+
+/*
+ * Test of the interpretation of parsed dates (with use-utc-for-legacy-dates=true).
+ *
+ * @option timezone=IST
+ * @option use-utc-for-legacy-dates=true
+ */
+
+load('assert.js');
+load('date_parse_common.js');
+
+// use-utc-for-legacy-dates=true is the default mode
+// so, it should be the same as date_parse.js
+
+load('date_parse.js');