8364752: java.time.Instant should be able to parse ISO 8601 offsets of the form HH:mm:ss

Reviewed-by: rriggs, vyazici, scolebourne

Author: naotoj

src/java.base/share/classes/java/time/format/DateTimeFormatter.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2012, 2023, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2012, 2025, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -1199,8 +1199,10 @@ public static DateTimeFormatter ofLocalizedPattern(String requestedTemplate) {
      * When formatting, the instant will always be suffixed by 'Z' to indicate UTC.
      * The second-of-minute is always output.
      * The nano-of-second outputs zero, three, six or nine digits as necessary.
-     * When parsing, the behaviour of {@link DateTimeFormatterBuilder#appendOffsetId()}
-     * will be used to parse the offset, converting the instant to UTC as necessary.
+     * When parsing, the lenient mode behavior of
+     * {@link DateTimeFormatterBuilder#appendOffset(String, String)
+     * appendOffset("+HH", "Z")} will be used to parse the offset,
+     * converting the instant to UTC as necessary.
      * The time to at least the seconds field is required.
      * Fractional seconds from zero to nine are parsed.
      * The localized decimal style is not used.

src/java.base/share/classes/java/time/format/DateTimeFormatterBuilder.java

@@ -894,8 +894,10 @@ public Iterator<Entry<String, Long>> getTextIterator(TemporalField field,
      * {@link DateTimeFormatter#parsedLeapSecond()} for full details.
      * <p>
      * When formatting, the instant will always be suffixed by 'Z' to indicate UTC.
-     * When parsing, the behaviour of {@link DateTimeFormatterBuilder#appendOffsetId()}
-     * will be used to parse the offset, converting the instant to UTC as necessary.
+     * When parsing, the lenient mode behaviour of
+     * {@link DateTimeFormatterBuilder#appendOffset(String, String)
+     * appendOffset("+HH", "Z")} will be used to parse the offset,
+     * converting the instant to UTC as necessary.
      * <p>
      * An alternative to this method is to format/parse the instant as a single
      * epoch-seconds value. That is achieved using {@code appendValue(INSTANT_SECONDS)}.
@@ -956,7 +958,7 @@ public DateTimeFormatterBuilder appendInstant(int fractionalDigits) {
      * Appends the zone offset, such as '+01:00', to the formatter.
      * <p>
      * This appends an instruction to format/parse the offset ID to the builder.
-     * This is equivalent to calling {@code appendOffset("+HH:mm:ss", "Z")}.
+     * This is equivalent to calling {@code appendOffset("+HH:MM:ss", "Z")}.
      * See {@link #appendOffset(String, String)} for details on formatting
      * and parsing.
      *
@@ -3887,7 +3889,8 @@ public int parse(DateTimeParseContext context, CharSequence text, int position)
                     .appendValue(MINUTE_OF_HOUR, 2).appendLiteral(':')
                     .appendValue(SECOND_OF_MINUTE, 2)
                     .appendFraction(NANO_OF_SECOND, minDigits, maxDigits, true)
-                    .appendOffsetId()
+                    .parseLenient()
+                    .appendOffset("+HH", "Z")
                     .toFormatter().toPrinterParser(false);
             DateTimeParseContext newContext = context.copy();
             int pos = parser.parse(newContext, text, position);

test/jdk/java/time/test/java/time/TestInstant.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2012, 2024, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2012, 2025, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -61,6 +61,9 @@
 
 import java.time.Duration;
 import java.time.Instant;
+import java.time.OffsetDateTime;
+import java.time.ZoneOffset;
+import java.time.format.DateTimeParseException;
 import java.time.temporal.ChronoUnit;
 
 import org.testng.annotations.Test;
@@ -70,7 +73,7 @@
 
 /**
  * Test Instant.
- * @bug 8273369 8331202
+ * @bug 8273369 8331202 8364752
  */
 @Test
 public class TestInstant extends AbstractTest {
@@ -151,4 +154,58 @@ public void test_until_1arg_NPE() {
             Instant.now().until(null);
         });
     }
+
+    @DataProvider
+    private Object[][] valid_instants() {
+        var I1 = OffsetDateTime.of(2017, 1, 1, 0, 0, 0, 0, ZoneOffset.of("+02")).toInstant();
+        var I2 = OffsetDateTime.of(2017, 1, 1, 0, 0, 0, 0, ZoneOffset.of("+02:02")).toInstant();
+        var I3 = OffsetDateTime.of(2017, 1, 1, 0, 0, 0, 0, ZoneOffset.of("+02:02:02")).toInstant();
+        var I4 = OffsetDateTime.of(2017, 1, 1, 0, 0, 0, 0, ZoneOffset.of("Z")).toInstant();
+        return new Object[][] {
+            {"2017-01-01T00:00:00.000+02", I1},
+            {"2017-01-01T00:00:00.000+0200", I1},
+            {"2017-01-01T00:00:00.000+02:00", I1},
+            {"2017-01-01T00:00:00.000+020000", I1},
+            {"2017-01-01T00:00:00.000+02:00:00", I1},
+
+            {"2017-01-01T00:00:00.000+0202", I2},
+            {"2017-01-01T00:00:00.000+02:02", I2},
+
+            {"2017-01-01T00:00:00.000+020202", I3},
+            {"2017-01-01T00:00:00.000+02:02:02", I3},
+
+            {"2017-01-01T00:00:00.000Z", I4},
+        };
+    }
+
+    @Test(dataProvider = "valid_instants")
+    public void test_parse_valid(String instant, Instant expected) {
+        assertEquals(Instant.parse(instant), expected);
+    }
+
+    @DataProvider
+    private Object[][] invalid_instants() {
+        return new Object[][] {
+            {"2017-01-01T00:00:00.000"},
+            {"2017-01-01T00:00:00.000+0"},
+            {"2017-01-01T00:00:00.000+0:"},
+            {"2017-01-01T00:00:00.000+02:"},
+            {"2017-01-01T00:00:00.000+020"},
+            {"2017-01-01T00:00:00.000+02:0"},
+            {"2017-01-01T00:00:00.000+02:0:"},
+            {"2017-01-01T00:00:00.000+02:00:"},
+            {"2017-01-01T00:00:00.000+02:000"},
+            {"2017-01-01T00:00:00.000+02:00:0"},
+            {"2017-01-01T00:00:00.000+02:00:0:"},
+            {"2017-01-01T00:00:00.000+0200000"},
+            {"2017-01-01T00:00:00.000+02:00:000"},
+            {"2017-01-01T00:00:00.000+02:00:00:"},
+            {"2017-01-01T00:00:00.000UTC"},
+        };
+    }
+
+    @Test(dataProvider = "invalid_instants")
+    public void test_parse_invalid(String instant) {
+        assertThrows(DateTimeParseException.class, () -> Instant.parse(instant));
+    }
 }