Timestamps.parse: Add error handling for invalid hours/minutes in the timezone offset.

Before this CL, bad offsets result in a NumberFormatException (from parseLong) instead of the documented ParseException/IllegalArgumentException.

PiperOrigin-RevId: 572266056

java/util/src/main/java/com/google/protobuf/util/Timestamps.java

@@ -510,7 +510,13 @@ public final class Timestamps {
     }
     String hours = value.substring(0, pos);
     String minutes = value.substring(pos + 1);
+    try {
       return (Long.parseLong(hours) * 60 + Long.parseLong(minutes)) * 60;
+    } catch (NumberFormatException e) {
+      ParseException ex = new ParseException("Invalid offset value: " + value, 0);
+      ex.initCause(e);
+      throw ex;
+    }
   }
 
   static int parseNanos(String value) throws ParseException {

java/util/src/test/java/com/google/protobuf/util/TimestampsTest.java

@@ -28,6 +28,7 @@ import org.junit.runners.JUnit4;
 
 /** Unit tests for {@link Timestamps}. */
 @RunWith(JUnit4.class)
+@SuppressWarnings("JavaUtilDate")
 public class TimestampsTest {
   private static final int MILLIS_PER_SECOND = 1000;
   private static final long MILLIS = 1409130915111L;
@@ -169,6 +170,7 @@ public class TimestampsTest {
     }
 
     @Override
+    @SuppressWarnings("ProtoTimestampGetSecondsGetNano")
     public void run() {
       int index = 0;
       while (!stopParsingThreads) {
@@ -350,6 +352,22 @@ public class TimestampsTest {
     }
   }
 
+  @Test
+  public void testTimestampInvalidOffsetWithDot() {
+    try {
+      Timestamps.parse("2021-08-19T10:24:25-07.:00");
+      assertWithMessage("ParseException is expected.").fail();
+    } catch (ParseException expected) {
+      assertThat(expected).hasMessageThat().isNotNull();
+    }
+    try {
+      Timestamps.parseUnchecked("2021-08-19T10:24:25-07.:00");
+      assertWithMessage("IllegalArgumentException is expected.").fail();
+    } catch (IllegalArgumentException expected) {
+      assertThat(expected).hasMessageThat().isNotNull();
+    }
+  }
+
   @Test
   public void testTimestampInvalidTrailingText() {
     try {