Convert DateTime::from_timestamp_millis to return Result

Author: pitdicker

src/datetime/mod.rs

@@ -792,24 +792,25 @@ impl DateTime<Utc> {
     ///
     /// # Errors
     ///
-    /// Returns `None` on out-of-range number of milliseconds, otherwise returns `Some(DateTime {...})`.
+    /// Returns [`Error::OutOfRange`] if the timestamp in milliseconds is outside the range of a
+    /// `DateTime` (more than ca. 262,000 years away from common era).
     ///
     /// # Example
     ///
     /// ```
     /// use chrono::DateTime;
     ///
-    /// let dt = DateTime::from_timestamp_millis(947638923004).expect("invalid timestamp");
+    /// let dt = DateTime::from_timestamp_millis(947638923004)?;
     ///
     /// assert_eq!(dt.to_string(), "2000-01-12 01:02:03.004 UTC");
-    /// assert_eq!(DateTime::from_timestamp_millis(dt.timestamp_millis()).unwrap(), dt);
+    /// assert_eq!(DateTime::from_timestamp_millis(dt.timestamp_millis())?, dt);
+    /// # Ok::<(), chrono::Error>(())
     /// ```
     #[inline]
-    #[must_use]
-    pub const fn from_timestamp_millis(millis: i64) -> Option<Self> {
+    pub const fn from_timestamp_millis(millis: i64) -> Result<Self, Error> {
         let secs = millis.div_euclid(1000);
         let nsecs = millis.rem_euclid(1000) as u32 * 1_000_000;
-        ok!(Self::from_timestamp(secs, nsecs))
+        Self::from_timestamp(secs, nsecs)
     }
 
     /// Creates a new `DateTime<Utc>` from the number of non-leap microseconds

src/datetime/tests.rs

@@ -141,17 +141,14 @@ fn test_datetime_from_timestamp_millis() {
 
     for timestamp_millis in invalid.iter().copied() {
         let datetime = DateTime::from_timestamp_millis(timestamp_millis);
-        assert!(datetime.is_none());
+        assert_eq!(datetime, Err(Error::OutOfRange));
     }
 
     // Test that the result of `from_timestamp_millis` compares equal to
     // that of `from_timestamp_opt`.
     let secs_test = [0, 1, 2, 1000, 1234, 12345678, -1, -2, -1000, -12345678];
     for secs in secs_test.iter().cloned() {
-        assert_eq!(
-            DateTime::from_timestamp_millis(secs * 1000),
-            DateTime::from_timestamp(secs, 0).ok()
-        );
+        assert_eq!(DateTime::from_timestamp_millis(secs * 1000), DateTime::from_timestamp(secs, 0));
     }
 }
 

src/offset/mod.rs

@@ -182,8 +182,8 @@ pub trait TimeZone: Sized + Clone {
     /// ```
     fn timestamp_millis(&self, millis: i64) -> LocalResult<DateTime<Self>> {
         match DateTime::from_timestamp_millis(millis) {
-            Some(dt) => LocalResult::Single(self.from_utc_datetime(&dt.naive_utc())),
-            None => LocalResult::None,
+            Ok(dt) => LocalResult::Single(self.from_utc_datetime(&dt.naive_utc())),
+            Err(_) => LocalResult::None,
         }
     }