Fix panic in default impl of TimeZone::from_local_datetime

chronotope · Sep 26, 2023 · cf62e46 · cf62e46
1 parent 652bd78
commit cf62e46
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Showing 2 changed files with 66 additions and 4 deletions.
diff --git a/src/naive/datetime/tests.rs b/src/naive/datetime/tests.rs
@@ -1,7 +1,6 @@
 use super::NaiveDateTime;
 use crate::duration::Duration as OldDuration;
-use crate::NaiveDate;
-use crate::{Datelike, FixedOffset, Utc};
+use crate::{Datelike, FixedOffset, LocalResult, NaiveDate, Utc};
 
 #[test]
 fn test_datetime_from_timestamp_millis() {
@@ -490,3 +489,24 @@ fn test_checked_sub_offset() {
  assert_eq!(dt.checked_add_offset(positive_offset), Some(dt + positive_offset));
  assert_eq!(dt.checked_sub_offset(positive_offset), Some(dt - positive_offset));
 }
+
+#[test]
+fn test_and_timezone_min_max_dates() {
+ for offset_hour in -23..=23 {
+ dbg!(offset_hour);
+ let offset = FixedOffset::east_opt(offset_hour * 60 * 60).unwrap();
+
+ let local_max = NaiveDateTime::MAX.and_local_timezone(offset);
+ if offset_hour >= 0 {
+ assert_eq!(local_max.unwrap().naive_local(), NaiveDateTime::MAX);
+ } else {
+ assert_eq!(local_max, LocalResult::None);
+ }
+ let local_min = NaiveDateTime::MIN.and_local_timezone(offset);
+ if offset_hour <= 0 {
+ assert_eq!(local_min.unwrap().naive_local(), NaiveDateTime::MIN);
+ } else {
+ assert_eq!(local_min, LocalResult::None);
+ }
+ }
+}
diff --git a/src/offset/mod.rs b/src/offset/mod.rs
@@ -500,8 +500,24 @@ pub trait TimeZone: Sized + Clone {
  /// Converts the local `NaiveDateTime` to the timezone-aware `DateTime` if possible.
  #[allow(clippy::wrong_self_convention)]
  fn from_local_datetime(&self, local: &NaiveDateTime) -> LocalResult<DateTime<Self>> {
- self.offset_from_local_datetime(local)
- .map(|offset| DateTime::from_naive_utc_and_offset(*local - offset.fix(), offset))
+ // Return `LocalResult::None` when the offset pushes a value out of range, instead of
+ // panicking.
+ match self.offset_from_local_datetime(local) {
+ LocalResult::None => LocalResult::None,
+ LocalResult::Single(offset) => match local.checked_sub_offset(offset.fix()) {
+ Some(dt) => LocalResult::Single(DateTime::from_naive_utc_and_offset(dt, offset)),
+ None => LocalResult::None,
+ },
+ LocalResult::Ambiguous(o1, o2) => {
+ match (local.checked_sub_offset(o1.fix()), local.checked_sub_offset(o2.fix())) {
+ (Some(d1), Some(d2)) => LocalResult::Ambiguous(
+ DateTime::from_naive_utc_and_offset(d1, o1),
+ DateTime::from_naive_utc_and_offset(d2, o2),
+ ),
+ _ => LocalResult::None,
+ }
+ }
+ }
  }
 
  /// Creates the offset for given UTC `NaiveDate`. This cannot fail.
@@ -531,6 +547,32 @@ pub trait TimeZone: Sized + Clone {
 mod tests {
  use super::*;
 
+ #[test]
+ fn test_fixed_offset_min_max_dates() {
+ for offset_hour in -23..=23 {
+ dbg!(offset_hour);
+ let offset = FixedOffset::east_opt(offset_hour * 60 * 60).unwrap();
+
+ let local_max = offset.from_utc_datetime(&NaiveDateTime::MAX);
+ assert_eq!(local_max.naive_utc(), NaiveDateTime::MAX);
+ let local_min = offset.from_utc_datetime(&NaiveDateTime::MIN);
+ assert_eq!(local_min.naive_utc(), NaiveDateTime::MIN);
+
+ let local_max = offset.from_local_datetime(&NaiveDateTime::MAX);
+ if offset_hour >= 0 {
+ assert_eq!(local_max.unwrap().naive_local(), NaiveDateTime::MAX);
+ } else {
+ assert_eq!(local_max, LocalResult::None);
+ }
+ let local_min = offset.from_local_datetime(&NaiveDateTime::MIN);
+ if offset_hour <= 0 {
+ assert_eq!(local_min.unwrap().naive_local(), NaiveDateTime::MIN);
+ } else {
+ assert_eq!(local_min, LocalResult::None);
+ }
+ }
+ }
+
  #[test]
  fn test_negative_millis() {
  let dt = Utc.timestamp_millis_opt(-1000).unwrap();