Convert NaiveDate::from_ymd to return Result

src/error.rs

@@ -18,13 +18,21 @@ pub enum Error {
     ///
     /// An example is creating a `NaiveTime` with 25 as the hour value.
     InvalidArgument,
+
+    /// The result, or an intermediate value necessary for calculating a result, would be out of
+    /// range.
+    ///
+    /// An example is a date for the year 500.000, which is out of the range supported by chrono's
+    /// types.
+    OutOfRange,
 }
 
 impl fmt::Display for Error {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         match self {
             Error::DoesNotExist => write!(f, "date or datetime does not exist"),
             Error::InvalidArgument => write!(f, "invalid parameter"),
+            Error::OutOfRange => write!(f, "date outside of the supported range"),
         }
     }
 }

src/format/parsed.rs

@@ -390,7 +390,7 @@ impl Parsed {
         let (verified, parsed_date) = match (given_year, given_isoyear, self) {
             (Some(year), _, &Parsed { month: Some(month), day: Some(day), .. }) => {
                 // year, month, day
-                let date = NaiveDate::from_ymd_opt(year, month, day).ok_or(OUT_OF_RANGE)?;
+                let date = NaiveDate::from_ymd_opt(year, month, day).map_err(|_| OUT_OF_RANGE)?;
                 (verify_isoweekdate(date) && verify_ordinal(date), date)
             }
 

src/lib.rs

@@ -129,20 +129,20 @@
 //! # fn doctest() -> Option<()> {
 //!
 //! let dt = Utc.with_ymd_and_hms(2014, 7, 8, 9, 10, 11).unwrap(); // `2014-07-08T09:10:11Z`
-//! assert_eq!(dt, NaiveDate::from_ymd_opt(2014, 7, 8)?.and_hms_opt(9, 10, 11).unwrap().and_local_timezone(Utc).unwrap());
+//! assert_eq!(dt, NaiveDate::from_ymd_opt(2014, 7, 8).unwrap().and_hms_opt(9, 10, 11).unwrap().and_local_timezone(Utc).unwrap());
 //!
 //! // July 8 is 188th day of the year 2014 (`o` for "ordinal")
 //! assert_eq!(dt, NaiveDate::from_yo_opt(2014, 189)?.and_hms_opt(9, 10, 11).unwrap().and_utc());
 //! // July 8 is Tuesday in ISO week 28 of the year 2014.
 //! assert_eq!(dt, NaiveDate::from_isoywd_opt(2014, 28, Weekday::Tue)?.and_hms_opt(9, 10, 11).unwrap().and_utc());
 //!
-//! let dt = NaiveDate::from_ymd_opt(2014, 7, 8)?.and_hms_milli_opt(9, 10, 11, 12).unwrap().and_local_timezone(Utc).unwrap(); // `2014-07-08T09:10:11.012Z`
-//! assert_eq!(dt, NaiveDate::from_ymd_opt(2014, 7, 8)?.and_hms_micro_opt(9, 10, 11, 12_000).unwrap().and_local_timezone(Utc).unwrap());
-//! assert_eq!(dt, NaiveDate::from_ymd_opt(2014, 7, 8)?.and_hms_nano_opt(9, 10, 11, 12_000_000).unwrap().and_local_timezone(Utc).unwrap());
+//! let dt = NaiveDate::from_ymd_opt(2014, 7, 8).unwrap().and_hms_milli_opt(9, 10, 11, 12).unwrap().and_local_timezone(Utc).unwrap(); // `2014-07-08T09:10:11.012Z`
+//! assert_eq!(dt, NaiveDate::from_ymd_opt(2014, 7, 8).unwrap().and_hms_micro_opt(9, 10, 11, 12_000).unwrap().and_local_timezone(Utc).unwrap());
+//! assert_eq!(dt, NaiveDate::from_ymd_opt(2014, 7, 8).unwrap().and_hms_nano_opt(9, 10, 11, 12_000_000).unwrap().and_local_timezone(Utc).unwrap());
 //!
 //! // dynamic verification
 //! assert_eq!(Utc.with_ymd_and_hms(2014, 7, 8, 21, 15, 33),
-//!            LocalResult::Single(NaiveDate::from_ymd_opt(2014, 7, 8)?.and_hms_opt(21, 15, 33).unwrap().and_utc()));
+//!            LocalResult::Single(NaiveDate::from_ymd_opt(2014, 7, 8).unwrap().and_hms_opt(21, 15, 33).unwrap().and_utc()));
 //! assert_eq!(Utc.with_ymd_and_hms(2014, 7, 8, 80, 15, 33), LocalResult::None);
 //! assert_eq!(Utc.with_ymd_and_hms(2014, 7, 38, 21, 15, 33), LocalResult::None);
 //!

src/naive/date/mod.rs

@@ -141,46 +141,42 @@ impl NaiveDate {
 
     /// Makes a new `NaiveDate` from year and packed month-day-flags.
     /// Does not check whether the flags are correct for the provided year.
-    const fn from_mdf(year: i32, mdf: Mdf) -> Option<NaiveDate> {
+    #[inline]
+    const fn from_mdf(year: i32, mdf: Mdf) -> Result<NaiveDate, Error> {
         if year < MIN_YEAR || year > MAX_YEAR {
-            return None; // Out-of-range
+            return Err(Error::OutOfRange);
         }
-        Some(NaiveDate::from_yof((year << 13) | try_opt!(ok!(mdf.ordinal_and_flags()))))
+        Ok(NaiveDate::from_yof((year << 13) | try_err!(mdf.ordinal_and_flags())))
     }
 
     /// Makes a new `NaiveDate` from the [calendar date](#calendar-date)
     /// (year, month and day).
     ///
     /// # Errors
     ///
-    /// Returns `None` if:
-    /// - The specified calendar day does not exist (for example 2023-04-31).
-    /// - The value for `month` or `day` is invalid.
-    /// - `year` is out of range for `NaiveDate`.
+    /// This method returns:
+    /// - [`Error::DoesNotExist`] if the specified calendar day does not exist (for example
+    ///   2023-04-31).
+    /// - [`Error::InvalidArgument`] if the value for `month` or `day` is invalid.
+    /// - [`Error::OutOfRange`] if `year` is out of range for a `NaiveDate`.
     ///
     /// # Example
     ///
     /// ```
-    /// use chrono::NaiveDate;
+    /// use chrono::{Error, NaiveDate};
     ///
     /// let from_ymd_opt = NaiveDate::from_ymd_opt;
     ///
-    /// assert!(from_ymd_opt(2015, 3, 14).is_some());
-    /// assert!(from_ymd_opt(2015, 0, 14).is_none());
-    /// assert!(from_ymd_opt(2015, 2, 29).is_none());
-    /// assert!(from_ymd_opt(-4, 2, 29).is_some()); // 5 BCE is a leap year
-    /// assert!(from_ymd_opt(400000, 1, 1).is_none());
-    /// assert!(from_ymd_opt(-400000, 1, 1).is_none());
+    /// assert!(from_ymd_opt(2015, 3, 14).is_ok());
+    /// assert_eq!(from_ymd_opt(2015, 0, 14), Err(Error::InvalidArgument));
+    /// assert_eq!(from_ymd_opt(2015, 2, 29), Err(Error::DoesNotExist));
+    /// assert!(from_ymd_opt(-4, 2, 29).is_ok()); // 5 BCE is a leap year
+    /// assert_eq!(from_ymd_opt(400000, 1, 1), Err(Error::OutOfRange));
+    /// assert_eq!(from_ymd_opt(-400000, 1, 1), Err(Error::OutOfRange));
     /// ```
-    #[must_use]
-    pub const fn from_ymd_opt(year: i32, month: u32, day: u32) -> Option<NaiveDate> {
+    pub const fn from_ymd_opt(year: i32, month: u32, day: u32) -> Result<NaiveDate, Error> {
         let flags = YearFlags::from_year(year);
-
-        if let Ok(mdf) = Mdf::new(month, day, flags) {
-            NaiveDate::from_mdf(year, mdf)
-        } else {
-            None
-        }
+        NaiveDate::from_mdf(year, try_err!(Mdf::new(month, day, flags)))
     }
 
     /// Makes a new `NaiveDate` from the [ordinal date](#ordinal-date)
@@ -346,7 +342,7 @@ impl NaiveDate {
     /// ```
     /// use chrono::{NaiveDate, Weekday};
     /// assert_eq!(NaiveDate::from_weekday_of_month_opt(2017, 3, Weekday::Fri, 2),
-    ///            NaiveDate::from_ymd_opt(2017, 3, 10))
+    ///            NaiveDate::from_ymd_opt(2017, 3, 10).ok())
     /// ```
     #[must_use]
     pub const fn from_weekday_of_month_opt(
@@ -358,10 +354,10 @@ impl NaiveDate {
         if n == 0 {
             return None;
         }
-        let first = try_opt!(NaiveDate::from_ymd_opt(year, month, 1)).weekday();
+        let first = try_opt!(ok!(NaiveDate::from_ymd_opt(year, month, 1))).weekday();
         let first_to_dow = (7 + weekday.number_from_monday() - first.number_from_monday()) % 7;
         let day = (n - 1) as u32 * 7 + first_to_dow + 1;
-        NaiveDate::from_ymd_opt(year, month, day)
+        ok!(NaiveDate::from_ymd_opt(year, month, day))
     }
 
     /// Parses a string with the specified format string and returns a new `NaiveDate`.
@@ -546,7 +542,7 @@ impl NaiveDate {
             day = day_max;
         };
 
-        NaiveDate::from_mdf(year, try_opt!(ok!(Mdf::new(month as u32, day, flags))))
+        ok!(NaiveDate::from_mdf(year, try_opt!(ok!(Mdf::new(month as u32, day, flags)))))
     }
 
     /// Add a duration in [`Days`] to the date
@@ -853,7 +849,7 @@ impl NaiveDate {
         let new_shifted_ordinal = (self.yof() & ORDINAL_MASK) - (1 << 4);
         match new_shifted_ordinal > 0 {
             true => Some(NaiveDate::from_yof(self.yof() & !ORDINAL_MASK | new_shifted_ordinal)),
-            false => NaiveDate::from_ymd_opt(self.year() - 1, 12, 31),
+            false => ok!(NaiveDate::from_ymd_opt(self.year() - 1, 12, 31)),
         }
     }
 
@@ -1467,7 +1463,7 @@ impl Datelike for NaiveDate {
         let flags = YearFlags::from_year(year);
         let mdf = mdf.with_flags(flags);
 
-        NaiveDate::from_mdf(year, mdf)
+        ok!(NaiveDate::from_mdf(year, mdf))
     }
 
     /// Makes a new `NaiveDate` with the month number (starting from 1) changed.
@@ -2151,7 +2147,10 @@ where
         Some(NaiveDate::from_ymd_opt(2016, 7, 8).unwrap())
     );
     assert_eq!(from_str(r#""2016-7-8""#).ok(), Some(NaiveDate::from_ymd_opt(2016, 7, 8).unwrap()));
-    assert_eq!(from_str(r#""+002016-07-08""#).ok(), NaiveDate::from_ymd_opt(2016, 7, 8));
+    assert_eq!(
+        from_str(r#""+002016-07-08""#).ok(),
+        Some(NaiveDate::from_ymd_opt(2016, 7, 8).unwrap())
+    );
     assert_eq!(from_str(r#""0000-01-01""#).ok(), Some(NaiveDate::from_ymd_opt(0, 1, 1).unwrap()));
     assert_eq!(from_str(r#""0-1-1""#).ok(), Some(NaiveDate::from_ymd_opt(0, 1, 1).unwrap()));
     assert_eq!(

src/naive/date/tests.rs

@@ -1,6 +1,6 @@
 use super::{Days, Months, NaiveDate, MAX_YEAR, MIN_YEAR};
 use crate::naive::internals::{YearFlags, A, AG, B, BA, C, CB, D, DC, E, ED, F, FE, G, GF};
-use crate::{Datelike, TimeDelta, Weekday};
+use crate::{Datelike, Error, TimeDelta, Weekday};
 
 // as it is hard to verify year flags in `NaiveDate::MIN` and `NaiveDate::MAX`,
 // we use a separate run-time test.
@@ -153,16 +153,16 @@ fn test_readme_doomsday() {
 fn test_date_from_ymd() {
     let ymd_opt = NaiveDate::from_ymd_opt;
 
-    assert!(ymd_opt(2012, 0, 1).is_none());
-    assert!(ymd_opt(2012, 1, 1).is_some());
-    assert!(ymd_opt(2012, 2, 29).is_some());
-    assert!(ymd_opt(2014, 2, 29).is_none());
-    assert!(ymd_opt(2014, 3, 0).is_none());
-    assert!(ymd_opt(2014, 3, 1).is_some());
-    assert!(ymd_opt(2014, 3, 31).is_some());
-    assert!(ymd_opt(2014, 3, 32).is_none());
-    assert!(ymd_opt(2014, 12, 31).is_some());
-    assert!(ymd_opt(2014, 13, 1).is_none());
+    assert_eq!(ymd_opt(2012, 0, 1), Err(Error::InvalidArgument));
+    assert!(ymd_opt(2012, 1, 1).is_ok());
+    assert!(ymd_opt(2012, 2, 29).is_ok());
+    assert_eq!(ymd_opt(2014, 2, 29), Err(Error::DoesNotExist));
+    assert_eq!(ymd_opt(2014, 3, 0), Err(Error::InvalidArgument));
+    assert!(ymd_opt(2014, 3, 1).is_ok());
+    assert!(ymd_opt(2014, 3, 31).is_ok());
+    assert_eq!(ymd_opt(2014, 3, 32), Err(Error::InvalidArgument));
+    assert!(ymd_opt(2014, 12, 31).is_ok());
+    assert_eq!(ymd_opt(2014, 13, 1), Err(Error::InvalidArgument));
 }
 
 #[test]
@@ -255,7 +255,7 @@ fn test_date_from_isoywd_and_iso_week() {
         for month in 1..13 {
             for day in 1..32 {
                 let d = NaiveDate::from_ymd_opt(year, month, day);
-                if let Some(d) = d {
+                if let Ok(d) = d {
                     let w = d.iso_week();
                     let d_ = NaiveDate::from_isoywd_opt(w.year(), w.week(), d.weekday());
                     assert_eq!(d, d_.unwrap());
@@ -667,13 +667,13 @@ fn test_date_parse_from_str() {
     assert!(NaiveDate::parse_from_str("2014", "%Y").is_err()); // insufficient
 
     assert_eq!(
-        NaiveDate::parse_from_str("2020-01-0", "%Y-%W-%w").ok(),
-        NaiveDate::from_ymd_opt(2020, 1, 12),
+        NaiveDate::parse_from_str("2020-01-0", "%Y-%W-%w").unwrap(),
+        NaiveDate::from_ymd_opt(2020, 1, 12).unwrap(),
     );
 
     assert_eq!(
-        NaiveDate::parse_from_str("2019-01-0", "%Y-%W-%w").ok(),
-        NaiveDate::from_ymd_opt(2019, 1, 13),
+        NaiveDate::parse_from_str("2019-01-0", "%Y-%W-%w").unwrap(),
+        NaiveDate::from_ymd_opt(2019, 1, 13).unwrap(),
     );
 }
 
@@ -700,12 +700,12 @@ fn test_weeks_from() {
     // tests per: https://github.com/chronotope/chrono/issues/961
     // these internally use `weeks_from` via the parsing infrastructure
     assert_eq!(
-        NaiveDate::parse_from_str("2020-01-0", "%Y-%W-%w").ok(),
-        NaiveDate::from_ymd_opt(2020, 1, 12),
+        NaiveDate::parse_from_str("2020-01-0", "%Y-%W-%w").unwrap(),
+        NaiveDate::from_ymd_opt(2020, 1, 12).unwrap(),
     );
     assert_eq!(
-        NaiveDate::parse_from_str("2019-01-0", "%Y-%W-%w").ok(),
-        NaiveDate::from_ymd_opt(2019, 1, 13),
+        NaiveDate::parse_from_str("2019-01-0", "%Y-%W-%w").unwrap(),
+        NaiveDate::from_ymd_opt(2019, 1, 13).unwrap(),
     );
 
     // direct tests
@@ -730,7 +730,7 @@ fn test_weeks_from() {
         ] {
             assert_eq!(
                 NaiveDate::from_ymd_opt(*y, 1, 1).map(|d| d.weeks_from(*day)),
-                Some(if day == starts_on { 1 } else { 0 })
+                Ok(if day == starts_on { 1 } else { 0 })
             );
 
             // last day must always be in week 52 or 53

src/naive/datetime/mod.rs

@@ -21,7 +21,7 @@ use crate::naive::{Days, IsoWeek, NaiveDate, NaiveTime};
 use crate::offset::Utc;
 use crate::time_delta::NANOS_PER_SEC;
 use crate::{
-    expect, try_opt, DateTime, Datelike, FixedOffset, LocalResult, Months, TimeDelta, TimeZone,
+    expect, ok, try_opt, DateTime, Datelike, FixedOffset, LocalResult, Months, TimeDelta, TimeZone,
     Timelike, Weekday,
 };
 
@@ -1046,7 +1046,7 @@ impl NaiveDateTime {
 
     /// The Unix Epoch, 1970-01-01 00:00:00.
     pub const UNIX_EPOCH: Self =
-        expect!(NaiveDate::from_ymd_opt(1970, 1, 1), "").and_time(NaiveTime::MIN);
+        expect!(ok!(NaiveDate::from_ymd_opt(1970, 1, 1)), "").and_time(NaiveTime::MIN);
 }
 
 impl From<NaiveDate> for NaiveDateTime {

src/offset/local/windows.rs

@@ -166,6 +166,7 @@ fn system_time_from_naive_date_time(st: SYSTEMTIME, year: i32) -> Option<NaiveDa
     let day_of_week = Weekday::try_from(u8::try_from(st.wDayOfWeek).ok()?).ok()?.pred();
     if st.wYear != 0 {
         return NaiveDate::from_ymd_opt(st.wYear as i32, st.wMonth as u32, st.wDay as u32)
+            .ok()
             .map(|d| d.and_time(time));
     }
     let date = if let Some(date) =

src/offset/mod.rs

@@ -130,11 +130,10 @@ pub trait TimeZone: Sized + Clone {
         min: u32,
         sec: u32,
     ) -> LocalResult<DateTime<Self>> {
-        match NaiveDate::from_ymd_opt(year, month, day)
-            .and_then(|d| d.and_hms_opt(hour, min, sec).ok())
+        match NaiveDate::from_ymd_opt(year, month, day).and_then(|d| d.and_hms_opt(hour, min, sec))
         {
-            Some(dt) => self.from_local_datetime(&dt),
-            None => LocalResult::None,
+            Ok(dt) => self.from_local_datetime(&dt),
+            Err(_) => LocalResult::None,
         }
     }
 

src/traits.rs

@@ -146,7 +146,7 @@ pub trait Datelike: Sized {
     ///
     /// Don't combine multiple `Datelike::with_*` methods. The intermediate value may not exist.
     /// ```
-    /// use chrono::{NaiveDate, Datelike};
+    /// use chrono::{Error, NaiveDate, Datelike};
     ///
     /// fn with_year_month(date: NaiveDate, year: i32, month: u32) -> Option<NaiveDate> {
     ///     date.with_year(year)?.with_month(month)
@@ -155,7 +155,7 @@ pub trait Datelike: Sized {
     /// assert!(with_year_month(d, 2019, 1).is_none()); // fails because of invalid intermediate value
     ///
     /// // Correct version:
-    /// fn with_year_month_fixed(date: NaiveDate, year: i32, month: u32) -> Option<NaiveDate> {
+    /// fn with_year_month_fixed(date: NaiveDate, year: i32, month: u32) -> Result<NaiveDate, Error> {
     ///     NaiveDate::from_ymd_opt(year, month, date.day())
     /// }
     /// let d = NaiveDate::from_ymd_opt(2020, 2, 29).unwrap();