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Merged
merged 15 commits into from
Oct 15, 2025
Merged

Implement DateFromFieldsError, a narrow error type for Date::try_from_fields #7100

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7e6a1f6
Initial migration to DateFromFieldsError
sffc Oct 14, 2025
219caa9
Fix up docs tests
sffc Oct 14, 2025
1c904dd
ci
sffc Oct 14, 2025
37267ab
passing tests
sffc Oct 15, 2025
9af0e42
Error mapping commentary
sffc Oct 15, 2025
ab70a67
try_parse
sffc Oct 15, 2025
753bbdf
clippy, fmt
sffc Oct 15, 2025
c4b2e3c
use enums for all errors
sffc Oct 15, 2025
50b78f7
Remove MonthCode field from DateFromFieldsError
sffc Oct 15, 2025
1de767e
Merge branch 'main' into datefromfieldserror
sffc Oct 15, 2025
ffc284c
diplomat-coverage
sffc Oct 15, 2025
e78a06d
Fix errors in FFI and in new coverage test
sffc Oct 15, 2025
b5b027f
Fix rust link
sffc Oct 15, 2025
0624665
Add re-exports to diplomat-coverage allowlist
sffc Oct 15, 2025
f2de676
diplomat-gen
sffc Oct 15, 2025
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4 changes: 2 additions & 2 deletions components/calendar/src/any_calendar.rs
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Expand Up @@ -6,7 +6,7 @@

use crate::cal::iso::IsoDateInner;
use crate::cal::*;
use crate::error::DateError;
use crate::error::{DateError, DateFromFieldsError};
use crate::options::DateFromFieldsOptions;
use crate::options::{DateAddOptions, DateDifferenceOptions};
use crate::types::{DateFields, YearInfo};
Expand Down Expand Up @@ -279,7 +279,7 @@ impl Calendar for AnyCalendar {
&self,
fields: DateFields,
options: DateFromFieldsOptions,
) -> Result<Self::DateInner, DateError> {
) -> Result<Self::DateInner, DateFromFieldsError> {
Ok(match_cal!(match self: (c) => c.from_fields(fields, options)?))
}

Expand Down
20 changes: 12 additions & 8 deletions components/calendar/src/cal/abstract_gregorian.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -6,7 +6,7 @@ use crate::cal::iso::{IsoDateInner, IsoEra};
use crate::calendar_arithmetic::{
ArithmeticDate, ArithmeticDateBuilder, CalendarArithmetic, DateFieldsResolver,
};
use crate::error::DateError;
use crate::error::{DateError, DateFromFieldsError, EcmaReferenceYearError, UnknownEraError};
use crate::options::DateFromFieldsOptions;
use crate::options::{DateAddOptions, DateDifferenceOptions};
use crate::preferences::CalendarAlgorithm;
Expand All @@ -22,7 +22,7 @@ pub(crate) trait GregorianYears: Clone + core::fmt::Debug {
// Positive if after 0 CE
const EXTENDED_YEAR_OFFSET: i32 = 0;

fn extended_from_era_year(&self, era: Option<&str>, year: i32) -> Result<i32, DateError>;
fn extended_from_era_year(&self, era: Option<&str>, year: i32) -> Result<i32, UnknownEraError>;

fn era_year_from_extended(&self, extended_year: i32, month: u8, day: u8) -> EraYear;

Expand Down Expand Up @@ -88,7 +88,11 @@ impl<Y: GregorianYears> DateFieldsResolver for AbstractGregorian<Y> {
type YearInfo = i32;

#[inline]
fn year_info_from_era(&self, era: &str, era_year: i32) -> Result<Self::YearInfo, DateError> {
fn year_info_from_era(
&self,
era: &str,
era_year: i32,
) -> Result<Self::YearInfo, UnknownEraError> {
Ok(self.0.extended_from_era_year(Some(era), era_year)? + Y::EXTENDED_YEAR_OFFSET)
}

Expand All @@ -102,7 +106,7 @@ impl<Y: GregorianYears> DateFieldsResolver for AbstractGregorian<Y> {
&self,
_month_code: types::MonthCode,
_day: u8,
) -> Result<Self::YearInfo, DateError> {
) -> Result<Self::YearInfo, EcmaReferenceYearError> {
Ok(REFERENCE_YEAR)
}
}
Expand All @@ -118,10 +122,10 @@ impl<Y: GregorianYears> Calendar for AbstractGregorian<Y> {
&self,
fields: types::DateFields,
options: DateFromFieldsOptions,
) -> Result<Self::DateInner, DateError> {
) -> Result<Self::DateInner, DateFromFieldsError> {
let builder = ArithmeticDateBuilder::try_from_fields(fields, self, options)?;
ArithmeticDate::try_from_builder(builder, options)
.map_err(|e| e.maybe_with_month_code(fields.month_code))
let arithmetic_date = ArithmeticDate::try_from_builder(builder, options)?;
Ok(arithmetic_date)
}

fn from_rata_die(&self, date: RataDie) -> Self::DateInner {
Expand Down Expand Up @@ -232,7 +236,7 @@ macro_rules! impl_with_abstract_gregorian {
&self,
fields: crate::types::DateFields,
options: crate::options::DateFromFieldsOptions,
) -> Result<Self::DateInner, DateError> {
) -> Result<Self::DateInner, crate::error::DateFromFieldsError> {
let $self_ident = self;
crate::cal::abstract_gregorian::AbstractGregorian($eras_expr)
.from_fields(fields, options)
Expand Down
5 changes: 3 additions & 2 deletions components/calendar/src/cal/buddhist.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -2,6 +2,7 @@
// called LICENSE at the top level of the ICU4X source tree
// (online at: https://github.com/unicode-org/icu4x/blob/main/LICENSE ).

use crate::error::UnknownEraError;
use crate::preferences::CalendarAlgorithm;
use crate::{
cal::abstract_gregorian::{impl_with_abstract_gregorian, GregorianYears},
Expand Down Expand Up @@ -47,10 +48,10 @@ pub(crate) struct BuddhistEra;
impl GregorianYears for BuddhistEra {
const EXTENDED_YEAR_OFFSET: i32 = -543;

fn extended_from_era_year(&self, era: Option<&str>, year: i32) -> Result<i32, DateError> {
fn extended_from_era_year(&self, era: Option<&str>, year: i32) -> Result<i32, UnknownEraError> {
match era {
Some("be") | None => Ok(year),
_ => Err(DateError::UnknownEra),
_ => Err(UnknownEraError),
}
}

Expand Down
65 changes: 38 additions & 27 deletions components/calendar/src/cal/chinese.rs
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Expand Up @@ -7,7 +7,9 @@ use crate::calendar_arithmetic::DateFieldsResolver;
use crate::calendar_arithmetic::{
ArithmeticDate, ArithmeticDateBuilder, CalendarArithmetic, ToExtendedYear,
};
use crate::error::DateError;
use crate::error::{
DateError, DateFromFieldsError, EcmaReferenceYearError, MonthCodeError, UnknownEraError,
};
use crate::options::{DateAddOptions, DateDifferenceOptions};
use crate::options::{DateFromFieldsOptions, Overflow};
use crate::provider::chinese_based::PackedChineseBasedYearInfo;
Expand Down Expand Up @@ -122,8 +124,8 @@ pub trait Rules: Clone + core::fmt::Debug + crate::cal::scaffold::UnstableSealed
&self,
_month_code: types::MonthCode,
_day: u8,
) -> Result<i32, DateError> {
Err(DateError::NotEnoughFields)
) -> Result<i32, EcmaReferenceYearError> {
Err(EcmaReferenceYearError::NotEnoughFields)
}

/// The debug name for the calendar defined by these [`Rules`].
Expand Down Expand Up @@ -201,10 +203,12 @@ impl Rules for China {
}
}

fn ecma_reference_year(&self, month_code: types::MonthCode, day: u8) -> Result<i32, DateError> {
let Some((number, is_leap)) = month_code.parsed() else {
return Err(DateError::UnknownMonthCode(month_code));
};
fn ecma_reference_year(
&self,
month_code: types::MonthCode,
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suggestion: if we allow invalid month codes to be constructed, this method should take ordinal: u8, is_leap: bool to remove the parsing error case (or introduce a new ValidMonthCode type). once we move to &str inputs we basically don't need MonthCode anymore.

this also applies to all other (internal) methods that use MonthCode. validate early so not every method needs a InvalidMonthCode error variant

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i cautiously like this idea, though I think it can be a non-2.1 blocking followup as a part of graduating these traits.

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it can only be non-blocking if we don't sprinkle MonthCode in other parts of the API, like error variants, and the input itself

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Oh, sure.

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If you both are okay with adding icu_calendar::types::ValidMonthCode, I will proceed with that.

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@Manishearth Manishearth Oct 15, 2025 •
edited
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I'm in favor of that. This issue is a mandatory 2.1 blocker so we can do things piecemeal

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(Looked at the PR, not in favor of the PR, stated why there)

I think here we can have MonthCode, or a tuple, or an unstable lightweight ValidMonthCode type. The latter two are more optimized, and we can change our mind when graduating the trait. We should note this thing as a decision-to-be-made on the graduation issue and move on.

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This is a decision about unstable code and does not block this PR, nor should its fix involve public stable API changes.

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I can make ValidMonthCode pub(crate)/unstable in the other PR for now, and remove it from the error variant. I think in both cases where we convert to DateError, we have access to the input month code.

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Okay, that works!

day: u8,
) -> Result<i32, EcmaReferenceYearError> {
let (number, is_leap) = month_code.try_parse()?;
// Computed by `generate_reference_years`
Ok(match (number, is_leap, day > 29) {
(1, false, false) => 1972,
Expand Down Expand Up @@ -258,7 +262,7 @@ impl Rules for China {
(12, false, true) => 1971,
(12, true, false) => 1878,
(12, true, true) => 1783,
_ => return Err(DateError::UnknownMonthCode(month_code)),
_ => return Err(EcmaReferenceYearError::UnknownMonthCodeForCalendar),
})
}

Expand Down Expand Up @@ -380,10 +384,12 @@ impl Rules for Korea {
}
}

fn ecma_reference_year(&self, month_code: types::MonthCode, day: u8) -> Result<i32, DateError> {
let Some((number, is_leap)) = month_code.parsed() else {
return Err(DateError::UnknownMonthCode(month_code));
};
fn ecma_reference_year(
&self,
month_code: types::MonthCode,
day: u8,
) -> Result<i32, EcmaReferenceYearError> {
let (number, is_leap) = month_code.try_parse()?;
// Computed by `generate_reference_years`
Ok(match (number, is_leap, day > 29) {
(1, false, false) => 1972,
Expand Down Expand Up @@ -437,7 +443,7 @@ impl Rules for Korea {
(12, false, true) => 1971,
(12, true, false) => 1878,
(12, true, true) => 1783,
_ => return Err(DateError::UnknownMonthCode(month_code)),
_ => return Err(EcmaReferenceYearError::UnknownMonthCodeForCalendar),
})
}

Expand Down Expand Up @@ -554,9 +560,13 @@ impl<R: Rules> DateFieldsResolver for LunarChinese<R> {
type YearInfo = LunarChineseYearData;

#[inline]
fn year_info_from_era(&self, _era: &str, _era_year: i32) -> Result<Self::YearInfo, DateError> {
fn year_info_from_era(
&self,
_era: &str,
_era_year: i32,
) -> Result<Self::YearInfo, UnknownEraError> {
// This calendar has no era codes
Err(DateError::UnknownEra)
Err(UnknownEraError)
}

#[inline]
Expand All @@ -569,7 +579,7 @@ impl<R: Rules> DateFieldsResolver for LunarChinese<R> {
&self,
month_code: types::MonthCode,
day: u8,
) -> Result<Self::YearInfo, DateError> {
) -> Result<Self::YearInfo, EcmaReferenceYearError> {
Ok(self
.0
.year_data(self.0.ecma_reference_year(month_code, day)?))
Expand All @@ -580,15 +590,17 @@ impl<R: Rules> DateFieldsResolver for LunarChinese<R> {
year: &Self::YearInfo,
month_code: types::MonthCode,
options: DateFromFieldsOptions,
) -> Result<u8, DateError> {
) -> Result<u8, MonthCodeError> {
match year.parse_month_code(month_code) {
ComputedOrdinalMonth::Exact(val) => Ok(val),
ComputedOrdinalMonth::LeapToNormal(val)
if options.overflow == Some(Overflow::Constrain) =>
{
Ok(val)
ComputedOrdinalMonth::LeapToNormal(val) => {
if options.overflow == Some(Overflow::Constrain) {
Ok(val)
} else {
Err(MonthCodeError::UnknownMonthCodeForYear)
}
}
_ => Err(DateError::UnknownMonthCode(month_code)),
ComputedOrdinalMonth::NotFound => Err(MonthCodeError::UnknownMonthCodeForCalendar),
}
}

Expand All @@ -611,11 +623,10 @@ impl<R: Rules> Calendar for LunarChinese<R> {
&self,
fields: types::DateFields,
options: DateFromFieldsOptions,
) -> Result<Self::DateInner, DateError> {
) -> Result<Self::DateInner, DateFromFieldsError> {
let builder = ArithmeticDateBuilder::try_from_fields(fields, self, options)?;
Ok(ChineseDateInner(ArithmeticDate::try_from_builder(
builder, options,
)?))
let arithmetic_date = ArithmeticDate::try_from_builder(builder, options)?;
Ok(ChineseDateInner(arithmetic_date))
}

fn from_rata_die(&self, rd: RataDie) -> Self::DateInner {
Expand Down Expand Up @@ -1709,7 +1720,7 @@ mod test {
let cal = LunarChinese::new_china();
assert!(matches!(
Date::try_from_fields(fields, options, cal).unwrap_err(),
DateError::Range { .. }
DateFromFieldsError::Range { .. }
));
}

Expand Down
35 changes: 19 additions & 16 deletions components/calendar/src/cal/coptic.rs
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Expand Up @@ -5,7 +5,9 @@
use crate::cal::iso::{Iso, IsoDateInner};
use crate::calendar_arithmetic::{ArithmeticDate, CalendarArithmetic};
use crate::calendar_arithmetic::{ArithmeticDateBuilder, DateFieldsResolver};
use crate::error::DateError;
use crate::error::{
DateError, DateFromFieldsError, EcmaReferenceYearError, MonthCodeError, UnknownEraError,
};
use crate::options::DateFromFieldsOptions;
use crate::options::{DateAddOptions, DateDifferenceOptions};
use crate::{types, Calendar, Date, RangeError};
Expand Down Expand Up @@ -85,10 +87,14 @@ impl DateFieldsResolver for Coptic {
type YearInfo = i32;

#[inline]
fn year_info_from_era(&self, era: &str, era_year: i32) -> Result<Self::YearInfo, DateError> {
fn year_info_from_era(
&self,
era: &str,
era_year: i32,
) -> Result<Self::YearInfo, UnknownEraError> {
match era {
"am" => Ok(era_year),
_ => Err(DateError::UnknownEra),
_ => Err(UnknownEraError),
}
}

Expand All @@ -102,7 +108,7 @@ impl DateFieldsResolver for Coptic {
&self,
month_code: types::MonthCode,
day: u8,
) -> Result<Self::YearInfo, DateError> {
) -> Result<Self::YearInfo, EcmaReferenceYearError> {
Coptic::reference_year_from_month_day(month_code, day)
}

Expand All @@ -112,10 +118,10 @@ impl DateFieldsResolver for Coptic {
_year: &Self::YearInfo,
month_code: types::MonthCode,
_options: DateFromFieldsOptions,
) -> Result<u8, DateError> {
match month_code.parsed() {
Some((month_number @ 1..=13, false)) => Ok(month_number),
_ => Err(DateError::UnknownMonthCode(month_code)),
) -> Result<u8, MonthCodeError> {
match month_code.try_parse()? {
(month_number @ 1..=13, false) => Ok(month_number),
_ => Err(MonthCodeError::UnknownMonthCodeForCalendar),
}
}
}
Expand All @@ -124,10 +130,8 @@ impl Coptic {
pub(crate) fn reference_year_from_month_day(
month_code: types::MonthCode,
day: u8,
) -> Result<i32, DateError> {
let (ordinal_month, _is_leap) = month_code
.parsed()
.ok_or(DateError::UnknownMonthCode(month_code))?;
) -> Result<i32, EcmaReferenceYearError> {
let (ordinal_month, _is_leap) = month_code.try_parse()?;
// December 31, 1972 occurs on 4th month, 22nd day, 1689 AM
let anno_martyrum_year = if ordinal_month < 4 || (ordinal_month == 4 && day <= 22) {
1689
Expand All @@ -153,11 +157,10 @@ impl Calendar for Coptic {
&self,
fields: types::DateFields,
options: DateFromFieldsOptions,
) -> Result<Self::DateInner, DateError> {
) -> Result<Self::DateInner, DateFromFieldsError> {
let builder = ArithmeticDateBuilder::try_from_fields(fields, self, options)?;
ArithmeticDate::try_from_builder(builder, options)
.map(CopticDateInner)
.map_err(|e| e.maybe_with_month_code(fields.month_code))
let arithmetic_date = ArithmeticDate::try_from_builder(builder, options)?;
Ok(CopticDateInner(arithmetic_date))
}

fn from_rata_die(&self, rd: RataDie) -> Self::DateInner {
Expand Down
30 changes: 17 additions & 13 deletions components/calendar/src/cal/ethiopian.rs
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Expand Up @@ -6,7 +6,9 @@ use crate::cal::coptic::CopticDateInner;
use crate::cal::iso::IsoDateInner;
use crate::cal::Coptic;
use crate::calendar_arithmetic::{ArithmeticDate, ArithmeticDateBuilder, DateFieldsResolver};
use crate::error::DateError;
use crate::error::{
DateError, DateFromFieldsError, EcmaReferenceYearError, MonthCodeError, UnknownEraError,
};
use crate::options::DateFromFieldsOptions;
use crate::options::{DateAddOptions, DateDifferenceOptions};
use crate::types::DateFields;
Expand Down Expand Up @@ -75,11 +77,15 @@ impl DateFieldsResolver for Ethiopian {
type YearInfo = i32;

#[inline]
fn year_info_from_era(&self, era: &str, era_year: i32) -> Result<Self::YearInfo, DateError> {
fn year_info_from_era(
&self,
era: &str,
era_year: i32,
) -> Result<Self::YearInfo, UnknownEraError> {
match (self.era_style(), era) {
(EthiopianEraStyle::AmeteMihret, "am") => Ok(era_year + AMETE_MIHRET_OFFSET),
(_, "aa") => Ok(era_year + AMETE_ALEM_OFFSET),
(_, _) => Err(DateError::UnknownEra),
(_, _) => Err(UnknownEraError),
}
}

Expand All @@ -98,7 +104,7 @@ impl DateFieldsResolver for Ethiopian {
&self,
month_code: types::MonthCode,
day: u8,
) -> Result<Self::YearInfo, DateError> {
) -> Result<Self::YearInfo, EcmaReferenceYearError> {
crate::cal::Coptic::reference_year_from_month_day(month_code, day)
}

Expand All @@ -108,10 +114,10 @@ impl DateFieldsResolver for Ethiopian {
_year: &Self::YearInfo,
month_code: types::MonthCode,
_options: DateFromFieldsOptions,
) -> Result<u8, DateError> {
match month_code.parsed() {
Some((month_number @ 1..=13, false)) => Ok(month_number),
_ => Err(DateError::UnknownMonthCode(month_code)),
) -> Result<u8, MonthCodeError> {
match month_code.try_parse()? {
(month_number @ 1..=13, false) => Ok(month_number),
_ => Err(MonthCodeError::UnknownMonthCodeForCalendar),
}
}
}
Expand All @@ -126,12 +132,10 @@ impl Calendar for Ethiopian {
&self,
fields: DateFields,
options: DateFromFieldsOptions,
) -> Result<Self::DateInner, DateError> {
) -> Result<Self::DateInner, DateFromFieldsError> {
let builder = ArithmeticDateBuilder::try_from_fields(fields, self, options)?;
ArithmeticDate::try_from_builder(builder, options)
.map(CopticDateInner)
.map(EthiopianDateInner)
.map_err(|e| e.maybe_with_month_code(fields.month_code))
let arithmetic_date = ArithmeticDate::try_from_builder(builder, options)?;
Ok(EthiopianDateInner(CopticDateInner(arithmetic_date)))
}

fn from_rata_die(&self, rd: RataDie) -> Self::DateInner {
Expand Down
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