Bump ICU4X to 1.4 and finish Intl impls with new APIs (#3469)

* Migrate to workspace lints

* Fix last warnings

* Bump ICU4X@1.4 and implement missing APIs

Cargo.toml

@@ -66,24 +66,25 @@ thin-vec = "0.2.12"
 
 # ICU4X
 
-icu_provider = { version = "~1.3.1", default-features = false }
+icu_provider = { version = "~1.4.0", default-features = false }
-icu_locid = { version = "~1.3.2", default-features = false }
+icu_locid = { version = "~1.4.0", default-features = false }
-icu_locid_transform = { version = "~1.3.1", default-features = false }
+icu_locid_transform = { version = "~1.4.0", default-features = false }
-icu_datetime = { version = "~1.3.2", default-features = false }
+icu_datetime = { version = "~1.4.0", default-features = false }
-icu_calendar = { version = "~1.3.2", default-features = false }
+icu_calendar = { version = "~1.4.0", default-features = false }
-icu_collator = { version = "~1.3.3", default-features = false }
+icu_collator = { version = "~1.4.0", default-features = false }
-icu_plurals = { version = "~1.3.0", default-features = false }
+icu_plurals = { version = "~1.4.0", default-features = false }
-icu_list = { version = "~1.3.2", default-features = false }
+icu_list = { version = "~1.4.0", default-features = false }
-icu_casemap = { version = "~1.3.2", default-features = false }
+icu_casemap = { version = "~1.4.0", default-features = false }
-icu_segmenter = { version = "~1.3.2", default-features = false }
+icu_segmenter = { version = "~1.4.0", default-features = false }
-icu_datagen = { version = "~1.3.3", default-features = false }
+icu_datagen = { version = "~1.4.0", default-features = false }
-icu_provider_adapters = { version = "~1.3.0", default-features = false }
+icu_provider_adapters = { version = "~1.4.0", default-features = false }
-icu_provider_blob = { version = "~1.3.2", default-features = false }
+icu_provider_blob = { version = "~1.4.0", default-features = false }
-icu_properties = { version = "~1.3.0", default-features = true }
+icu_properties = { version = "~1.4.0", default-features = true }
-writeable = "~0.5.3"
+icu_normalizer = { version = "~1.4.0", default-features = true }
-yoke = "~0.7.2"
+writeable = "~0.5.4"
+yoke = "~0.7.3"
 zerofrom = "~0.1.3"
-fixed_decimal = "~0.5.4"
+fixed_decimal = "~0.5.5"
 
 [workspace.metadata.workspaces]
 allow_branch = "main"

boa_engine/Cargo.toml

@@ -85,7 +85,7 @@ num_enum = "0.7.1"
 pollster.workspace = true
 thin-vec.workspace = true
 itertools = { version = "0.12.0", default-features = false }
-icu_normalizer = "~1.3.0"
+icu_normalizer.workspace = true
 paste = "1.0"
 portable-atomic = "1.5.1"
 bytemuck = { version = "1.14.0", features = ["derive"] }
@@ -102,14 +102,14 @@ icu_locid_transform = { workspace = true, default-features = false, features = [
 icu_datetime = { workspace = true, default-features = false, features = ["serde", "experimental"], optional = true }
 icu_calendar = { workspace = true, default-features = false, optional = true }
 icu_collator = { workspace = true, default-features = false, features = ["serde"], optional = true }
-icu_plurals = { workspace = true, default-features = false, features = ["serde"], optional = true }
+icu_plurals = { workspace = true, default-features = false, features = ["serde", "experimental"], optional = true }
 icu_list = { workspace = true, default-features = false, features = ["serde"], optional = true }
 icu_casemap = { workspace = true, default-features = false, features = ["serde"], optional = true}
 icu_segmenter = { workspace = true, default-features = false, features = ["auto", "serde"], optional = true }
 writeable = { workspace = true, optional = true }
 yoke = { workspace = true, optional = true }
 zerofrom = { workspace = true, optional = true }
-fixed_decimal = { workspace = true, features = ["ryu"], optional = true}
+fixed_decimal = { workspace = true, features = ["ryu", "experimental"], optional = true}
 hashbrown.workspace = true
 
 [target.'cfg(all(target_family = "wasm", not(any(target_os = "emscripten", target_os = "wasi"))))'.dependencies]

boa_engine/src/builtins/intl/locale/utils.rs

@@ -325,6 +325,8 @@ where
         //    extension sequences removed.
         let mut locale = locale.clone();
         let id = std::mem::take(&mut locale.id);
+        locale.extensions.transform.clear();
+        locale.extensions.private.clear();
 
         // b. Let availableLocale be ! BestAvailableLocale(availableLocales, noExtensionsLocale).
         let available_locale = best_available_locale::<M>(id, icu.provider());
@@ -371,6 +373,8 @@ where
         }))
     {
         let id = std::mem::take(&mut locale.id);
+        locale.extensions.transform.clear();
+        locale.extensions.private.clear();
 
         if let Some(available) = best_locale_for_provider(id, icu.provider()) {
             locale.id = available;

boa_engine/src/builtins/intl/number_format/options.rs

@@ -2,10 +2,12 @@ use std::fmt;
 
 use crate::builtins::options::{ParsableOptionType, RoundingMode};
 
+use super::RoundingIncrement;
+
 #[derive(Debug)]
 pub(crate) struct DigitFormatOptions {
     pub(crate) minimum_integer_digits: u8,
-    pub(crate) rounding_increment: u16,
+    pub(crate) rounding_increment: RoundingIncrement,
     pub(crate) rounding_mode: RoundingMode,
     pub(crate) trailing_zero_display: TrailingZeroDisplay,
     pub(crate) rounding_type: RoundingType,

boa_engine/src/builtins/intl/number_format/utils.rs

@@ -1,5 +1,5 @@
 use boa_macros::utf16;
-use fixed_decimal::{FixedDecimal, FloatPrecision};
+use fixed_decimal::{FixedDecimal, FloatPrecision, RoundingIncrement as BaseMultiple};
 
 use crate::{
     builtins::{
@@ -14,6 +14,76 @@ use crate::{
 
 use super::{DigitFormatOptions, Notation, RoundingPriority};
 
+/// The increment of a rounding operation.
+///
+/// This differs from [`fixed_decimal::RoundingIncrement`] because ECMA402 accepts
+/// several more increments than `fixed_decimal`, but all increments can be decomposed
+/// into the target multiple and the magnitude offset.
+///
+/// For example, rounding the number `0.02456` to the increment 200 at position
+/// -3 is equivalent to rounding the same number to the increment 2 at position -1, and adding
+/// trailing zeroes.
+#[derive(Debug, Copy, Clone, Eq, PartialEq)]
+pub(crate) struct RoundingIncrement {
+    multiple: BaseMultiple,
+    // INVARIANT: can only be 0, 1, 2, or 3
+    magnitude_offset: u8,
+}
+
+impl RoundingIncrement {
+    /// Creates a `RoundingIncrement` from the numeric value of the increment.
+    fn from_u16(increment: u16) -> Option<Self> {
+        let mut offset = 0u8;
+        let multiple = loop {
+            let rem = increment % 10u16.checked_pow(u32::from(offset + 1))?;
+
+            if rem != 0 {
+                break increment / 10u16.pow(u32::from(offset));
+            }
+
+            offset += 1;
+        };
+
+        if offset > 3 {
+            return None;
+        }
+
+        let multiple = match multiple {
+            1 => BaseMultiple::MultiplesOf1,
+            2 => BaseMultiple::MultiplesOf2,
+            5 => BaseMultiple::MultiplesOf5,
+            25 => BaseMultiple::MultiplesOf25,
+            _ => return None,
+        };
+
+        Some(RoundingIncrement {
+            multiple,
+            magnitude_offset: offset,
+        })
+    }
+
+    /// Gets the numeric value of this `RoundingIncrement`.
+    pub(crate) fn to_u16(self) -> u16 {
+        u16::from(self.magnitude_offset + 1)
+            * match self.multiple {
+                BaseMultiple::MultiplesOf1 => 1,
+                BaseMultiple::MultiplesOf2 => 2,
+                BaseMultiple::MultiplesOf5 => 5,
+                BaseMultiple::MultiplesOf25 => 25,
+                _ => {
+                    debug_assert!(false, "base multiples can only be 1, 2, 5, or 25");
+                    1
+                }
+            }
+    }
+
+    /// Gets the magnitude offset that needs to be added to the rounding position
+    /// for this rounding increment.
+    fn magnitude_offset(self) -> i16 {
+        i16::from(self.magnitude_offset)
+    }
+}
+
 /// Abstract operation [`SetNumberFormatDigitOptions ( intlObj, options, mnfdDefault, mxfdDefault, notation )`][spec].
 ///
 /// Gets the digit format options of the number formatter from the options object and the requested notation.
@@ -26,10 +96,6 @@ pub(crate) fn get_digit_format_options(
     notation: Notation,
     context: &mut Context,
 ) -> JsResult<DigitFormatOptions> {
-    const VALID_ROUNDING_INCREMENTS: [u16; 15] = [
-        1, 2, 5, 10, 20, 25, 50, 100, 200, 250, 500, 1000, 2000, 2500, 5000,
-    ];
-
     // 1. Let mnid be ? GetNumberOption(options, "minimumIntegerDigits,", 1, 21, 1).
     let minimum_integer_digits =
         get_number_option(options, utf16!("minimumIntegerDigits"), 1, 21, context)?.unwrap_or(1);
@@ -51,11 +117,9 @@ pub(crate) fn get_digit_format_options(
     let rounding_increment =
         get_number_option(options, utf16!("roundingIncrement"), 1, 5000, context)?.unwrap_or(1);
 
-    if !VALID_ROUNDING_INCREMENTS.contains(&rounding_increment) {
+    let rounding_increment = RoundingIncrement::from_u16(rounding_increment).ok_or_else(|| {
-        return Err(JsNativeError::range()
+        JsNativeError::range().with_message("invalid value for option `roundingIncrement`")
-            .with_message("invalid value for option `roundingIncrement`")
+    })?;
-            .into());
-    }
 
     // 10. Let roundingMode be ? GetOption(options, "roundingMode", string, « "ceil", "floor", "expand", "trunc", "halfCeil", "halfFloor", "halfExpand", "halfTrunc", "halfEven" », "halfExpand").
     let rounding_mode = get_option(options, utf16!("roundingMode"), context)?.unwrap_or_default();
@@ -67,7 +131,7 @@ pub(crate) fn get_digit_format_options(
     // 12. NOTE: All fields required by SetNumberFormatDigitOptions have now been read from options. The remainder of this AO interprets the options and may throw exceptions.
 
     // 13. If roundingIncrement is not 1, set mxfdDefault to mnfdDefault.
-    if rounding_increment != 1 {
+    if rounding_increment.to_u16() != 1 {
         max_float_digits_default = min_float_digits_default;
     }
 
@@ -220,7 +284,7 @@ pub(crate) fn get_digit_format_options(
         (None, Some(frac)) => RoundingType::FractionDigits(frac),
     };
 
-    if rounding_increment != 1 {
+    if rounding_increment.to_u16() != 1 {
         let RoundingType::FractionDigits(range) = rounding_type else {
             return Err(JsNativeError::typ()
                 .with_message("option `roundingIncrement` invalid for the current set of options")
@@ -257,17 +321,17 @@ pub(crate) fn f64_to_formatted_fixed_decimal(
     number: f64,
     options: &DigitFormatOptions,
 ) -> FixedDecimal {
-    fn round(number: &mut FixedDecimal, position: i16, mode: RoundingMode) {
+    fn round(number: &mut FixedDecimal, position: i16, mode: RoundingMode, multiple: BaseMultiple) {
         match mode {
-            RoundingMode::Ceil => number.ceil(position),
+            RoundingMode::Ceil => number.ceil_to_increment(position, multiple),
-            RoundingMode::Floor => number.floor(position),
+            RoundingMode::Floor => number.floor_to_increment(position, multiple),
-            RoundingMode::Expand => number.expand(position),
+            RoundingMode::Expand => number.expand_to_increment(position, multiple),
-            RoundingMode::Trunc => number.trunc(position),
+            RoundingMode::Trunc => number.trunc_to_increment(position, multiple),
-            RoundingMode::HalfCeil => number.half_ceil(position),
+            RoundingMode::HalfCeil => number.half_ceil_to_increment(position, multiple),
-            RoundingMode::HalfFloor => number.half_floor(position),
+            RoundingMode::HalfFloor => number.half_floor_to_increment(position, multiple),
-            RoundingMode::HalfExpand => number.half_expand(position),
+            RoundingMode::HalfExpand => number.half_expand_to_increment(position, multiple),
-            RoundingMode::HalfTrunc => number.half_trunc(position),
+            RoundingMode::HalfTrunc => number.half_trunc_to_increment(position, multiple),
-            RoundingMode::HalfEven => number.half_even(position),
+            RoundingMode::HalfEven => number.half_even_to_increment(position, multiple),
         }
     }
 
@@ -282,7 +346,7 @@ pub(crate) fn f64_to_formatted_fixed_decimal(
         let min_msb = msb - i16::from(min_precision) + 1;
         let max_msb = msb - i16::from(max_precision) + 1;
         number.pad_end(min_msb);
-        round(number, max_msb, rounding_mode);
+        round(number, max_msb, rounding_mode, BaseMultiple::MultiplesOf1);
         max_msb
     }
 
@@ -291,12 +355,21 @@ pub(crate) fn f64_to_formatted_fixed_decimal(
         number: &mut FixedDecimal,
         min_fraction: u8,
         max_fraction: u8,
-        // TODO: missing support for `roundingIncrement` on `FixedDecimal`.
+        rounding_increment: RoundingIncrement,
-        _rounding_increment: u16,
         rounding_mode: RoundingMode,
     ) -> i16 {
+        #[cfg(debug_assertions)]
+        if rounding_increment.to_u16() != 1 {
+            assert_eq!(min_fraction, max_fraction);
+        }
+
         number.pad_end(-i16::from(min_fraction));
-        round(number, -i16::from(max_fraction), rounding_mode);
+        round(
+            number,
+            rounding_increment.magnitude_offset() - i16::from(max_fraction),
+            rounding_mode,
+            rounding_increment.multiple,
+        );
         -i16::from(max_fraction)
     }
 
@@ -405,3 +478,48 @@ pub(crate) fn f64_to_formatted_fixed_decimal(
     // 14. Return the Record { [[RoundedNumber]]: x, [[FormattedString]]: string }.
     number
 }
+
+#[cfg(test)]
+mod tests {
+    use crate::builtins::intl::number_format::RoundingIncrement;
+    use fixed_decimal::RoundingIncrement::*;
+
+    #[test]
+    fn u16_to_rounding_increment_sunny_day() {
+        #[rustfmt::skip]
+        const VALID_CASES: [(u16, RoundingIncrement); 15] = [
+            // Singles
+            (1, RoundingIncrement { multiple: MultiplesOf1, magnitude_offset: 0 }),
+            (2, RoundingIncrement { multiple: MultiplesOf2, magnitude_offset: 0 }),
+            (5, RoundingIncrement { multiple: MultiplesOf5, magnitude_offset: 0 }),
+            // Tens
+            (10, RoundingIncrement { multiple: MultiplesOf1, magnitude_offset: 1 }),
+            (20, RoundingIncrement { multiple: MultiplesOf2, magnitude_offset: 1 }),
+            (25, RoundingIncrement { multiple: MultiplesOf25, magnitude_offset: 0 }),
+            (50, RoundingIncrement { multiple: MultiplesOf5, magnitude_offset: 1 }),
+            // Hundreds
+            (100, RoundingIncrement { multiple: MultiplesOf1, magnitude_offset: 2 }),
+            (200, RoundingIncrement { multiple: MultiplesOf2, magnitude_offset: 2 }),
+            (250, RoundingIncrement { multiple: MultiplesOf25, magnitude_offset: 1 }),
+            (500, RoundingIncrement { multiple: MultiplesOf5, magnitude_offset: 2 }),
+            // Thousands
+            (1000, RoundingIncrement { multiple: MultiplesOf1, magnitude_offset: 3 }),
+            (2000, RoundingIncrement { multiple: MultiplesOf2, magnitude_offset: 3 }),
+            (2500, RoundingIncrement { multiple: MultiplesOf25, magnitude_offset: 2 }),
+            (5000, RoundingIncrement { multiple: MultiplesOf5, magnitude_offset: 3 }),
+        ];
+
+        for (num, increment) in VALID_CASES {
+            assert_eq!(RoundingIncrement::from_u16(num), Some(increment));
+        }
+    }
+
+    #[test]
+    fn u16_to_rounding_increment_rainy_day() {
+        const INVALID_CASES: [u16; 9] = [0, 4, 6, 24, 10000, 65535, 7373, 140, 1500];
+
+        for num in INVALID_CASES {
+            assert!(RoundingIncrement::from_u16(num).is_none());
+        }
+    }
+}

boa_engine/src/builtins/intl/plural_rules/mod.rs

@@ -6,6 +6,7 @@ use fixed_decimal::FixedDecimal;
 use icu_locid::Locale;
 use icu_plurals::{
     provider::CardinalV1Marker, PluralCategory, PluralRuleType, PluralRules as NativePluralRules,
+    PluralRulesWithRanges,
 };
 use icu_provider::DataLocale;
 
@@ -36,7 +37,7 @@ use super::{
 #[derive(Debug)]
 pub struct PluralRules {
     locale: Locale,
-    native: NativePluralRules,
+    native: PluralRulesWithRanges<NativePluralRules>,
     rule_type: PluralRuleType,
     format_options: DigitFormatOptions,
 }
@@ -64,6 +65,7 @@ impl IntrinsicObject for PluralRules {
             )
             .method(Self::resolved_options, js_string!("resolvedOptions"), 0)
             .method(Self::select, js_string!("select"), 1)
+            .method(Self::select_range, js_string!("selectRange"), 2)
             .build();
     }
 
@@ -93,6 +95,12 @@ impl BuiltInConstructor for PluralRules {
                 .with_message("cannot call `Intl.PluralRules` constructor without `new`")
                 .into());
         }
+        let proto = get_prototype_from_constructor(
+            new_target,
+            StandardConstructors::plural_rules,
+            context,
+        )?;
+
         // 2. Let pluralRules be ? OrdinaryCreateFromConstructor(NewTarget, "%PluralRules.prototype%",
         //    « [[InitializedPluralRules]], [[Locale]], [[Type]], [[MinimumIntegerDigits]],
         //    [[MinimumFractionDigits]], [[MaximumFractionDigits]], [[MinimumSignificantDigits]],
@@ -136,11 +144,11 @@ impl BuiltInConstructor for PluralRules {
         );
 
         let native = match rule_type {
-            PluralRuleType::Cardinal => NativePluralRules::try_new_cardinal_unstable(
+            PluralRuleType::Cardinal => PluralRulesWithRanges::try_new_cardinal_unstable(
                 context.icu().provider(),
                 &DataLocale::from(&locale),
             ),
-            PluralRuleType::Ordinal => NativePluralRules::try_new_ordinal_unstable(
+            PluralRuleType::Ordinal => PluralRulesWithRanges::try_new_ordinal_unstable(
                 context.icu().provider(),
                 &DataLocale::from(&locale),
             ),
@@ -152,12 +160,6 @@ impl BuiltInConstructor for PluralRules {
         }
         .map_err(|e| JsNativeError::typ().with_message(e.to_string()))?;
 
-        let proto = get_prototype_from_constructor(
-            new_target,
-            StandardConstructors::plural_rules,
-            context,
-        )?;
-
         // 12. Return pluralRules.
         Ok(JsObject::from_proto_and_data_with_shared_shape(
             context.root_shape(),
@@ -187,20 +189,86 @@ impl PluralRules {
         // 1. Let pr be the this value.
         // 2. Perform ? RequireInternalSlot(pr, [[InitializedPluralRules]]).
         let plural_rules = this.as_object().map(JsObject::borrow).ok_or_else(|| {
-            JsNativeError::typ().with_message(
+            JsNativeError::typ()
-                "`resolved_options` can only be called on an `Intl.PluralRules` object",
+                .with_message("`select` can only be called on an `Intl.PluralRules` object")
-            )
         })?;
         let plural_rules = plural_rules.as_plural_rules().ok_or_else(|| {
-            JsNativeError::typ().with_message(
+            JsNativeError::typ()
-                "`resolved_options` can only be called on an `Intl.PluralRules` object",
+                .with_message("`select` can only be called on an `Intl.PluralRules` object")
-            )
         })?;
 
         let n = args.get_or_undefined(0).to_number(context)?;
 
         Ok(plural_category_to_js_string(resolve_plural(plural_rules, n).category).into())
     }
+
+    /// [`Intl.PluralRules.prototype.selectRange ( start, end )`][spec].
+    ///
+    /// Receives two values and returns a string indicating which plural rule to use for
+    /// locale-aware formatting of the indicated range.
+    ///
+    /// More information:
+    /// - [MDN documentation][mdn]
+    ///
+    /// [spec]: https://tc39.es/ecma402/#sec-intl.pluralrules.prototype.selectrange
+    /// [mdn]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Intl/PluralRules/selectRange
+    fn select_range(this: &JsValue, args: &[JsValue], context: &mut Context) -> JsResult<JsValue> {
+        // 1. Let pr be the this value.
+        // 2. Perform ? RequireInternalSlot(pr, [[InitializedPluralRules]]).
+        let plural_rules = this.as_object().map(JsObject::borrow).ok_or_else(|| {
+            JsNativeError::typ()
+                .with_message("`select_range` can only be called on an `Intl.PluralRules` object")
+        })?;
+        let plural_rules = plural_rules.as_plural_rules().ok_or_else(|| {
+            JsNativeError::typ()
+                .with_message("`select_range` can only be called on an `Intl.PluralRules` object")
+        })?;
+
+        // 3. If start is undefined or end is undefined, throw a TypeError exception.
+        let x = args.get_or_undefined(0);
+        let y = args.get_or_undefined(1);
+        if x.is_undefined() || y.is_undefined() {
+            return Err(JsNativeError::typ()
+                .with_message("extremum of range cannot be `undefined`")
+                .into());
+        }
+
+        // 4. Let x be ? ToNumber(start).
+        let x = x.to_number(context)?;
+        // 5. Let y be ? ToNumber(end).
+        let y = y.to_number(context)?;
+
+        // 6. Return ? ResolvePluralRange(pr, x, y).
+        // ResolvePluralRange(pr, x, y)
+        // <https://tc39.es/ecma402/#sec-resolvepluralrange>
+
+        // 1. If x is NaN or y is NaN, throw a RangeError exception.
+        if x.is_nan() || y.is_nan() {
+            return Err(JsNativeError::typ()
+                .with_message("extremum of range cannot be NaN")
+                .into());
+        }
+
+        // 2. Let xp be ResolvePlural(pluralRules, x).
+        let x = resolve_plural(plural_rules, x);
+        // 3. Let yp be ResolvePlural(pluralRules, y).
+        let y = resolve_plural(plural_rules, y);
+
+        // 4. If xp.[[FormattedString]] is yp.[[FormattedString]], then
+        if x.formatted == y.formatted {
+            // a. Return xp.[[PluralCategory]].
+            return Ok(plural_category_to_js_string(x.category).into());
+        }
+
+        // 5. Let locale be pluralRules.[[Locale]].
+        // 6. Let type be pluralRules.[[Type]].
+        // 7. Return PluralRuleSelectRange(locale, type, xp.[[PluralCategory]], yp.[[PluralCategory]]).
+        Ok(
+            plural_category_to_js_string(plural_rules.native.resolve_range(x.category, y.category))
+                .into(),
+        )
+    }
+
     /// [`Intl.PluralRules.supportedLocalesOf ( locales [ , options ] )`][spec].
     ///
     /// Returns an array containing those of the provided locales that are supported in plural rules
@@ -322,7 +390,7 @@ impl PluralRules {
             )
             .property(
                 js_string!("roundingIncrement"),
-                plural_rules.format_options.rounding_increment,
+                plural_rules.format_options.rounding_increment.to_u16(),
                 Attribute::all(),
             )
             .property(
@@ -339,6 +407,7 @@ impl PluralRules {
         let plural_categories = Array::create_array_from_list(
             plural_rules
                 .native
+                .rules()
                 .categories()
                 .map(|category| plural_category_to_js_string(category).into()),
             options.context(),
@@ -401,7 +470,7 @@ fn resolve_plural(plural_rules: &PluralRules, n: f64) -> ResolvedPlural {
     // 8. Let s be res.[[FormattedString]].
     // 9. Let operands be ! GetOperands(s).
     // 10. Let p be ! PluralRuleSelect(locale, type, n, operands).
-    let category = plural_rules.native.category_for(&fixed);
+    let category = plural_rules.native.rules().category_for(&fixed);
 
     // 11. Return the Record { [[PluralCategory]]: p, [[FormattedString]]: s }.
     ResolvedPlural {

boa_engine/src/object/mod.rs

@@ -438,7 +438,7 @@ pub enum ObjectKind {
     SegmentIterator(SegmentIterator),
     /// The `PluralRules` object kind.
     #[cfg(feature = "intl")]
-    PluralRules(PluralRules),
+    PluralRules(Box<PluralRules>),
 
     /// The `Temporal.Instant` object kind.
     #[cfg(feature = "temporal")]
@@ -982,7 +982,7 @@ impl ObjectData {
     #[must_use]
     pub fn plural_rules(plural_rules: PluralRules) -> Self {
         Self {
-            kind: ObjectKind::PluralRules(plural_rules),
+            kind: ObjectKind::PluralRules(Box::new(plural_rules)),
             internal_methods: &ORDINARY_INTERNAL_METHODS,
         }
     }

boa_icu_provider/Cargo.toml

@@ -13,19 +13,20 @@ rust-version.workspace = true
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
-icu_provider = { workspace = true, features = ["serde", "sync"] }
+icu_provider = { workspace = true, features = ["serde", "sync", "datagen"] }
 icu_provider_blob = { workspace = true, features = ["export"] }
 icu_provider_adapters = { workspace = true, features = ["serde"] }
 once_cell = { workspace = true, default-features = false, features = ["critical-section"] }
 
 icu_datagen = { workspace = true, optional = true, features = ["networking", "use_wasm"] }
+icu_plurals = { workspace = true, optional = true, features = ["datagen", "experimental"] }
 log = { version = "0.4.20", optional = true }
 simple_logger = { version = "4.2.0", optional = true }
 
 [features]
 default = ["std"]
 std = ["once_cell/std"]
-bin = ["dep:icu_datagen", "dep:simple_logger", "dep:log"]
+bin = ["dep:icu_datagen", "dep:simple_logger", "dep:log", "dep:icu_plurals"]
 
 [[bin]]
 name = "boa_datagen"

boa_icu_provider/src/bin/datagen.rs

@@ -12,8 +12,78 @@ use std::{error::Error, fs::File};
 
 use boa_icu_provider::data_root;
 use icu_datagen::{all_keys, CoverageLevel, DatagenDriver, DatagenProvider};
+use icu_plurals::provider::{PluralRangesV1, PluralRangesV1Marker};
+use icu_provider::{
+    datagen::{ExportMarker, IterableDynamicDataProvider},
+    dynutil::UpcastDataPayload,
+    prelude::*,
+};
 use icu_provider_blob::export::BlobExporter;
 
+/// Hack that associates the `und` locale with an empty plural ranges data.
+/// This enables the default behaviour for all locales without data.
+#[derive(Debug)]
+struct PluralRangesFallbackHack(DatagenProvider);
+
+// We definitely don't want to import dependencies just to do `T::default`.
+#[allow(clippy::default_trait_access)]
+impl DynamicDataProvider<AnyMarker> for PluralRangesFallbackHack {
+    fn load_data(
+        &self,
+        key: DataKey,
+        req: DataRequest<'_>,
+    ) -> Result<DataResponse<AnyMarker>, DataError> {
+        if req.locale.is_und() && key.hashed() == PluralRangesV1Marker::KEY.hashed() {
+            let payload = <AnyMarker as UpcastDataPayload<PluralRangesV1Marker>>::upcast(
+                DataPayload::from_owned(PluralRangesV1 {
+                    ranges: Default::default(),
+                }),
+            );
+            Ok(DataResponse {
+                metadata: DataResponseMetadata::default(),
+                payload: Some(payload),
+            })
+        } else {
+            self.0.load_data(key, req)
+        }
+    }
+}
+
+#[allow(clippy::default_trait_access)]
+impl DynamicDataProvider<ExportMarker> for PluralRangesFallbackHack {
+    fn load_data(
+        &self,
+        key: DataKey,
+        req: DataRequest<'_>,
+    ) -> Result<DataResponse<ExportMarker>, DataError> {
+        if req.locale.is_und() && key.hashed() == PluralRangesV1Marker::KEY.hashed() {
+            let payload = <ExportMarker as UpcastDataPayload<PluralRangesV1Marker>>::upcast(
+                DataPayload::from_owned(PluralRangesV1 {
+                    ranges: Default::default(),
+                }),
+            );
+            Ok(DataResponse {
+                metadata: DataResponseMetadata::default(),
+                payload: Some(payload),
+            })
+        } else {
+            self.0.load_data(key, req)
+        }
+    }
+}
+
+impl IterableDynamicDataProvider<ExportMarker> for PluralRangesFallbackHack {
+    fn supported_locales_for_key(&self, key: DataKey) -> Result<Vec<DataLocale>, DataError> {
+        if key.hashed() == PluralRangesV1Marker::KEY.hashed() {
+            let mut locales = self.0.supported_locales_for_key(key)?;
+            locales.push(DataLocale::default());
+            Ok(locales)
+        } else {
+            self.0.supported_locales_for_key(key)
+        }
+    }
+}
+
 fn main() -> Result<(), Box<dyn Error>> {
     simple_logger::SimpleLogger::new()
         .env()
@@ -27,7 +97,7 @@ fn main() -> Result<(), Box<dyn Error>> {
         .with_locales(provider.locales_for_coverage_levels([CoverageLevel::Modern])?)
         .with_additional_collations([String::from("search*")])
         .export(
-            &provider,
+            &PluralRangesFallbackHack(provider),
             BlobExporter::new_with_sink(Box::new(File::create(
                 data_root().join("icudata.postcard"),
             )?)),