dedupe against script root

components/datetime/Cargo.toml

@@ -75,6 +75,7 @@ serde = [
     "dep:serde",
     "icu_calendar/serde",
     "icu_decimal/serde",
+    "icu_locale_core/serde",
     "icu_pattern/serde",
     "icu_plurals/serde",
     "icu_provider/serde",
@@ -89,6 +90,7 @@ datagen = [
     "dep:databake",
     "dep:litemap",
     "icu_calendar/datagen",
+    "icu_locale_core/databake",
     "icu_pattern/databake",
     "icu_plurals/datagen",
     "icu_timezone/datagen",

components/datetime/src/pattern/names.rs

@@ -1912,14 +1912,35 @@ impl<FSet: DateTimeNamesMarker> RawDateTimeNames<FSet> {
             id: DataIdentifierBorrowed::for_locale(&locale),
             ..Default::default()
         };
-        self.locations_root
-            .load_put(provider, Default::default(), variables)
-            .map_err(|e| MaybePayloadError::into_load_error(e, error_field))?
-            .map_err(|e| PatternLoadError::Data(e, error_field))?;
         self.locations
             .load_put(provider, req, variables)
             .map_err(|e| MaybePayloadError::into_load_error(e, error_field))?
             .map_err(|e| PatternLoadError::Data(e, error_field))?;
+
+        #[allow(clippy::unwrap_used)] // we just loaded it
+        let (dedupe_language, dedupe_script) = self
+            .locations
+            .get()
+            .inner
+            .get_with_variables(variables)
+            .unwrap()
+            .dedupe_target;
+        let dedupe_locale = DataLocale {
+            language: dedupe_language,
+            script: dedupe_script,
+            ..Default::default()
+        };
+        self.locations_root
+            .load_put(
+                provider,
+                DataRequest {
+                    id: DataIdentifierBorrowed::for_locale(&dedupe_locale),
+                    ..Default::default()
+                },
+                variables,
+            )
+            .map_err(|e| MaybePayloadError::into_load_error(e, error_field))?
+            .map_err(|e| PatternLoadError::Data(e, error_field))?;
         Ok(())
     }
 

components/datetime/src/provider/time_zones.rs

@@ -5,6 +5,7 @@
 //! Data provider structs for time zones.
 
 use alloc::borrow::Cow;
+use icu_locale_core::subtags::{Language, Script};
 use icu_pattern::{DoublePlaceholderPattern, SinglePlaceholderPattern};
 use icu_provider::prelude::*;
 use tinystr::TinyAsciiStr;
@@ -82,6 +83,8 @@ pub struct TimeZoneEssentialsV1<'data> {
 #[cfg_attr(feature = "serde", derive(serde::Deserialize))]
 #[yoke(prove_covariance_manually)]
 pub struct LocationsV1<'data> {
+    /// The data struct against which the location names are deduplicated.
+    pub dedupe_target: (Language, Option<Script>),
     /// Per-zone location display name
     #[cfg_attr(feature = "serde", serde(borrow))]
     pub locations: ZeroMap<'data, TimeZoneBcp47Id, str>,