Use dynamic replacement instead of _typeByName for internationalization upcalls (#756)

* Use dynamic replacement instead of _typeByName for internationalization upcalls

* Make FOUNDATION_FRAMEWORK function non-dynamic

* Fix build failures

Author: jmschonfeld

Sources/FoundationEssentials/Calendar/Calendar_Cache.swift

@@ -15,30 +15,26 @@ internal import _ForSwiftFoundation
 import CoreFoundation
 #endif
 
-/// Singleton which listens for notifications about preference changes for Calendar and holds cached singletons for the current locale, calendar, and time zone.
-struct CalendarCache : Sendable {
-    
-    // MARK: - Concrete Classes
-    
-    // _CalendarICU, if present
-    static func calendarICUClass(identifier: Calendar.Identifier, useGregorian: Bool) -> _CalendarProtocol.Type? {
 #if FOUNDATION_FRAMEWORK && canImport(_FoundationICU)
-        if useGregorian && identifier == .gregorian {
-            return _CalendarGregorian.self
-        } else {
-            return _CalendarICU.self
-        }
+internal func _calendarICUClass() -> _CalendarProtocol.Type? {
+    _CalendarICU.self
+}
 #else
-        if useGregorian && identifier == .gregorian {
-            return _CalendarGregorian.self
-        } else if let name = _typeByName("FoundationInternationalization._CalendarICU"), let t = name as? _CalendarProtocol.Type {
-            return t
-        } else {
-            return nil
-        }
+dynamic package func _calendarICUClass() -> _CalendarProtocol.Type? {
+    nil
+}
 #endif
+
+func _calendarClass(identifier: Calendar.Identifier, useGregorian: Bool) -> _CalendarProtocol.Type? {
+    if useGregorian && identifier == .gregorian {
+        return _CalendarGregorian.self
+    } else {
+        return _calendarICUClass()
     }
+}
 
+/// Singleton which listens for notifications about preference changes for Calendar and holds cached singletons for the current locale, calendar, and time zone.
+struct CalendarCache : Sendable {
     // MARK: - State
 
     struct State : Sendable {
@@ -78,7 +74,7 @@ struct CalendarCache : Sendable {
             } else {
                 let id = Locale.current._calendarIdentifier
                 // If we cannot create the right kind of class, we fail immediately here
-                let calendarClass = CalendarCache.calendarICUClass(identifier: id, useGregorian: true)!
+                let calendarClass = _calendarClass(identifier: id, useGregorian: true)!
                 let calendar = calendarClass.init(identifier: id, timeZone: nil, locale: Locale.current, firstWeekday: nil, minimumDaysInFirstWeek: nil, gregorianStartDate: nil)
                 currentCalendar = calendar
                 return calendar
@@ -101,7 +97,7 @@ struct CalendarCache : Sendable {
                 return cached
             } else {
                 // If we cannot create the right kind of class, we fail immediately here
-                let calendarClass = CalendarCache.calendarICUClass(identifier: id, useGregorian: true)!
+                let calendarClass = _calendarClass(identifier: id, useGregorian: true)!
                 let new = calendarClass.init(identifier: id, timeZone: nil, locale: nil, firstWeekday: nil, minimumDaysInFirstWeek: nil, gregorianStartDate: nil)
                 fixedCalendars[id] = new
                 return new
@@ -140,7 +136,7 @@ struct CalendarCache : Sendable {
     func fixed(identifier: Calendar.Identifier, locale: Locale?, timeZone: TimeZone?, firstWeekday: Int?, minimumDaysInFirstWeek: Int?, gregorianStartDate: Date?) -> any _CalendarProtocol {
         // Note: Only the ObjC NSCalendar initWithCoder supports gregorian start date values. For Swift it is always nil.
         // If we cannot create the right kind of class, we fail immediately here
-        let calendarClass = CalendarCache.calendarICUClass(identifier: identifier, useGregorian: true)!
+        let calendarClass = _calendarClass(identifier: identifier, useGregorian: true)!
         return calendarClass.init(identifier: identifier, timeZone: timeZone, locale: locale, firstWeekday: firstWeekday, minimumDaysInFirstWeek: minimumDaysInFirstWeek, gregorianStartDate: gregorianStartDate)
     }
 

Sources/FoundationEssentials/FileManager/FileManager+Files.swift

@@ -118,9 +118,11 @@ public protocol _NSNumberInitializer {
     static func initialize(value: some BinaryInteger) -> Any
 }
 
-private let _nsNumberInitializer: (any _NSNumberInitializer.Type)? = {
+@_spi(SwiftCorelibsFoundation)
+dynamic public func _nsNumberInitializer() -> (any _NSNumberInitializer.Type)? {
+    // TODO: return nil here after swift-corelibs-foundation begins dynamically replacing this function
     _typeByName("Foundation._FoundationNSNumberInitializer") as? any _NSNumberInitializer.Type
-}()
+}
 #endif
 
 func _writeFileAttributePrimitive<T: BinaryInteger, U: BinaryInteger>(_ value: T, as type: U.Type) -> Any {
@@ -131,7 +133,7 @@ func _writeFileAttributePrimitive<T: BinaryInteger, U: BinaryInteger>(_ value: T
         NSNumber(value: UInt64(value))
     }
     #else
-    if let ns = _nsNumberInitializer?.initialize(value: value) {
+    if let ns = _nsNumberInitializer()?.initialize(value: value) {
         return ns
     } else {
         return U(value)
@@ -143,7 +145,7 @@ func _writeFileAttributePrimitive(_ value: Bool) -> Any {
     #if FOUNDATION_FRAMEWORK
     NSNumber(value: value)
     #else
-    if let ns = _nsNumberInitializer?.initialize(value: value) {
+    if let ns = _nsNumberInitializer()?.initialize(value: value) {
         return ns
     } else {
         return value

Sources/FoundationEssentials/Locale/Locale_Cache.swift

@@ -19,23 +19,20 @@ internal import os
 
 internal import _FoundationCShims
 
-/// Singleton which listens for notifications about preference changes for Locale and holds cached singletons.
-struct LocaleCache : Sendable {
-    // MARK: - Concrete Classes
-    
-    // _LocaleICU, if present. Otherwise we use _LocaleUnlocalized. The `Locale` initializers are not failable, so we just fall back to the unlocalized type when needed without failure.
-    static let localeICUClass: _LocaleProtocol.Type = {
 #if FOUNDATION_FRAMEWORK && canImport(_FoundationICU)
-        return _LocaleICU.self
+// Here, we always have access to _LocaleICU
+internal func _localeICUClass() -> _LocaleProtocol.Type {
+    _LocaleICU.self
+}
 #else
-        if let name = _typeByName("FoundationInternationalization._LocaleICU"), let t = name as? _LocaleProtocol.Type {
-            return t
-        } else {
-            return _LocaleUnlocalized.self
-        }
+dynamic package func _localeICUClass() -> _LocaleProtocol.Type {
+    // Return _LocaleUnlocalized if FoundationInternationalization isn't loaded. The `Locale` initializers are not failable, so we just fall back to the unlocalized type when needed without failure.
+    _LocaleUnlocalized.self
+}
 #endif
-    }()
 
+/// Singleton which listens for notifications about preference changes for Locale and holds cached singletons.
+struct LocaleCache : Sendable {
     // MARK: - State
 
     struct State {
@@ -99,7 +96,7 @@ struct LocaleCache : Sendable {
                 return nil
             }
 
-            let locale = LocaleCache.localeICUClass.init(name: nil, prefs: preferences, disableBundleMatching: disableBundleMatching)
+            let locale = _localeICUClass().init(name: nil, prefs: preferences, disableBundleMatching: disableBundleMatching)
             if cache {
                 // It's possible this was an 'incomplete locale', in which case we will want to calculate it again later.
                 self.cachedCurrentLocale = locale
@@ -122,7 +119,7 @@ struct LocaleCache : Sendable {
             if let locale = cachedFixedLocales[id] {
                 return locale
             } else {
-                let locale = LocaleCache.localeICUClass.init(identifier: id, prefs: nil)
+                let locale = _localeICUClass().init(identifier: id, prefs: nil)
                 cachedFixedLocales[id] = locale
                 return locale
             }
@@ -217,7 +214,7 @@ struct LocaleCache : Sendable {
             if let l = cachedFixedComponentsLocales[comps] {
                 return l
             } else {
-                let new = LocaleCache.localeICUClass.init(components: comps)
+                let new = _localeICUClass().init(components: comps)
 
                 cachedFixedComponentsLocales[comps] = new
                 return new
@@ -229,7 +226,7 @@ struct LocaleCache : Sendable {
                 return locale
             }
 
-            let locale = LocaleCache.localeICUClass.init(identifier: "", prefs: nil)
+            let locale = _localeICUClass().init(identifier: "", prefs: nil)
             cachedSystemLocale = locale
             return locale
         }
@@ -415,13 +412,13 @@ struct LocaleCache : Sendable {
         var (prefs, _) = preferences()
         if let overrides { prefs.apply(overrides) }
 
-        let inner = LocaleCache.localeICUClass.init(name: name, prefs: prefs, disableBundleMatching: disableBundleMatching)
+        let inner = _localeICUClass().init(name: name, prefs: prefs, disableBundleMatching: disableBundleMatching)
         return Locale(inner: inner)
     }
 
     func localeWithPreferences(identifier: String, prefs: LocalePreferences?) -> Locale {
         if let prefs {
-            let inner = LocaleCache.localeICUClass.init(identifier: identifier, prefs: prefs)
+            let inner = _localeICUClass().init(identifier: identifier, prefs: prefs)
             return Locale(inner: inner)
         } else {
             return Locale(inner: LocaleCache.cache.fixed(identifier))

Sources/FoundationEssentials/TimeZone/TimeZone_Cache.swift

@@ -31,37 +31,25 @@ internal import _ForSwiftFoundation
 internal import CoreFoundation_Private.CFNotificationCenter
 #endif
 
-/// Singleton which listens for notifications about preference changes for TimeZone and holds cached values for current, fixed time zones, etc.
-struct TimeZoneCache : Sendable {
-    
-    // MARK: - Concrete Classes
-    
-    // _TimeZoneICU, if present
-    static let timeZoneICUClass: _TimeZoneProtocol.Type? = {
-#if FOUNDATION_FRAMEWORK && canImport(_FoundationICU)
-        _TimeZoneICU.self
-#else
-        if let name = _typeByName("FoundationInternationalization._TimeZoneICU"), let t = name as? _TimeZoneProtocol.Type {
-            return t
-        } else {
-            return nil
-        }
-#endif
-    }()
-    
-    // _TimeZoneGMTICU or _TimeZoneGMT
-    static let timeZoneGMTClass: _TimeZoneProtocol.Type = {
+
 #if FOUNDATION_FRAMEWORK && canImport(_FoundationICU)
-        _TimeZoneGMTICU.self
+internal func _timeZoneICUClass() -> _TimeZoneProtocol.Type? {
+    _TimeZoneICU.self
+}
+internal func _timeZoneGMTClass() -> _TimeZoneProtocol.Type {
+    _TimeZoneGMTICU.self
+}
 #else
-        if let name = _typeByName("FoundationInternationalization._TimeZoneGMTICU"), let t = name as? _TimeZoneProtocol.Type {
-            return t
-        } else {
-            return _TimeZoneGMT.self
-        }
+dynamic package func _timeZoneICUClass() -> _TimeZoneProtocol.Type? {
+    nil
+}
+dynamic package func _timeZoneGMTClass() -> _TimeZoneProtocol.Type {
+    _TimeZoneGMT.self
+}
 #endif
-    }()
 
+/// Singleton which listens for notifications about preference changes for TimeZone and holds cached values for current, fixed time zones, etc.
+struct TimeZoneCache : Sendable {
     // MARK: - State
 
     struct State {
@@ -239,7 +227,7 @@ struct TimeZoneCache : Sendable {
             } else if let cached = fixedTimeZones[identifier] {
                 return cached
             } else {
-                if let innerTz = TimeZoneCache.timeZoneICUClass?.init(identifier: identifier) {
+                if let innerTz = _timeZoneICUClass()?.init(identifier: identifier) {
                     fixedTimeZones[identifier] = innerTz
                     return innerTz
                 } else {
@@ -254,7 +242,7 @@ struct TimeZoneCache : Sendable {
             } else {
                 // In order to avoid bloating a cache with weird time zones, only cache values that are 30min offsets (including 1hr offsets).
                 let doCache = abs(offset) % 1800 == 0
-                if let innerTz = TimeZoneCache.timeZoneGMTClass.init(secondsFromGMT: offset) {
+                if let innerTz = _timeZoneGMTClass().init(secondsFromGMT: offset) {
                     if doCache {
                         offsetTimeZones[offset] = innerTz
                     }

Sources/FoundationEssentials/URL/URLParser.swift

@@ -158,17 +158,18 @@ package protocol UIDNAHook {
     static func decode(_ host: some StringProtocol) -> String?
 }
 
+#if FOUNDATION_FRAMEWORK && canImport(_FoundationICU)
+internal func _uidnaHook() -> UIDNAHook.Type? {
+    UIDNAHookICU.self
+}
+#else
+dynamic package func _uidnaHook() -> UIDNAHook.Type? {
+    nil
+}
+#endif
+
 internal struct RFC3986Parser: URLParserProtocol {
     static let kind: URLParserKind = .RFC3986
-    static let uidnaHook: UIDNAHook.Type? = {
-        #if FOUNDATION_FRAMEWORK && !canImport(_FoundationICU)
-        nil
-        #elseif FOUNDATION_FRAMEWORK
-        UIDNAHookICU.self
-        #else
-        _typeByName("FoundationInternationalization.UIDNAHookICU") as? UIDNAHook.Type
-        #endif
-    }()
 
     // MARK: - Encoding
 
@@ -233,7 +234,7 @@ internal struct RFC3986Parser: URLParserProtocol {
     }
 
     static func shouldPercentEncodeHost(_ host: some StringProtocol, forScheme scheme: (some StringProtocol)?) -> Bool {
-        guard uidnaHook != nil else {
+        guard _uidnaHook() != nil else {
             // Always percent-encode the host if we can't access UIDNA encoding functions
             return true
         }
@@ -279,13 +280,13 @@ internal struct RFC3986Parser: URLParserProtocol {
     static func IDNAEncodeHost(_ host: (some StringProtocol)?) -> String? {
         guard let host else { return nil }
         guard !host.isEmpty else { return "" }
-        return uidnaHook?.encode(host)
+        return _uidnaHook()?.encode(host)
     }
 
     static func IDNADecodeHost(_ host: (some StringProtocol)?) -> String? {
         guard let host else { return nil }
         guard !host.isEmpty else { return "" }
-        guard let uidnaHook else { return String(host) }
+        guard let uidnaHook = _uidnaHook() else { return String(host) }
         return uidnaHook.decode(host)
     }
 

Sources/FoundationInternationalization/Calendar/Calendar_ICU.swift

@@ -26,6 +26,13 @@ import Darwin
 
 internal import _FoundationICU
 
+#if !FOUNDATION_FRAMEWORK
+@_dynamicReplacement(for: _calendarICUClass())
+private func _calendarICUClass_localized() -> _CalendarProtocol.Type? {
+    return _CalendarICU.self
+}
+#endif
+
 internal final class _CalendarICU: _CalendarProtocol, @unchecked Sendable {
     let lock: LockedState<Void>
     let identifier: Calendar.Identifier

Sources/FoundationInternationalization/Locale/Locale_ICU.swift

@@ -27,6 +27,13 @@ internal import _FoundationICU
 import Glibc
 #endif
 
+#if !FOUNDATION_FRAMEWORK
+@_dynamicReplacement(for: _localeICUClass())
+private func _localeICUClass_localized() -> any _LocaleProtocol.Type {
+    return _LocaleICU.self
+}
+#endif
+
 let MAX_ICU_NAME_SIZE: Int32 = 1024
 
 internal final class _LocaleICU: _LocaleProtocol, Sendable {

Sources/FoundationInternationalization/TimeZone/TimeZone_GMTICU.swift

@@ -16,6 +16,13 @@ import FoundationEssentials
 
 internal import _FoundationICU
 
+#if !FOUNDATION_FRAMEWORK
+@_dynamicReplacement(for: _timeZoneGMTClass())
+private func _timeZoneGMTClass_localized() -> _TimeZoneProtocol.Type {
+    return _TimeZoneGMTICU.self
+}
+#endif
+
 internal final class _TimeZoneGMTICU : _TimeZoneProtocol, @unchecked Sendable {
     let offset: Int
     let name: String

Sources/FoundationInternationalization/TimeZone/TimeZone_ICU.swift

@@ -25,6 +25,13 @@ import ucrt
 #if canImport(_FoundationICU)
 internal import _FoundationICU
 
+#if !FOUNDATION_FRAMEWORK
+@_dynamicReplacement(for: _timeZoneICUClass())
+private func _timeZoneICUClass_localized() -> _TimeZoneProtocol.Type? {
+    return _TimeZoneICU.self
+}
+#endif
+
 internal final class _TimeZoneICU: _TimeZoneProtocol, Sendable {
     init?(secondsFromGMT: Int) {
         fatalError("Unexpected init")

Sources/FoundationInternationalization/URLParser+ICU.swift

@@ -15,7 +15,14 @@ import FoundationEssentials
 
 internal import _FoundationICU
 
-internal final class UIDNAHookICU: UIDNAHook {
+#if !FOUNDATION_FRAMEWORK
+@_dynamicReplacement(for: _uidnaHook())
+private func _uidnaHook_localized() -> UIDNAHook.Type? {
+    return UIDNAHookICU.self
+}
+#endif
+
+struct UIDNAHookICU: UIDNAHook {
     // `Sendable` notes: `UIDNA` from ICU is thread safe.
     struct UIDNAPointer : @unchecked Sendable {
         init(_ ptr: OpaquePointer?) { self.idnaTranscoder = ptr }