rdar://152532669 (Work around inefficient compiler-synthesized Codable conformance of enums)

kperryua · Charles Hu · commit 6078dda7d152 · 2025-07-14T14:36:28.000-07:00
diff --git a/Sources/FoundationEssentials/AttributedString/FoundationAttributes.swift b/Sources/FoundationEssentials/AttributedString/FoundationAttributes.swift
@@ -520,6 +520,11 @@ extension AttributeScopes.FoundationAttributes {
             case spelledOutValue
             case unit(Unit)
             case actualByteCount
+            
+            private typealias ValueCodingKeys = EmptyCodingKeys
+            private typealias SpelledOutValueCodingKeys = EmptyCodingKeys
+            private typealias UnitCodingKeys = DefaultAssociatedValueCodingKeys1
+            private typealias ActualByteCountCodingKeys = EmptyCodingKeys
         }
         
         public enum Unit: Codable, Sendable {
@@ -532,6 +537,16 @@ extension AttributeScopes.FoundationAttributes {
             case eb
             case zb
             case yb
+            
+            private typealias ByteCodingKeys = EmptyCodingKeys
+            private typealias KbCodingKeys = EmptyCodingKeys
+            private typealias MbCodingKeys = EmptyCodingKeys
+            private typealias GbCodingKeys = EmptyCodingKeys
+            private typealias TbCodingKeys = EmptyCodingKeys
+            private typealias PbCodingKeys = EmptyCodingKeys
+            private typealias EbCodingKeys = EmptyCodingKeys
+            private typealias ZbCodingKeys = EmptyCodingKeys
+            private typealias YbCodingKeys = EmptyCodingKeys
         }
     }
 
@@ -583,6 +598,11 @@ extension AttributeScopes.FoundationAttributes {
                 case int(Int64)
                 case double(Double)
                 case decimal(Decimal)
+                
+                private typealias UintCodingKeys = DefaultAssociatedValueCodingKeys1
+                private typealias IntCodingKeys = DefaultAssociatedValueCodingKeys1
+                private typealias DoubleCodingKeys = DefaultAssociatedValueCodingKeys1
+                private typealias DecimalCodingKeys = DefaultAssociatedValueCodingKeys1
             }
         }
         
@@ -941,5 +961,8 @@ extension AttributedString {
         /// - Note: In vertical scripts, this equivalent to a bottom-to-top
         /// writing direction.
         case rightToLeft
+        
+        private typealias LeftToRightCodingKeys = EmptyCodingKeys
+        private typealias RightToLeftCodingKeys = EmptyCodingKeys
     }
 }
diff --git a/Sources/FoundationEssentials/Calendar/Calendar.swift b/Sources/FoundationEssentials/Calendar/Calendar.swift
@@ -94,6 +94,34 @@ public struct Calendar : Hashable, Equatable, Sendable {
         
         @available(FoundationPreview 6.2, *)
         case vietnamese
+        
+        private typealias GregorianCodingKeys = EmptyCodingKeys
+        private typealias ChineseCodingKeys = EmptyCodingKeys
+        private typealias BuddhistCodingKeys = EmptyCodingKeys
+        private typealias CopticCodingKeys = EmptyCodingKeys
+        private typealias EthiopicAmeteMihretCodingKeys = EmptyCodingKeys
+        private typealias EthiopicAmeteAlemCodingKeys = EmptyCodingKeys
+        private typealias HebrewCodingKeys = EmptyCodingKeys
+        private typealias Iso8601CodingKeys = EmptyCodingKeys
+        private typealias IndianCodingKeys = EmptyCodingKeys
+        private typealias IslamicCodingKeys = EmptyCodingKeys
+        private typealias IslamicCivilCodingKeys = EmptyCodingKeys
+        private typealias JapaneseCodingKeys = EmptyCodingKeys
+        private typealias PersianCodingKeys = EmptyCodingKeys
+        private typealias RepublicOfChinaCodingKeys = EmptyCodingKeys
+        private typealias IslamicTabularCodingKeys = EmptyCodingKeys
+        private typealias IslamicUmmAlQuraCodingKeys = EmptyCodingKeys
+        private typealias BanglaCodingKeys = EmptyCodingKeys
+        private typealias GujaratiCodingKeys = EmptyCodingKeys
+        private typealias KannadaCodingKeys = EmptyCodingKeys
+        private typealias MalayalamCodingKeys = EmptyCodingKeys
+        private typealias MarathiCodingKeys = EmptyCodingKeys
+        private typealias OdiaCodingKeys = EmptyCodingKeys
+        private typealias TamilCodingKeys = EmptyCodingKeys
+        private typealias TeluguCodingKeys = EmptyCodingKeys
+        private typealias VikramCodingKeys = EmptyCodingKeys
+        private typealias DangiCodingKeys = EmptyCodingKeys
+        private typealias VietnameseCodingKeys = EmptyCodingKeys
 
         package static let cldrKeywordKey = "ca"
         package static let legacyKeywordKey = ICULegacyKey("calendar")
diff --git a/Sources/FoundationEssentials/CodableUtilities.swift b/Sources/FoundationEssentials/CodableUtilities.swift
@@ -687,3 +687,14 @@ extension BufferView where Element == UInt8 {
     }
 }
 
+// Non-RawRepresentable Codable enum cases with the same number and labels of associated values all share equivalent CodingKeys, but the compiler-synthesized implementation generates a new type for each case.
+// Each of these types has their own set of `metadata instantiation cache for protocol conformance descriptor` symbols for each of 5 protocol conformances which consumes DATA space.
+// Instead of using the synthesized CodingKey types, you can make a `private typealias <CaseName>CodingKeys = <one of these types>` inside the Codable enum to reduce the amount of redundant DATA.
+package enum EmptyCodingKeys: CodingKey { }
+package enum DefaultAssociatedValueCodingKeys1: String, CodingKey {
+    case _0
+}
+package enum DefaultAssociatedValueCodingKeys2: String, CodingKey {
+    case _0
+    case _1
+}
diff --git a/Sources/FoundationEssentials/Predicate/Expressions/Arithmetic.swift b/Sources/FoundationEssentials/Predicate/Expressions/Arithmetic.swift
@@ -14,6 +14,10 @@
 extension PredicateExpressions {
     public enum ArithmeticOperator: Codable, Sendable {
         case add, subtract, multiply
+        
+        private typealias AddCodingKeys = EmptyCodingKeys
+        private typealias SubtractCodingKeys = EmptyCodingKeys
+        private typealias MultiplyCodingKeys = EmptyCodingKeys
     }
     
     public struct Arithmetic<
diff --git a/Sources/FoundationEssentials/Predicate/Expressions/Comparison.swift b/Sources/FoundationEssentials/Predicate/Expressions/Comparison.swift
@@ -14,6 +14,11 @@
 extension PredicateExpressions {
     public enum ComparisonOperator: Codable, Sendable {
         case lessThan, lessThanOrEqual, greaterThan, greaterThanOrEqual
+        
+        private typealias LessThanCodingKeys = EmptyCodingKeys
+        private typealias LessThanOrEqualCodingKeys = EmptyCodingKeys
+        private typealias GreaterThanCodingKeys = EmptyCodingKeys
+        private typealias GreaterThanOrEqualCodingKeys = EmptyCodingKeys
     }
 
     public struct Comparison<
diff --git a/Sources/FoundationInternationalization/Formatting/Date/Date+RelativeFormatStyle.swift b/Sources/FoundationInternationalization/Formatting/Date/Date+RelativeFormatStyle.swift
@@ -150,6 +150,9 @@ extension Date {
         enum ComponentAdjustmentStrategy : Codable, Hashable {
             case alignedWithComponentBoundary
             case rounded
+            
+            private typealias AlignedWithComponentBoundaryCodingKeys = EmptyCodingKeys
+            private typealias RoundedCodingKeys = EmptyCodingKeys
         }
 
         var componentAdjustmentStrategy: ComponentAdjustmentStrategy {
diff --git a/Sources/FoundationInternationalization/Formatting/Date/DateFormatStyle.swift b/Sources/FoundationInternationalization/Formatting/Date/DateFormatStyle.swift
@@ -297,7 +297,11 @@ extension Date {
         enum InnerStyle: Codable, Hashable {
             case formatStyle(Date.FormatStyle)
             case verbatimFormatStyle(VerbatimFormatStyle)
+            
+            private typealias FormatStyleCodingKeys = DefaultAssociatedValueCodingKeys1
+            private typealias VerbatimFormatStyleCodingKeys = DefaultAssociatedValueCodingKeys1
         }
+        
         var innerStyle: InnerStyle
 
         init(style: InnerStyle) {
diff --git a/Sources/FoundationInternationalization/Formatting/Number/Decimal+FormatStyle.swift b/Sources/FoundationInternationalization/Formatting/Number/Decimal+FormatStyle.swift
@@ -267,6 +267,10 @@ extension Decimal.FormatStyle {
             case decimal(Decimal.FormatStyle)
             case currency(Decimal.FormatStyle.Currency)
             case percent(Decimal.FormatStyle.Percent)
+            
+            private typealias DecimalCodingKeys = DefaultAssociatedValueCodingKeys1
+            private typealias CurrencyCodingKeys = DefaultAssociatedValueCodingKeys1
+            private typealias PercentCodingKeys = DefaultAssociatedValueCodingKeys1
         }
 
         var style: Style
diff --git a/Sources/FoundationInternationalization/Formatting/Number/FloatingPointFormatStyle.swift b/Sources/FoundationInternationalization/Formatting/Number/FloatingPointFormatStyle.swift
@@ -344,6 +344,10 @@ extension FloatingPointFormatStyle {
             case floatingPoint(FloatingPointFormatStyle)
             case currency(FloatingPointFormatStyle.Currency)
             case percent(FloatingPointFormatStyle.Percent)
+            
+            private typealias FloatingPointCodingKeys = DefaultAssociatedValueCodingKeys1
+            private typealias CurrencyCodingKeys = DefaultAssociatedValueCodingKeys1
+            private typealias PercentCodingKeys = DefaultAssociatedValueCodingKeys1
 
             var formatter: ICUNumberFormatterBase? {
                 switch self {
diff --git a/Sources/FoundationInternationalization/Formatting/Number/ICULegacyNumberFormatter.swift b/Sources/FoundationInternationalization/Formatting/Number/ICULegacyNumberFormatter.swift
@@ -125,6 +125,10 @@ internal final class ICULegacyNumberFormatter : @unchecked Sendable {
         case percent(NumberFormatStyleConfiguration.Collection)
         case currency(CurrencyFormatStyleConfiguration.Collection, currencyCode: String)
         case descriptive(DescriptiveNumberFormatConfiguration.Collection)
+        
+        private typealias NumberCodingKeys = DefaultAssociatedValueCodingKeys1
+        private typealias PercentCodingKeys = DefaultAssociatedValueCodingKeys1
+        private typealias DescriptiveCodingKeys = DefaultAssociatedValueCodingKeys1
     }
 
     private struct Signature : Hashable {
diff --git a/Sources/FoundationInternationalization/Formatting/Number/IntegerFormatStyle.swift b/Sources/FoundationInternationalization/Formatting/Number/IntegerFormatStyle.swift
@@ -492,6 +492,10 @@ extension IntegerFormatStyle {
             case integer(IntegerFormatStyle)
             case percent(IntegerFormatStyle.Percent)
             case currency(IntegerFormatStyle.Currency)
+            
+            private typealias IntegerCodingKeys = DefaultAssociatedValueCodingKeys1
+            private typealias PercentCodingKeys = DefaultAssociatedValueCodingKeys1
+            private typealias CurrencyCodingKeys = DefaultAssociatedValueCodingKeys1
         }
 
         var style: Style

Original file line number	Diff line number	Diff line change
`@@ -687,3 +687,14 @@ extension BufferView where Element == UInt8 {`
`687`	`687`	`}`
`688`	`688`	`}`
`689`	`689`
	`690`	`+// Non-RawRepresentable Codable enum cases with the same number and labels of associated values all share equivalent CodingKeys, but the compiler-synthesized implementation generates a new type for each case.`
	`691`	+// Each of these types has their own set of `metadata instantiation cache for protocol conformance descriptor` symbols for each of 5 protocol conformances which consumes DATA space.
	`692`	+// Instead of using the synthesized CodingKey types, you can make a `private typealias <CaseName>CodingKeys = <one of these types>` inside the Codable enum to reduce the amount of redundant DATA.
	`693`	`+package enum EmptyCodingKeys: CodingKey { }`
	`694`	`+package enum DefaultAssociatedValueCodingKeys1: String, CodingKey {`
	`695`	`+ case _0`
	`696`	`+}`
	`697`	`+package enum DefaultAssociatedValueCodingKeys2: String, CodingKey {`
	`698`	`+ case _0`
	`699`	`+ case _1`
	`700`	`+}`
Original file line number	Diff line number	Diff line change
`@@ -150,6 +150,9 @@ extension Date {`
`150`	`150`	`enum ComponentAdjustmentStrategy : Codable, Hashable {`
`151`	`151`	`case alignedWithComponentBoundary`
`152`	`152`	`case rounded`
	`153`	`+`
	`154`	`+ private typealias AlignedWithComponentBoundaryCodingKeys = EmptyCodingKeys`
	`155`	`+ private typealias RoundedCodingKeys = EmptyCodingKeys`
`153`	`156`	`}`
`154`	`157`
`155`	`158`	`var componentAdjustmentStrategy: ComponentAdjustmentStrategy {`