Add shouldNotifyObservers to ObservableState

.github/workflows/ci.yml

@@ -21,7 +21,7 @@ jobs:
       matrix:
         command: [test, '']
         platform: [IOS, MACOS]
-        xcode: ['16.2']
+        xcode: ['16.4']
     steps:
       - uses: actions/checkout@v4
       - name: Select Xcode ${{ matrix.xcode }}
@@ -49,6 +49,9 @@ jobs:
   examples:
     name: Examples
     runs-on: macos-15
+    strategy:
+      matrix:
+        xcode: ['16.4']
     steps:
       - uses: actions/checkout@v4
       - name: Cache derived data
@@ -60,7 +63,7 @@ jobs:
           restore-keys: |
             deriveddata-examples-
       - name: Select Xcode 16
-        run: sudo xcode-select -s /Applications/Xcode_16.2.app
+        run: sudo xcode-select -s /Applications/Xcode_${{ matrix.xcode }}.app
       - name: Update xcbeautify
         run: brew update && brew upgrade xcbeautify
       - name: Set IgnoreFileSystemDeviceInodeChanges flag

Sources/ComposableArchitecture/Macros.swift

@@ -128,7 +128,7 @@ public macro ReducerCaseIgnored() =
 
 /// Defines and implements conformance of the Observable protocol.
 @attached(extension, conformances: Observable, ObservableState)
-@attached(member, names: named(_$id), named(_$observationRegistrar), named(_$willModify))
+@attached(member, names: named(_$id), named(_$observationRegistrar), named(_$willModify), named(shouldNotifyObservers))
 @attached(memberAttribute)
 public macro ObservableState() =
   #externalMacro(module: "ComposableArchitectureMacros", type: "ObservableStateMacro")

Sources/ComposableArchitecture/Observation/ObservationStateRegistrar.swift

@@ -51,9 +51,10 @@ extension ObservationStateRegistrar: Equatable, Hashable, Codable {
       keyPath: KeyPath<Subject, Member>,
       _ value: inout Value,
       _ newValue: Value,
-      _ isIdentityEqual: (Value, Value) -> Bool
+      _ isIdentityEqual: (Value, Value) -> Bool,
+      _ shouldNotifyObservers: (Value, Value) -> Bool = { _, _ in true }
     ) {
-      if isIdentityEqual(value, newValue) {
+      if isIdentityEqual(value, newValue) || !shouldNotifyObservers(value, newValue) {
         value = newValue
       } else {
         self.registrar.withMutation(of: subject, keyPath: keyPath) {
@@ -101,12 +102,20 @@ extension ObservationStateRegistrar: Equatable, Hashable, Codable {
       keyPath: KeyPath<Subject, Member>,
       _ member: inout Member,
       _ oldValue: Member,
-      _ isIdentityEqual: (Member, Member) -> Bool
+      _ isIdentityEqual: (Member, Member) -> Bool,
+      _ shouldNotifyObservers: (Member, Member) -> Bool = { _, _ in true }
     ) {
       if !isIdentityEqual(oldValue, member) {
         let newValue = member
         member = oldValue
-        self.mutate(subject, keyPath: keyPath, &member, newValue, isIdentityEqual)
+        self.mutate(
+          subject,
+          keyPath: keyPath,
+          &member,
+          newValue,
+          isIdentityEqual,
+          shouldNotifyObservers
+        )
       }
     }
   }
@@ -130,9 +139,10 @@ extension ObservationStateRegistrar: Equatable, Hashable, Codable {
       keyPath: KeyPath<Subject, Member>,
       _ value: inout Value,
       _ newValue: Value,
-      _ isIdentityEqual: (Value, Value) -> Bool
+      _ isIdentityEqual: (Value, Value) -> Bool,
+      _ shouldNotifyObservers: (Value, Value) -> Bool = { _, _ in true }
     ) {
-      if isIdentityEqual(value, newValue) {
+      if isIdentityEqual(value, newValue) || !shouldNotifyObservers(value, newValue) {
         value = newValue
       } else {
         self.registrar.withMutation(of: subject, keyPath: keyPath) {
@@ -169,12 +179,20 @@ extension ObservationStateRegistrar: Equatable, Hashable, Codable {
       keyPath: KeyPath<Subject, Member>,
       _ member: inout Member,
       _ oldValue: Member,
-      _ isIdentityEqual: (Member, Member) -> Bool
+      _ isIdentityEqual: (Member, Member) -> Bool,
+      _ shouldNotifyObservers: (Member, Member) -> Bool = { _, _ in true }
     ) {
       if !isIdentityEqual(oldValue, member) {
         let newValue = member
         member = oldValue
-        self.mutate(subject, keyPath: keyPath, &member, newValue, isIdentityEqual)
+        self.mutate(
+          subject,
+          keyPath: keyPath,
+          &member,
+          newValue,
+          isIdentityEqual,
+          shouldNotifyObservers
+        )
       }
     }
   }

Sources/ComposableArchitectureMacros/ObservableStateMacro.swift

@@ -77,6 +77,38 @@ public struct ObservableStateMacro {
       """
   }
 
+  static func shouldNotifyObserversNonEquatableFunction(_ perceptibleType: TokenSyntax, context: some MacroExpansionContext) -> DeclSyntax {
+    let memberGeneric = context.makeUniqueName("Member")
+    return
+      """
+       private nonisolated func shouldNotifyObservers<\(memberGeneric)>(_ lhs: \(memberGeneric), _ rhs: \(memberGeneric)) -> Bool { true }
+      """
+  }
+
+  static func shouldNotifyObserversEquatableFunction(_ perceptibleType: TokenSyntax, context: some MacroExpansionContext) -> DeclSyntax {
+    let memberGeneric = context.makeUniqueName("Member")
+    return
+      """
+      private nonisolated func shouldNotifyObservers<\(memberGeneric): Equatable>(_ lhs: \(memberGeneric), _ rhs: \(memberGeneric)) -> Bool { lhs != rhs }
+      """
+  }
+
+  static func shouldNotifyObserversNonEquatableObjectFunction(_ perceptibleType: TokenSyntax, context: some MacroExpansionContext) -> DeclSyntax {
+    let memberGeneric = context.makeUniqueName("Member")
+    return
+      """
+       private nonisolated func shouldNotifyObservers<\(memberGeneric): AnyObject>(_ lhs: \(memberGeneric), _ rhs: \(memberGeneric)) -> Bool { lhs !== rhs }
+      """
+  }
+
+  static func shouldNotifyObserversEquatableObjectFunction(_ perceptibleType: TokenSyntax, context: some MacroExpansionContext) -> DeclSyntax {
+    let memberGeneric = context.makeUniqueName("Member")
+    return
+      """
+      private nonisolated func shouldNotifyObservers<\(memberGeneric): Equatable & AnyObject>(_ lhs: \(memberGeneric), _ rhs: \(memberGeneric)) -> Bool { lhs != rhs }
+      """
+  }
+
   static var ignoredAttribute: AttributeSyntax {
     AttributeSyntax(
       leadingTrivia: .space,
@@ -298,6 +330,10 @@ extension ObservableStateMacro: MemberMacro {
     )
     declaration.addIfNeeded(ObservableStateMacro.idVariable(), to: &declarations)
     declaration.addIfNeeded(ObservableStateMacro.willModifyFunction(), to: &declarations)
+    declaration.addIfNeeded(ObservableStateMacro.shouldNotifyObserversNonEquatableFunction(observableType, context: context), to: &declarations)
+    declaration.addIfNeeded(ObservableStateMacro.shouldNotifyObserversEquatableFunction(observableType, context: context), to: &declarations)
+    declaration.addIfNeeded(ObservableStateMacro.shouldNotifyObserversNonEquatableObjectFunction(observableType, context: context), to: &declarations)
+    declaration.addIfNeeded(ObservableStateMacro.shouldNotifyObserversEquatableObjectFunction(observableType, context: context), to: &declarations)
 
     return declarations
   }
@@ -611,7 +647,7 @@ public struct ObservationStateTrackedMacro: AccessorMacro {
     let setAccessor: AccessorDeclSyntax =
       """
       set {
-      \(raw: ObservableStateMacro.registrarVariableName).mutate(self, keyPath: \\.\(identifier), &_\(identifier), newValue, _$isIdentityEqual)
+      \(raw: ObservableStateMacro.registrarVariableName).mutate(self, keyPath: \\.\(identifier), &_\(identifier), newValue, _$isIdentityEqual, shouldNotifyObservers)
       }
       """
     let modifyAccessor: AccessorDeclSyntax = """

Tests/ComposableArchitectureMacrosTests/MacroBaseTestCase.swift

@@ -8,7 +8,7 @@
   class MacroBaseTestCase: XCTestCase {
     override func invokeTest() {
       MacroTesting.withMacroTesting(
-        //isRecording: true,
+        record: .failed,
         macros: [
           ObservableStateMacro.self,
           ObservationStateTrackedMacro.self,

Tests/ComposableArchitectureMacrosTests/ObservableStateMacroTests.swift

@@ -7,7 +7,9 @@
 
   final class ObservableStateMacroTests: MacroBaseTestCase {
     override func invokeTest() {
-      withMacroTesting {
+      withMacroTesting(
+        // record: .failed,
+      ) {
         super.invokeTest()
       }
     }
@@ -35,7 +37,7 @@
               return _count
             }
             set {
-              _$observationRegistrar.mutate(self, keyPath: \.count, &_count, newValue, _$isIdentityEqual)
+              _$observationRegistrar.mutate(self, keyPath: \.count, &_count, newValue, _$isIdentityEqual, shouldNotifyObservers)
             }
             _modify {
               let oldValue = _$observationRegistrar.willModify(self, keyPath: \.count, &_count)
@@ -55,6 +57,22 @@
           public mutating func _$willModify() {
             _$observationRegistrar._$willModify()
           }
+
+          private nonisolated func shouldNotifyObservers<__macro_local_6MemberfMu_>(_ lhs: __macro_local_6MemberfMu_, _ rhs: __macro_local_6MemberfMu_) -> Bool {
+            true
+          }
+
+          private nonisolated func shouldNotifyObservers<__macro_local_6MemberfMu0_: Equatable>(_ lhs: __macro_local_6MemberfMu0_, _ rhs: __macro_local_6MemberfMu0_) -> Bool {
+            lhs != rhs
+          }
+
+          private nonisolated func shouldNotifyObservers<__macro_local_6MemberfMu1_: AnyObject>(_ lhs: __macro_local_6MemberfMu1_, _ rhs: __macro_local_6MemberfMu1_) -> Bool {
+            lhs !== rhs
+          }
+
+          private nonisolated func shouldNotifyObservers<__macro_local_6MemberfMu2_: Equatable & AnyObject>(_ lhs: __macro_local_6MemberfMu2_, _ rhs: __macro_local_6MemberfMu2_) -> Bool {
+            lhs != rhs
+          }
         }
         """#
       }
@@ -81,7 +99,7 @@
               return _count
             }
             set {
-              _$observationRegistrar.mutate(self, keyPath: \.count, &_count, newValue, _$isIdentityEqual)
+              _$observationRegistrar.mutate(self, keyPath: \.count, &_count, newValue, _$isIdentityEqual, shouldNotifyObservers)
             }
             _modify {
               let oldValue = _$observationRegistrar.willModify(self, keyPath: \.count, &_count)
@@ -101,6 +119,22 @@
           public mutating func _$willModify() {
             _$observationRegistrar._$willModify()
           }
+
+          private nonisolated func shouldNotifyObservers<__macro_local_6MemberfMu_>(_ lhs: __macro_local_6MemberfMu_, _ rhs: __macro_local_6MemberfMu_) -> Bool {
+            true
+          }
+
+          private nonisolated func shouldNotifyObservers<__macro_local_6MemberfMu0_: Equatable>(_ lhs: __macro_local_6MemberfMu0_, _ rhs: __macro_local_6MemberfMu0_) -> Bool {
+            lhs != rhs
+          }
+
+          private nonisolated func shouldNotifyObservers<__macro_local_6MemberfMu1_: AnyObject>(_ lhs: __macro_local_6MemberfMu1_, _ rhs: __macro_local_6MemberfMu1_) -> Bool {
+            lhs !== rhs
+          }
+
+          private nonisolated func shouldNotifyObservers<__macro_local_6MemberfMu2_: Equatable & AnyObject>(_ lhs: __macro_local_6MemberfMu2_, _ rhs: __macro_local_6MemberfMu2_) -> Bool {
+            lhs != rhs
+          }
         }
         """#
       }
@@ -127,7 +161,7 @@
               return _count
             }
             set {
-              _$observationRegistrar.mutate(self, keyPath: \.count, &_count, newValue, _$isIdentityEqual)
+              _$observationRegistrar.mutate(self, keyPath: \.count, &_count, newValue, _$isIdentityEqual, shouldNotifyObservers)
             }
             _modify {
               let oldValue = _$observationRegistrar.willModify(self, keyPath: \.count, &_count)
@@ -147,6 +181,22 @@
           public mutating func _$willModify() {
             _$observationRegistrar._$willModify()
           }
+
+          private nonisolated func shouldNotifyObservers<__macro_local_6MemberfMu_>(_ lhs: __macro_local_6MemberfMu_, _ rhs: __macro_local_6MemberfMu_) -> Bool {
+            true
+          }
+
+          private nonisolated func shouldNotifyObservers<__macro_local_6MemberfMu0_: Equatable>(_ lhs: __macro_local_6MemberfMu0_, _ rhs: __macro_local_6MemberfMu0_) -> Bool {
+            lhs != rhs
+          }
+
+          private nonisolated func shouldNotifyObservers<__macro_local_6MemberfMu1_: AnyObject>(_ lhs: __macro_local_6MemberfMu1_, _ rhs: __macro_local_6MemberfMu1_) -> Bool {
+            lhs !== rhs
+          }
+
+          private nonisolated func shouldNotifyObservers<__macro_local_6MemberfMu2_: Equatable & AnyObject>(_ lhs: __macro_local_6MemberfMu2_, _ rhs: __macro_local_6MemberfMu2_) -> Bool {
+            lhs != rhs
+          }
         }
         """#
       }
@@ -170,7 +220,7 @@
               return _count
             }
             set {
-              _$observationRegistrar.mutate(self, keyPath: \.count, &_count, newValue, _$isIdentityEqual)
+              _$observationRegistrar.mutate(self, keyPath: \.count, &_count, newValue, _$isIdentityEqual, shouldNotifyObservers)
             }
             _modify {
               let oldValue = _$observationRegistrar.willModify(self, keyPath: \.count, &_count)
@@ -190,6 +240,22 @@
           public mutating func _$willModify() {
             _$observationRegistrar._$willModify()
           }
+
+          private nonisolated func shouldNotifyObservers<__macro_local_6MemberfMu_>(_ lhs: __macro_local_6MemberfMu_, _ rhs: __macro_local_6MemberfMu_) -> Bool {
+            true
+          }
+
+          private nonisolated func shouldNotifyObservers<__macro_local_6MemberfMu0_: Equatable>(_ lhs: __macro_local_6MemberfMu0_, _ rhs: __macro_local_6MemberfMu0_) -> Bool {
+            lhs != rhs
+          }
+
+          private nonisolated func shouldNotifyObservers<__macro_local_6MemberfMu1_: AnyObject>(_ lhs: __macro_local_6MemberfMu1_, _ rhs: __macro_local_6MemberfMu1_) -> Bool {
+            lhs !== rhs
+          }
+
+          private nonisolated func shouldNotifyObservers<__macro_local_6MemberfMu2_: Equatable & AnyObject>(_ lhs: __macro_local_6MemberfMu2_, _ rhs: __macro_local_6MemberfMu2_) -> Bool {
+            lhs != rhs
+          }
         }
         """#
       }
@@ -218,6 +284,22 @@
           public mutating func _$willModify() {
             _$observationRegistrar._$willModify()
           }
+
+          private nonisolated func shouldNotifyObservers<__macro_local_6MemberfMu_>(_ lhs: __macro_local_6MemberfMu_, _ rhs: __macro_local_6MemberfMu_) -> Bool {
+            true
+          }
+
+          private nonisolated func shouldNotifyObservers<__macro_local_6MemberfMu0_: Equatable>(_ lhs: __macro_local_6MemberfMu0_, _ rhs: __macro_local_6MemberfMu0_) -> Bool {
+            lhs != rhs
+          }
+
+          private nonisolated func shouldNotifyObservers<__macro_local_6MemberfMu1_: AnyObject>(_ lhs: __macro_local_6MemberfMu1_, _ rhs: __macro_local_6MemberfMu1_) -> Bool {
+            lhs !== rhs
+          }
+
+          private nonisolated func shouldNotifyObservers<__macro_local_6MemberfMu2_: Equatable & AnyObject>(_ lhs: __macro_local_6MemberfMu2_, _ rhs: __macro_local_6MemberfMu2_) -> Bool {
+            lhs != rhs
+          }
         }
         """
       }
@@ -673,6 +755,22 @@
           public mutating func _$willModify() {
             _$observationRegistrar._$willModify()
           }
+
+          private nonisolated func shouldNotifyObservers<__macro_local_6MemberfMu_>(_ lhs: __macro_local_6MemberfMu_, _ rhs: __macro_local_6MemberfMu_) -> Bool {
+            true
+          }
+
+          private nonisolated func shouldNotifyObservers<__macro_local_6MemberfMu0_: Equatable>(_ lhs: __macro_local_6MemberfMu0_, _ rhs: __macro_local_6MemberfMu0_) -> Bool {
+            lhs != rhs
+          }
+
+          private nonisolated func shouldNotifyObservers<__macro_local_6MemberfMu1_: AnyObject>(_ lhs: __macro_local_6MemberfMu1_, _ rhs: __macro_local_6MemberfMu1_) -> Bool {
+            lhs !== rhs
+          }
+
+          private nonisolated func shouldNotifyObservers<__macro_local_6MemberfMu2_: Equatable & AnyObject>(_ lhs: __macro_local_6MemberfMu2_, _ rhs: __macro_local_6MemberfMu2_) -> Bool {
+            lhs != rhs
+          }
         }
         """
       }

Tests/ComposableArchitectureMacrosTests/PresentsMacroTests.swift

@@ -8,7 +8,7 @@
   final class PresentsMacroTests: XCTestCase {
     override func invokeTest() {
       withMacroTesting(
-        // isRecording: true,
+        // record: .failed,
         macros: [PresentsMacro.self]
       ) {
         super.invokeTest()
@@ -200,6 +200,22 @@
           public mutating func _$willModify() {
             _$observationRegistrar._$willModify()
           }
+
+          private nonisolated func shouldNotifyObservers<__macro_local_6MemberfMu_>(_ lhs: __macro_local_6MemberfMu_, _ rhs: __macro_local_6MemberfMu_) -> Bool {
+            true
+          }
+
+          private nonisolated func shouldNotifyObservers<__macro_local_6MemberfMu0_: Equatable>(_ lhs: __macro_local_6MemberfMu0_, _ rhs: __macro_local_6MemberfMu0_) -> Bool {
+            lhs != rhs
+          }
+
+          private nonisolated func shouldNotifyObservers<__macro_local_6MemberfMu1_: AnyObject>(_ lhs: __macro_local_6MemberfMu1_, _ rhs: __macro_local_6MemberfMu1_) -> Bool {
+            lhs !== rhs
+          }
+
+          private nonisolated func shouldNotifyObservers<__macro_local_6MemberfMu2_: Equatable & AnyObject>(_ lhs: __macro_local_6MemberfMu2_, _ rhs: __macro_local_6MemberfMu2_) -> Bool {
+            lhs != rhs
+          }
         }
         """#
       }