Support nested enum reducer (#2813) (#2814)

* Support nested enum reducer (#2813)

* Support nested enum reducer without Macro (#2813)

* Support nested enum reducer without Macro (#2813)

* Support nested enum reducer with default initializer (#2813)

* Minor fixes (#2813)

* Minor fixes (#2813)

---------

Co-authored-by: kobayashi_shoto <[email protected]>

Author: sk409

Sources/ComposableArchitectureMacros/ReducerMacro.swift

@@ -467,7 +467,7 @@ private enum ReducerCase {
         let parameter = parameterClause.parameters.first,
         parameter.type.is(IdentifierTypeSyntax.self) || parameter.type.is(MemberTypeSyntax.self)
       {
-        let stateCase = attribute == .ephemeral ? element : element.suffixed("State")
+        let stateCase = attribute == .ephemeral ? element : element.suffixed("State").type
         return "case \(stateCase.trimmedDescription)"
       } else {
         return "case \(element.trimmedDescription)"
@@ -495,7 +495,7 @@ private enum ReducerCase {
         let parameter = parameterClause.parameters.first,
         parameter.type.is(IdentifierTypeSyntax.self) || parameter.type.is(MemberTypeSyntax.self)
       {
-        return "case \(element.suffixed("Action").trimmedDescription)"
+        return "case \(element.suffixed("Action").type.trimmedDescription)"
       } else {
         return "case \(element.name)(Swift.Never)"
       }
@@ -544,11 +544,12 @@ private enum ReducerCase {
       {
         let name = element.name.text
         let type = parameter.type
+        let reducer = parameter.defaultValue?.value.trimmedDescription ?? "\(type.trimmed)()"
         return """
           ComposableArchitecture.Scope(\
           state: \\Self.State.Cases.\(name), action: \\Self.Action.Cases.\(name)\
           ) {
-          \(type.trimmed)()
+          \(reducer)
           }
           """
       } else {
@@ -750,12 +751,21 @@ extension EnumCaseDeclSyntax {
 }
 
 extension EnumCaseElementSyntax {
+  fileprivate var type: Self {
+    var element = self
+    if var parameterClause = element.parameterClause {
+      parameterClause.parameters[parameterClause.parameters.startIndex].defaultValue = nil
+      element.parameterClause = parameterClause
+    }
+    return element
+  }
+  
   fileprivate func suffixed(_ suffix: TokenSyntax) -> Self {
     var element = self
     if var parameterClause = element.parameterClause,
       let type = parameterClause.parameters.first?.type
     {
-      let type = MemberTypeSyntax(baseType: type, name: suffix)
+      let type = MemberTypeSyntax(baseType: type.trimmed, name: suffix)
       parameterClause.parameters[parameterClause.parameters.startIndex].type = TypeSyntax(type)
       element.parameterClause = parameterClause
     }

Tests/ComposableArchitectureMacrosTests/ReducerMacroTests.swift

@@ -340,6 +340,67 @@
         """#
       }
     }
+    
+    func testEnum_DefaultInitializer() {
+      assertMacro {
+        """
+        @Reducer
+        enum Destination {
+          case timeline(Timeline)
+          case meeting(Meeting = Meeting(context: .sheet))
+        }
+        """
+      } expansion: {
+        #"""
+        enum Destination {
+          case timeline(Timeline)
+          case meeting(Meeting = Meeting(context: .sheet))
+
+          @CasePathable
+          @dynamicMemberLookup
+          @ObservableState
+          enum State: ComposableArchitecture.CaseReducerState {
+            typealias StateReducer = Destination
+            case timeline(Timeline.State)
+            case meeting(Meeting.State)
+          }
+
+          @CasePathable
+          enum Action {
+            case timeline(Timeline.Action)
+            case meeting(Meeting.Action)
+          }
+
+          @ComposableArchitecture.ReducerBuilder<Self.State, Self.Action>
+          static var body: ComposableArchitecture.ReducerBuilder<Self.State, Self.Action>._Sequence<ComposableArchitecture.Scope<Self.State, Self.Action, Timeline>, ComposableArchitecture.Scope<Self.State, Self.Action, Meeting>> {
+            ComposableArchitecture.Scope(state: \Self.State.Cases.timeline, action: \Self.Action.Cases.timeline) {
+              Timeline()
+            }
+            ComposableArchitecture.Scope(state: \Self.State.Cases.meeting, action: \Self.Action.Cases.meeting) {
+              Meeting(context: .sheet)
+            }
+          }
+
+          enum CaseScope {
+            case timeline(ComposableArchitecture.StoreOf<Timeline>)
+            case meeting(ComposableArchitecture.StoreOf<Meeting>)
+          }
+
+          static func scope(_ store: ComposableArchitecture.Store<Self.State, Self.Action>) -> CaseScope {
+            switch store.state {
+            case .timeline:
+              return .timeline(store.scope(state: \.timeline, action: \.timeline)!)
+            case .meeting:
+              return .meeting(store.scope(state: \.meeting, action: \.meeting)!)
+            }
+          }
+        }
+
+        extension Destination: ComposableArchitecture.CaseReducer, ComposableArchitecture.Reducer {
+        }
+        """#
+      }
+    }
 
     func testEnum_Empty() {
       assertMacro {

Tests/ComposableArchitectureTests/EnumReducerMacroTests.swift

@@ -28,4 +28,15 @@
       #endif
     }
   }
+
+  private enum TestEnumReducer_DefaultInitializer {
+    @Reducer
+    struct Feature {
+      let context: String
+    }
+    @Reducer
+    enum Destination1 {
+      case feature1(Feature = Feature(context: "context"))
+    }
+  }
 #endif