Fix #route expansion indentation via DeclSyntax interpolation.

Co-authored-by: Cursor <cursoragent@cursor.com>

Author: vnixx

Sources/ReerRouterMacros/ReerRouterMacros.swift

@@ -33,8 +33,7 @@ public struct WriteRouteActionToSectionMacro: DeclarationMacro {
     ) throws -> [DeclSyntax] {
         let argumentList = node.arguments
         var key: String = ""
-        var functionBody: String = ""
-        var signature: String?
+        var actionClosure: ClosureExprSyntax?
 
         for argument in argumentList {
             switch argument.label?.text {
@@ -49,41 +48,38 @@ public struct WriteRouteActionToSectionMacro: DeclarationMacro {
                     key = hostValue
                 }
             case "action":
-                if let closureExpr = argument.expression.as(ClosureExprSyntax.self) {
-                    functionBody = closureExpr.statements.trimmedDescription
-                    if let sig = closureExpr.signature {
-                        signature = sig.trimmedDescription
-                    }
-                }
+                actionClosure = argument.expression.as(ClosureExprSyntax.self)
             default:
                 break
             }
         }
 
         // `#route(key: "haha") { params in ... }` puts the closure in trailingClosure.
-        if functionBody.isEmpty, let trailing = node.trailingClosure {
-            functionBody = trailing.statements.trimmedDescription
-            if let sig = trailing.signature {
-                signature = sig.trimmedDescription
-            }
+        actionClosure = actionClosure ?? node.trailingClosure
+        
+        // Interpolate as a syntax node (not `raw:`) so SwiftSyntax's Indenter
+        // applies the insertion-site indent to every line of the closure.
+        let closure: ExprSyntax
+        if let actionClosure {
+            closure = ExprSyntax(actionClosure.trimmed)
+        } else {
+            closure = "{ param in }"
         }
 
         let isGlobal = context.lexicalContext.isEmpty
         let staticString = isGlobal ? "" : "static "
         let infoName = "\(context.makeUniqueName("rhea"))"
         let hashLiteral = fnv1aHashLiteral(key)
 
-        let declarationString = """
-            @used 
+        let declaration: DeclSyntax = """
+            @used
             @section("__DATA,__rerouter_ac")
-            \(staticString)let \(infoName): RouteActionInfo = (
-                \(hashLiteral),
-                { \(signature ?? "param in")
-                \(functionBody)
-                }
+            \(raw: staticString)let \(raw: infoName): RouteActionInfo = (
+                \(raw: hashLiteral),
+                \(closure)
             )
             """
-        return [DeclSyntax(stringLiteral: declarationString)]
+        return [declaration]
     }
 }
 

Tests/ReerRouterTests/RouteMacroExpansionTests.swift

@@ -26,7 +26,7 @@ final class RouteMacroExpansionTests: XCTestCase {
             let __macro_local_4rheafMu_: RouteActionInfo = (
                 0x2e25cdcc7406360d,
                 { params in
-                print(123333333)
+                    print(123333333)
                 }
             )
             """,
@@ -51,7 +51,7 @@ final class RouteMacroExpansionTests: XCTestCase {
             let __macro_local_4rheafMu_: RouteActionInfo = (
                 0x2e25cdcc7406360d,
                 { params in
-                print(6666666)
+                    print(6666666)
                 }
             )
             """,