Fix Swift syntax error in scaffolded projects

Replace Kotlin 'val' keyword with Swift 'let' during template processing.
This prevents compilation errors when scaffolding iOS/macOS projects.

- Added fixSwiftSyntax() to convert 'val' to 'let' in Swift files
- Applied fix to both iOS and macOS scaffold processing
- Added tests to verify the fix works correctly
- Updated CHANGELOG.md

Fixes XCODEBUILD-MCP-132X

Author: cursoragent

CHANGELOG.md

@@ -15,6 +15,7 @@
 - Update UI automation guard guidance to point at `debug_continue` when paused.
 - Fix tool loading bugs in static tool registration.
 - Fix xcodemake command argument corruption when project directory path appears as substring in non-path arguments.
+- Fixed Swift syntax error in scaffolded projects by replacing Kotlin 'val' keyword with Swift 'let' (Fixes XCODEBUILD-MCP-132X).
 
 ## [1.16.0] - 2025-12-30
 - Remove dynamic tool discovery (`discover_tools`) and `XCODEBUILDMCP_DYNAMIC_TOOLS`. Use `XCODEBUILDMCP_ENABLED_WORKFLOWS` to limit startup tool registration.

src/mcp/tools/project-scaffolding/__tests__/scaffold_ios_project.test.ts

@@ -666,4 +666,114 @@ describe('scaffold_ios_project plugin', () => {
       process.env.XCODEBUILDMCP_IOS_TEMPLATE_PATH = '/mock/template/path';
     });
   });
+
+  describe('Swift Syntax Fixes', () => {
+    it('should fix Kotlin val keyword in Swift test files', async () => {
+      // Track written files
+      let writtenFiles: Record<string, string> = {};
+      const trackingFileSystemExecutor = createMockFileSystemExecutor({
+        existsSync: (path) => {
+          return (
+            path.includes('xcodebuild-mcp-template') ||
+            path.includes('XcodeBuildMCP-iOS-Template') ||
+            path.includes('/template') ||
+            path.endsWith('template') ||
+            path.includes('extracted') ||
+            path.includes('/mock/template/path')
+          );
+        },
+        readFile: async (path) => {
+          // Simulate a Swift test file with Kotlin 'val' keyword
+          if (path.includes('.swift')) {
+            return 'val equal = XCTAssertEqual(actual, expected, message, file: file, line: line)';
+          }
+          return 'template content with MyProject placeholder';
+        },
+        readdir: async () => [
+          { name: 'MyProjectTests.swift', isDirectory: () => false, isFile: () => true } as any,
+        ],
+        mkdir: async () => {},
+        rm: async () => {},
+        cp: async () => {},
+        writeFile: async (path, content) => {
+          writtenFiles[path] = content as string;
+        },
+        stat: async () => ({ isDirectory: () => true, mtimeMs: 0 }),
+      });
+
+      await scaffold_ios_projectLogic(
+        {
+          projectName: 'TestApp',
+          customizeNames: true,
+          outputPath: '/tmp/test-projects',
+        },
+        mockCommandExecutor,
+        trackingFileSystemExecutor,
+      );
+
+      // Verify that the written Swift file has 'let' instead of 'val'
+      const swiftFiles = Object.entries(writtenFiles).filter(([path]) => path.endsWith('.swift'));
+      expect(swiftFiles.length).toBeGreaterThan(0);
+
+      const [, content] = swiftFiles[0];
+      expect(content).toContain('let equal =');
+      expect(content).not.toContain('val equal =');
+    });
+
+    it('should handle multiple val keywords in a file', async () => {
+      // Track written files
+      let writtenFiles: Record<string, string> = {};
+      const trackingFileSystemExecutor = createMockFileSystemExecutor({
+        existsSync: (path) => {
+          return (
+            path.includes('xcodebuild-mcp-template') ||
+            path.includes('XcodeBuildMCP-iOS-Template') ||
+            path.includes('/template') ||
+            path.endsWith('template') ||
+            path.includes('extracted') ||
+            path.includes('/mock/template/path')
+          );
+        },
+        readFile: async (path) => {
+          // Simulate a Swift test file with multiple Kotlin 'val' keywords
+          if (path.includes('.swift')) {
+            return `val foo = 1
+val bar = 2
+val baz = XCTAssertEqual(a, b)`;
+          }
+          return 'template content with MyProject placeholder';
+        },
+        readdir: async () => [
+          { name: 'MyProjectTests.swift', isDirectory: () => false, isFile: () => true } as any,
+        ],
+        mkdir: async () => {},
+        rm: async () => {},
+        cp: async () => {},
+        writeFile: async (path, content) => {
+          writtenFiles[path] = content as string;
+        },
+        stat: async () => ({ isDirectory: () => true, mtimeMs: 0 }),
+      });
+
+      await scaffold_ios_projectLogic(
+        {
+          projectName: 'TestApp',
+          customizeNames: true,
+          outputPath: '/tmp/test-projects',
+        },
+        mockCommandExecutor,
+        trackingFileSystemExecutor,
+      );
+
+      // Verify that all 'val' keywords are replaced with 'let'
+      const swiftFiles = Object.entries(writtenFiles).filter(([path]) => path.endsWith('.swift'));
+      expect(swiftFiles.length).toBeGreaterThan(0);
+
+      const [, content] = swiftFiles[0];
+      expect(content).toContain('let foo =');
+      expect(content).toContain('let bar =');
+      expect(content).toContain('let baz =');
+      expect(content).not.toContain('val ');
+    });
+  });
 });

src/mcp/tools/project-scaffolding/scaffold_ios_project.ts

@@ -230,6 +230,19 @@ function updateXCConfigFile(content: string, params: Record<string, unknown>): s
   return result;
 }
 
+/**
+ * Fix Swift syntax issues (e.g., Kotlin 'val' keyword should be 'let')
+ */
+function fixSwiftSyntax(content: string): string {
+  let result = content;
+
+  // Replace Kotlin 'val' keyword with Swift 'let'
+  // Match 'val' followed by whitespace and an identifier (variable name)
+  result = result.replace(/\bval\s+(\w+)\s*=/g, 'let $1 =');
+
+  return result;
+}
+
 /**
  * Replace placeholders in a string (for non-XCConfig files)
  */
@@ -301,6 +314,7 @@ async function processFile(
   const isTextFile = textExtensions.some((textExt) => ext.endsWith(textExt));
   const isXCConfig = sourcePath.endsWith('.xcconfig');
   const isPackageSwift = sourcePath.endsWith('Package.swift');
+  const isSwiftFile = sourcePath.endsWith('.swift');
 
   if (isTextFile && customizeNames) {
     // Read the file content
@@ -322,6 +336,11 @@ async function processFile(
       processedContent = replacePlaceholders(content, projectName, bundleIdentifier);
     }
 
+    // Apply Swift syntax fixes if this is a Swift file
+    if (isSwiftFile) {
+      processedContent = fixSwiftSyntax(processedContent);
+    }
+
     await fileSystemExecutor.mkdir(dirname(finalDestPath), { recursive: true });
     await fileSystemExecutor.writeFile(finalDestPath, processedContent, 'utf-8');
   } else {

src/mcp/tools/project-scaffolding/scaffold_macos_project.ts

@@ -145,6 +145,19 @@ function updateXCConfigFile(
   return result;
 }
 
+/**
+ * Fix Swift syntax issues (e.g., Kotlin 'val' keyword should be 'let')
+ */
+function fixSwiftSyntax(content: string): string {
+  let result = content;
+
+  // Replace Kotlin 'val' keyword with Swift 'let'
+  // Match 'val' followed by whitespace and an identifier (variable name)
+  result = result.replace(/\bval\s+(\w+)\s*=/g, 'let $1 =');
+
+  return result;
+}
+
 /**
  * Replace placeholders in a string (for non-XCConfig files)
  */
@@ -212,6 +225,7 @@ async function processFile(
   const isTextFile = textExtensions.some((textExt) => ext.endsWith(textExt));
   const isXCConfig = sourcePath.endsWith('.xcconfig');
   const isPackageSwift = sourcePath.endsWith('Package.swift');
+  const isSwiftFile = sourcePath.endsWith('.swift');
 
   if (isTextFile && params.customizeNames) {
     // Read the file content
@@ -233,6 +247,11 @@ async function processFile(
       processedContent = replacePlaceholders(content, params.projectName, bundleIdentifier);
     }
 
+    // Apply Swift syntax fixes if this is a Swift file
+    if (isSwiftFile) {
+      processedContent = fixSwiftSyntax(processedContent);
+    }
+
     await fileSystemExecutor.mkdir(dirname(finalDestPath), { recursive: true });
     await fileSystemExecutor.writeFile(finalDestPath, processedContent, 'utf-8');
   } else {