Fix configFiles creating duplicate group inside synced folder

When configFiles reference paths inside a synced folder source,
getContainedFileReference() created a separate PBXGroup hierarchy
that duplicated the PBXFileSystemSynchronizedRootGroup already
managing those files.

Skip group creation in getContainedFileReference when the file
path falls inside an existing synced folder root.

Fixes the same class of issue as #1602, but for configFiles
rather than target sources.

Author: AlexNsbmr

Sources/XcodeGenKit/SourceGenerator.swift

@@ -201,6 +201,14 @@ class SourceGenerator {
 
         let parentPath = path.parent()
         let fileReference = getFileReference(path: path, inPath: parentPath)
+
+        // Synced folders already own their file hierarchy, so creating a PBXGroup would duplicate it.
+        // We check the project spec directly because configFiles are resolved before target sources
+        // populate syncedGroupsByPath.
+        guard !isInsideSyncedFolder(path: path) else {
+            return fileReference
+        }
+
         let parentGroup = getGroup(
             path: parentPath,
             mergingChildren: [fileReference],
@@ -277,6 +285,17 @@ class SourceGenerator {
         }
     }
 
+    /// Whether the given path falls inside a target source configured as a synced folder.
+    private func isInsideSyncedFolder(path: Path) -> Bool {
+        let relativePath = (try? path.relativePath(from: project.basePath)) ?? path
+        return project.targets.contains { target in
+            target.sources.contains { source in
+                let resolvedType = source.type ?? (project.options.defaultSourceDirectoryType ?? .group)
+                return resolvedType == .syncedFolder && relativePath.string.hasPrefix(source.path + "/")
+            }
+        }
+    }
+
     /// returns a default build phase for a given path. This is based off the filename
     private func getDefaultBuildPhase(for path: Path, targetType: PBXProductType) -> BuildPhaseSpec? {
         if let buildPhase = getFileType(path: path)?.buildPhase {

Tests/XcodeGenKitTests/SourceGeneratorTests.swift

@@ -491,6 +491,34 @@ class SourceGeneratorTests: XCTestCase {
                 try expect(appGroup === testsGroup) == true
             }
 
+            $0.it("does not create duplicate group for configFiles inside synced folder") {
+                let directories = """
+                Sources:
+                  - a.swift
+                  - Config:
+                    - config.xcconfig
+                """
+                try createDirectories(directories)
+
+                let source = TargetSource(path: "Sources", type: .syncedFolder)
+                let target = Target(name: "Target1", type: .application, platform: .iOS, sources: [source])
+                let project = Project(
+                    basePath: directoryPath,
+                    name: "Test",
+                    targets: [target],
+                    configFiles: ["Debug": "Sources/Config/config.xcconfig"]
+                )
+
+                let pbxProj = try project.generatePbxProj()
+                let mainGroup = try pbxProj.getMainGroup()
+
+                let sourcesChildren = mainGroup.children.filter { $0.path == "Sources" || $0.name == "Sources" }
+                try expect(sourcesChildren.count) == 1
+
+                let syncedFolders = mainGroup.children.compactMap { $0 as? PBXFileSystemSynchronizedRootGroup }
+                try expect(syncedFolders.count) == 1
+            }
+
             $0.it("supports frameworks in sources") {
                 let directories = """
                 Sources: