Prevent cached groups from being reparented

Co-authored-by: Copilot <[email protected]>
eschwieb · Aug 21, 2026 · Aug 21, 2026 · Aug 22, 2026 · Aug 22, 2026 · 195ac1865c8326cb14f0ca328b331bfad759b4fa
commit 195ac1865c8326cb14f0ca328b331bfad759b4fa
diff --git a/Sources/XcodeGenKit/SourceGenerator.swift b/Sources/XcodeGenKit/SourceGenerator.swift
@@ -368,6 +368,12 @@ class SourceGenerator {
         if let cachedGroup = groupsByPath[path] {
             var cachedGroupChildren = cachedGroup.children
             for child in children {
+                guard !(child is PBXGroup)
+                    || (!rootGroups.contains(child)
+                        && (child.parent == nil || child.parent === cachedGroup)) else {
+                    continue
+                }
+
                 // only add the children that aren't already in the cachedGroup
                 // Variant groups with the same name may select different localizations for different
                 // targets, so only the same variant group object is a duplicate.
@@ -403,9 +409,12 @@ class SourceGenerator {
             let groupName = name ?? path.lastComponent
 
             let groupPath = resolveGroupPath(path, isTopLevelGroup: hasCustomParent || isTopLevelGroup)
+            let unattachedChildren = children.filter {
+                !($0 is PBXGroup) || (!rootGroups.contains($0) && $0.parent == nil)
+            }
 
             let group = PBXGroup(
-                children: children,
+                children: unattachedChildren,
                 sourceTree: .group,
                 name: groupName != groupPath ? groupName : nil,
                 path: groupPath

diff --git a/Tests/XcodeGenKitTests/SourceGeneratorTests.swift b/Tests/XcodeGenKitTests/SourceGeneratorTests.swift
@@ -84,6 +84,83 @@ class SourceGeneratorTests: XCTestCase {
                 try pbxProj.expectFile(paths: ["Sources", "A", "C2.0", "c.swift"], buildPhase: .sources)
             }
 
+            $0.it("does not reparent a top-level group discovered by a broader source") {
+                let directories = """
+                Sources:
+                  Resources:
+                    - Localizable.strings
+                """
+                try createDirectories(directories)
+
+                let resourcesTarget = Target(
+                    name: "Resources",
+                    type: .bundle,
+                    platform: .iOS,
+                    sources: ["Sources/Resources"]
+                )
+                let broadTarget = Target(
+                    name: "Broad",
+                    type: .application,
+                    platform: .iOS,
+                    sources: ["Sources"]
+                )
+                let project = Project(
+                    basePath: directoryPath,
+                    name: "Test",
+                    targets: [resourcesTarget, broadTarget]
+                )
+
+                let pbxProj = try project.generatePbxProj()
+                let mainGroup = try pbxProj.getMainGroup()
+                let resourcesGroups = pbxProj.groups.filter { $0.nameOrPath == "Resources" }
+                let resourcesGroup = try unwrap(resourcesGroups.first)
+
+                try expect(resourcesGroups.count) == 1
+                try expect(resourcesGroup.path) == "Sources/Resources"
+                try expect(mainGroup.children.contains { $0 === resourcesGroup }) == true
+                try expect(
+                    pbxProj.groups
+                        .first { $0.nameOrPath == "Sources" }?
+                        .children
+                        .contains { $0 === resourcesGroup }
+                ) == false
+            }
+
+            $0.it("preserves an explicit custom group for a top-level folder reference") {
+                let directories = """
+                Folder:
+                  - resource.txt
+                """
+                try createDirectories(directories)
+
+                let target = Target(
+                    name: "Test",
+                    type: .application,
+                    platform: .iOS,
+                    sources: [
+                        TargetSource(
+                            path: "Folder",
+                            group: "CustomGroup",
+                            type: .folder,
+                            buildPhase: BuildPhaseSpec.none
+                        ),
+                    ]
+                )
+                let project = Project(basePath: directoryPath, name: "Test", targets: [target])
+
+                let pbxProj = try project.generatePbxProj()
+                let mainGroup = try pbxProj.getMainGroup()
+                let customGroup = try unwrap(
+                    pbxProj.groups.first { $0.nameOrPath == "CustomGroup" }
+                )
+                let folderReference = try unwrap(
+                    pbxProj.fileReferences.first { $0.nameOrPath == "Folder" }
+                )
+
+                try expect(mainGroup.children.contains { $0 === folderReference }) == true
+                try expect(customGroup.children.contains { $0 === folderReference }) == true
+            }
+
             $0.it("generates synced folder") {
                 let directories = """
                 Sources: