From 604db13d167b59ad807f5026094c003386768a07 Mon Sep 17 00:00:00 2001
From: Giacomo Balli <giacomoballi@gmail.com>
Date: Thu, 2 Apr 2026 11:35:00 -0700
Subject: [PATCH] Embed watchOS apps in PlugIns directory for Xcode 16+

Starting with Xcode 16, watchOS apps must be embedded in the parent
app bundle's PlugIns/ directory (dstSubfolderSpec=13) instead of the
legacy Watch/ directory (dstSubfolderSpec=16). Gate the behavior on
xcodeVersion so older projects continue to work.

Fixes #1613
---
 Sources/XcodeGenKit/PBXProjGenerator.swift | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/Sources/XcodeGenKit/PBXProjGenerator.swift b/Sources/XcodeGenKit/PBXProjGenerator.swift
index 1f20e850..3cdaabc2 100644
--- a/Sources/XcodeGenKit/PBXProjGenerator.swift
+++ b/Sources/XcodeGenKit/PBXProjGenerator.swift
@@ -1295,11 +1295,15 @@ public class PBXProjGenerator {
         }
         
         if !copyWatchReferences.isEmpty {
+            // Xcode 16+ requires watchOS apps to be embedded in PlugIns/
+            // (as foundation extensions) instead of the legacy Watch/ directory.
+            let xcodeVersionNumber = Int(project.xcodeVersion.prefix(2)) ?? 0
+            let usePlugIns = xcodeVersionNumber >= 16
 
             let copyFilesPhase = addObject(
                 PBXCopyFilesBuildPhase(
-                    dstPath: "$(CONTENTS_FOLDER_PATH)/Watch",
-                    dstSubfolderSpec: .productsDirectory,
+                    dstPath: usePlugIns ? "" : "$(CONTENTS_FOLDER_PATH)/Watch",
+                    dstSubfolderSpec: usePlugIns ? .plugins : .productsDirectory,
                     name: "Embed Watch Content",
                     files: copyWatchReferences
                 )