Fix missing dstPath in Copy Bundle Resources phases (#1654)

* Write an empty destination path for the bundle copy phase

The generated "Copy Bundle Resources" phase omitted `dstPath`, and
converting such a project to the Xcode 27.2 JSON format fails with
"A copy build phase is missing a required value for destination path".
Xcode-written projects carry the key with an empty path when no subpath
is needed, and every other phase XcodeGen generates already does.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

* Add changelog entry for #1654

---------

Co-authored-by: Claude Opus 5 (1M context) <noreply@anthropic.com>
Co-authored-by: Yonas Kolb <yonaskolb@users.noreply.github.com>

Author: 3 people

CHANGELOG.md

@@ -14,6 +14,7 @@
 - Fix `syncedFolder` source paths being relative to the spec directory instead of the project directory when they differ, which caused Xcode to treat the synced folder as empty #1636 @Ckitakishi
 - Fix nested target attributes (e.g. `attributes.SystemCapabilities`) being serialized as a stringified Swift `Dictionary` description instead of a proper nested plist dictionary, which also caused non-deterministic key ordering in generated `project.pbxproj` files across runs #1639 @imadaan @sergeyospanov
 - Fix `.DS_Store` and `.orig` files causing projects to be regenerated when using `--use-cache` #1622 @kimjune01
+- Fix generated "Copy Bundle Resources" phases missing `dstPath`, which caused Xcode 27.2 project conversion to fail #1654 @Ckitakishi
 
 ### Internal
 - Use a dedicated local package in the SPM fixture so generated fixtures don't depend on the checkout directory name, such as when running tests from a git worktree @yonaskolb

Sources/XcodeGenKit/PBXProjGenerator.swift

@@ -1221,6 +1221,8 @@ public class PBXProjGenerator {
 
         if !copyBundlesReferences.isEmpty {
             let copyBundlesPhase = addObject(PBXCopyFilesBuildPhase(
+                // Xcode expects the key to be present, even when the path is empty.
+                dstPath: "",
                 dstSubfolderSpec: .resources,
                 name: "Copy Bundle Resources",
                 files: copyBundlesReferences

Tests/Fixtures/TestProject/Project.xcodeproj/project.pbxproj

@@ -616,6 +616,7 @@
 		E8BC0F358D693454E5027ECC /* Copy Bundle Resources */ = {
 			isa = PBXCopyFilesBuildPhase;
 			buildActionMask = 2147483647;
+			dstPath = "";
 			dstSubfolderSpec = 7;
 			files = (
 				3BBCA6F76E5F212E9C55FB78 /* BundleX.bundle in Copy Bundle Resources */,

Tests/XcodeGenKitTests/ProjectGeneratorTests.swift

@@ -998,6 +998,7 @@ class ProjectGeneratorTests: XCTestCase {
                         let copyBundles = (copyBundlesPhase?.files ?? [])
                             .compactMap { $0.file?.nameOrPath }
                         try expect(Set(copyBundles)) == expectedBundlesFiles
+                        try expect(copyBundlesPhase?.dstPath) == ""
                     }
                     try expect(copyFilesPhases.count) == expectedCopyFilesPhasesCount
                 }
@@ -3724,7 +3725,7 @@ class ProjectGeneratorTests: XCTestCase {
 
                     // then
                     /// XcodeGen ignores embed: false for bundles
-                    try expectCopyPhase(in: pbxProject, withFilePaths: ["bundleA.bundle", "bundleB.bundle"], toSubFolder: .resources)
+                    try expectCopyPhase(in: pbxProject, withFilePaths: ["bundleA.bundle", "bundleB.bundle"], toSubFolder: .resources, dstPath: "")
                 }
 
                 $0.it("ignores custom copy phase spec") {
@@ -3740,7 +3741,7 @@ class ProjectGeneratorTests: XCTestCase {
 
                     // then
                     /// XcodeGen ignores embed: false for bundles
-                    try expectCopyPhase(in: pbxProject, withFilePaths: ["bundleA.bundle", "bundleB.bundle"], toSubFolder: .resources)
+                    try expectCopyPhase(in: pbxProject, withFilePaths: ["bundleA.bundle", "bundleB.bundle"], toSubFolder: .resources, dstPath: "")
                 }
             }
         }