Swift Package resource colors coming back as nil in CI test cases. But return fine during local test cases

Question

Strangely, this only happens when running on CI (GitHub Actions).

here is my asset catalog:

Here is my extension to UIColor to access these colors:

// MARK: - UIKit

public extension UIColor {
    // MARK: Design System Colors

    static let primaryColor = UIColor(named: "PrimaryColor", in: .module, compatibleWith: nil)!
    static let primaryVariant = UIColor(named: "PrimaryVariant", in: .module, compatibleWith: nil)!
    static let onPrimary = UIColor(named: "OnPrimary", in: .module, compatibleWith: nil)!
    static let onPrimaryMedium = UIColor(named: "OnPrimaryMedium", in: .module, compatibleWith: nil)!
    static let onPrimaryDisabled = UIColor(named: "OnPrimaryDisabled", in: .module, compatibleWith: nil)!

    static let surface = UIColor(named: "Surface", in: .module, compatibleWith: nil)!
    static let onSurface = UIColor(named: "OnSurface", in: .module, compatibleWith: nil)!
    static let onSurfaceMedium = UIColor(named: "OnSurfaceMedium", in: .module, compatibleWith: nil)!
    static let onSurfaceDisabled = UIColor(named: "OnSurfaceDisabled", in: .module, compatibleWith: nil)!

    static let background = UIColor(named: "Background", in: .module, compatibleWith: nil)!
    static let onBackground = UIColor(named: "OnBackground", in: .module, compatibleWith: nil)!

    static let accent = UIColor(named: "Accent", in: .module, compatibleWith: nil)!
    static let divider = UIColor(named: "Divider", in: .module, compatibleWith: nil)!

    // MARK: Status Colors

    static let statusSuccess = UIColor(named: "StatusSuccess", in: .module, compatibleWith: nil)!
    static let statusWarning = UIColor(named: "StatusWarning", in: .module, compatibleWith: nil)!
    static let statusError = UIColor(named: "StatusError", in: .module, compatibleWith: nil)!

    // MARK: Map Colors

    static let pinPlace = UIColor(named: "PinPlace", in: .module, compatibleWith: nil)!
    static let pinRoute = UIColor(named: "PinRoute", in: .module, compatibleWith: nil)!
    static let polyline = UIColor(named: "Polyline", in: .module, compatibleWith: nil)!
    static let polylineRoute = UIColor(named: "PolylineRoute", in: .module, compatibleWith: nil)!
}

I have a test case that just runs through all these colors and checks if they can be loaded from the module bundle (so that its safe to force unwrap them):

@testable import MyProject
import SwiftUI
import UIKit
import XCTest

/// Test to ensure that the colors can be loaded from the module bundle without crashing.
class MyProjectColorTest: XCTestCase {
    func testLoadUIColorFromBundle() {
        for color in UIColor.myProjectUIColors {
            XCTAssertNotNil(color)
        }
    }
}

fileprivate extension UIColor {
    static var myProjectUIColors: [UIColor] = [
        UIColor.primaryColor,
        UIColor.primaryVariant, //It fails when it tries to access this color.
        UIColor.onPrimary,
        UIColor.onPrimaryMedium,
        UIColor.onPrimaryDisabled,
        UIColor.surface,
        UIColor.onSurface,
        UIColor.onSurfaceMedium,
        UIColor.onSurfaceDisabled,
        UIColor.background,
        UIColor.onBackground,
        UIColor.accent,
        UIColor.divider,
        UIColor.statusSuccess,
        UIColor.statusWarning,
        UIColor.statusError,
        UIColor.pinPlace,
        UIColor.pinRoute,
        UIColor.polyline,
        UIColor.polylineRoute,
    ]
}

Finally:

Here is my package manifest:

// swift-tools-version:5.3
// The swift-tools-version declares the minimum version of Swift required to build this package.

import PackageDescription

let package = Package(
    name: "MyProject",
    defaultLocalization: "en",
    platforms: [
        .iOS(.v13),
        .watchOS(.v6),
    ],
    products: [
        // Products define the executables and libraries a package produces, and make them visible to other packages.
        .library(
            name: "MyProject",
            targets: ["MyProject"]
        ),
    ],
    dependencies: [
        // Dependencies declare other packages that this package depends on.
        // .package(url: /* package url */, from: "1.0.0"),
    ],
    targets: [
        // Targets are the basic building blocks of a package. A target can define a module or a test suite.
        // Targets can depend on other targets in this package, and on products in packages this package depends on.
        .target(
            name: "MyProject",
            dependencies: [],
            exclude: [
                "MyProjectDemo/*",
            ],
            // I've also tried omitting this and letting SPM handle it automatically.
            resources: [
                .process("*.xcassets"),
            ]
        ),
        .testTarget(
            name: "MyProjectTests",
            dependencies: ["MyProject"]
        ),
    ]
)

Also, here's my GitHub action script:

name: Build

on:
  push:
    branches: [ master ]
    paths:
       - '.github/workflows/swiftlint.yml'
       - '.swiftlint.yml'
       - '**/*.swift'
  pull_request:
    branches: [ master, develop ]
    paths:
       - '.github/workflows/swiftlint.yml'
       - '.swiftlint.yml'
       - '**/*.swift'

jobs:
  Build:
    runs-on: macos-latest
    steps:
      - name: Checkout
        uses: actions/checkout@v2.3.4
      - name: List available Xcode versions
        run: ls /Applications | grep Xcode
      - name: Select Xcode
        run: sudo xcode-select -switch /Applications/Xcode_12.2.app
      - name: Show Build Destinations
        run: xcodebuild -showdestinations -scheme MyProject
      - name: Build
        run: xcodebuild test -scheme MyProject -destination 'platform=iOS Simulator,OS=14.2,name=iPhone 12'
  Lint:
    runs-on: ubuntu-latest
    steps:
      - name: Checkout
        uses: actions/checkout@v2.3.4
      - name: Lint
        uses: norio-nomura/action-swiftlint@3.2.0

Answer 1

there is a workaround for this. Founded Here -> https://developer.apple.com/forums/thread/664295

import Foundation

class CurrentBundleFinder {}

extension Foundation.Bundle {
        
    static var myModule: Bundle = {
        /* The name of your local package, prepended by "LocalPackages_" */
        let bundleName = "UI_UI"
        let candidates = [
            /* Bundle should be present here when the package is linked into an App. */
            Bundle.main.resourceURL,
            /* Bundle should be present here when the package is linked into a framework. */
            Bundle(for: CurrentBundleFinder.self).resourceURL,
            /* For command-line tools. */
            Bundle.main.bundleURL,
            /* Bundle should be present here when running previews from a different package (this is the path to "…/Debug-iphonesimulator/"). */
            Bundle(for: CurrentBundleFinder.self).resourceURL?.deletingLastPathComponent().deletingLastPathComponent(),
        ]
        for candidate in candidates {
            let bundlePath = candidate?.appendingPathComponent(bundleName + ".bundle")
            if let bundle = bundlePath.flatMap(Bundle.init(url:)) {
                return bundle
            }
        }
        fatalError("unable to find bundle named \(bundleName)")
    }()
}