favour flattened error hierarchy

README.md

@@ -167,7 +167,7 @@ extension MyViewController: ShopifyCheckoutDelegate {
 
 	/// Issued when the provided checkout URL results in an error related to shop being on checkout.liquid.
 	/// The SDK only supports stores migrated for extensibility. 
-	case sdkError(underlying: CheckoutLiquidError.unmigratedCheckout)
+	case checkoutLiquidNotMigrated(message: String)
 
 	/// Unavailable error: checkout cannot be initiated or completed, e.g. due to network or server-side error
         /// The provided message describes the error and may be logged and presented to the buyer.

Samples/MobileBuyIntegration/MobileBuyIntegration/CartViewController.swift

@@ -172,9 +172,14 @@ extension CartViewController: CheckoutDelegate {
 
 	func checkoutDidFail(error: ShopifyCheckout.CheckoutError) {
 		switch error {
-		case .sdkError(let underlying): print(#function, underlying)
+		case .sdkError(let underlying):
+			print(#function, underlying)
+			forceCloseCheckout("Checkout Unavailable")
 		case .checkoutExpired(let message): forceCloseCheckout(message)
 		case .checkoutUnavailable(let message): forceCloseCheckout(message)
+		case .checkoutLiquidNotMigrated(let message):
+			print(#function, message)
+			forceCloseCheckout("Checkout Unavailable")
 		}
 	}
 

Sources/ShopifyCheckout/CheckoutDelegate.swift

@@ -45,6 +45,10 @@ extension CheckoutDelegate {
 		handleUrl(url)
 	}
 
+	public func checkoutDidFail(error: CheckoutError) throws {
+		throw error
+	}
+
 	private func handleUrl(_ url: URL) {
 		if UIApplication.shared.canOpenURL(url) {
 			UIApplication.shared.open(url)

Sources/ShopifyCheckout/CheckoutError.swift

@@ -28,6 +28,10 @@ public enum CheckoutError: Swift.Error {
 	/// if the issue persists, it is recommended to open a bug report in http://github.com/Shopify/mobile-checkout-sdk-ios
 	case sdkError(underlying: Swift.Error)
 
+	/// Issued when the provided checkout URL results in an error related to shop being on checkout.liquid.
+	/// The SDK only supports stores migrated for extensibility. 
+	case checkoutLiquidNotMigrated(message: String)
+
 	/// Issued when checkout has encountered a unrecoverable error (for example server side error)
 	/// if the issue persists, it is recommended to open a bug report in http://github.com/Shopify/mobile-checkout-sdk-ios
 	case checkoutUnavailable(message: String)
@@ -38,8 +42,3 @@ public enum CheckoutError: Swift.Error {
 	case checkoutExpired(message: String)
 }
 
-public enum CheckoutLiquidError: Swift.Error {
-	/// Issued when the provided checkout URL results in an error related to shop being on checkout.liquid.
-	/// The SDK only supports stores migrated for extensibility. 
-	case unmigratedCheckoutError(message: String)
-}

Sources/ShopifyCheckout/CheckoutView.swift

@@ -148,7 +148,7 @@ extension CheckoutView: WKNavigationDelegate {
 			case 410:
 				viewDelegate?.checkoutViewDidFailWithError(error: .checkoutExpired(message: "Checkout has expired"))
 			case 404:
-				viewDelegate?.checkoutViewDidFailWithError(error: .sdkError(underlying: CheckoutLiquidError.unmigratedCheckoutError(message: "The checkout url provided has resulted in an error. The store is still using checkout.liquid, whereas the checkout SDK only supports checkout with extensibility.")))
+				viewDelegate?.checkoutViewDidFailWithError(error: .checkoutLiquidNotMigrated(message: "The checkout url provided has resulted in an error. The store is still using checkout.liquid, whereas the checkout SDK only supports checkout with extensibility."))
 			case 500:
 				viewDelegate?.checkoutViewDidFailWithError(error: .checkoutUnavailable(message: "Checkout unavailable due to error"))
 			default: