Fix crash when diffing LocalizedStringKey with FormatStyle

Sources/CustomDump/Conformances/SwiftUI.swift

@@ -51,17 +51,14 @@
  let arguments: [CVarArg] = Array(Mirror(reflecting: children[2].value).children)
  .compactMap {
  let children = Array(Mirror(reflecting: $0.value).children)
- let value: Any
- let formatter: Formatter?
  // `LocalizedStringKey.FormatArgument` differs depending on OS/platform.
  if children[0].label == "storage" {
- (value, formatter) =
- Array(Mirror(reflecting: children[0].value).children)[0].value as! (Any, Formatter?)
+ return formattedArgumentFromStorage(children[0])
  } else {
- value = children[0].value
- formatter = children[1].value as? Formatter
+ let value = children[0].value
+ let formatter = children[1].value as? Formatter
+ return formatter?.string(for: value) ?? value as! CVarArg
  }
- return formatter?.string(for: value) ?? value as! CVarArg
  }
 
  let format = NSLocalizedString(
@@ -73,5 +70,25 @@
  )
  return String(format: format, locale: locale, arguments: arguments)
  }
+
+ private func formattedArgumentFromStorage(_ storage: Mirror.Child) -> CVarArg {
+ let storage = Array(Mirror(reflecting: storage.value).children)[0].value
+
+ // Check if storage is a FormatStyle
+ if #available(macOS 12.0, iOS 15.0, tvOS 15.0, watchOS 8.0, *) {
+ let formatStyleBoxChildren = Array(Mirror(reflecting: storage).children)
+ if formatStyleBoxChildren.count == 2, let formatStyle = formatStyleBoxChildren[1].value as? (any FormatStyle) {
+ func formatValue<S: FormatStyle>(style: S, input: Any) -> String {
+ let input = input as! S.FormatInput
+ return style.format(input) as! String
+ }
+ return formatValue(style: formatStyle, input: formatStyleBoxChildren[0].value)
+ }
+ }
+
+ // Fallback to Formatter
+ let (value, formatter) = storage as! (Any, Formatter?)
+ return formatter?.string(for: value) ?? value as! CVarArg
+ }
  }
 #endif

Tests/CustomDumpTests/DiffTests.swift

@@ -1,5 +1,8 @@
 import CustomDump
 import XCTest
+#if canImport(SwiftUI)
+import SwiftUI
+#endif
 
 @available(macOS 10.15, iOS 13, tvOS 13, watchOS 6, *)
 final class DiffTests: XCTestCase {
@@ -1088,6 +1091,46 @@ final class DiffTests: XCTestCase {
  )
  }
 
+#if canImport(SwiftUI)
+ @available(macOS 13, iOS 16, tvOS 16, watchOS 9, *)
+ func testLocalizedStringKey() {
+ XCTAssertNoDifference(
+ diff(
+ "My name is Jack" as LocalizedStringKey,
+ "My name is Jill" as LocalizedStringKey
+ ),
+ """
+ - "My name is Jack"
+ + "My name is Jill"
+ """
+ )
+
+ let name1 = "Jack"
+ let name2 = "Jill"
+ XCTAssertNoDifference(
+ diff(
+ "My name is \(name1)" as LocalizedStringKey,
+ "My name is \(name2)" as LocalizedStringKey
+ ),
+ """
+ - "My name is Jack"
+ + "My name is Jill"
+ """
+ )
+
+ XCTAssertNoDifference(
+ diff(
+ "Time remaining: \(Duration.seconds(10), format: .time(pattern: .minuteSecond))" as LocalizedStringKey,
+ "Time remaining: \(Duration.seconds(9), format: .time(pattern: .minuteSecond))" as LocalizedStringKey
+ ),
+ """
+ - "Time remaining: 0:10"
+ + "Time remaining: 0:09"
+ """
+ )
+ }
+#endif
+
  func testCustomDictionary() {
  XCTAssertEqual(
  String(customDumping: Stack(elements: [(.init(rawValue: 0), "Hello")])),