PropertyListEncoder: Reference the property on the class itself instead of the options struct

Author: parkera

Sources/FoundationEssentials/PropertyList/PlistEncoder.swift

@@ -95,8 +95,9 @@ open class PropertyListEncoder {
     /// - throws: `EncodingError.invalidValue` if a non-conforming floating-point value is encountered during encoding, and the encoding strategy is `.throw`.
     /// - throws: An error if any value throws an error during encoding.
     open func encode<Value : Encodable>(_ value: Value) throws -> Data {
+        let format = self.outputFormat
         do {
-            switch options.outputFormat {
+            switch format {
             case .binary:
                 return try _encodeBPlist(value)
             case .xml:
@@ -105,7 +106,7 @@ open class PropertyListEncoder {
                 throw CocoaError(.propertyListWriteInvalid, userInfo: [NSDebugDescriptionErrorKey:"Property list format .openStep not supported for writing"])
 #if FOUNDATION_FRAMEWORK
             @unknown default:
-                throw CocoaError(.propertyListWriteInvalid, userInfo: [NSDebugDescriptionErrorKey:"Unknown property list format \(options.outputFormat)"])
+                throw CocoaError(.propertyListWriteInvalid, userInfo: [NSDebugDescriptionErrorKey:"Unknown property list format \(format)"])
 #endif
             }
         } catch {
@@ -166,8 +167,9 @@ open class PropertyListEncoder {
 
     @available(FoundationPreview 0.1, *)
     open func encode<T : EncodableWithConfiguration>(_ value: T, configuration: T.EncodingConfiguration) throws -> Data {
+        let format = self.outputFormat
         do {
-            switch options.outputFormat {
+            switch format {
             case .binary:
                 return try _encodeBPlist(value, configuration: configuration)
             case .xml:
@@ -176,7 +178,7 @@ open class PropertyListEncoder {
                 throw CocoaError(.propertyListWriteInvalid, userInfo: [NSDebugDescriptionErrorKey:"Property list format .openStep not supported for writing"])
 #if FOUNDATION_FRAMEWORK
             @unknown default:
-                throw CocoaError(.propertyListWriteInvalid, userInfo: [NSDebugDescriptionErrorKey:"Unknown property list format \(options.outputFormat)"])
+                throw CocoaError(.propertyListWriteInvalid, userInfo: [NSDebugDescriptionErrorKey:"Unknown property list format \(format)"])
 #endif
             }
         } catch {

Tests/FoundationEssentialsTests/PropertyListEncoderTests.swift

@@ -1503,6 +1503,15 @@ data1 = <7465
             _testRoundTrip(of: input, in: .xml)
         }
     }
+    
+    func testCustomSubclass() throws {
+        // verify we consult the subclass for the output format
+        let encodeMe = ["hello":"world"]
+        let encoder = XMLOnlyEncoder()
+        let data = try encoder.encode(encodeMe)
+        let dataAsStr = String(data: data, encoding: .utf8)!
+        XCTAssertTrue(dataAsStr.hasPrefix("<?xml"))
+    }
 }
 
 
@@ -2036,3 +2045,11 @@ private struct MultipleDecodeOptionsTestType : Codable, Equatable {
     }
 }
 
+// MARK: - Helper Class
+
+class XMLOnlyEncoder : PropertyListEncoder, @unchecked Sendable {
+    override var outputFormat: PropertyListDecoder.PropertyListFormat {
+        get { return .xml }
+        set { }
+    }
+}