Use empty initializer for options structs, create PopulatorConstructable

Author: mrabiciu

Sources/SwiftProtobuf/JSONEncodingOptions.swift

@@ -13,7 +13,7 @@
 // -----------------------------------------------------------------------------
 
 /// Options for JSONEncoding.
-public struct JSONEncodingOptions: Sendable {
+public struct JSONEncodingOptions: Sendable, PopulatorConstructable {
 
   /// Always prints int64s values as numbers.
   /// By default, they are printed as strings as per proto3 JSON mapping rules.

Sources/SwiftProtobuf/JSONEncodingVisitor.swift

@@ -42,7 +42,9 @@ internal struct JSONEncodingVisitor: Visitor {
       throw JSONEncodingError.missingFieldNames
     }
     self.options = options
-    traversalOptions = TraversalOptions(alwaysVisitPrimitiveFields: options.alwaysPrintPrimitiveFields)
+      traversalOptions = TraversalOptions.with {
+        $0.alwaysVisitPrimitiveFields = options.alwaysPrintPrimitiveFields
+      }
   }
 
   mutating func startArray() {

Sources/SwiftProtobuf/Message.swift

@@ -31,7 +31,7 @@
 ///
 /// The actual functionality is implemented either in the generated code or in
 /// default implementations of the below methods and properties.
-public protocol Message: _CommonMessageConformances {
+public protocol Message: _CommonMessageConformances, PopulatorConstructable {
   /// Creates a new message with all of its fields initialized to their default
   /// values.
   init()
@@ -150,28 +150,6 @@ extension Message {
     return header + textFormatString()
   }
   #endif
-
-  /// Creates an instance of the message type on which this method is called,
-  /// executes the given block passing the message in as its sole `inout`
-  /// argument, and then returns the message.
-  ///
-  /// This method acts essentially as a "builder" in that the initialization of
-  /// the message is captured within the block, allowing the returned value to
-  /// be set in an immutable variable. For example,
-  ///
-  ///     let msg = MyMessage.with { $0.myField = "foo" }
-  ///     msg.myOtherField = 5  // error: msg is immutable
-  ///
-  /// - Parameter populator: A block or function that populates the new message,
-  ///   which is passed into the block as an `inout` argument.
-  /// - Returns: The message after execution of the block.
-  public static func with(
-    _ populator: (inout Self) throws -> ()
-  ) rethrows -> Self {
-    var message = Self()
-    try populator(&message)
-    return message
-  }
 }
 
 /// Implementation base for all messages; not intended for client use.

Sources/SwiftProtobuf/PopulatorConstructable.swift

@@ -0,0 +1,46 @@
+// Sources/SwiftProtobuf/PopulatorConstructable.swift
+//
+// Copyright (c) 2014 - 2023 Apple Inc. and the project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See LICENSE.txt for license information:
+// https://github.com/apple/swift-protobuf/blob/main/LICENSE.txt
+//
+
+
+import Foundation
+
+public protocol PopulatorConstructable {
+    
+    init()
+
+    /// Creates an instance of the `Self` on which this method is called,
+    /// executes the given block passing the message in as its sole `inout`
+    /// argument, and then returns the message.
+    ///
+    /// This method acts essentially as a "builder" in that the initialization of
+    /// the message is captured within the block, allowing the returned value to
+    /// be set in an immutable variable. For example,
+    ///
+    ///     let msg = MyMessage.with { $0.myField = "foo" }
+    ///     msg.myOtherField = 5  // error: msg is immutable
+    ///
+    /// - Parameter populator: A block or function that populates the new message,
+    ///   which is passed into the block as an `inout` argument.
+    /// - Returns: The `Self` instance after execution of the block.
+    static func with(
+      _ populator: (inout Self) throws -> ()
+    ) rethrows -> Self
+}
+
+
+public extension PopulatorConstructable {
+
+    static func with(
+      _ populator: (inout Self) throws -> ()
+    ) rethrows -> Self {
+      var message = Self()
+      try populator(&message)
+      return message
+    }
+}

Sources/SwiftProtobuf/Visitor.swift

@@ -449,8 +449,7 @@ public protocol Visitor {
 }
 
 /// Provides options for how visitor traversal should be carried out
-public struct TraversalOptions {
-  static let `default` = TraversalOptions()
+public struct TraversalOptions: PopulatorConstructable {
 
   /// Determines if non-optional fields that are equal to their default values should be visited.
   /// Defaults to `false`.
@@ -460,11 +459,9 @@ public struct TraversalOptions {
   /// - map fields: Will always be visited, even if they are empty.
   /// - singular message and group fields: Will be visited only if they are set.
   /// - singular primitive fields: Will always be visited under proto2. Under proto3 unset optional primitive fields will not be visited.
-  public var alwaysVisitPrimitiveFields: Bool
+  public var alwaysVisitPrimitiveFields: Bool = false
 
-  public init(alwaysVisitPrimitiveFields: Bool = false) {
-    self.alwaysVisitPrimitiveFields = alwaysVisitPrimitiveFields
-  }
+  public init() {}
 }
 
 
@@ -473,7 +470,7 @@ extension Visitor {
 
   // Use the default traversal options if not set
   public var traversalOptions: TraversalOptions {
-    .default
+    TraversalOptions()
   }
 
   // Default definitions of numeric serializations.

Tests/SwiftProtobufTests/Test_JSON.swift

@@ -1062,8 +1062,9 @@ final class Test_JSONDefaultValues: XCTestCase {
         + #""FieldName18":0"#
         + "}"
 
-        var encodingOptions = JSONEncodingOptions()
-        encodingOptions.alwaysPrintPrimitiveFields = true
+        let encodingOptions = JSONEncodingOptions.with {
+            $0.alwaysPrintPrimitiveFields = true
+        }
 
         let msg = SwiftProtoTesting_Test3_TestJsonAllTypesProto3()
         XCTAssertEqual(try msg.jsonString(options: encodingOptions), expected)
@@ -1161,9 +1162,10 @@ final class Test_JSONDefaultValues: XCTestCase {
         + #""FieldName18":0"#
         + "}"
 
-        var encodingOptions = JSONEncodingOptions()
-        encodingOptions.alwaysPrintPrimitiveFields = true
-                
+        let encodingOptions = JSONEncodingOptions.with {
+            $0.alwaysPrintPrimitiveFields = true
+        }
+
         let msg = SwiftProtoTesting_Test3_TestJsonAllTypesProto3.with {
             $0.optionalNestedMessage = .init()
             $0.optionalString = "i am a test string value"
@@ -1243,8 +1245,9 @@ final class Test_JSONDefaultValues: XCTestCase {
         + #""defaultCord":"123""#
         + "}"
 
-        var encodingOptions = JSONEncodingOptions()
-        encodingOptions.alwaysPrintPrimitiveFields = true
+        let encodingOptions = JSONEncodingOptions.with {
+            $0.alwaysPrintPrimitiveFields = true
+        }
         let msg = SwiftProtoTesting_TestAllTypes()
         XCTAssertEqual(try msg.jsonString(options: encodingOptions), expected)
     }
@@ -1318,8 +1321,9 @@ final class Test_JSONDefaultValues: XCTestCase {
         + #""defaultCord":"123""#
         + "}"
 
-        var encodingOptions = JSONEncodingOptions()
-        encodingOptions.alwaysPrintPrimitiveFields = true
+        let encodingOptions = JSONEncodingOptions.with {
+            $0.alwaysPrintPrimitiveFields = true
+        }
         let msg = SwiftProtoTesting_TestAllTypes.with {
             $0.optionalNestedMessage = .init()
             $0.optionalString = "i am a test string value"
@@ -1360,8 +1364,9 @@ final class Test_JSONDefaultValues: XCTestCase {
         + #""replacementString":"${unknown}""#
         + "}"
 
-        var encodingOptions = JSONEncodingOptions()
-        encodingOptions.alwaysPrintPrimitiveFields = true
+        let encodingOptions = JSONEncodingOptions.with {
+            $0.alwaysPrintPrimitiveFields = true
+        }
         let msg = SwiftProtoTesting_TestExtremeDefaultValues()
         XCTAssertEqual(try msg.jsonString(options: encodingOptions), expected)
     }