Fix comments

Author: Pouya Yarandi

Sources/SwiftProtobuf/Message+FieldMask.swift

@@ -56,7 +56,7 @@ extension Message {
   ///   - source: Message should be merged to the original one.
   ///   - fieldMask: FieldMask specifies which fields should be merged.
   public mutating func merge(
-    to source: Self,
+    from source: Self,
     fieldMask: Google_Protobuf_FieldMask,
     mergeOption: MergeOption = .init()
   ) throws {
@@ -96,7 +96,7 @@ extension Message where Self: Equatable, Self: _ProtoNameProviding {
     }
     var tmp = Self(removingAllFieldsOf: self)
     do {
-      try tmp.merge(to: self, fieldMask: fieldMask)
+      try tmp.merge(from: self, fieldMask: fieldMask)
       let changed = tmp != self
       self = tmp
       return changed

Sources/SwiftProtobuf/SetPathDecoder.swift

@@ -66,8 +66,10 @@ struct SetPathDecoder<T: Message>: Decoder {
     if let firstComponent = path.first,
        let number = T.number(for: firstComponent) {
       self.number = number
+      self.nextPath = .init(path.dropFirst())
+    } else {
+      self.nextPath = []
     }
-    self.nextPath = .init(path.dropFirst())
     self.value = value
     self.mergeOption = mergeOption
   }

Tests/SwiftProtobufTests/Test_FieldMask.swift

@@ -124,12 +124,12 @@ final class Test_FieldMask: XCTestCase, PBTestHelpers {
         }
 
         // Checks nested message merge
-        try message.merge(to: secondMessage, fieldMask: .init(protoPaths: "optional_nested_message.bb"))
+        try message.merge(from: secondMessage, fieldMask: .init(protoPaths: "optional_nested_message.bb"))
         XCTAssertEqual(message.optionalInt32, 1)
         XCTAssertEqual(message.optionalNestedMessage.bb, 3)
 
         // Checks primitive type merge
-        try message.merge(to: secondMessage, fieldMask: .init(protoPaths: "optional_int32"))
+        try message.merge(from: secondMessage, fieldMask: .init(protoPaths: "optional_int32"))
         XCTAssertEqual(message.optionalInt32, 2)
         XCTAssertEqual(message.optionalNestedMessage.bb, 3)
     }
@@ -147,11 +147,11 @@ final class Test_FieldMask: XCTestCase, PBTestHelpers {
         let fieldMask = Google_Protobuf_FieldMask(protoPaths: ["repeated_int32"])
 
         // Checks without replacing repeated fields
-        try message.merge(to: secondMessage, fieldMask: fieldMask)
+        try message.merge(from: secondMessage, fieldMask: fieldMask)
         XCTAssertEqual(message.repeatedInt32, [1, 2, 3, 4])
 
         // Checks with replacing repeated fields
-        try message.merge(to: secondMessage, fieldMask: fieldMask, mergeOption: .init(replaceRepeatedFields: true))
+        try message.merge(from: secondMessage, fieldMask: fieldMask, mergeOption: .init(replaceRepeatedFields: true))
         XCTAssertEqual(message.repeatedInt32, [3, 4])
     }
 
@@ -168,11 +168,11 @@ final class Test_FieldMask: XCTestCase, PBTestHelpers {
         let fieldMask = Google_Protobuf_FieldMask(protoPaths: ["map_int32_string"])
 
         // Checks without replacing repeated fields
-        try message.merge(to: secondMessage, fieldMask: fieldMask)
+        try message.merge(from: secondMessage, fieldMask: fieldMask)
         XCTAssertEqual(message.mapInt32String, [1: "a", 2: "b"])
 
         // Checks with replacing repeated fields
-        try message.merge(to: secondMessage, fieldMask: fieldMask, mergeOption: .init(replaceRepeatedFields: true))
+        try message.merge(from: secondMessage, fieldMask: fieldMask, mergeOption: .init(replaceRepeatedFields: true))
         XCTAssertEqual(message.mapInt32String, [2: "b"])
     }