From 313ef908cfbcd58d06746044a6a0c87eb5600bed Mon Sep 17 00:00:00 2001
From: Pavel Djundik <xPaw@users.noreply.github.com>
Date: Mon, 16 Nov 2020 10:59:45 +0200
Subject: [PATCH] Write empty values (null and no children) as an object when
 saving to binary

---
 SteamKit2/SteamKit2/Types/KeyValue.cs |  4 +--
 SteamKit2/Tests/KeyValueFacts.cs      | 49 +++++++++++++++++++++++++++
 2 files changed, 51 insertions(+), 2 deletions(-)

diff --git a/SteamKit2/SteamKit2/Types/KeyValue.cs b/SteamKit2/SteamKit2/Types/KeyValue.cs
index 676718936..9c977d50c 100644
--- a/SteamKit2/SteamKit2/Types/KeyValue.cs
+++ b/SteamKit2/SteamKit2/Types/KeyValue.cs
@@ -733,7 +733,7 @@ void RecursiveSaveBinaryToStreamCore( Stream f )
             // Only supported types ATM:
             // 1. KeyValue with children (no value itself)
             // 2. String KeyValue
-            if ( Children.Any() )
+            if ( Value == null )
             {
                 f.WriteByte( ( byte )Type.None );
                 f.WriteNullTermString( GetNameForSerialization(), Encoding.UTF8 );
@@ -747,7 +747,7 @@ void RecursiveSaveBinaryToStreamCore( Stream f )
             {
                 f.WriteByte( ( byte )Type.String );
                 f.WriteNullTermString( GetNameForSerialization(), Encoding.UTF8 );
-                f.WriteNullTermString( Value ?? string.Empty, Encoding.UTF8 );
+                f.WriteNullTermString( Value, Encoding.UTF8 );
             }
         }
 
diff --git a/SteamKit2/Tests/KeyValueFacts.cs b/SteamKit2/Tests/KeyValueFacts.cs
index 17b243576..56b5545c2 100644
--- a/SteamKit2/Tests/KeyValueFacts.cs
+++ b/SteamKit2/Tests/KeyValueFacts.cs
@@ -478,6 +478,55 @@ public void KeyValuesEscapesTextWhenSerializing()
             Assert.Equal( expectedValue, text );
         }
 
+        [Fact]
+        public void KeyValuesTextPreserveEmptyObjects()
+        {
+            var kv = new KeyValue( "key" );
+            kv.Children.Add( new KeyValue( "emptyObj" ) );
+            kv.Children.Add( new KeyValue( "emptyString", string.Empty ) );
+
+            string text;
+            using ( var ms = new MemoryStream() )
+            {
+                kv.SaveToStream( ms, asBinary: false );
+                ms.Seek( 0, SeekOrigin.Begin );
+                using ( var reader = new StreamReader( ms ) )
+                {
+                    text = reader.ReadToEnd();
+                }
+            }
+
+            var expectedValue = "\"key\"\n{\n\t\"emptyObj\"\n\t{\n\t}\n\t\"emptyString\"\t\t\"\"\n}\n";
+            Assert.Equal( expectedValue, text );
+        }
+
+        [Fact]
+        public void KeyValuesBinaryPreserveEmptyObjects()
+        {
+            var expectedHexString = "006B65790000656D7074794F626A000801656D707479537472696E6700000808";
+
+            var kv = new KeyValue( "key" );
+            kv.Children.Add( new KeyValue( "emptyObj" ) );
+            kv.Children.Add( new KeyValue( "emptyString", string.Empty ) );
+            
+            var deserializedKv = new KeyValue();
+            byte[] binaryValue;
+            using ( var ms = new MemoryStream() )
+            {
+                kv.SaveToStream( ms, asBinary: true );
+                ms.Seek( 0, SeekOrigin.Begin );
+                binaryValue = ms.ToArray();
+                deserializedKv.TryReadAsBinary( ms );
+            }
+
+            var hexValue = BitConverter.ToString( binaryValue ).Replace( "-", "" );
+
+            Assert.Equal( expectedHexString, hexValue );
+            Assert.Null( deserializedKv["emptyObj"].Value );
+            Assert.Empty( deserializedKv["emptyObj"].Children );
+            Assert.Equal( string.Empty, deserializedKv["emptyString"].Value );
+        }
+
         [Fact]
         public void DecodesBinaryWithFieldType10()
         {