Fix arrays merge (#139)

* Added failing test

* Updated array concatenation implementation

Author: IgorFedchenko

src/Hocon.Tests/DuplicateKeysAndObjectMerging.cs

@@ -10,6 +10,7 @@
 using System.Linq;
 using System.Text;
 using System.Threading.Tasks;
+using FluentAssertions;
 using Xunit;
 using Xunit.Abstractions;
 
@@ -147,6 +148,27 @@ public void ObjectCanMixBraceAndDotSyntax()
             Assert.Equal(32, config.GetInt("foo.z"));
         }
 
+        // Fix for https://github.com/akkadotnet/HOCON/issues/137
+        [Fact]
+        public void ObjectsWithArraysShouldMergeCorrectly()
+        {
+            var hocon = @"
+c: { 
+    a: [2, 5] 
+    a: [6] 
+}
+";
+            var hocon2 = @"
+c: { 
+    a: [2, 5] [6] 
+}
+";
+            var config = Parser.Parse(hocon);
+            config.GetIntList("c.a").Should().Equal(new [] { 6 });
+            config = Parser.Parse(hocon2);
+            config.GetIntList("c.a").Should().Equal(new [] { 2, 5, 6 });
+        }
+
         [Fact]
         public void CanMixObjectMergeAndSubstitutions_Issue92()
         {

src/Hocon.Tests/Hocon.Tests.csproj

@@ -12,6 +12,7 @@
   </ItemGroup>
 
   <ItemGroup>
+    <PackageReference Include="FluentAssertions" Version="5.9.0" />
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="$(TestSdkVersion)" />
     <PackageReference Include="xunit" Version="$(XunitVersion)" />
     <DotNetCliToolReference Include="dotnet-xunit" Version="$(XunitCliVersion)" />

src/Hocon/Parser.cs

@@ -690,6 +690,11 @@ private HoconValue ParseValue(IHoconElement owner)
                     case TokenType.StartOfArray:
                         if (value == null)
                             value = GetHoconValueFromParentElement(owner, _tokens.Current.Type);
+                        
+                        // If this array is already initialized, we are going to overwrite it
+                        if (value.Type == HoconType.Array && value.Count > 0)
+                            value.Clear();
+                        
                         value.Add(ParseArray(value));
                         break;
 
@@ -902,7 +907,19 @@ private HoconArray ParseArray(IHoconElement owner)
 
                     case TokenType.EndOfArray:
                         valueWasParsed = false;
-                        parsing = false;
+
+                        // If there is a next array on the same like - let's move to it's first element
+                        if (_tokens.ForwardMatch(TokenType.StartOfArray))
+                        {
+                            _tokens.ToNextSignificant();
+                            _tokens.Next();
+                        }
+                        else
+                        {
+                            // Otherwise, array value is fully loaded and nothing to do here
+                            parsing = false;
+                        }
+                        
                         break;
 
                     case TokenType.Comment: