Version: 264.0.6-fix-physics

83ad6042a7 & b267cd6fb4

Does not include test code to avoid risking merge conflicts.

(cherry picked from commit 415585a30d74fcae61f581808220a7aaeca3eaf5)
(cherry picked from commit e36628a6d436ea08d6d31441c101a88a5504c515)

Directory.Packages.props

@@ -57,7 +57,7 @@
     <PackageVersion Include="SharpZstd.Interop" Version="1.5.2-beta2" />
     <PackageVersion Include="SixLabors.ImageSharp" Version="3.1.7" />
     <PackageVersion Include="SpaceWizards.HttpListener" Version="0.1.1" />
-    <PackageVersion Include="SpaceWizards.NFluidsynth" Version="0.1.1" />
+    <PackageVersion Include="SpaceWizards.NFluidsynth" Version="0.2.2" />
     <PackageVersion Include="SpaceWizards.SharpFont" Version="1.0.2" />
     <PackageVersion Include="SpaceWizards.Sodium" Version="0.2.1" />
     <PackageVersion Include="TerraFX.Interop.Windows" Version="10.0.26100.1" />

MSBuild/Robust.Engine.Version.props

@@ -1,4 +1,4 @@
 <Project>
 
-    <!-- This file automatically reset by Tools/version.py -->
+    <!-- This file automatically reset by Tools/version.py -->
 

RELEASE-NOTES.md

@@ -54,6 +54,27 @@ END TEMPLATE-->
 *None yet*
 
 
+## 264.0.6-fix-physics
+
+
+## 264.0.5-fix-physics
+
+
+## 264.0.4-fix-physics
+
+
+## 264.0.3-fix-physics
+
+
+## 264.0.2-fix-physics
+
+
+## 264.0.1-fix-physics
+
+
+## 264.0.0-fix-physics
+
+
 ## 264.0.0
 
 ### Breaking changes

Robust.Client.WebView/Cef/Program.cs

@@ -6,7 +6,7 @@ using Xilium.CefGlue;
 
 namespace Robust.Client.WebView.Cef
 {
-    public static class Program
+    internal static class Program
     {
         // This was supposed to be the main entry for the subprocess program... It doesn't work.
         public static int Main(string[] args)

Robust.Client.WebView/Cef/WebViewManagerCef.cs

@@ -5,6 +5,7 @@ using System.Net;
 using System.Reflection;
 using System.Text;
 using Robust.Client.Console;
+using Robust.Client.Utility;
 using Robust.Shared.Configuration;
 using Robust.Shared.ContentPack;
 using Robust.Shared.IoC;
@@ -24,6 +25,7 @@ namespace Robust.Client.WebView.Cef
 
         [Dependency] private readonly IDependencyCollection _dependencyCollection = default!;
         [Dependency] private readonly IPrototypeManager _prototypeManager = default!;
+        [Dependency] private readonly IGameControllerInternal _gameController = default!;
         [Dependency] private readonly IResourceManagerInternal _resourceManager = default!;
         [Dependency] private readonly IClientConsoleHost _consoleHost = default!;
         [Dependency] private readonly IConfigurationManager _cfg = default!;
@@ -61,7 +63,10 @@ namespace Robust.Client.WebView.Cef
 
             var cachePath = "";
             if (_resourceManager.UserData is WritableDirProvider userData)
-                cachePath = userData.GetFullPath(new ResPath("/cef_cache"));
+            {
+                var rootDir = UserDataDir.GetRootUserDataDir(_gameController);
+                cachePath = Path.Combine(rootDir, "cef_cache", "0");
+            }
 
             var settings = new CefSettings()
             {

Robust.Client/GameController/GameController.cs

@@ -387,7 +387,7 @@ namespace Robust.Client
 
             _prof.Initialize();
 
-            _resManager.Initialize(Options.LoadConfigAndUserData ? userDataDir : null);
+            _resManager.Initialize(Options.LoadConfigAndUserData ? userDataDir : null, hideUserDataDir: true);
 
             var mountOptions = _commandLineArgs != null
                 ? MountOptions.Merge(_commandLineArgs.MountOptions, Options.MountOptions)

Robust.Client/UserInterface/Controls/OutputPanel.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Diagnostics.Contracts;
 using System.Numerics;
 using Robust.Client.Graphics;
 using Robust.Client.UserInterface.RichText;
@@ -154,6 +155,7 @@ namespace Robust.Client.UserInterface.Controls
 
         public void SetMessage(Index index, FormattedMessage message, Type[]? tagsAllowed = null, Color? defaultColor = null)
         {
+            var atBottom = !_scrollDownButton.Visible;
             var oldEntry = _entries[index];
             var font = _getFont();
             _totalContentHeight -= oldEntry.Height + font.GetLineSeparation(UIScale);
@@ -164,6 +166,10 @@ namespace Robust.Client.UserInterface.Controls
             _entries[index] = entry;
 
             AddNewItemHeight(font, in entry);
+
+            _scrollBar.MaxValue = Math.Max(_scrollBar.Page, _totalContentHeight);
+            if (atBottom)
+                _scrollBar.Value = _scrollBar.MaxValue;
         }
 
         private void AddNewItemHeight(Font font, in RichTextEntry entry)
@@ -278,7 +284,7 @@ namespace Robust.Client.UserInterface.Controls
             }
         }
 
-        [System.Diagnostics.Contracts.Pure]
+        [Pure]
         private Font _getFont()
         {
             if (TryGetStyleProperty<Font>("font", out var font))
@@ -289,7 +295,7 @@ namespace Robust.Client.UserInterface.Controls
             return UserInterfaceManager.ThemeDefaults.DefaultFont;
         }
 
-        [System.Diagnostics.Contracts.Pure]
+        [Pure]
         private StyleBox? _getStyleBox()
         {
             if (StyleBoxOverride != null)
@@ -301,14 +307,14 @@ namespace Robust.Client.UserInterface.Controls
             return box;
         }
 
-        [System.Diagnostics.Contracts.Pure]
+        [Pure]
         private float _getScrollSpeed()
         {
             // The scroll speed depends on the UI scale because the scroll bar is working with physical pixels.
             return GetScrollSpeed(_getFont(), UIScale);
         }
 
-        [System.Diagnostics.Contracts.Pure]
+        [Pure]
         private UIBox2 _getContentBox()
         {
             var style = _getStyleBox();

Robust.Server/BaseServer.cs

@@ -297,7 +297,7 @@ namespace Robust.Server
                 : null;
 
             // Set up the VFS
-            _resources.Initialize(dataDir);
+            _resources.Initialize(dataDir, hideUserDataDir: false);
 
             var mountOptions = _commandLineArgs != null
                 ? MountOptions.Merge(_commandLineArgs.MountOptions, Options.MountOptions) : Options.MountOptions;

Robust.Shared.Maths/Properties/AssemblyInfo.cs

@@ -6,4 +6,3 @@
 
 [assembly: InternalsVisibleTo("Robust.Client")]
 [assembly: InternalsVisibleTo("Robust.UnitTesting")]
-[assembly: InternalsVisibleTo("Content.Benchmarks")]

Robust.Shared/ContentPack/AssemblyTypeChecker.Config.cs

@@ -88,6 +88,7 @@ namespace Robust.Shared.ContentPack
             public string SystemAssemblyName = default!;
             public HashSet<VerifierError> AllowedVerifierErrors = default!;
             public List<string> WhitelistedNamespaces = default!;
+            public List<string> AllowedAssemblyPrefixes = default!;
             public Dictionary<string, Dictionary<string, TypeConfig>> Types = default!;
         }
 

Robust.Shared/ContentPack/AssemblyTypeChecker.cs

@@ -131,6 +131,16 @@ namespace Robust.Shared.ContentPack
                 return false;
             }
 
+#pragma warning disable RA0004
+            var loadedConfig = _config.Result;
+#pragma warning restore RA0004
+
+            if (!loadedConfig.AllowedAssemblyPrefixes.Any(allowedNamePrefix => asmName.StartsWith(allowedNamePrefix)))
+            {
+                _sawmill.Error($"Assembly name '{asmName}' is not allowed for a content assembly");
+                return false;
+            }
+
             if (VerifyIL)
             {
                 if (!DoVerifyIL(asmName, resolver, peReader, reader))
@@ -179,10 +189,6 @@ namespace Robust.Shared.ContentPack
                 return true;
             }
 
-#pragma warning disable RA0004
-            var loadedConfig = _config.Result;
-#pragma warning restore RA0004
-
             var badRefs = new ConcurrentBag<EntityHandle>();
 
             // We still do explicit type reference scanning, even though the actual whitelists work with raw members.

Robust.Shared/ContentPack/DirLoader.cs

@@ -60,9 +60,7 @@ namespace Robust.Shared.ContentPack
 
             internal string GetPath(ResPath relPath)
             {
-                return Path.GetFullPath(Path.Combine(_directory.FullName, relPath.ToRelativeSystemPath()))
-                    // Sanitise platform-specific path and standardize it for engine use.
-                    .Replace(Path.DirectorySeparatorChar, '/');
+                return PathHelpers.SafeGetResourcePath(_directory.FullName, relPath);
             }
 
             /// <inheritdoc />

Robust.Shared/ContentPack/IResourceManagerInternal.cs

@@ -14,7 +14,11 @@ namespace Robust.Shared.ContentPack
         /// The directory to use for user data.
         /// If null, a virtual temporary file system is used instead.
         /// </param>
-        void Initialize(string? userData);
+        /// <param name="hideUserDataDir">
+        /// If true, <see cref="IWritableDirProvider.RootDir"/> will be hidden on
+        /// <see cref="IResourceManager.UserData"/>.
+        /// </param>
+        void Initialize(string? userData, bool hideUserDataDir);
 
         /// <summary>
         ///     Mounts a single stream as a content file. Useful for unit testing.

Robust.Shared/ContentPack/IWritableDirProvider.cs

@@ -13,7 +13,7 @@ namespace Robust.Shared.ContentPack
     {
         /// <summary>
         /// The root path of this provider.
-        /// Can be null if it's a virtual provider.
+        /// Can be null if it's a virtual provider or the path is protected (e.g. on the client).
         /// </summary>
         string? RootDir { get; }
 

Robust.Shared/ContentPack/ModLoader.cs

@@ -93,19 +93,23 @@ namespace Robust.Shared.ContentPack
         {
             var sw = Stopwatch.StartNew();
             Sawmill.Debug("LOADING modules");
-            var files = new Dictionary<string, (ResPath Path, string[] references)>();
+            var files = new Dictionary<string, (ResPath Path, MemoryStream data, string[] references)>();
 
             // Find all modules we want to load.
             foreach (var fullPath in paths)
             {
                 using var asmFile = _res.ContentFileRead(fullPath);
-                var refData = GetAssemblyReferenceData(asmFile);
+                var ms = new MemoryStream();
+                asmFile.CopyTo(ms);
+
+                ms.Position = 0;
+                var refData = GetAssemblyReferenceData(ms);
                 if (refData == null)
                     continue;
 
                 var (asmRefs, asmName) = refData.Value;
 
-                if (!files.TryAdd(asmName, (fullPath, asmRefs)))
+                if (!files.TryAdd(asmName, (fullPath, ms, asmRefs)))
                 {
                     Sawmill.Error("Found multiple modules with the same assembly name " +
                                   $"'{asmName}', A: {files[asmName].Path}, B: {fullPath}.");
@@ -122,10 +126,10 @@ namespace Robust.Shared.ContentPack
 
                 Parallel.ForEach(files, pair =>
                 {
-                    var (name, (path, _)) = pair;
+                    var (name, (_, data, _)) = pair;
 
-                    using var stream = _res.ContentFileRead(path);
-                    if (!typeChecker.CheckAssembly(stream, resolver))
+                    data.Position = 0;
+                    if (!typeChecker.CheckAssembly(data, resolver))
                     {
                         throw new TypeCheckFailedException($"Assembly {name} failed type checks.");
                     }
@@ -137,14 +141,15 @@ namespace Robust.Shared.ContentPack
             var nodes = TopologicalSort.FromBeforeAfter(
                 files,
                 kv => kv.Key,
-                kv => kv.Value.Path,
+                kv => kv.Value,
                 _ => Array.Empty<string>(),
                 kv => kv.Value.references,
                 allowMissing: true); // missing refs would be non-content assemblies so allow that.
 
             // Actually load them in the order they depend on each other.
-            foreach (var path in TopologicalSort.Sort(nodes))
+            foreach (var item in TopologicalSort.Sort(nodes))
             {
+                var (path, memory, _) = item;
                 Sawmill.Debug($"Loading module: '{path}'");
                 try
                 {
@@ -156,9 +161,9 @@ namespace Robust.Shared.ContentPack
                     }
                     else
                     {
-                        using var assemblyStream = _res.ContentFileRead(path);
+                        memory.Position = 0;
                         using var symbolsStream = _res.ContentFileReadOrNull(path.WithExtension("pdb"));
-                        LoadGameAssembly(assemblyStream, symbolsStream, skipVerify: true);
+                        LoadGameAssembly(memory, symbolsStream, skipVerify: true);
                     }
                 }
                 catch (Exception e)
@@ -174,7 +179,7 @@ namespace Robust.Shared.ContentPack
 
         private (string[] refs, string name)? GetAssemblyReferenceData(Stream stream)
         {
-            using var reader = ModLoader.MakePEReader(stream);
+            using var reader = ModLoader.MakePEReader(stream, leaveOpen: true);
             var metaReader = reader.GetMetadataReader();
 
             var name = metaReader.GetString(metaReader.GetAssemblyDefinition().Name);

Robust.Shared/ContentPack/PathHelpers.cs

@@ -2,6 +2,7 @@
 using System.Collections.Generic;
 using System.IO;
 using System.Runtime.InteropServices;
+using Robust.Shared.Utility;
 
 namespace Robust.Shared.ContentPack
 {
@@ -63,5 +64,27 @@ namespace Robust.Shared.ContentPack
             !OperatingSystem.IsWindows()
             && !OperatingSystem.IsMacOS();
 
+
+        internal static string SafeGetResourcePath(string baseDir, ResPath path)
+        {
+            var relSysPath = path.ToRelativeSystemPath();
+            if (relSysPath.Contains("\\..") || relSysPath.Contains("/.."))
+            {
+                // Hard cap on any exploit smuggling a .. in there.
+                // Since that could allow leaving sandbox.
+                throw new InvalidOperationException($"This branch should never be reached. Path: {path}");
+            }
+
+            var retPath = Path.GetFullPath(Path.Join(baseDir, relSysPath));
+            // better safe than sorry check
+            if (!retPath.StartsWith(baseDir))
+            {
+                // Allow path to match if it's just missing the directory separator at the end.
+                if (retPath != baseDir.TrimEnd(Path.DirectorySeparatorChar))
+                    throw new InvalidOperationException($"This branch should never be reached. Path: {path}");
+            }
+
+            return retPath;
+        }
     }
 }

Robust.Shared/ContentPack/ResourceManager.cs

@@ -41,13 +41,13 @@ namespace Robust.Shared.ContentPack
         public IWritableDirProvider UserData { get; private set; } = default!;
 
         /// <inheritdoc />
-        public virtual void Initialize(string? userData)
+        public virtual void Initialize(string? userData, bool hideRootDir)
         {
             Sawmill = _logManager.GetSawmill("res");
 
             if (userData != null)
             {
-                UserData = new WritableDirProvider(Directory.CreateDirectory(userData));
+                UserData = new WritableDirProvider(Directory.CreateDirectory(userData), hideRootDir);
             }
             else
             {
@@ -379,6 +379,10 @@ namespace Robust.Shared.ContentPack
                 {
                     var rootDir = loader.GetPath(new ResPath(@"/"));
 
+                    // TODO: GET RID OF THIS.
+                    // This code shouldn't be passing OS disk paths through ResPath.
+                    rootDir = rootDir.Replace(Path.DirectorySeparatorChar, '/');
+
                     yield return new ResPath(rootDir);
                 }
             }

Robust.Shared/ContentPack/Sandbox.yml

@@ -17,6 +17,10 @@ WhitelistedNamespaces:
 - Content
 - OpenDreamShared
 
+AllowedAssemblyPrefixes:
+- OpenDream
+- Content
+
 # The type whitelist does NOT care about which assembly types come from.
 # This is because types switch assembly all the time.
 # Just look up stuff like StreamReader on https://apisof.net.

Robust.Shared/ContentPack/WritableDirProvider.cs

@@ -10,17 +10,22 @@ namespace Robust.Shared.ContentPack
     /// <inheritdoc />
     internal sealed class WritableDirProvider : IWritableDirProvider
     {
-        /// <inheritdoc />
+        private readonly bool _hideRootDir;
+
         public string RootDir { get; }
 
+        string? IWritableDirProvider.RootDir => _hideRootDir ? null : RootDir;
+
         /// <summary>
         /// Constructs an instance of <see cref="WritableDirProvider"/>.
         /// </summary>
         /// <param name="rootDir">Root file system directory to allow writing.</param>
-        public WritableDirProvider(DirectoryInfo rootDir)
+        /// <param name="hideRootDir">If true, <see cref="IWritableDirProvider.RootDir"/> is reported as null.</param>
+        public WritableDirProvider(DirectoryInfo rootDir, bool hideRootDir)
         {
             // FullName does not have a trailing separator, and we MUST have a separator.
             RootDir = rootDir.FullName + Path.DirectorySeparatorChar.ToString();
+            _hideRootDir = hideRootDir;
         }
 
         #region File Access
@@ -119,7 +124,7 @@ namespace Robust.Shared.ContentPack
                 throw new FileNotFoundException();
 
             var dirInfo = new DirectoryInfo(GetFullPath(path));
-            return new WritableDirProvider(dirInfo);
+            return new WritableDirProvider(dirInfo, _hideRootDir);
         }
 
         /// <inheritdoc />
@@ -180,20 +185,7 @@ namespace Robust.Shared.ContentPack
 
             path = path.Clean();
 
-            return GetFullPath(RootDir, path);
-        }
-
-        private static string GetFullPath(string root, ResPath path)
-        {
-            var relPath = path.ToRelativeSystemPath();
-            if (relPath.Contains("\\..") || relPath.Contains("/.."))
-            {
-                // Hard cap on any exploit smuggling a .. in there.
-                // Since that could allow leaving sandbox.
-                throw new InvalidOperationException($"This branch should never be reached. Path: {path}");
-            }
-
-            return Path.GetFullPath(Path.Combine(root, relPath));
+            return PathHelpers.SafeGetResourcePath(RootDir, path);
         }
     }
 }

Robust.Shared/Network/Messages/MsgConVars.cs

@@ -2,7 +2,6 @@
 using System.Collections.Generic;
 using Lidgren.Network;
 using Robust.Shared.Log;
-using Robust.Shared.Maths;
 using Robust.Shared.Serialization;
 using Robust.Shared.Timing;
 
@@ -11,7 +10,7 @@ namespace Robust.Shared.Network.Messages
     public sealed class MsgConVars : NetMessage
     {
         // Max buffer could potentially be 255 * 128 * 1024 = ~33MB, so if MaxMessageSize starts being a problem it can be increased.
-        private const int MaxMessageSize = 0x4000; // Arbitrarily chosen as a 'sane' value as the maximum size of the entire message.
+        private const int MaxMessageSize = 0x8000; // Arbitrarily chosen as a 'sane' value as the maximum size of the entire message.
         private const int MaxNameSize = 4 * 32; // UTF8 Max char size is 4 bytes, 32 chars.
         private const int MaxStringValSize = 4 * 256; // UTF8 Max char size is 4 bytes, 256 chars.
 
@@ -27,7 +26,7 @@ namespace Robust.Shared.Network.Messages
                 Logger.WarningS("net", $"{MsgChannel}: received a large {nameof(MsgConVars)}, {buffer.LengthBytes}B > {MaxMessageSize}B");
 
             Tick = new GameTick(buffer.ReadVariableUInt32());
-            var nVars = buffer.ReadByte();
+            var nVars = buffer.ReadInt16();
 
             NetworkedVars = new List<(string name, object value)>(nVars);
 
@@ -82,11 +81,11 @@ namespace Robust.Shared.Network.Messages
             if(NetworkedVars == null)
                 throw new InvalidOperationException($"{nameof(NetworkedVars)} collection is null.");
 
-            if(NetworkedVars.Count > byte.MaxValue)
+            if(NetworkedVars.Count > short.MaxValue)
                 throw new InvalidOperationException($"{nameof(NetworkedVars)} collection count is greater than {short.MaxValue}.");
 
             buffer.WriteVariableUInt32(Tick.Value);
-            buffer.Write((byte)NetworkedVars.Count);
+            buffer.Write((short)NetworkedVars.Count);
 
             foreach (var (name, value) in NetworkedVars)
             {

Robust.Shared/Physics/Systems/SharedPhysicsSystem.Island.cs

@@ -4,7 +4,6 @@ using System.Collections.Generic;
 using System.Numerics;
 using System.Threading.Tasks;
 using Microsoft.Extensions.ObjectPool;
-using Robust.Shared.Collections;
 using Robust.Shared.GameObjects;
 using Robust.Shared.Physics.Components;
 using Robust.Shared.Physics.Dynamics;
@@ -1040,7 +1039,10 @@ public abstract partial class SharedPhysicsSystem
                 continue;
 
             var xform = ent.Comp2;
-            var (_, parentRot, parentInvMatrix) = _transform.GetWorldPositionRotationInvMatrix(xform.ParentUid);
+            if (!TryComp(xform.ParentUid, out TransformComponent? transform))
+                continue;
+
+            var (_, parentRot, parentInvMatrix) = _transform.GetWorldPositionRotationInvMatrix(transform);
             var worldRot = (float) (parentRot + xform._localRotation);
 
             var angle = angles[i];

Robust.Shared/Properties/AssemblyInfo.cs

@@ -9,7 +9,6 @@
 [assembly: InternalsVisibleTo("Robust.UnitTesting")]
 [assembly: InternalsVisibleTo("OpenToolkit.GraphicsLibraryFramework")]
 [assembly: InternalsVisibleTo("DynamicProxyGenAssembly2")] // Gives access to Castle(Moq)
-[assembly: InternalsVisibleTo("Content.Benchmarks")]
 [assembly: InternalsVisibleTo("Robust.Benchmarks")]
 [assembly: InternalsVisibleTo("Robust.Client.WebView")]
 [assembly: InternalsVisibleTo("Robust.Packaging")]

Robust.Shared/Serialization/NetBitArraySerializer.cs

@@ -0,0 +1,78 @@
+using System;
+using System.Collections;
+using System.Collections.Generic;
+using System.IO;
+using System.Reflection;
+using System.Runtime.Serialization;
+using JetBrains.Annotations;
+using NetSerializer;
+
+namespace Robust.Shared.Serialization;
+
+/// <summary>
+/// Custom serializer implementation for <see cref="BitArray"/>.
+/// </summary>
+/// <remarks>
+/// <para>
+/// This type is necessary as, since .NET 10, the internal layout of <see cref="BitArray"/> was changed.
+/// The type now (internally) implements <see cref="ISerializable"/> for backwards compatibility with existing
+/// <c>BinaryFormatter</c> code, but NetSerializer does not support <see cref="ISerializable"/>.
+/// </para>
+/// <para>
+/// This code is designed to be backportable &amp; network compatible with the previous behavior on .NET 9.
+/// </para>
+/// </remarks>
+internal sealed class NetBitArraySerializer : IStaticTypeSerializer
+{
+    // For reference, the layout of BitArray before .NET 10 was:
+    // private int[] m_array;
+    // private int m_length;
+    // private int _version;
+    // NetSerializer serialized these in the following order (sorted by name):
+    // _version, m_array, m_length
+
+    public bool Handles(Type type)
+    {
+        return type == typeof(BitArray);
+    }
+
+    public IEnumerable<Type> GetSubtypes(Type type)
+    {
+        return [typeof(int[]), typeof(int)];
+    }
+
+    public MethodInfo GetStaticWriter(Type type)
+    {
+        return typeof(NetBitArraySerializer).GetMethod("Write", BindingFlags.Static | BindingFlags.NonPublic)!;
+    }
+
+    public MethodInfo GetStaticReader(Type type)
+    {
+        return typeof(NetBitArraySerializer).GetMethod("Read", BindingFlags.Static | BindingFlags.NonPublic)!;
+    }
+
+    [UsedImplicitly]
+    private static void Write(Serializer serializer, Stream stream, BitArray value)
+    {
+        var intCount = (31 + value.Length) >> 5;
+        var ints = new int[intCount];
+        value.CopyTo(ints, 0);
+
+        serializer.SerializeDirect(stream, 0); // _version
+        serializer.SerializeDirect(stream, ints); // m_array
+        serializer.SerializeDirect(stream, value.Length); // m_length
+    }
+
+    [UsedImplicitly]
+    private static void Read(Serializer serializer, Stream stream, out BitArray value)
+    {
+        serializer.DeserializeDirect<int>(stream, out _); // _version
+        serializer.DeserializeDirect<int[]>(stream, out var array); // m_array
+        serializer.DeserializeDirect<int>(stream, out var length); // m_length
+
+        value = new BitArray(array)
+        {
+            Length = length
+        };
+    }
+}

Robust.Shared/Serialization/RobustSerializer.cs

@@ -91,6 +91,7 @@ namespace Robust.Shared.Serialization
                     MappedStringSerializer.TypeSerializer,
                     new Vector2Serializer(),
                     new Matrix3x2Serializer(),
+                    new NetBitArraySerializer()
                 }
             };
             _serializer = new Serializer(types, settings);

Robust.UnitTesting/Shared/Resources/WritableDirProviderTest.cs

@@ -24,7 +24,7 @@ namespace Robust.UnitTesting.Shared.Resources
             _testDir = Directory.CreateDirectory(_testDirPath);
             var subDir = Path.Combine(_testDirPath, "writable");
 
-            _dirProvider = new WritableDirProvider(Directory.CreateDirectory(subDir));
+            _dirProvider = new WritableDirProvider(Directory.CreateDirectory(subDir), hideRootDir: false);
         }
 
         [OneTimeTearDown]