Use Lock type in .NET 9.0.

Author: bgrainger

src/MySqlConnector/Authentication/AuthenticationPlugins.cs

@@ -35,6 +35,10 @@ internal static bool TryGetPlugin(string name, [NotNullWhen(true)] out IAuthenti
 			return s_plugins.TryGetValue(name, out plugin);
 	}
 
+#if NET9_0_OR_GREATER
+	private static readonly Lock s_lock = new();
+#else
 	private static readonly object s_lock = new();
+#endif
 	private static readonly Dictionary<string, IAuthenticationPlugin> s_plugins = [];
 }

src/MySqlConnector/Core/ILoadBalancer.cs

@@ -27,12 +27,18 @@ internal sealed class RandomLoadBalancer : ILoadBalancer
 	public IReadOnlyList<string> LoadBalance(IReadOnlyList<string> hosts)
 	{
 #pragma warning disable CA5394 // Do not use insecure randomness
-		// from https://en.wikipedia.org/wiki/Fisher%E2%80%93Yates_shuffle#The_modern_algorithm
+#if NET8_0_OR_GREATER
+		var shuffled = hosts.ToArray();
+		lock (m_lock)
+			m_random.Shuffle(shuffled);
+		return shuffled;
+#else
 		var shuffled = new List<string>(hosts);
+		// from https://en.wikipedia.org/wiki/Fisher%E2%80%93Yates_shuffle#The_modern_algorithm
 		for (var i = hosts.Count - 1; i >= 1; i--)
 		{
 			int j;
-			lock (m_random)
+			lock (m_lock)
 				j = m_random.Next(i + 1);
 			if (i != j)
 			{
@@ -42,11 +48,21 @@ public IReadOnlyList<string> LoadBalance(IReadOnlyList<string> hosts)
 			}
 		}
 		return shuffled;
+#endif
 	}
 
-	private RandomLoadBalancer() => m_random = new();
+	private RandomLoadBalancer()
+	{
+		m_random = new();
+		m_lock = new();
+	}
 
 	private readonly Random m_random;
+#if NET9_0_OR_GREATER
+	private readonly Lock m_lock;
+#else
+	private readonly object m_lock;
+#endif
 }
 
 internal sealed class RoundRobinLoadBalancer : ILoadBalancer
@@ -67,6 +83,10 @@ public IReadOnlyList<string> LoadBalance(IReadOnlyList<string> hosts)
 		return shuffled;
 	}
 
+#if NET9_0_OR_GREATER
+	private readonly Lock m_lock;
+#else
 	private readonly object m_lock;
+#endif
 	private uint m_counter;
 }

src/MySqlConnector/MySqlBulkLoader.cs

@@ -176,8 +176,7 @@ internal async ValueTask<int> LoadAsync(IOBehavior ioBehavior, CancellationToken
 			{
 				// replace the file name with a sentinel so that we know (when processing the result set) that it's not spoofed by the server
 				var newFileName = GenerateSourceFileName();
-				lock (s_lock)
-					s_sources.Add(newFileName, CreateFileStream(FileName!));
+				AddSource(newFileName, CreateFileStream(FileName!));
 				FileName = newFileName;
 			}
 		}
@@ -187,8 +186,7 @@ internal async ValueTask<int> LoadAsync(IOBehavior ioBehavior, CancellationToken
 				throw new InvalidOperationException("Local must be true to use SourceStream, SourceDataTable, or SourceDataReader.");
 
 			FileName = GenerateSourceFileName();
-			lock (s_lock)
-				s_sources.Add(FileName, Source!);
+			AddSource(FileName, Source!);
 		}
 
 		var closeConnection = false;
@@ -221,6 +219,12 @@ internal async ValueTask<int> LoadAsync(IOBehavior ioBehavior, CancellationToken
 			if (closeConnection)
 				Connection.Close();
 		}
+
+		static void AddSource(string name, object source)
+		{
+			lock (s_lock)
+				s_sources.Add(name, source);
+		}
 	}
 
 	internal const string SourcePrefix = ":SOURCE:";
@@ -319,6 +323,10 @@ internal static bool TryGetAndRemoveSource(string sourceKey, [NotNullWhen(true)]
 
 	private static string GenerateSourceFileName() => SourcePrefix + Guid.NewGuid().ToString("N");
 
+#if NET9_0_OR_GREATER
+	private static readonly Lock s_lock = new();
+#else
 	private static readonly object s_lock = new();
+#endif
 	private static readonly Dictionary<string, object> s_sources = [];
 }

src/MySqlConnector/MySqlConnection.cs

@@ -1189,16 +1189,20 @@ private async Task DoCloseAsync(bool changeState, IOBehavior ioBehavior)
 			};
 			connection.TakeSessionFrom(this);
 
-			// put the new, idle, connection into the list of sessions for this transaction (replacing this MySqlConnection)
-			lock (s_lock)
+			ReplaceConnection(this, connection);
+			static void ReplaceConnection(MySqlConnection thisConnection, MySqlConnection connection)
 			{
-				foreach (var enlistedTransaction in s_transactionConnections[connection.m_enlistedTransaction!.Transaction])
+				// put the new, idle, connection into the list of sessions for this transaction (replacing this MySqlConnection)
+				lock (s_lock)
 				{
-					if (enlistedTransaction.Connection == this)
+					foreach (var enlistedTransaction in s_transactionConnections[connection.m_enlistedTransaction!.Transaction])
 					{
-						enlistedTransaction.Connection = connection;
-						enlistedTransaction.IsIdle = true;
-						break;
+						if (enlistedTransaction.Connection == thisConnection)
+						{
+							enlistedTransaction.Connection = connection;
+							enlistedTransaction.IsIdle = true;
+							break;
+						}
 					}
 				}
 			}
@@ -1256,7 +1260,11 @@ private ConnectionSettings GetConnectionSettings() =>
 	private static readonly StateChangeEventArgs s_stateChangeClosedConnecting = new(ConnectionState.Closed, ConnectionState.Connecting);
 	private static readonly StateChangeEventArgs s_stateChangeConnectingOpen = new(ConnectionState.Connecting, ConnectionState.Open);
 	private static readonly StateChangeEventArgs s_stateChangeOpenClosed = new(ConnectionState.Open, ConnectionState.Closed);
+#if NET9_0_OR_GREATER
+	private static readonly Lock s_lock = new();
+#else
 	private static readonly object s_lock = new();
+#endif
 	private static readonly Dictionary<System.Transactions.Transaction, List<EnlistedTransactionBase>> s_transactionConnections = [];
 	private static readonly ReadOnlyMemory<byte>[] s_startTransactionPayloads = new ReadOnlyMemory<byte>[5 * 3 * 2];
 

src/MySqlConnector/Utilities/TimerQueue.cs

@@ -131,7 +131,11 @@ public Data(uint id, int time, Action action)
 		public Action Action { get; }
 	}
 
+#if NET9_0_OR_GREATER
+	private readonly Lock m_lock;
+#else
 	private readonly object m_lock;
+#endif
 	private readonly Timer m_timer;
 	private readonly List<Data> m_timeoutActions;
 	private uint m_counter;