Add NET472 TFM with native support for ValueTask, IAsyncEnumerable<T>…

… and IAsyncDisposable (#2890)

Build/linq2db.Source.props

@@ -2,7 +2,6 @@
 	<Import Project="linq2db.Default.props" />
 
 	<PropertyGroup>
-		<TargetFrameworks>net45;net46;netstandard2.0;netcoreapp2.1;netstandard2.1;netcoreapp3.1</TargetFrameworks>
 		<Configurations>Debug;Release</Configurations>
 	</PropertyGroup>
 

CONTRIBUTING.md

@@ -39,17 +39,18 @@ Solutions:
 
 #### Source projects
 
-| Project \ Target                                 |.NET 4.5 |.NET 4.6 | .NET Standard 2.0 | .NET Core 2.1 | .NET Standard 2.1 | .NET Core 3.1 |
-|-------------------------------------------------:|:-------:|:-------:|:-----------------:|:-------------:|:-----------------:|:-------------:|
-| `.\Source\LinqToDB\LinqToDB.csproj`              |    √    |    √    |         √         |       √       |         √         |       √       |
-| `.\Source\LinqToDB\LinqToDB.Tools.csproj`        |    √    |    √    |         √         |               |                   |               |
-| `.\Source\LinqToDB\LinqToDB.AspNet.csproj`       |    √    |         |         √         |               |                   |               |
+| Project \ Target                                 |.NET 4.5 |.NET 4.6 |.NET 4.7.2 | .NET Standard 2.0 | .NET Core 2.1 | .NET Standard 2.1 | .NET Core 3.1 |
+|-------------------------------------------------:|:-------:|:-------:|:---------:|:-----------------:|:-------------:|:-----------------:|:-------------:|
+| `.\Source\LinqToDB\LinqToDB.csproj`              |    √    |    √    |     √     |         √         |       √       |         √         |       √       |
+| `.\Source\LinqToDB\LinqToDB.Tools.csproj`        |    √    |    √    |           |         √         |               |                   |               |
+| `.\Source\LinqToDB\LinqToDB.AspNet.csproj`       |    √    |         |           |         √         |               |                   |               |
 
 Preferred target defines:
-- `NETFRAMEWORK` - `net45` and `net46` target ifdef
+- `NETFRAMEWORK` - `net45`, `net46` and `net472` target ifdef
 - `!NETFRAMEWORK` - `netstandard2.0` and newer target ifdef
 - `NETCOREAPP` - `netcoreapp2.1` and `netcoreapp3.1` target ifdef
 - `NETSTANDARD2_1PLUS` - `netstandard2.1` and `netcoreapp3.1` target ifdef
+- `NATIVE_ASYNC` - ifdef with native support for `ValueTask`, `IAsyncEnumerable<T>` and `IAsyncDisposable` types
 
 Other allowed target defines:
 - `NETSTANDARD2_1` - `netstandard2.1` target ifdef
@@ -58,6 +59,7 @@ Other allowed target defines:
 - `NETCOREAPP2_1` - `netcoreapp2.1` target ifdef
 - `NET45` - `net45` target ifdef
 - `NET46` - `net46` target ifdef
+- `NET472` - `net472` target ifdef
 
 Allowed debugging defines:
 - `TRACK_BUILD`
@@ -66,17 +68,16 @@ Allowed debugging defines:
 
 #### Test projects
 
-| Project \ Target                                   |.NET 4.7.2 | .NET Core 2.1 | .NET Core 3.1 | .NET 5.0 | Xamarin.Forms Android v8.1 |
-|---------------------------------------------------:|:---------:|:-------------:|:-------------:|:--------:|:--------------------------:|
-| `.\Tests\Base\Tests.Base.csproj`                   |     √     |       √       |       √       |    √     |                            |
-| `.\Tests\FSharp\Tests.FSharp.fsproj`               |     √     |       √       |       √       |    √     |                            |
-| `.\Tests\Linq\Tests.csproj`                        |     √     |       √       |       √       |    √     |                            |
-| `.\Tests\Model\Tests.Model.csproj`                 |     √     |       √       |       √       |    √     |                            |
-| `.\Tests\Tests.Android\Tests.Android.csproj`       |           |               |               |          |              √             |
-| `.\Tests\Tests.Benchmarks\Tests.Benchmarks.csproj` |     √     |       √       |       √       |    √     |                            |
-| `.\Tests\Tests.Playground\Tests.Playground.csproj` |     √     |       √       |       √       |    √     |                            |
-| `.\Tests\Tests.T4\Tests.T4.csproj`                 |     √     |       √       |       √       |    √     |                            |
-| `.\Tests\VisualBasic\Tests.VisualBasic.vbproj`     |     √     |       √       |       √       |    √     |                            |
+| Project \ Target                                   |.NET 4.7.2 | .NET Core 2.1 | .NET Core 3.1 | .NET 5.0 |
+|---------------------------------------------------:|:---------:|:-------------:|:-------------:|:--------:|
+| `.\Tests\Base\Tests.Base.csproj`                   |     √     |       √       |       √       |    √     |
+| `.\Tests\FSharp\Tests.FSharp.fsproj`               |     √     |       √       |       √       |    √     |
+| `.\Tests\Linq\Tests.csproj`                        |     √     |       √       |       √       |    √     |
+| `.\Tests\Model\Tests.Model.csproj`                 |     √     |       √       |       √       |    √     |
+| `.\Tests\Tests.Benchmarks\Tests.Benchmarks.csproj` |     √     |       √       |       √       |    √     |
+| `.\Tests\Tests.Playground\Tests.Playground.csproj` |     √     |       √       |       √       |    √     |
+| `.\Tests\Tests.T4\Tests.T4.csproj`                 |     √     |       √       |       √       |    √     |
+| `.\Tests\VisualBasic\Tests.VisualBasic.vbproj`     |     √     |       √       |       √       |    √     |
 
 
 Allowed target defines:

NuGet/linq2db.nuspec

@@ -11,6 +11,9 @@
 		<dependencies>
 			<group targetFramework=".NETFramework4.5" />
 			<group targetFramework=".NETFramework4.6" />
+			<group targetFramework=".NETFramework4.7.2">
+				<dependency id="Microsoft.Bcl.AsyncInterfaces"     version="5.0.0" />
+			</group>
 			<group targetFramework=".NETStandard2.0">
 				<dependency id="Microsoft.CSharp"                  version="4.7.0" />
 				<dependency id="System.ComponentModel.Annotations" version="5.0.0" />

Source/LinqToDB/Async/AsyncDbConnection.cs

@@ -37,7 +37,7 @@ public virtual string ConnectionString
 
 		public virtual IDbConnection Connection => _connection;
 
-#if NETFRAMEWORK
+#if !NATIVE_ASYNC
 		public virtual Task<IAsyncDbTransaction> BeginTransactionAsync(CancellationToken cancellationToken = default)
 			=> Task.FromResult(AsyncFactory.Create(BeginTransaction()));
 #elif !NETSTANDARD2_1PLUS
@@ -67,7 +67,7 @@ public virtual async ValueTask<IAsyncDbTransaction> BeginTransactionAsync(Isolat
 			}
 			return AsyncFactory.Create(BeginTransaction(isolationLevel));
 		}
-#elif !NETFRAMEWORK
+#elif NATIVE_ASYNC
 		public virtual ValueTask<IAsyncDbTransaction> BeginTransactionAsync(IsolationLevel isolationLevel, CancellationToken cancellationToken = default)
 			=> new ValueTask<IAsyncDbTransaction>(AsyncFactory.Create(BeginTransaction(isolationLevel)));
 #else
@@ -129,7 +129,7 @@ public virtual void Dispose()
 			Connection.Dispose();
 		}
 
-#if NETFRAMEWORK
+#if !NATIVE_ASYNC
 		public virtual Task DisposeAsync()
 		{
 			Dispose();
@@ -143,7 +143,7 @@ public virtual ValueTask DisposeAsync()
 				return asyncDisposable.DisposeAsync();
 
 			Dispose();
-			return new ValueTask(Task.CompletedTask);
+			return default;
 		}
 #endif
 

Source/LinqToDB/Async/AsyncDbTransaction.cs

@@ -49,7 +49,7 @@ public virtual void Dispose()
 			Transaction.Dispose();
 		}
 
-#if NETFRAMEWORK
+#if !NATIVE_ASYNC
 		public virtual Task DisposeAsync()
 		{
 			Dispose();
@@ -63,7 +63,7 @@ public virtual ValueTask DisposeAsync()
 				return asyncDisposable.DisposeAsync();
 
 			Dispose();
-			return new ValueTask(Task.CompletedTask);
+			return default;
 		}
 #endif
 

Source/LinqToDB/Async/AsyncEnumeratorAsyncWrapper.cs

@@ -7,15 +7,15 @@ namespace LinqToDB.Async
 	internal class AsyncEnumeratorAsyncWrapper<T> : IAsyncEnumerator<T>
 	{
 		private IAsyncEnumerator<T>? _enumerator;
-#if NETFRAMEWORK
+#if !NATIVE_ASYNC
 		private readonly Func<Task<Tuple<IAsyncEnumerator<T>, IDisposable?>>> _init;
 		private IDisposable? _disposable;
 #else
 		private readonly Func<Task<Tuple<IAsyncEnumerator<T>, IAsyncDisposable?>>> _init;
 		private IAsyncDisposable? _disposable;
 #endif
 
-#if NETFRAMEWORK
+#if !NATIVE_ASYNC
 		public AsyncEnumeratorAsyncWrapper(Func<Task<Tuple<IAsyncEnumerator<T>, IDisposable?>>> init)
 #else
 		public AsyncEnumeratorAsyncWrapper(Func<Task<Tuple<IAsyncEnumerator<T>, IAsyncDisposable?>>> init)
@@ -26,7 +26,7 @@ public AsyncEnumeratorAsyncWrapper(Func<Task<Tuple<IAsyncEnumerator<T>, IAsyncDi
 
 		T IAsyncEnumerator<T>.Current => _enumerator!.Current;
 
-#if NETFRAMEWORK
+#if !NATIVE_ASYNC
 		async Task IAsyncDisposable.DisposeAsync()
 		{
 			await _enumerator!.DisposeAsync().ConfigureAwait(Common.Configuration.ContinueOnCapturedContext);

Source/LinqToDB/Async/AsyncExtensions.cs

@@ -35,7 +35,7 @@ internal static class AsyncExtensions
 
 			var result = new List<T>();
 			var enumerator = source.GetAsyncEnumerator(cancellationToken);
-#if NETFRAMEWORK
+#if !NATIVE_ASYNC
 			await using (enumerator)
 #else
 			await using (enumerator.ConfigureAwait(Common.Configuration.ContinueOnCapturedContext))
@@ -95,7 +95,7 @@ await using (enumerator.ConfigureAwait(Common.Configuration.ContinueOnCapturedCo
 			if (source == null) throw new ArgumentNullException(nameof(source));
 
 			var enumerator = source.GetAsyncEnumerator(cancellationToken);
-#if NETFRAMEWORK
+#if !NATIVE_ASYNC
 			await using (enumerator)
 #else
 			await using (enumerator.ConfigureAwait(Common.Configuration.ContinueOnCapturedContext))
@@ -120,7 +120,7 @@ public static async Task<TSource> FirstAsync<TSource>(this IAsyncEnumerable<TSou
 			if (source == null) throw new ArgumentNullException(nameof(source));
 
 			var enumerator = source.GetAsyncEnumerator(token);
-#if NETFRAMEWORK
+#if !NATIVE_ASYNC
 			await using (enumerator)
 #else
 			await using (enumerator.ConfigureAwait(Common.Configuration.ContinueOnCapturedContext))

Source/LinqToDB/Async/AsyncFactory.cs

@@ -1,18 +1,16 @@
-using JetBrains.Annotations;
-using LinqToDB.Common;
-using LinqToDB.Expressions;
-using LinqToDB.Extensions;
-using System;
+using System;
 using System.Collections.Concurrent;
 using System.Collections.Generic;
 using System.Data;
-using System.Data.Common;
-using System.Diagnostics.CodeAnalysis;
 using System.Linq;
 using System.Linq.Expressions;
 using System.Reflection;
 using System.Threading;
 using System.Threading.Tasks;
+using JetBrains.Annotations;
+using LinqToDB.Common;
+using LinqToDB.Expressions;
+using LinqToDB.Extensions;
 
 namespace LinqToDB.Async
 {
@@ -33,7 +31,7 @@ public static class AsyncFactory
 		private static readonly ConcurrentDictionary<Type, Func<IDbTransaction, IAsyncDbTransaction>> _transactionFactories
 			= new ConcurrentDictionary<Type, Func<IDbTransaction, IAsyncDbTransaction>>();
 
-#if NETFRAMEWORK
+#if !NATIVE_ASYNC
 		private static readonly MethodInfo _transactionWrap      = MemberHelper.MethodOf(() => Wrap<IDbTransaction>(default!)).GetGenericMethodDefinition();
 #else
 #pragma warning disable CA2012 // ValueTask instances returned from method calls should be directly awaited...
@@ -103,7 +101,7 @@ private static async Task<IAsyncDbTransaction> Wrap<TTransaction>(Task<TTransact
 			return Create(await transaction.ConfigureAwait(Common.Configuration.ContinueOnCapturedContext));
 		}
 
-#if !NETFRAMEWORK
+#if NATIVE_ASYNC
 		private static async ValueTask<IAsyncDbTransaction> WrapValue<TTransaction>(ValueTask<TTransaction> transaction)
 			where TTransaction : IDbTransaction
 		{
@@ -131,15 +129,15 @@ private static async ValueTask<IAsyncDbTransaction> WrapValue<TTransaction>(Valu
 			// Availability:
 			// - DbTransaction (netstandard2.1, netcoreapp3.0)
 			// - Npgsql 4.1.2+
-#if NETFRAMEWORK
+#if !NATIVE_ASYNC
 			var disposeAsync  = CreateDelegate<Func<IDbConnection               ,      Task>, IDbConnection >(type, "DisposeAsync" , Array<Type>.Empty, Array<Type>.Empty, Array<Type>.Empty, true , false)
 #else
 			var disposeAsync  = CreateDelegate<Func<IDbConnection               , ValueTask>, IDbConnection >(type, "DisposeAsync" , Array<Type>.Empty, Array<Type>.Empty, Array<Type>.Empty, true , true )
 #endif
 			// Task DisposeAsync()
 			// Availability:
 			// - MySqlConnector 0.57+
-#if NETFRAMEWORK
+#if !NATIVE_ASYNC
 							 ?? CreateDelegate<Func<IDbConnection               ,      Task>, IDbConnection >(type, "DisposeAsync" , Array<Type>.Empty, Array<Type>.Empty, Array<Type>.Empty, false, false);
 #else
 							 ?? CreateDelegate<Func<IDbConnection               , ValueTask>, IDbConnection >(type, "DisposeAsync" , Array<Type>.Empty, Array<Type>.Empty, Array<Type>.Empty, false, true );
@@ -162,7 +160,7 @@ private static async ValueTask<IAsyncDbTransaction> WrapValue<TTransaction>(Valu
 			// - (stub) DbConnection (netstandard2.1, netcoreapp3.0)
 			// - MySqlConnector 0.57+
 			// - Npgsql 4.1.2+
-#if NETFRAMEWORK
+#if !NATIVE_ASYNC
 			var beginTransactionAsync   = CreateTaskTDelegate<Func<IDbConnection, CancellationToken           ,      Task<IAsyncDbTransaction>>, IDbConnection, IDbTransaction>(type, "BeginTransactionAsync", _tokenParams           , _transactionWrap,      true, false)
 #else
 			var beginTransactionAsync   = CreateTaskTDelegate<Func<IDbConnection, CancellationToken           , ValueTask<IAsyncDbTransaction>>, IDbConnection, IDbTransaction>(type, "BeginTransactionAsync", _tokenParams           , _transactionValueWrap, true, true)
@@ -171,7 +169,7 @@ private static async ValueTask<IAsyncDbTransaction> WrapValue<TTransaction>(Valu
 			// Availability:
 			// - MySql.Data
 			// - MySqlConnector < 0.57
-#if NETFRAMEWORK
+#if !NATIVE_ASYNC
 									   ?? CreateTaskTDelegate<Func<IDbConnection, CancellationToken           ,      Task<IAsyncDbTransaction>>, IDbConnection, IDbTransaction>(type, "BeginTransactionAsync", _tokenParams           , _transactionWrap,      false, false);
 #else
 									   ?? CreateTaskTDelegate<Func<IDbConnection, CancellationToken           , ValueTask<IAsyncDbTransaction>>, IDbConnection, IDbTransaction>(type, "BeginTransactionAsync", _tokenParams           , _transactionValueWrap, false, true);
@@ -182,7 +180,7 @@ private static async ValueTask<IAsyncDbTransaction> WrapValue<TTransaction>(Valu
 			// - (stub) DbConnection (netstandard2.1, netcoreapp3.0)
 			// - MySqlConnector 0.57+
 			// - Npgsql 4.1.2+
-#if NETFRAMEWORK
+#if !NATIVE_ASYNC
 			var beginTransactionIlAsync = CreateTaskTDelegate<Func<IDbConnection, IsolationLevel, CancellationToken,      Task<IAsyncDbTransaction>>, IDbConnection, IDbTransaction>(type, "BeginTransactionAsync", _beginTransactionParams, _transactionWrap,      true, false)
 #else
 			var beginTransactionIlAsync = CreateTaskTDelegate<Func<IDbConnection, IsolationLevel, CancellationToken, ValueTask<IAsyncDbTransaction>>, IDbConnection, IDbTransaction>(type, "BeginTransactionAsync", _beginTransactionParams, _transactionValueWrap, true, true)
@@ -191,7 +189,7 @@ private static async ValueTask<IAsyncDbTransaction> WrapValue<TTransaction>(Valu
 			// Availability:
 			// - MySql.Data
 			// - MySqlConnector < 0.57
-#if NETFRAMEWORK
+#if !NATIVE_ASYNC
 									   ?? CreateTaskTDelegate<Func<IDbConnection, IsolationLevel, CancellationToken,      Task<IAsyncDbTransaction>>, IDbConnection, IDbTransaction>(type, "BeginTransactionAsync", _beginTransactionParams, _transactionWrap,      false, false);
 #else
 									   ?? CreateTaskTDelegate<Func<IDbConnection, IsolationLevel, CancellationToken, ValueTask<IAsyncDbTransaction>>, IDbConnection, IDbTransaction>(type, "BeginTransactionAsync", _beginTransactionParams, _transactionValueWrap, false, true);
@@ -217,15 +215,15 @@ private static async ValueTask<IAsyncDbTransaction> WrapValue<TTransaction>(Valu
 			// Availability:
 			// - (stub) DbConnection (netstandard2.1, netcoreapp3.0)
 			// - Npgsql 4.1.2+
-#if NETFRAMEWORK
+#if !NATIVE_ASYNC
 			var disposeAsync            = CreateDelegate<Func<IDbConnection, Task     >, IDbConnection>(type, "DisposeAsync", Array<Type>.Empty, Array<Type>.Empty, Array<Type>.Empty, true , false)
 #else
 			var disposeAsync            = CreateDelegate<Func<IDbConnection, ValueTask>, IDbConnection>(type, "DisposeAsync", Array<Type>.Empty, Array<Type>.Empty, Array<Type>.Empty, true , true)
 #endif
 			// Task DisposeAsync()
 			// Availability:
 			// - MySqlConnector 0.57+
-#if NETFRAMEWORK
+#if !NATIVE_ASYNC
 									   ?? CreateDelegate<Func<IDbConnection,      Task>, IDbConnection>(type, "DisposeAsync", Array<Type>.Empty, Array<Type>.Empty, Array<Type>.Empty, false, false);
 #else
 									   ?? CreateDelegate<Func<IDbConnection, ValueTask>, IDbConnection>(type, "DisposeAsync", Array<Type>.Empty, Array<Type>.Empty, Array<Type>.Empty, false, true);
@@ -283,7 +281,7 @@ private static async ValueTask<IAsyncDbTransaction> WrapValue<TTransaction>(Valu
 				//convert a ValueTask result to a Task
 				body = ToTask(body);
 			}
-#if !NETFRAMEWORK
+#if NATIVE_ASYNC
 			else if (!returnsValueTask && returnValueTask)
 			{
 				//convert a Task result to a ValueTask
@@ -306,7 +304,7 @@ private static MethodCallExpression ToTask(Expression body)
 			return Expression.Call(body, "AsTask", Array<Type>.Empty);
 		}
 
-#if !NETFRAMEWORK
+#if NATIVE_ASYNC
 		/// <summary>
 		/// Returns an expression which returns a <see cref="ValueTask"/> from a <see cref="Task"/>.
 		/// </summary>
@@ -373,7 +371,7 @@ private static NewExpression ToValueTTask(Expression body)
 				//convert a ValueTask result to a Task
 				body = ToTask(body);
 			}
-#if !NETFRAMEWORK
+#if NATIVE_ASYNC
 			else if (!returnsValueTask && returnValueTask)
 			{
 				//convert a Task result to a ValueTask

Source/LinqToDB/Async/IAsyncDbConnection.cs

@@ -11,17 +11,14 @@ namespace LinqToDB.Async
 	/// Asynchronous version of the <see cref="IDbConnection"/> interface, allowing asynchronous operations, missing from <see cref="IDbConnection"/>.
 	/// </summary>
 	[PublicAPI]
-	public interface IAsyncDbConnection : IDbConnection
-#if !NETFRAMEWORK
-		, IAsyncDisposable
-#endif
+	public interface IAsyncDbConnection : IDbConnection, IAsyncDisposable
 	{
 		/// <summary>
 		/// Starts new transaction asynchronously for current connection with default isolation level.
 		/// </summary>
 		/// <param name="cancellationToken">Asynchronous operation cancellation token.</param>
 		/// <returns>Database transaction object.</returns>
-#if !NETFRAMEWORK
+#if NATIVE_ASYNC
 		ValueTask<IAsyncDbTransaction> BeginTransactionAsync(CancellationToken cancellationToken = default);
 #else
 		Task<IAsyncDbTransaction> BeginTransactionAsync(CancellationToken cancellationToken = default);
@@ -33,7 +30,7 @@ public interface IAsyncDbConnection : IDbConnection
 		/// <param name="isolationLevel">Transaction isolation level.</param>
 		/// <param name="cancellationToken">Asynchronous operation cancellation token.</param>
 		/// <returns>Database transaction object.</returns>
-#if !NETFRAMEWORK
+#if NATIVE_ASYNC
 		ValueTask<IAsyncDbTransaction> BeginTransactionAsync(IsolationLevel isolationLevel, CancellationToken cancellationToken = default);
 #else
 		Task<IAsyncDbTransaction> BeginTransactionAsync(IsolationLevel isolationLevel, CancellationToken cancellationToken = default);
@@ -52,14 +49,6 @@ public interface IAsyncDbConnection : IDbConnection
 		/// <returns>Async operation task.</returns>
 		Task OpenAsync(CancellationToken cancellationToken = default);
 
-#if NETFRAMEWORK
-		/// <summary>
-		/// Disposes current connection asynchonously.
-		/// </summary>
-		/// <returns>Async operation task.</returns>
-		Task DisposeAsync();
-#endif
-
 		/// <summary>
 		/// Gets underlying connection instance.
 		/// </summary>

Source/LinqToDB/Async/IAsyncDbTransaction.cs

@@ -11,10 +11,7 @@ namespace LinqToDB.Async
 	/// Asynchronous version of the <see cref="IDbTransaction"/> interface, allowing asynchronous operations, missing from <see cref="IDbTransaction"/>.
 	/// </summary>
 	[PublicAPI]
-	public interface IAsyncDbTransaction : IDbTransaction
-#if !NETFRAMEWORK
-		, IAsyncDisposable
-#endif
+	public interface IAsyncDbTransaction : IDbTransaction, IAsyncDisposable
 	{
 		/// <summary>
 		/// Commits transaction asynchronously.
@@ -34,13 +31,5 @@ public interface IAsyncDbTransaction : IDbTransaction
 		/// Gets underlying transaction instance.
 		/// </summary>
 		IDbTransaction Transaction { get; }
-
-#if NETFRAMEWORK
-		/// <summary>
-		/// Disposes transaction asynchronously.
-		/// </summary>
-		/// <returns>Asynchronous operation completion task.</returns>
-		Task DisposeAsync();
-#endif
 	}
 }