#124 added missing nullable attributes from net6-8

src/log4net/Diagnostics/CodeAnalysis/AllowNullAttribute.cs

@@ -0,0 +1,35 @@
+#region Apache License
+//
+// Licensed to the Apache Software Foundation (ASF) under one or more 
+// contributor license agreements. See the NOTICE file distributed with
+// this work for additional information regarding copyright ownership. 
+// The ASF licenses this file to you under the Apache License, Version 2.0
+// (the "License"); you may not use this file except in compliance with 
+// the License. You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+#endregion
+
+#if !NET6_0_OR_GREATER
+namespace System.Diagnostics.CodeAnalysis;
+
+/// <summary>
+/// Specifies that null is allowed as an input even if the corresponding type disallows it.
+/// </summary>
+[AttributeUsage(AttributeTargets.Property | AttributeTargets.Field | AttributeTargets.Parameter, Inherited = false)]
+internal sealed class AllowNullAttribute : Attribute
+{
+  /// <summary>
+  /// Initializes a new instance of the System.Diagnostics.CodeAnalysis.AllowNullAttribute  class.
+  /// </summary>
+  public AllowNullAttribute()
+  { }
+}
+#endif

src/log4net/Diagnostics/CodeAnalysis/CallerArgumentExpressionAttribute.cs

@@ -0,0 +1,37 @@
+#region Apache License
+//
+// Licensed to the Apache Software Foundation (ASF) under one or more 
+// contributor license agreements. See the NOTICE file distributed with
+// this work for additional information regarding copyright ownership. 
+// The ASF licenses this file to you under the Apache License, Version 2.0
+// (the "License"); you may not use this file except in compliance with 
+// the License. You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+#endregion
+
+#if !NET6_0_OR_GREATER
+namespace System.Runtime.CompilerServices;
+
+/// <summary>
+/// Indicates that a parameter captures the expression passed for another parameter as a string.
+/// </summary>
+[AttributeUsage(AttributeTargets.Parameter, AllowMultiple = false, Inherited = false)]
+internal sealed class CallerArgumentExpressionAttribute : Attribute
+{
+  /// <summary>
+  /// Name of the parameter whose expression should be captured as a string
+  /// </summary>
+  public string ParameterName { get; }
+
+  /// <inheritdoc/>
+  public CallerArgumentExpressionAttribute(string parameterName) => ParameterName = parameterName;
+}
+#endif

src/log4net/Diagnostics/CodeAnalysis/CompilerFeatureRequiredAttribute.cs

@@ -0,0 +1,56 @@
+#region Apache License
+//
+// Licensed to the Apache Software Foundation (ASF) under one or more 
+// contributor license agreements. See the NOTICE file distributed with
+// this work for additional information regarding copyright ownership. 
+// The ASF licenses this file to you under the Apache License, Version 2.0
+// (the "License"); you may not use this file except in compliance with 
+// the License. You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+#endregion
+
+#if !NET7_0_OR_GREATER
+namespace System.Runtime.CompilerServices;
+
+/// <summary>
+/// Indicates that compiler support for a particular feature is required for the location where this attribute is applied
+/// </summary>
+[AttributeUsage(AttributeTargets.All, AllowMultiple = true, Inherited = false)]
+internal sealed class CompilerFeatureRequiredAttribute : Attribute
+{
+  /// <summary>
+  /// The <see cref="FeatureName" /> used for the ref structs C# feature
+  /// </summary>
+  public const string RefStructs = nameof(RefStructs);
+
+  /// <summary>
+  /// The <see cref="FeatureName" /> used for the required members C# feature
+  /// </summary>
+  public const string RequiredMembers = nameof(RequiredMembers);
+
+  /// <summary>
+  /// The name of the compiler feature
+  /// </summary>
+  public string FeatureName { get; }
+
+  ///  <summary>
+  ///  Gets a value that indicates whether the compiler can choose to allow access to the location
+  ///  where this attribute is applied if it does not understand <see cref="FeatureName" />
+  ///  </summary>
+  public bool IsOptional { get; init; }
+
+  /// <summary>
+  /// Initializes a <see cref="CompilerFeatureRequiredAttribute" /> instance for the passed in compiler feature
+  /// </summary>
+  /// <param name="featureName">The name of the compiler feature</param>
+  public CompilerFeatureRequiredAttribute(string featureName) => FeatureName = featureName;
+}
+#endif

src/log4net/Diagnostics/CodeAnalysis/DisallowNullAttribute.cs

@@ -0,0 +1,34 @@
+#region Apache License
+//
+// Licensed to the Apache Software Foundation (ASF) under one or more 
+// contributor license agreements. See the NOTICE file distributed with
+// this work for additional information regarding copyright ownership. 
+// The ASF licenses this file to you under the Apache License, Version 2.0
+// (the "License"); you may not use this file except in compliance with 
+// the License. You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+#endregion
+
+#if !NET6_0_OR_GREATER
+namespace System.Diagnostics.CodeAnalysis;
+
+/// <summary>
+/// Specifies that null is disallowed as an input even if the corresponding type allows it.
+/// </summary>
+[AttributeUsage(AttributeTargets.Property | AttributeTargets.Field | AttributeTargets.Parameter, Inherited = false)]
+internal sealed class DisallowNullAttribute : Attribute
+{
+  /// <summary>
+  /// Initializes a new instance of the System.Diagnostics.CodeAnalysis.DisallowNullAttribute class.
+  /// </summary>
+  public DisallowNullAttribute() { }
+}
+#endif

src/log4net/Diagnostics/CodeAnalysis/DoesNotReturnAttribute.cs

@@ -0,0 +1,35 @@
+#region Apache License
+//
+// Licensed to the Apache Software Foundation (ASF) under one or more 
+// contributor license agreements. See the NOTICE file distributed with
+// this work for additional information regarding copyright ownership. 
+// The ASF licenses this file to you under the Apache License, Version 2.0
+// (the "License"); you may not use this file except in compliance with 
+// the License. You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+#endregion
+
+#if !NET6_0_OR_GREATER
+namespace System.Diagnostics.CodeAnalysis;
+
+/// <summary>
+/// Specifies that a method that will never return under any circumstance.
+/// </summary>
+[AttributeUsage(AttributeTargets.Method, Inherited = false)]
+internal sealed class DoesNotReturnAttribute : Attribute
+{
+  /// <summary>
+  /// Initializes a new instance of the System.Diagnostics.CodeAnalysis.DoesNotReturnAttribute class.
+  /// </summary>
+  public DoesNotReturnAttribute()
+  { }
+}
+#endif

src/log4net/Diagnostics/CodeAnalysis/DoesNotReturnIfAttribute.cs

@@ -0,0 +1,49 @@
+#region Apache License
+//
+// Licensed to the Apache Software Foundation (ASF) under one or more 
+// contributor license agreements. See the NOTICE file distributed with
+// this work for additional information regarding copyright ownership. 
+// The ASF licenses this file to you under the Apache License, Version 2.0
+// (the "License"); you may not use this file except in compliance with 
+// the License. You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+#endregion
+
+#if !NET6_0_OR_GREATER
+namespace System.Diagnostics.CodeAnalysis;
+
+/// <summary>
+/// Specifies that the method will not return if the associated System.Boolean parameter is passed the specified value.
+/// </summary>
+[AttributeUsage(AttributeTargets.Parameter, Inherited = false)]
+internal sealed class DoesNotReturnIfAttribute : Attribute
+{
+  /// <summary>
+  /// Initializes a new instance of the System.Diagnostics.CodeAnalysis.DoesNotReturnIfAttribute class
+  /// with the specified parameter value.
+  /// </summary>
+  /// <param name="parameterValue">
+  ///   The condition parameter value.
+  ///   Code after the method is considered unreachable by diagnostics if the argument to the associated parameter
+  ///   matches this value.
+  /// </param>
+  public DoesNotReturnIfAttribute(bool parameterValue) => ParameterValue = parameterValue;
+
+  /// <summary>
+  /// Gets the condition parameter value.
+  /// </summary>
+  /// <returns>The condition parameter value. Code after the method is considered unreachable
+  /// by diagnostics if the argument to the associated parameter matches this value.
+  /// </returns>
+  public bool ParameterValue { get; }
+}
+
+#endif

src/log4net/Diagnostics/CodeAnalysis/IsExternalInit.cs

@@ -0,0 +1,29 @@
+#region Apache License
+//
+// Licensed to the Apache Software Foundation (ASF) under one or more 
+// contributor license agreements. See the NOTICE file distributed with
+// this work for additional information regarding copyright ownership. 
+// The ASF licenses this file to you under the Apache License, Version 2.0
+// (the "License"); you may not use this file except in compliance with 
+// the License. You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+#endregion
+
+#if !NET6_0_OR_GREATER
+using System.ComponentModel;
+
+namespace System.Runtime.CompilerServices;
+
+/// <inheritdoc/>
+[EditorBrowsable(EditorBrowsableState.Never)]
+internal static class IsExternalInit
+{ }
+#endif

src/log4net/Diagnostics/CodeAnalysis/MaybeNullAttribute.cs

@@ -0,0 +1,10 @@
+#if !NET6_0_OR_GREATER
+namespace System.Diagnostics.CodeAnalysis;
+
+/// <summary>
+/// Specifies that an output may be null even if the corresponding type disallows it.
+/// </summary>
+[AttributeUsage(AttributeTargets.Property | AttributeTargets.Field | AttributeTargets.Parameter | AttributeTargets.ReturnValue, Inherited = false)]
+internal sealed class MaybeNullAttribute : Attribute
+{ }
+#endif

src/log4net/Diagnostics/CodeAnalysis/MaybeNullWhenAttribute.cs

@@ -0,0 +1,22 @@
+#if !NET6_0_OR_GREATER
+namespace System.Diagnostics.CodeAnalysis;
+
+/// <summary>
+/// Specifies that when a method returns System.Diagnostics.CodeAnalysis.MaybeNullWhenAttribute.ReturnValue,
+/// the parameter may be null even if the corresponding type disallows it.
+/// </summary>
+[AttributeUsage(AttributeTargets.Parameter, Inherited = false)]
+internal sealed class MaybeNullWhenAttribute : Attribute
+{
+  /// <summary>
+  /// Initializes the attribute with the specified return value condition.
+  /// </summary>
+  /// <param name="returnValue">The return value condition. If the method returns this value, the associated parameter may be null.</param>
+  public MaybeNullWhenAttribute(bool returnValue) => ReturnValue = returnValue;
+
+  /// <summary>
+  /// Gets the return value condition.
+  /// </summary>
+  public bool ReturnValue { get; }
+}
+#endif

src/log4net/Diagnostics/CodeAnalysis/MemberNotNullAttribute.cs

@@ -0,0 +1,49 @@
+#region Apache License
+//
+// Licensed to the Apache Software Foundation (ASF) under one or more 
+// contributor license agreements. See the NOTICE file distributed with
+// this work for additional information regarding copyright ownership. 
+// The ASF licenses this file to you under the Apache License, Version 2.0
+// (the "License"); you may not use this file except in compliance with 
+// the License. You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+#endregion
+
+#if !NET6_0_OR_GREATER
+namespace System.Diagnostics.CodeAnalysis;
+
+/// <summary>
+/// Specifies that the method or property will ensure that the listed field and property members have values that aren't null.
+/// </summary>
+[AttributeUsage(AttributeTargets.Method | AttributeTargets.Property, Inherited = false, AllowMultiple = true)]
+internal sealed class MemberNotNullAttribute : Attribute
+{
+  /// <summary>
+  /// Initializes the attribute with list of field or property members.
+  /// </summary>
+  /// <param name="members">The list of field and property members that are promised to be non-null.</param>
+  public MemberNotNullAttribute(params string[] members) => Members = members;
+
+  /// <summary>
+  /// Initializes the attribute with a field or property member.
+  /// </summary>
+  /// <param name="member">The field or property member that is promised to be non-null.</param>
+  [SuppressMessage("Design", "CA1019:Define accessors for attribute arguments", Justification = "LuGe: 1-zu-1 von DotNet geklaut")]
+  public MemberNotNullAttribute(string member)
+    : this(new[] { member })
+  { }
+
+  /// <summary>
+  /// Gets field or property member names.
+  /// </summary>
+  public string[] Members { get; }
+}
+#endif