Options validation source generator

src/libraries/Common/src/System/ThrowHelper.cs

@@ -31,6 +31,46 @@ internal static void ThrowIfNull(
         [DoesNotReturn]
 #endif
         private static void Throw(string? paramName) => throw new ArgumentNullException(paramName);
+
+        /// <summary>
+        /// Throws either an <see cref="System.ArgumentNullException"/> or an <see cref="System.ArgumentException"/>
+        /// if the specified string is <see langword="null"/> or whitespace respectively.
+        /// </summary>
+        /// <param name="argument">String to be checked for <see langword="null"/> or whitespace.</param>
+        /// <param name="paramName">The name of the parameter being checked.</param>
+        /// <returns>The original value of <paramref name="argument"/>.</returns>
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+#if NETCOREAPP3_0_OR_GREATER
+        [return: NotNull]
+#endif
+        public static string IfNullOrWhitespace(
+#if NETCOREAPP3_0_OR_GREATER
+            [NotNull]
+#endif
+            string? argument,
+            [CallerArgumentExpression(nameof(argument))] string paramName = "")
+        {
+#if !NETCOREAPP3_1_OR_GREATER
+            if (argument == null)
+            {
+                throw new ArgumentNullException(paramName);
+            }
+#endif
+
+            if (string.IsNullOrWhiteSpace(argument))
+            {
+                if (argument == null)
+                {
+                    throw new ArgumentNullException(paramName);
+                }
+                else
+                {
+                    throw new ArgumentException(paramName, "Argument is whitespace");
+                }
+            }
+
+            return argument;
+        }
     }
 }
 

src/libraries/Microsoft.Extensions.Options/gen/DiagDescriptors.cs

@@ -0,0 +1,95 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using Microsoft.CodeAnalysis;
+using System;
+
+namespace Microsoft.Extensions.Options.Generators
+{
+    internal sealed class DiagDescriptors : DiagDescriptorsBase
+    {
+        private const string Category = "Microsoft.Extensions.Options.SourceGeneration";
+
+        public static DiagnosticDescriptor CantUseWithGenericTypes { get; } = Make(
+            id: "SYSLIB1201",
+            title: SR.CantUseWithGenericTypesTitle,
+            messageFormat: SR.CantUseWithGenericTypesMessage,
+            category: Category);
+
+        public static DiagnosticDescriptor NoEligibleMember { get; } = Make(
+            id: "SYSLIB1202",
+            title: SR.NoEligibleMemberTitle,
+            messageFormat: SR.NoEligibleMemberMessage,
+            category: Category,
+            defaultSeverity: DiagnosticSeverity.Warning);
+
+        public static DiagnosticDescriptor NoEligibleMembersFromValidator { get; } = Make(
+            id: "SYSLIB1203",
+            title: SR.NoEligibleMembersFromValidatorTitle,
+            messageFormat: SR.NoEligibleMembersFromValidatorMessage,
+            category: Category,
+            defaultSeverity: DiagnosticSeverity.Warning);
+
+        public static DiagnosticDescriptor DoesntImplementIValidateOptions { get; } = Make(
+            id: "SYSLIB1204",
+            title: SR.DoesntImplementIValidateOptionsTitle,
+            messageFormat: SR.DoesntImplementIValidateOptionsMessage,
+            category: Category);
+
+        public static DiagnosticDescriptor AlreadyImplementsValidateMethod { get; } = Make(
+            id: "SYSLIB1205",
+            title: SR.AlreadyImplementsValidateMethodTitle,
+            messageFormat: SR.AlreadyImplementsValidateMethodMessage,
+            category: Category);
+
+        public static DiagnosticDescriptor MemberIsInaccessible { get; } = Make(
+            id: "SYSLIB1206",
+            title: SR.MemberIsInaccessibleTitle,
+            messageFormat: SR.MemberIsInaccessibleMessage,
+            category: Category);
+
+        public static DiagnosticDescriptor NotEnumerableType { get; } = Make(
+            id: "SYSLIB1207",
+            title: SR.NotEnumerableTypeTitle,
+            messageFormat: SR.NotEnumerableTypeMessage,
+            category: Category);
+
+        public static DiagnosticDescriptor ValidatorsNeedSimpleConstructor { get; } = Make(
+            id: "SYSLIB1208",
+            title: SR.ValidatorsNeedSimpleConstructorTitle,
+            messageFormat: SR.ValidatorsNeedSimpleConstructorMessage,
+            category: Category);
+
+        public static DiagnosticDescriptor CantBeStaticClass { get; } = Make(
+            id: "SYSLIB1209",
+            title: SR.CantBeStaticClassTitle,
+            messageFormat: SR.CantBeStaticClassMessage,
+            category: Category);
+
+        public static DiagnosticDescriptor NullValidatorType { get; } = Make(
+            id: "SYSLIB1210",
+            title: SR.NullValidatorTypeTitle,
+            messageFormat: SR.NullValidatorTypeMessage,
+            category: Category);
+
+        public static DiagnosticDescriptor CircularTypeReferences { get; } = Make(
+            id: "SYSLIB1211",
+            title: SR.CircularTypeReferencesTitle,
+            messageFormat: SR.CircularTypeReferencesMessage,
+            category: Category);
+
+        public static DiagnosticDescriptor PotentiallyMissingTransitiveValidation { get; } = Make(
+            id: "SYSLIB1212",
+            title: SR.PotentiallyMissingTransitiveValidationTitle,
+            messageFormat: SR.PotentiallyMissingTransitiveValidationMessage,
+            category: Category,
+            defaultSeverity: DiagnosticSeverity.Warning);
+
+        public static DiagnosticDescriptor PotentiallyMissingEnumerableValidation { get; } = Make(
+            id: "SYSLIB1213",
+            title: SR.PotentiallyMissingEnumerableValidationTitle,
+            messageFormat: SR.PotentiallyMissingEnumerableValidationMessage,
+            category: Category,
+            defaultSeverity: DiagnosticSeverity.Warning);
+    }
+}

src/libraries/Microsoft.Extensions.Options/gen/DiagDescriptorsBase.cs

@@ -0,0 +1,30 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System;
+using Microsoft.CodeAnalysis;
+
+namespace Microsoft.Extensions.Options.Generators
+{
+    #pragma warning disable CA1052 // Static holder types should be Static or NotInheritable
+    internal class DiagDescriptorsBase
+    #pragma warning restore CA1052
+    {
+        protected static DiagnosticDescriptor Make(
+                string id,
+                string title,
+                string messageFormat,
+                string category,
+                DiagnosticSeverity defaultSeverity = DiagnosticSeverity.Error,
+                bool isEnabledByDefault = true)
+        {
+            return new(
+                id,
+                title,
+                messageFormat,
+                category,
+                defaultSeverity,
+                isEnabledByDefault);
+        }
+    }
+}