When an Add call to the component parameter collection builder was used to select a parameter that was inherited from a base component, the builder incorrectly reported the selected property/parameter as missing on the type

Author: egil

CHANGELOG.md

@@ -4,9 +4,9 @@ All notable changes to **bUnit** will be documented in this file. The project ad
 
 <!-- The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/) -->
 
-## UNRELEASED [1.0.0-preview 1]
+## UNRELEASED [1.0.0 preview 01]
 
-The following section list all changes in 1.0.0 preview 1.
+The following section list all changes in 1.0.0 preview 01.
 
 ### Added
 List of new features.
@@ -22,6 +22,8 @@ List of now removed features.
 ### Fixed
 List of any bug fixes.
 
+- When an `Add` call to the component parameter collection builder was used to select a parameter that was inherited from a base component, the builder incorrectly reported the selected property/parameter as missing on the type. Reported by [@nickmuller](https://github.com/nickmuller) in [#250](https://github.com/egil/bUnit/issues/250).
+
 ## [1.0.0-beta 10] - 2020-09-15
 
 The following section list all changes in beta-10.

src/bunit.core/ComponentParameterCollectionBuilder.cs

@@ -345,13 +345,17 @@ private static (string paramName, string? cascadingValueName, bool isCascading)
 		{
 			if (parameterSelector is null) throw new ArgumentNullException(nameof(parameterSelector));
 
-			if (!(parameterSelector.Body is MemberExpression memberExpression) || !(memberExpression.Member is PropertyInfo propertyInfo))
+			if (!(parameterSelector.Body is MemberExpression memberExpression) || !(memberExpression.Member is PropertyInfo propInfoCandidate))
 				throw new ArgumentException($"The parameter selector '{parameterSelector}' does not resolve to a public property on the component '{typeof(TComponent)}'.");
 
-			var paramAttr = propertyInfo.GetCustomAttribute<ParameterAttribute>(inherit: false);
-			var cascadingParamAttr = propertyInfo.GetCustomAttribute<CascadingParameterAttribute>(inherit: false);
+			var propertyInfo = propInfoCandidate.DeclaringType != TComponentType
+				? TComponentType.GetProperty(propInfoCandidate.Name, propInfoCandidate.PropertyType)
+				: propInfoCandidate;
+			
+			var paramAttr = propertyInfo?.GetCustomAttribute<ParameterAttribute>(inherit: true);
+			var cascadingParamAttr = propertyInfo?.GetCustomAttribute<CascadingParameterAttribute>(inherit: true);
 
-			if (paramAttr is null && cascadingParamAttr is null)
+			if (propertyInfo is null || paramAttr is null && cascadingParamAttr is null)
 				throw new ArgumentException($"The parameter selector '{parameterSelector}' does not resolve to a public property on the component '{typeof(TComponent)}' with a [Parameter] or [CascadingParameter] attribute.");
 
 			return (propertyInfo.Name, cascadingParamAttr?.Name, cascadingParamAttr is not null);

tests/bunit.core.tests/ComponentParameterCollectionBuilderTests.cs

@@ -544,6 +544,30 @@ public void Test203()
 				.ShouldBeParameter(name + "NAME", input, isCascadingValue: true);
 		}
 
+		[Fact(DisplayName = "Add of inherited overriden parameter works")]
+		public void Test300()
+		{
+			var sut = new ComponentParameterCollectionBuilder<InheritedParamsWithOverride>();
+
+			sut.Add(x => x.Value, true);
+
+			sut.Build()
+				.ShouldHaveSingleItem()
+				.ShouldBeParameter("Value", true, isCascadingValue: false);
+		}
+
+		[Fact(DisplayName = "Add of inherited parameter works")]
+		public void Test301()
+		{
+			var sut = new ComponentParameterCollectionBuilder<InheritedParamsWithoutOverride>();
+
+			sut.Add(x => x.Value, true);
+
+			sut.Build()
+				.ShouldHaveSingleItem()
+				.ShouldBeParameter("Value", true, isCascadingValue: false);
+		}
+
 		private class Params : ComponentBase
 		{
 			[Parameter(CaptureUnmatchedValues = true)] public IReadOnlyDictionary<string, object>? Attributes { get; set; }
@@ -565,13 +589,22 @@ private class Params : ComponentBase
 			[CascadingParameter] public RenderFragment? RFCC { get; set; }
 			public int _nonParam = -1;
 			public object? NonParamProp { get; set; }
-
-			[SuppressMessage("Performance", "CA1822:Mark members as static", Justification = "<Pending>")]
 			public void SomeMethod() { }
 		}
 
 		private class NoParams : ComponentBase { }
 		private class NonChildContentParameter : ComponentBase { public RenderFragment? ChildContent { get; set; } }
 		private class InhertedParams : Params { }
+		private abstract class ParamsBase<T> : ComponentBase
+		{
+			public abstract T Value { get; set; }
+		}
+		private class InheritedParamsWithOverride : ParamsBase<bool?>
+		{
+			[Parameter] public override bool? Value { get; set; }
+		}
+		private class InheritedParamsWithoutOverride : InheritedParamsWithOverride
+		{
+		}
 	}
 }

version.json

@@ -1,6 +1,6 @@
 {
   "$schema": "https://raw.githubusercontent.com/dotnet/Nerdbank.GitVersioning/master/src/NerdBank.GitVersioning/version.schema.json",
-  "version": "1.0.0-beta-12",
+  "version": "1.0.0-preview-01",
   "publicReleaseRefSpec": [
     "^refs/heads/main$",
     "^refs/heads/v\\d+(?:\\.\\d+)?$"