Skip to content

Add test validating current behavior for extra parenthesis in Blazor attribute bindings #12690

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Draft
Copilot wants to merge 4 commits into
base: main
Choose a base branch
from
Draft

Add test validating current behavior for extra parenthesis in Blazor attribute bindings #12690

Changes from all commits
Commits
Show all changes
4 commits
Select commit Hold shift + click to select a range
10c4491
Initial plan
Copilot Jan 16, 2026
e092bf4
Add test reproducing extra parenthesis issue in Blazor attribute binding
Copilot Jan 16, 2026
be23824
Document the bug behavior in test comments
Copilot Jan 16, 2026
5232657
Update test to validate current behavior instead of failing
Copilot Jan 24, 2026
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
43 changes: 43 additions & 0 deletions ...spNetCore.Razor.Language/test/IntegrationTests/ComponentDiagnosticRazorIntegrationTest.cs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -2,6 +2,7 @@
// The .NET Foundation licenses this file to you under the MIT license.

using System.Globalization;
using Roslyn.Test.Utilities;
using Xunit;

namespace Microsoft.AspNetCore.Razor.Language.IntegrationTests;
Expand Down Expand Up @@ -217,4 +218,46 @@ public class MyComponent : ComponentBase
"The start tag name 'MyComponent' does not match the end tag name 'mycomponent'. Components must have matching start and end tag names (case-sensitive).",
diagnostic.GetMessage(CultureInfo.CurrentCulture));
}

[Fact, WorkItem("https://github.com/dotnet/aspnetcore/issues/23228")]
public void AttributeBinding_ExtraClosingParenthesis_TreatedAsLiteralText()
{
// Arrange/Act
// This reproduces https://github.com/dotnet/aspnetcore/issues/23228
// An extra closing parenthesis in an attribute binding is currently treated as literal text
// rather than producing a diagnostic error
var generated = CompileToCSharp(@"
@page ""/""

@foreach (var item in new[] { Architecture.Windows, Architecture.MacOSX, Architecture.Linux })
{
<label class=""col-auto"">
<input name=""arch"" type=""radio""
value=""@item""
checked=""@IsActive(item))""
@onchange=""@( _ => ChangeArchitecture(item))"" />
@item.ToString()
</label>
}
<h1>@current</h1>
@code {
enum Architecture
{
None,
Windows,
MacOSX,
Linux
}
Architecture current = Architecture.None;
bool IsActive(Architecture arch) => current == arch;
void ChangeArchitecture(Architecture arch) => current = arch;
}");

// Assert
// The compiler currently treats the extra ')' as literal text and generates:
// __builder.AddAttribute(6, "checked", (IsActive(item)) + ")");
// This is valid C# but produces incorrect Blazor behavior (UI out of sync)
// No diagnostic is currently reported for this issue
Assert.Empty(generated.RazorDiagnostics);
}
}