Add BL0010 analyzer: Recommend InvokeVoidAsync over InvokeAsync<object> by Copilot · Pull Request #64623 · dotnet/aspnetcore

Copilot · 2025-12-03T08:53:21Z

Add BL0010 analyzer: Recommend InvokeVoidAsync over InvokeAsync

You've read the Contributor Guide and Code of Conduct.

You've included unit or integration tests for your change, where applicable.

You've included inline docs for your change, where applicable.

There's an open issue for the PR that you are making. If you'd like to propose a new feature or change, please open an issue to discuss the change or find an existing issue.

Adds Roslyn analyzer BL0010 to detect `InvokeAsync<object>` and recommend `InvokeVoidAsync`

Description

Using InvokeAsync<object> for JS interop calls that don't return a value can cause serialization failures when JavaScript returns non-serializable values (e.g., window). This analyzer catches the antipattern at compile time.

Note: The diagnostic intentionally fires even when the result is assigned to a variable (e.g., var res = await JS.InvokeAsync<object>(...)), because object cannot be properly deserialized from JSON - the result will either be null or cause serialization errors if JavaScript returns a non-serializable value.

Changes:

InvokeAsyncOfObjectAnalyzer.cs - Detects InvokeAsync<object> on IJSRuntime, IJSObjectReference, and in-process variants (both direct and extension method calls)
DiagnosticDescriptors.cs - Added BL0010 descriptor (Warning, enabled by default)
Resources.resx - Localized diagnostic strings
InvokeAsyncOfObjectAnalyzerTest.cs - 14 unit tests

Example flagged code:

// BL0010: Use 'InvokeVoidAsync' instead of 'InvokeAsync<object>'
await jsRuntime.InvokeAsync<object>("window.open", url, "_blank");

// Correct
await jsRuntime.InvokeVoidAsync("window.open", url, "_blank");

Fixes #38549

Original prompt

This section details on the original issue you should resolve

<issue_title>Consider Razor Analyzer which Recommends InvokeVoidAsync instead of InvokeAsync<object></issue_title>
<issue_description>Analyzer / Code action pattern for this scenario.

Avoid issues like: #38501 (comment)</issue_description>

Comments on the Issue (you are @copilot in this section)
@ We've moved this issue to the Backlog milestone. This means that it is not going to be worked on for the coming release. We will reassess the backlog following the current release and consider this item at that time. To learn more about our issue management process and to have better expectation regarding different types of issues you can read our [Triage Process](https://github.com/dotnet/aspnetcore/blob/main/docs/TriageProcess.md). @ We've moved this issue to the Backlog milestone. This means that it is not going to be worked on for the coming release. We will reassess the backlog following the current release and consider this item at that time. To learn more about our issue management process and to have better expectation regarding different types of issues you can read our [Triage Process](https://github.com/dotnet/aspnetcore/blob/main/docs/TriageProcess.md).

Fixes Consider Razor Analyzer which Recommends InvokeVoidAsync instead of InvokeAsync<object> #38549

✨ Let Copilot coding agent set things up for you — coding agent works faster and does higher quality work when set up for your repo.

Co-authored-by: javiercn <6995051+javiercn@users.noreply.github.com>

… comparison Co-authored-by: javiercn <6995051+javiercn@users.noreply.github.com>

Copilot

Pull request overview

This PR adds a new Roslyn analyzer (BL0010) that detects usage of InvokeAsync<object> in JavaScript interop calls and recommends using InvokeVoidAsync instead. This addresses a common antipattern where developers use InvokeAsync<object> for JS calls that don't return a value, which can lead to serialization failures when JavaScript returns non-serializable values like window or undefined.

Key changes:

New analyzer that flags InvokeAsync<object> calls on IJSRuntime, IJSObjectReference, and their in-process variants
Comprehensive test coverage with 13 test cases covering various scenarios including extension methods
Diagnostic set as a Warning with enabled-by-default behavior

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 1 comment.

File	Description
`src/Components/Analyzers/src/InvokeAsyncOfObjectAnalyzer.cs`	Implements the new BL0010 analyzer to detect `InvokeAsync<object>` calls on JS interop types
`src/Components/Analyzers/src/DiagnosticDescriptors.cs`	Adds the BL0010 diagnostic descriptor with Warning severity
`src/Components/Analyzers/src/Resources.resx`	Adds localized resource strings for the diagnostic title, format, and description
`src/Components/Analyzers/test/InvokeAsyncOfObjectAnalyzerTest.cs`	Provides comprehensive test coverage with 13 test cases for the analyzer

Copilot · 2025-12-03T15:57:54Z

src/Components/Analyzers/src/InvokeAsyncOfObjectAnalyzer.cs

+using Microsoft.CodeAnalysis.Operations;
+
+namespace Microsoft.AspNetCore.Components.Analyzers;
+


Add #nullable enable directive after the namespace declaration to match the coding conventions used in other analyzers in this codebase. This ensures consistent nullable reference type handling across all analyzer files.

Suggested change

#nullable enable

Added #nullable enable directive in commit 61397d9.

oroztocil

Are we sure the diagnostic will not fire on legitimate cases where the result is not thrown away, e.g.:

var res = await JS.InvokeAsync<object>("...");

There should be tests for these cases.

javiercn · 2025-12-03T18:07:11Z

Are we sure the diagnostic will not fire on legitimate cases where the result is not thrown away, e.g.:
var res = await JS.InvokeAsync<object>("...");
There should be tests for these cases.

@copilot add a test for this if there isn't one. If there is one point out the test name.

Co-authored-by: javiercn <6995051+javiercn@users.noreply.github.com>

Copilot · 2025-12-03T18:12:59Z

Are we sure the diagnostic will not fire on legitimate cases where the result is not thrown away, e.g.:

...

Added test DiagnosticForInvokeAsyncWithObjectReturnAssignedToVariable in commit 61397d9. The diagnostic intentionally fires even when the result is assigned to a variable because using InvokeAsync<object> is problematic regardless - object cannot be properly deserialized from JSON, and the result will either be null or cause serialization errors if JavaScript returns a non-serializable value like window.

oroztocil · 2025-12-03T19:00:36Z

I see, I did not understand the reasoning from the description at first.

ilonatommy

It's fine but I saw that there's something like CodeFixProvider, e.g. https://github.com/dotnet/aspnetcore/blob/main/src/Components/Analyzers/src/ComponentParametersShouldBePublicCodeFixProvider.cs.
It would automatically add "Fix this issue" proposal. What about adding it?

javiercn · 2025-12-19T10:21:57Z

@ilonatommy code fixes don't work in .razor files.

Let's wait for adding a code fixer.

javiercn · 2026-01-20T14:14:11Z

/azp run aspnetcore-ci

azure-pipelines · 2026-01-20T14:14:25Z

Azure Pipelines successfully started running 1 pipeline(s).

Initial plan

eb42a34

Copilot AI assigned Copilot and javiercn Dec 3, 2025

dotnet-policy-service bot added the Attention: Shared Code Modified label Dec 3, 2025

Copilot started work on behalf of javiercn December 3, 2025 08:53 View session

Copilot AI and others added 2 commits December 3, 2025 09:05

Add BL0010 analyzer: Recommend InvokeVoidAsync over InvokeAsync<object>

33c4165

Co-authored-by: javiercn <6995051+javiercn@users.noreply.github.com>

Address code review feedback: use symbol comparison instead of string…

ef2960b

… comparison Co-authored-by: javiercn <6995051+javiercn@users.noreply.github.com>

Copilot AI changed the title ~~[WIP] Add Razor Analyzer for InvokeVoidAsync recommendation~~ Add BL0010 analyzer: Recommend InvokeVoidAsync over InvokeAsync<object> Dec 3, 2025

Copilot AI requested a review from javiercn December 3, 2025 09:11

Copilot finished work on behalf of javiercn December 3, 2025 09:11

javiercn added the area-blazor Includes: Blazor, Razor Components label Dec 3, 2025

javiercn marked this pull request as ready for review December 3, 2025 15:47

javiercn requested a review from a team as a code owner December 3, 2025 15:47

Copilot AI review requested due to automatic review settings December 3, 2025 15:47

Copilot started reviewing on behalf of javiercn December 3, 2025 15:48 View session

Copilot finished reviewing on behalf of javiercn December 3, 2025 15:50

Copilot AI reviewed Dec 3, 2025

View reviewed changes

oroztocil reviewed Dec 3, 2025

View reviewed changes

Copilot started work on behalf of javiercn December 3, 2025 18:07 View session

Add nullable enable directive and test for assigned result scenario

61397d9

Co-authored-by: javiercn <6995051+javiercn@users.noreply.github.com>

Copilot finished work on behalf of javiercn December 3, 2025 18:14

build-analysis bot mentioned this pull request Dec 3, 2025

Known Build Error: error : Cannot create a file when that file already exists. #61178

Open

dotnet-policy-service bot added the pending-ci-rerun When assigned to a PR indicates that the CI checks should be rerun label Dec 11, 2025

ilonatommy approved these changes Dec 19, 2025

View reviewed changes

javiercn merged commit 7e41b05 into main Jan 21, 2026
30 checks passed

javiercn deleted the copilot/consider-razor-analyzer-recommendation branch January 21, 2026 11:10

dotnet-policy-service bot added this to the 11.0-preview1 milestone Jan 21, 2026

dotnet-maestro bot mentioned this pull request Jan 22, 2026

[main] Source code updates from dotnet/aspnetcore dotnet/dotnet#4350

Merged

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

Add BL0010 analyzer: Recommend InvokeVoidAsync over InvokeAsync<object>#64623

Add BL0010 analyzer: Recommend InvokeVoidAsync over InvokeAsync<object>#64623
javiercn merged 4 commits intomainfrom
copilot/consider-razor-analyzer-recommendation

Copilot AI commented Dec 3, 2025 •

edited by ilonatommy

Loading

Uh oh!

Copilot AI left a comment

Uh oh!

Copilot AI Dec 3, 2025

Uh oh!

Copilot AI Dec 3, 2025

Uh oh!

oroztocil left a comment

Uh oh!

javiercn commented Dec 3, 2025

Uh oh!

Copilot AI commented Dec 3, 2025

Uh oh!

oroztocil commented Dec 3, 2025

Uh oh!

ilonatommy left a comment

Uh oh!

javiercn commented Dec 19, 2025

Uh oh!

javiercn commented Jan 20, 2026

Uh oh!

azure-pipelines bot commented Jan 20, 2026

Uh oh!

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

4 participants

		using Microsoft.CodeAnalysis.Operations;

		namespace Microsoft.AspNetCore.Components.Analyzers;

Conversation

Copilot AI commented Dec 3, 2025 • edited by ilonatommy Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Description

Comments on the Issue (you are @copilot in this section)

Uh oh!

Copilot AI left a comment

Choose a reason for hiding this comment

Pull request overview

Reviewed changes

Uh oh!

Copilot AI Dec 3, 2025

Choose a reason for hiding this comment

Uh oh!

Copilot AI Dec 3, 2025

Choose a reason for hiding this comment

Uh oh!

oroztocil left a comment

Choose a reason for hiding this comment

Uh oh!

javiercn commented Dec 3, 2025

Uh oh!

Copilot AI commented Dec 3, 2025

Uh oh!

oroztocil commented Dec 3, 2025

Uh oh!

ilonatommy left a comment

Choose a reason for hiding this comment

Uh oh!

javiercn commented Dec 19, 2025

Uh oh!

javiercn commented Jan 20, 2026

Uh oh!

azure-pipelines bot commented Jan 20, 2026

Uh oh!

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

4 participants

Copilot AI commented Dec 3, 2025 •

edited by ilonatommy

Loading