Add doc comment on AsyncValidationAttribute to not make threading assumptions

[Youssef1313]

Calling this out explicitly in the doc comment so attribute authors are very well aware.

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[Copilot]

Pull request overview

Updates the XML doc comment on AsyncValidationAttribute (System.ComponentModel.Annotations) to warn attribute implementers not to assume single-threaded / non-parallel execution when async validation is performed.

Changes:

• Add an explicit note in AsyncValidationAttribute documentation about avoiding threading assumptions (possible parallel invocation).

[ViveliDuCh]

I'd agree with Copilot's feedback here

[github-actions]

🤖 Copilot Code Review — PR #129172

Holistic Assessment

Motivation: Justified. Async validation attributes may reasonably be called in parallel by the framework, and making this explicit in documentation helps implementers avoid subtle concurrency bugs.

Approach: Adds a single sentence to the class-level <summary> XML doc comment. Simple and low-risk.

Summary: ✅ LGTM. This is a safe, helpful documentation improvement that makes an important threading contract explicit for implementers of AsyncValidationAttribute.

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Detailed Findings

✅ Correctness — Threading guidance is accurate

The statement that implementations "may or may not be called in parallel" is architecturally sound. IsValidAsync returns a Task<ValidationResult?>, and callers (e.g., the validation framework) could reasonably await multiple such tasks concurrently. Explicitly documenting this assumption is valuable.

💡 Style — Consider using <remarks> for implementation guidance

Per docs.prompt.md, <summary> should be a brief description of what the type does, while <remarks> is intended for "additional information, which can include implementation details, usage notes, or any other relevant context." The threading guidance is clearly a usage note for implementers rather than a description of the type's purpose.

That said, placing it in <summary> maximizes visibility in IntelliSense tooltips, which has practical value given how critical this guidance is. This is a minor stylistic point and not blocking.

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Models contributing to this review: claude-opus-4.6

Generated by Code Review for issue #129172 · ● 2.2M · ◷

[ViveliDuCh]

Modulo the comment left. Thanks!

[ViveliDuCh]

I'd agree with Copilot's feedback here