dotnet/aspnetcore

Misleading TaskCanceledException

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#4,747 opened on 2018年5月30日

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 (7 comments) (0 reactions) (0 assignees)C# (37,933 stars) (10,653 forks)batch import
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説明

I have a WebApi endpoint that parses out the Request.Body itself rather than using Model binding due to performance reasons.

During some requests, I was getting a TaskCanceledException from a TextReader that I never gave any CancellationTokens too. After investigation, I found out that any read operations on the Request.Body after the Request was aborted will throw TaskCanceledExceptions. The stack trace at the time didn't list any Kestrel level code so I spent a lot of time trying to find out how a Stream can possibly cancel a token I never gave it.

This is a bit misleading and should probably change I think.

コントリビューターガイド

技術スタック
csharp
領域
backend
Issue 種別
bug
難度新しい貢献者にとっての実装難度です。1 は非常に小さな変更、5 は専門的な作業です。
3
推定時間経験ある貢献者が調査、実装、テスト、pull request 準備にかけるおおよその時間範囲です。
half day
活動状況Issue が今どれだけ取り組みやすいかを示します。新しい、活発、古い、ブロック中、またはメンテナー入力待ちなどです。
stale
明確さ期待される変更、受け入れ条件、次の手順がどれだけ明確かを示します。
mostly clear
前提条件
understand ASP.NET Core request pipelineknow CancellationToken basics
初心者向け度初回貢献者にどれだけ取り組みやすいかを 1-100 で推定したスコアです。
30
調査方針
Investigate the source of the TaskCanceledException in the HttpRequest body stream, likely in the Kestrel server implementation. Look at the RequestBodyStream or similar classes in the dotnet/aspnetcore repository. The issue discussion (https://github.com/dotnet/aspnetcore/issues/4747) contains insights. Consider if the exception should be changed to a more specific one like OperationCanceledException, and whether the cancellation token is exposed appropriately.