non GET requests (PUT, POST, DELETE) requests stay with pending status and never "finish"

[ydolzhenko]

Basically all non-GET requests that return empty body (just 200 OK) get stuck with pending status and never end - while in fact they're working as expected.

The ones that return with any body content are being displayed fine.

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DevTools version: 2.37.3
IDE: Android-Studio
Connected Device:
CPU / OS: x64 (64 bit) ios
Connected app type: Flutter native (debug build)
Dart Version: 3.5.4
Flutter Version: 3.24.4 / stable
Framework / Engine: 603104015d / db49896cf2

[kenzieschmoll]

Can you provide a minimal repro of the case you are talking about so that we can reproduce the issue?

[ydolzhenko]

I can't right now, I'm on the road, but it's easily reproducible - basically all POST/PUT/DELETE (and I suggest GET, but empty GET wouldn't make sense so I don't have it) with empty bodies render as Pending.

[JulianSchmidtZollsoft]

We are experiencing the same behaviour. All requests that resolve with status 204 (and have an empty Response body) are still marked as "Pending" and are missing the "Request"- and "Response"-Tab.

[duytq94]

I have the same issue (currently I'm on ver 3.27.1)

[srawlins]

@ydolzhenko @duytq94 @JulianSchmidtZollsoft sorry for the delay. I can reproduce this, but I'd like some more details, if you can:

• What HTTP client is making these requests? I imagine something like dart:io's HttpClient, or package:http, or package:dio...
• What HTTP server is making the responses (with no bodies)? I am testing with dart:io's HttpServer, but I'm hoping the bug is not in HttpServer.

I suspect this is a bug in dart:io. Something like dart-lang/sdk#39548 or dart-lang/sdk#45679 or dart-lang/sdk#30842. I'm investigating in there at the moment.

[JulianSchmidtZollsoft]

@srawlins
We are using package:http on the Client. The Server is written in Java.

[srawlins]

Thanks! In the meantime I've developed a new theory that there is a race condition in the profiling code, in dart:io. When there is no response body, _HttpProfileData.finishResponse() seems to be called before _HttpProfileData.startResponse() 🙃.

[ydolzhenko]

@srawlins , same as @JulianSchmidtZollsoft - package:http on the client and a jvm/tomcat server.

[srawlins]

I see indeed that _HttpProfileData.finishResponse() is called before _HttpProfileData.startResponse(). I think this is just a result of microtask scheduling; when the response has no body, _incoming.dataDone completes before _httpRequest._responseCompleter.

Since startResponse is responsible for setting responseInProgress to true, the call to finishResponse short circuit returns immediately. We therefore don't finish the response timeline, or log the end time, etc.

[srawlins]

This should be fixed with https://dart-review.googlesource.com/c/sdk/+/415140. The fix will first appear in Dart 3.8 stable.