golang/go

net/http: Client.Do returns different errors on context deadline depending on req/conn state

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#31,863 opened on May 6, 2019

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Description

What version of Go are you using (go version)?

Does this issue reproduce with the latest release?

yes

What operating system and processor architecture are you using (go env)?

What did you do?

Run multiple times program on my server (24 cpu) https://play.golang.org/p/d00_wxKDN5f With single goroutine - problem did not appears. Problem appeared not every run, but in 3-4 runs at least one was faulty.

What did you expect to see?

all goroutines: done = true, err = Get http://240.0.0.1/test: context deadline exceeded

What did you see instead?

all gouroutines returned at the same time, after 4 seconds, like i specified in parent context.WithTimeout. But some goroutines returned before parentContext.Done was closed (error was i/o timeout), and some gorotines returned after parentCtx.Done was closed (with expected error "context deadline exceeded").

Contributor guide

Research direction
Investigate the race condition in net/http.Client.Do where context deadline and i/o timeout errors are inconsistently returned.
Tech stack
go
Domain
backend
Issue type
Bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
Half day
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
Go
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
50