golang/go

context: relax recommendation against putting Contexts in structs

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#22,602 opened on Nov 6, 2017

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Description

This is a follow-on from discussion in #14660.

Right now the context package documentation says

Do not store Contexts inside a struct type; instead, pass a Context explicitly to each function that needs it. The Context should be the first parameter, typically named ctx: [...]

This advice seems overly restrictive. @bradfitz wrote in that issue:

While we've told people not to add contexts to structs, I think that guidance is over-aggressive. The real advice is not to store contexts. They should be passed along like parameters. But if the struct is essentially just a parameter, it's okay. I think this concern can be addressed with package-level documentation and examples.

Let's address this concern with package-level documentation.

Also see @rsc's comment at https://github.com/golang/go/issues/14660#issuecomment-200145301.

/cc @Sajmani @bradfitz @rsc

Contributor guide

Research direction
Read the current documentation for the context package in the Go standard library, review the discussion in issue #14660 and the comment by rsc at https://github.com/golang/go/issues/14660#issuecomment 200145301, and propose updated wording that relaxes the recommendation against storing contexts in structs while preserving the core advice.
Tech stack
go
Domain
backend
Issue type
Documentation
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
1
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-3 hours
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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.
70