golang/go

x/tools/go/analysis/passes/modernize: add testingsetenv analyzer

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#77735 opened on Feb 22, 2026

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 (13 comments) (4 reactions) (1 assignee)Go (133,883 stars) (19,008 forks)batch import
FeatureRequestProposalToolshelp wanted

Description

Proposal Details

Add a new analyzer that replaces manual environment variable save/restore with t.Setenv (Go 1.17+).

// Before
defer os.Setenv("GOOS", os.Getenv("GOOS"))
os.Setenv("GOOS", f[0])

// After
t.Setenv("GOOS", f[0])

Conditions

  • Pattern: defer os.Setenv(key, os.Getenv(key)) followed by os.Setenv(key, value)
  • defer must precede os.Setenv (defer args are evaluated immediately)
  • Within test function, before any t.Parallel() call
  • Go 1.17+

Similar to testingcontext analyzer.

Contributor guide

Tech stack
go
Domain
testing
Issue type
feature
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.
1-2 days
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 programminggo/analysis packageAST inspectionGo testing with t.Setenv
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
50
Research direction
Study the existing testingcontext analyzer in golang.org/x/tools/go/analysis/passes/modernize. Understand its structure, pattern definition, and test setup. Then implement a similar analyzer for the setenv pattern, ensuring it adheres to the conditions (defer before os.Setenv, within test function, before t.Parallel, Go 1.17+). Review the 13 comments for any additional details or concerns.