punused: A Go repository from danp

This is a small utility that finds unused exported Go symbols (functions, methods ...) in Go. For all other similar use cases, use https://github.com/dominikh/go-tools

I have used this in Hugo (a monorepo with many packages), and it works, but there are some caveats:

It does not detect references from outside of your project.
It does not detect references via reflect.
Some possible surprises when it comes to interfaces.

So, you should inspect and test the proposed deletes. See this test repo for more information.

Install

go install github.com/bep/punused@latest

You also need gopls:

go install golang.org/x/tools/gopls@latest

Use

punused takes only one (optional) argument: A Glob filename pattern (Unix style slashes, double asterisk is supported) of Go files to check.

punused needs to be run from the root of a Go Module. To test a specific package you can target it with a Glob, e.g. punused "utils/*.go".

Running punused in this repository currently gives:

punused                                                                
internal/lib/gopls.go:125:2 field Detail is unused (EU1002)
internal/lib/gopls.go:135:2 field Tags is unused (EU1002)
internal/lib/gopls.go:141:2 field Deprecated is unused (EU1002)
internal/lib/gopls.go:147:2 field Range is unused (EU1002)
internal/lib/testpackages/firstpackage/code1.go:7:2 variable UnusedVar is unused (EU1002)
internal/lib/testpackages/firstpackage/code1.go:12:2 constant UnusedConst is unused (EU1002)
internal/lib/testpackages/firstpackage/code1.go:19:6 function UnusedFunction is unused (EU1002)
internal/lib/testpackages/firstpackage/code1.go:25:2 field UnusedField is unused (EU1002)
internal/lib/testpackages/firstpackage/code1.go:32:15 method (MyType).UnusedMethod is unused (EU1002)
internal/lib/testpackages/firstpackage/code1.go:36:6 interface UnusedInterfaceWithUsedAndUnusedMethod is unused (EU1002)
internal/lib/testpackages/firstpackage/code1.go:38:2 method UnusedInterfaceMethodReturningInt is unused (EU1002)
internal/lib/testpackages/firstpackage/code1.go:37:2 method UsedInterfaceMethodReturningInt is unused (EU1002)
internal/lib/testpackages/firstpackage/code1.go:41:6 interface UnusedInterface is unused (EU1002)
internal/lib/testpackages/firstpackage/code1.go:42:2 method UnusedInterfaceReturningInt is unused (EU1002)
internal/lib/testpackages/firstpackage/code1.go:45:6 interface UsedInterface is unused (EU1002)
internal/lib/testpackages/firstpackage/testlib1.go:4:2 constant OnlyUsedInTestConst is used in test only (EU1001)

Note that we currently skip checking test code, but you do warned about unused symbols only used in tests (see example above).

danp/punused

Install

Use