punused: A Go repository from rprtr258

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

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.

Differences from original:

Default pattern is **.go which scans all go files in workspace.
Configurable using config file.
Exits with non-zero code if found at least one unused symbol. So the linter is usable in CI pipelines.

Install

go install github.com/rprtr258/punused@latest
# you also need gopls
go install golang.org/x/tools/gopls@latest

Use

punused takes only one (optional) argument: A Glob filenam 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.

Config

Config is read from .punused.yaml:

timeout: 5m
exclude:
  paths:
    - pkg/api/grpc/*.pb.go # ignore all files in dir ending with .pb.go
    - internal/myapp/logic/** # ignore all subdirs and files
  symbols:
    - (*UserLogic).SendExampleLogic # ignore particular symbol

Running punused gives output similar to follosing:

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

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