nilerr

nilerr finds code which returns nil even though it checks that error is not nil.

func f() error {
	err := do()
	if err != nil {
		return nil // miss
	}
}

nilerr also finds code which returns error even though it checks that error is nil.

func f() error {
	err := do()
	if err == nil {
		return err // miss
	}
}

nilerr ignores code which has a miss with ignore comment.

func f() error {
	err := do()
	if err != nil {
		//lint:ignore nilerr reason
		return nil // ignore
	}
}

How to use

$ go install github.com/gostaticanalysis/nilerr/cmd/nilerr@latest
$ nilerr ./...