Makefile: add CI check to keep go.mod clean (go-critic#817)

Makefile

@@ -1,4 +1,4 @@
-.PHONY: test test-checker ci cover tools docs
+.PHONY: test test-checker test-goroot docs ci ci-tidy ci-tests ci-linter cover install
 
 export GO111MODULE := on
 
@@ -18,7 +18,13 @@ docs:
 	cd ./cmd/makedocs && go run main.go
 
 ci:
-	@if [ "$(TEST_SUITE)" = "linter" ]; then make ci-linter; else make ci-tests; fi
+	@if [ "$(TEST_SUITE)" = "linter" ]; then make ci-linter; else make ci-tidy; make ci-tests; fi
+
+ci-tidy:
+	go mod tidy
+	# If you are testing Go 1.11: https://github.com/golang/go/issues/27868#issuecomment-431413621
+	go list all > /dev/null
+	git diff --exit-code --quiet || (echo "Please run 'go mod tidy' to clean up the 'go.mod' and 'go.sum' files."; false)
 
 ci-tests:
 	go test -v -race -count=1 -coverprofile=coverage.out ./...

go.mod

@@ -11,5 +11,6 @@ require (
 	github.com/go-toolsmith/strparse v0.0.0-20180903215201-830b6daa1241
 	github.com/go-toolsmith/typep v0.0.0-20181030061450-d63dc7650676
 	github.com/mattn/goveralls v0.0.2
+	github.com/pborman/uuid v1.2.0 // indirect
 	golang.org/x/tools v0.0.0-20181205014116-22934f0fdb62
 )

go.sum

@@ -22,12 +22,16 @@ github.com/go-toolsmith/typep v0.0.0-20181030061450-d63dc7650676 h1:6Qrsp0+25KEk
 github.com/go-toolsmith/typep v0.0.0-20181030061450-d63dc7650676/go.mod h1:JSQCQMUPdRlMZFswiq3TGpNp1GMktqkR2Ns5AIQkATU=
 github.com/google/go-cmp v0.2.0 h1:+dTQ8DZQJz0Mb/HjFlkptS1FeQ4cWSnN941F8aEG4SQ=
 github.com/google/go-cmp v0.2.0/go.mod h1:oXzfMopK8JAjlY9xF4vHSVASa0yLyX7SntLO5aqRK0M=
+github.com/google/uuid v1.0.0 h1:b4Gk+7WdP/d3HZH8EJsZpvV7EtDOgaZLtnaNGIu1adA=
+github.com/google/uuid v1.0.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
 github.com/kisielk/gotool v1.0.0 h1:AV2c/EiW3KqPNT9ZKl07ehoAGi4C5/01Cfbblndcapg=
 github.com/kisielk/gotool v1.0.0/go.mod h1:XhKaO+MFFWcvkIS/tQcRk01m1F5IRFswLeQ+oQHNcck=
 github.com/logrusorgru/aurora v0.0.0-20181002194514-a7b3b318ed4e h1:9MlwzLdW7QSDrhDjFlsEYmxpFyIoXmYRon3dt0io31k=
 github.com/logrusorgru/aurora v0.0.0-20181002194514-a7b3b318ed4e/go.mod h1:7rIyQOR62GCctdiQpZ/zOJlFyk6y+94wXzv6RNZgaR4=
 github.com/mattn/goveralls v0.0.2 h1:7eJB6EqsPhRVxvwEXGnqdO2sJI0PTsrWoTMXEk9/OQc=
 github.com/mattn/goveralls v0.0.2/go.mod h1:8d1ZMHsd7fW6IRPKQh46F2WRpyib5/X4FOpevwGNQEw=
+github.com/pborman/uuid v1.2.0 h1:J7Q5mO4ysT1dv8hyrUGHb9+ooztCXu1D8MY8DZYsu3g=
+github.com/pborman/uuid v1.2.0/go.mod h1:X/NO0urCmaxf9VXbdlT7C2Yzkj2IKimNn4k+gtPdI/k=
 golang.org/x/tools v0.0.0-20181024171208-a2dc47679d30/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
 golang.org/x/tools v0.0.0-20181117154741-2ddaf7f79a09/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
 golang.org/x/tools v0.0.0-20181205014116-22934f0fdb62 h1:KRNg63y5nZTd4po+9IAmrqBNARjHSwNMrkRrJj0AViU=