Fix metalinter warnings and add to CI (#298)

* linting: address some checks

* add nolint warnings; remove duplicate megacheck from Makefile

* add metalinter to CI, closes #196

* Run metalinter on travis

* metalinter: don't run on CI yet

.travis.yml

@@ -11,7 +11,7 @@ os:
 
 install: make get_vendor_deps
 
-script: make test_coverage
+script: make test_coverage # && make metalinter (enable when CI can handle the memory)
 
 after_success:
   - bash <(curl -s https://codecov.io/bash)

Makefile

@@ -1,7 +1,6 @@
 GOTOOLS = \
 					github.com/karalabe/xgo \
 					github.com/Masterminds/glide \
-					honnef.co/go/tools/cmd/megacheck \
 					github.com/alecthomas/gometalinter
 PACKAGES=$(shell go list ./... | grep -v '/vendor/')
 BUILD_TAGS?=ethermint
@@ -69,9 +68,6 @@ test_race:
 test_integrations:
 	@bash ./tests/test.sh
 
-megacheck: ensure_tools
-	@for pkg in ${PACKAGES}; do megacheck "$$pkg"; done
-
 metalinter: ensure_tools
 	@gometalinter --install
 	gometalinter --vendor --deadline=600s --enable-all --disable=lll ./...

circle.yml

@@ -47,8 +47,9 @@ test:
     - cd "$REPO" && make install
     - cd "$REPO" && make test_coverage
     - cd "$REPO" && set -o pipefail && make test_integrations 2>&1 | tee test_integrations.log
-
+   # should be uncommented when CI is more robust
+   #- cd "$REPO" && make metalinter
 
   post:
     - cd "$PROJECT_PATH" && mv test_integrations.log "${CIRCLE_ARTIFACTS}"
-    - cd "$PROJECT_PATH" && bash <(curl -s https://codecov.io/bash)
+    - cd "$PROJECT_PATH" && bash <(curl -s https://codecov.io/bash)

cmd/utils/reset_test.go

@@ -23,8 +23,14 @@ func TestResetAll(t *testing.T) {
 	defer os.RemoveAll(tempDatadir) // nolint: errcheck
 
 	// set EMHOME env variable
-	os.Setenv(emHome, tempDatadir)
-	defer os.Unsetenv(emHome)
+	if err = os.Setenv(emHome, tempDatadir); err != nil {
+		t.Errorf("could not set env: %v", err)
+	}
+	defer func() {
+		if err = os.Unsetenv(emHome); err != nil {
+			t.Errorf("could not unset env: %v", err)
+		}
+	}()
 
 	// context with empty flag set
 	context := getContextNoFlag()
@@ -43,7 +49,7 @@ func TestResetAll(t *testing.T) {
 	}
 
 	// check dir exists
-	if _, err := os.Stat(dataDir); err != nil {
+	if _, err = os.Stat(dataDir); err != nil {
 		t.Errorf("database doesn't exist: %v", err)
 
 	}

cmd/utils/utils.go

@@ -15,6 +15,7 @@ import (
 	"github.com/tendermint/ethermint/ethereum"
 )
 
+// StartNode will start up the node.
 func StartNode(stack *ethereum.Node) {
 	if err := stack.Start(); err != nil {
 		ethUtils.Fatalf("Error starting protocol stack: %v", err)
@@ -25,7 +26,7 @@ func StartNode(stack *ethereum.Node) {
 		defer signal.Stop(sigc)
 		<-sigc
 		log.Info("Got interrupt, shutting down...")
-		go stack.Stop()
+		go stack.Stop() // nolint: errcheck
 		for i := 10; i > 0; i-- {
 			<-sigc
 			if i > 1 {
@@ -65,6 +66,7 @@ func DefaultDataDir() string {
 	return ""
 }
 
+// ResetAll will remove the data directory.
 func ResetAll(ctx *cli.Context) error {
 	dbDir := filepath.Join(MakeDataDir(ctx), "ethermint")
 	if err := os.RemoveAll(dbDir); err != nil {

ethereum/node.go

@@ -8,17 +8,19 @@ import (
 	"github.com/ethereum/go-ethereum/node"
 )
 
+// Node is the main object.
 type Node struct {
 	node.Node
 }
 
+// New creates a new node.
 func New(conf *node.Config) (*Node, error) {
 	stack, err := node.New(conf)
 	if err != nil {
 		return nil, err
 	}
 
-	return &Node{*stack}, nil
+	return &Node{*stack}, nil // nolint: vet
 }
 
 // Start starts base node and stop p2p server

ethereum/node_test.go

@@ -51,8 +51,7 @@ func TestEnsureDisabledEthereumP2PStack(t *testing.T) {
 		t.Fatalf("cannot initialise new node from config: %v", err)
 	}
 
-	node.Start()
-	if err != nil {
+	if err := node.Start(); err != nil {
 		t.Fatalf("cannot start node: %v", err)
 	}
 	// Make a listener and ensure that ListenAddr can be bound to