enable more linters (#1043)

* enable revive linter

* enable gochecknoinits linter

* enable unconvert linter

* enable unparam linter

* enable asciicheck linter

* enable depguard linter

* enable nakedret linter

* enable megacheck linter

* enable nolintlint linter

* enable predeclared linter

* Update go.yml

* Update go.yml

.golangci.yml

@@ -2,15 +2,31 @@ run:
   timeout: 5m
 linters:
   enable:
+    - asciicheck
+    - depguard
     - errorlint
     - gci
+    - gochecknoinits
     - gofmt
     - goimports
     - gosec
+    - megacheck
     - misspell
+    - nakedret
+    - nolintlint
+    - predeclared
+    - revive
+    - unconvert
+    - unparam
 issues:
   exclude-rules:
   - linters:
     - gosec
     text:  "Implicit memory aliasing in for loop."
     path: _test\.go
+  - linters:
+    - revive
+    text: "unexported-return"
+  - linters:
+    - revive
+    text: "var-naming"

pkg/yqlib/all_at_once_evaluator.go

@@ -50,7 +50,7 @@ func (e *allAtOnceEvaluator) EvaluateFiles(expression string, filenames []string
 	fileIndex := 0
 	firstFileLeadingContent := ""
 
-	var allDocuments *list.List = list.New()
+	var allDocuments = list.New()
 	for _, filename := range filenames {
 		reader, leadingContent, err := readStream(filename, fileIndex == 0 && leadingContentPreProcessing)
 		if err != nil {

pkg/yqlib/candidate_node.go

@@ -56,7 +56,7 @@ func (n *CandidateNode) AsList() *list.List {
 }
 
 func (n *CandidateNode) CreateChildInMap(key *yaml.Node, node *yaml.Node) *CandidateNode {
-	var value interface{} = nil
+	var value interface{}
 	if key != nil {
 		value = key.Value
 	}

pkg/yqlib/expression_tokeniser.go

@@ -135,7 +135,7 @@ func opTokenWithPrefs(op *operationType, assignOpType *operationType, preference
 func extractNumberParamter(value string) (int, error) {
 	parameterParser := regexp.MustCompile(`.*\(([0-9]+)\)`)
 	matches := parameterParser.FindStringSubmatch(value)
-	var indent, errParsingInt = strconv.ParseInt(matches[1], 10, 32) // nolint
+	var indent, errParsingInt = strconv.ParseInt(matches[1], 10, 32)
 	if errParsingInt != nil {
 		return 0, errParsingInt
 	}
@@ -198,7 +198,7 @@ func unwrap(value string) string {
 func numberValue() lex.Action {
 	return func(s *lex.Scanner, m *machines.Match) (interface{}, error) {
 		var numberString = string(m.Bytes)
-		var number, errParsingInt = strconv.ParseInt(numberString, 10, 64) // nolint
+		var number, errParsingInt = strconv.ParseInt(numberString, 10, 64)
 		if errParsingInt != nil {
 			return nil, errParsingInt
 		}
@@ -212,7 +212,7 @@ func hexValue() lex.Action {
 		var originalString = string(m.Bytes)
 		var numberString = originalString[2:]
 		log.Debugf("numberString: %v", numberString)
-		var number, errParsingInt = strconv.ParseInt(numberString, 16, 64) // nolint
+		var number, errParsingInt = strconv.ParseInt(numberString, 16, 64)
 		if errParsingInt != nil {
 			return nil, errParsingInt
 		}
@@ -224,7 +224,7 @@ func hexValue() lex.Action {
 func floatValue() lex.Action {
 	return func(s *lex.Scanner, m *machines.Match) (interface{}, error) {
 		var numberString = string(m.Bytes)
-		var number, errParsingInt = strconv.ParseFloat(numberString, 64) // nolint
+		var number, errParsingInt = strconv.ParseFloat(numberString, 64)
 		if errParsingInt != nil {
 			return nil, errParsingInt
 		}

pkg/yqlib/lib.go

@@ -203,10 +203,10 @@ func recursiveNodeEqual(lhs *yaml.Node, rhs *yaml.Node) bool {
 func parseInt(numberString string) (string, int64, error) {
 	if strings.HasPrefix(numberString, "0x") ||
 		strings.HasPrefix(numberString, "0X") {
-		num, err := strconv.ParseInt(numberString[2:], 16, 64) // nolint
+		num, err := strconv.ParseInt(numberString[2:], 16, 64)
 		return "0x%X", num, err
 	}
-	num, err := strconv.ParseInt(numberString, 10, 64) // nolint
+	num, err := strconv.ParseInt(numberString, 10, 64)
 	return "%v", num, err
 }
 

pkg/yqlib/operator_anchors_aliases.go

@@ -220,7 +220,7 @@ func explodeNode(node *yaml.Node, context Context) error {
 		if hasAlias {
 			// this is a slow op, which is why we want to check before running it.
 			return reconstructAliasedMap(node, context)
-		} else {
+		}
 		// this map has no aliases, but it's kids might
 		for index := 0; index < len(node.Content); index = index + 2 {
 			keyNode := node.Content[index]
@@ -235,7 +235,6 @@ func explodeNode(node *yaml.Node, context Context) error {
 			}
 		}
 		return nil
-		}
 	default:
 		return nil
 	}

pkg/yqlib/operator_collect_object.go

@@ -28,7 +28,7 @@ func collectObjectOperator(d *dataTreeNavigator, originalContext Context, expres
 		return context.SingleChildContext(candidate), nil
 	}
 	first := context.MatchingNodes.Front().Value.(*CandidateNode)
-	var rotated []*list.List = make([]*list.List, len(first.Node.Content))
+	var rotated = make([]*list.List, len(first.Node.Content))
 
 	for i := 0; i < len(first.Node.Content); i++ {
 		rotated[i] = list.New()
@@ -61,7 +61,7 @@ func collect(d *dataTreeNavigator, context Context, remainingMatches *list.List)
 
 	candidate := remainingMatches.Remove(remainingMatches.Front()).(*CandidateNode)
 
-	splatted, err := splat(d, context.SingleChildContext(candidate),
+	splatted, err := splat(context.SingleChildContext(candidate),
 		traversePreferences{DontFollowAlias: true, IncludeMapKeys: false})
 
 	for splatEl := splatted.MatchingNodes.Front(); splatEl != nil; splatEl = splatEl.Next() {

pkg/yqlib/operator_create_map.go

@@ -14,7 +14,7 @@ func createMapOperator(d *dataTreeNavigator, context Context, expressionNode *Ex
 
 	var path []interface{}
 
-	var document uint = 0
+	var document uint
 
 	sequences := list.New()
 
@@ -42,7 +42,7 @@ func createMapOperator(d *dataTreeNavigator, context Context, expressionNode *Ex
 
 func sequenceFor(d *dataTreeNavigator, context Context, matchingNode *CandidateNode, expressionNode *ExpressionNode) (*CandidateNode, error) {
 	var path []interface{}
-	var document uint = 0
+	var document uint
 	var matches = list.New()
 
 	if matchingNode != nil {

pkg/yqlib/operator_entries.go

@@ -68,7 +68,7 @@ func toEntriesOperator(d *dataTreeNavigator, context Context, expressionNode *Ex
 	return context.ChildContext(results), nil
 }
 
-func parseEntry(d *dataTreeNavigator, entry *yaml.Node, position int) (*yaml.Node, *yaml.Node, error) {
+func parseEntry(entry *yaml.Node, position int) (*yaml.Node, *yaml.Node, error) {
 	prefs := traversePreferences{DontAutoCreate: true}
 	candidateNode := &CandidateNode{Node: entry}
 
@@ -92,14 +92,14 @@ func parseEntry(d *dataTreeNavigator, entry *yaml.Node, position int) (*yaml.Nod
 
 }
 
-func fromEntries(d *dataTreeNavigator, candidateNode *CandidateNode) (*CandidateNode, error) {
+func fromEntries(candidateNode *CandidateNode) (*CandidateNode, error) {
 	var node = &yaml.Node{Kind: yaml.MappingNode, Tag: "!!map"}
 	var mapCandidateNode = candidateNode.CreateReplacement(node)
 
 	var contents = unwrapDoc(candidateNode.Node).Content
 
 	for index := 0; index < len(contents); index = index + 1 {
-		key, value, err := parseEntry(d, contents[index], index)
+		key, value, err := parseEntry(contents[index], index)
 		if err != nil {
 			return nil, err
 		}
@@ -117,7 +117,7 @@ func fromEntriesOperator(d *dataTreeNavigator, context Context, expressionNode *
 
 		switch candidateNode.Kind {
 		case yaml.SequenceNode:
-			mapResult, err := fromEntries(d, candidate)
+			mapResult, err := fromEntries(candidate)
 			if err != nil {
 				return Context{}, err
 			}
@@ -143,7 +143,7 @@ func withEntriesOperator(d *dataTreeNavigator, context Context, expressionNode *
 	for el := toEntries.MatchingNodes.Front(); el != nil; el = el.Next() {
 		//run expression against entries
 		// splat toEntries and pipe it into Rhs
-		splatted, err := splat(d, context.SingleChildContext(el.Value.(*CandidateNode)), traversePreferences{})
+		splatted, err := splat(context.SingleChildContext(el.Value.(*CandidateNode)), traversePreferences{})
 		if err != nil {
 			return Context{}, err
 		}

pkg/yqlib/operator_has.go

@@ -44,7 +44,7 @@ func hasOperator(d *dataTreeNavigator, context Context, expressionNode *Expressi
 		case yaml.SequenceNode:
 			candidateHasKey := false
 			if wanted.Tag == "!!int" {
-				var number, errParsingInt = strconv.ParseInt(wantedKey, 10, 64) // nolint
+				var number, errParsingInt = strconv.ParseInt(wantedKey, 10, 64)
 				if errParsingInt != nil {
 					return Context{}, errParsingInt
 				}

pkg/yqlib/operator_map.go

@@ -10,7 +10,7 @@ func mapValuesOperator(d *dataTreeNavigator, context Context, expressionNode *Ex
 		candidate := el.Value.(*CandidateNode)
 		//run expression against entries
 		// splat toEntries and pipe it into Rhs
-		splatted, err := splat(d, context.SingleChildContext(candidate), traversePreferences{})
+		splatted, err := splat(context.SingleChildContext(candidate), traversePreferences{})
 		if err != nil {
 			return Context{}, err
 		}
@@ -37,7 +37,7 @@ func mapOperator(d *dataTreeNavigator, context Context, expressionNode *Expressi
 		candidate := el.Value.(*CandidateNode)
 		//run expression against entries
 		// splat toEntries and pipe it into Rhs
-		splatted, err := splat(d, context.SingleChildContext(candidate), traversePreferences{})
+		splatted, err := splat(context.SingleChildContext(candidate), traversePreferences{})
 		if err != nil {
 			return Context{}, err
 		}

pkg/yqlib/operator_multiply.go

@@ -109,12 +109,12 @@ func mergeObjects(d *dataTreeNavigator, context Context, lhs *CandidateNode, rhs
 		TraversePreferences: traversePreferences{DontFollowAlias: true, IncludeMapKeys: true}}
 	log.Debugf("merge - preferences.DeepMergeArrays %v", preferences.DeepMergeArrays)
 	log.Debugf("merge - preferences.AppendArrays %v", preferences.AppendArrays)
-	err := recursiveDecent(d, results, context.SingleChildContext(rhs), prefs)
+	err := recursiveDecent(results, context.SingleChildContext(rhs), prefs)
 	if err != nil {
 		return nil, err
 	}
 
-	var pathIndexToStartFrom int = 0
+	var pathIndexToStartFrom int
 	if results.Front() != nil {
 		pathIndexToStartFrom = len(results.Front().Value.(*CandidateNode).Path)
 	}

pkg/yqlib/operator_recursive_descent.go

@@ -15,7 +15,7 @@ func recursiveDescentOperator(d *dataTreeNavigator, context Context, expressionN
 	var results = list.New()
 
 	preferences := expressionNode.Operation.Preferences.(recursiveDescentPreferences)
-	err := recursiveDecent(d, results, context, preferences)
+	err := recursiveDecent(results, context, preferences)
 	if err != nil {
 		return Context{}, err
 	}
@@ -23,7 +23,7 @@ func recursiveDescentOperator(d *dataTreeNavigator, context Context, expressionN
 	return context.ChildContext(results), nil
 }
 
-func recursiveDecent(d *dataTreeNavigator, results *list.List, context Context, preferences recursiveDescentPreferences) error {
+func recursiveDecent(results *list.List, context Context, preferences recursiveDescentPreferences) error {
 	for el := context.MatchingNodes.Front(); el != nil; el = el.Next() {
 		candidate := el.Value.(*CandidateNode)
 
@@ -35,12 +35,12 @@ func recursiveDecent(d *dataTreeNavigator, results *list.List, context Context,
 		if candidate.Node.Kind != yaml.AliasNode && len(candidate.Node.Content) > 0 &&
 			(preferences.RecurseArray || candidate.Node.Kind != yaml.SequenceNode) {
 
-			children, err := splat(d, context.SingleChildContext(candidate), preferences.TraversePreferences)
+			children, err := splat(context.SingleChildContext(candidate), preferences.TraversePreferences)
 
 			if err != nil {
 				return err
 			}
-			err = recursiveDecent(d, results, children, preferences)
+			err = recursiveDecent(results, children, preferences)
 			if err != nil {
 				return err
 			}

pkg/yqlib/operator_split_document.go

@@ -3,7 +3,7 @@ package yqlib
 func splitDocumentOperator(d *dataTreeNavigator, context Context, expressionNode *ExpressionNode) (Context, error) {
 	log.Debugf("-- splitDocumentOperator")
 
-	var index uint = 0
+	var index uint
 	for el := context.MatchingNodes.Front(); el != nil; el = el.Next() {
 		candidate := el.Value.(*CandidateNode)
 		candidate.Document = index

pkg/yqlib/operator_strings.go

@@ -62,7 +62,7 @@ func substituteStringOperator(d *dataTreeNavigator, context Context, expressionN
 		candidate := el.Value.(*CandidateNode)
 		node := unwrapDoc(candidate.Node)
 		if node.Tag != "!!str" {
-			return Context{}, fmt.Errorf("cannot substitute with %v, can only substitute strings. Hint: Most often you'll want to use '|=' over '=' for this operation.", node.Tag)
+			return Context{}, fmt.Errorf("cannot substitute with %v, can only substitute strings. Hint: Most often you'll want to use '|=' over '=' for this operation", node.Tag)
 		}
 
 		targetNode := substitute(node.Value, regEx, replacementText)

pkg/yqlib/operator_subtract.go

@@ -23,7 +23,7 @@ func subtractOperator(d *dataTreeNavigator, context Context, expressionNode *Exp
 	return crossFunction(d, context.ReadOnlyClone(), expressionNode, subtract, false)
 }
 
-func subtractArray(d *dataTreeNavigator, context Context, lhs *CandidateNode, rhs *CandidateNode) (*CandidateNode, error) {
+func subtractArray(lhs *CandidateNode, rhs *CandidateNode) (*CandidateNode, error) {
 	newLhsArray := make([]*yaml.Node, 0)
 
 	for lindex := 0; lindex < len(lhs.Node.Content); lindex = lindex + 1 {
@@ -60,7 +60,7 @@ func subtract(d *dataTreeNavigator, context Context, lhs *CandidateNode, rhs *Ca
 		if rhs.Node.Kind != yaml.SequenceNode {
 			return nil, fmt.Errorf("%v (%v) cannot be subtracted from %v", rhs.Node.Tag, rhs.Path, lhsNode.Tag)
 		}
-		return subtractArray(d, context, lhs, rhs)
+		return subtractArray(lhs, rhs)
 	case yaml.ScalarNode:
 		if rhs.Node.Kind != yaml.ScalarNode {
 			return nil, fmt.Errorf("%v (%v) cannot be subtracted from %v", rhs.Node.Tag, rhs.Path, lhsNode.Tag)

pkg/yqlib/operator_traverse_path.go

@@ -17,7 +17,7 @@ type traversePreferences struct {
 	OptionalTraverse     bool // e.g. .adf?
 }
 
-func splat(d *dataTreeNavigator, context Context, prefs traversePreferences) (Context, error) {
+func splat(context Context, prefs traversePreferences) (Context, error) {
 	return traverseNodesWithArrayIndices(context, make([]*yaml.Node, 0), prefs)
 }
 
@@ -26,7 +26,7 @@ func traversePathOperator(d *dataTreeNavigator, context Context, expressionNode
 	var matches = list.New()
 
 	for el := context.MatchingNodes.Front(); el != nil; el = el.Next() {
-		newNodes, err := traverse(d, context, el.Value.(*CandidateNode), expressionNode.Operation)
+		newNodes, err := traverse(context, el.Value.(*CandidateNode), expressionNode.Operation)
 		if err != nil {
 			return Context{}, err
 		}
@@ -36,7 +36,7 @@ func traversePathOperator(d *dataTreeNavigator, context Context, expressionNode
 	return context.ChildContext(matches), nil
 }
 
-func traverse(d *dataTreeNavigator, context Context, matchingNode *CandidateNode, operation *Operation) (*list.List, error) {
+func traverse(context Context, matchingNode *CandidateNode, operation *Operation) (*list.List, error) {
 	log.Debug("Traversing %v", NodeToString(matchingNode))
 	value := matchingNode.Node
 
@@ -66,11 +66,11 @@ func traverse(d *dataTreeNavigator, context Context, matchingNode *CandidateNode
 	case yaml.AliasNode:
 		log.Debug("its an alias!")
 		matchingNode.Node = matchingNode.Node.Alias
-		return traverse(d, context, matchingNode, operation)
+		return traverse(context, matchingNode, operation)
 	case yaml.DocumentNode:
 		log.Debug("digging into doc node")
 
-		return traverse(d, context, matchingNode.CreateChildInMap(nil, matchingNode.Node.Content[0]), operation)
+		return traverse(context, matchingNode.CreateChildInMap(nil, matchingNode.Node.Content[0]), operation)
 	default:
 		return list.New(), nil
 	}

pkg/yqlib/operators_test.go

@@ -91,7 +91,7 @@ func testScenario(t *testing.T, s *expressionScenario) {
 }
 
 func resultsToString(t *testing.T, results *list.List) []string {
-	var pretty []string = make([]string, 0)
+	var pretty = make([]string, 0)
 
 	for el := results.Front(); el != nil; el = el.Next() {
 		n := el.Value.(*CandidateNode)
@@ -129,7 +129,7 @@ func copyFromHeader(title string, out *os.File) error {
 	if os.IsNotExist(err) {
 		return nil
 	}
-	in, err := os.Open(source) // nolint gosec
+	in, err := os.Open(source)
 	if err != nil {
 		return err
 	}

pkg/yqlib/stream_evaluator.go

@@ -52,7 +52,7 @@ func (s *streamEvaluator) EvaluateNew(expression string, printer Printer, leadin
 }
 
 func (s *streamEvaluator) EvaluateFiles(expression string, filenames []string, printer Printer, leadingContentPreProcessing bool) error {
-	var totalProcessDocs uint = 0
+	var totalProcessDocs uint
 	node, err := s.treeCreator.ParseExpression(expression)
 	if err != nil {
 		return err

pkg/yqlib/utils.go

@@ -110,7 +110,7 @@ func processReadStream(reader *bufio.Reader) (io.Reader, string, error) {
 func readDocuments(reader io.Reader, filename string, fileIndex int) (*list.List, error) {
 	decoder := yaml.NewDecoder(reader)
 	inputList := list.New()
-	var currentIndex uint = 0
+	var currentIndex uint
 
 	for {
 		var dataBucket yaml.Node