refactor (rule/function-result-limit): replace AST walker by iteration over declarations (#1167)

Author: chavacava

rule/function_result_limit.go

@@ -15,39 +15,33 @@ type FunctionResultsLimitRule struct {
 	configureOnce sync.Once
 }
 
-const defaultResultsLimit = 3
-
-func (r *FunctionResultsLimitRule) configure(arguments lint.Arguments) {
-	if len(arguments) < 1 {
-		r.max = defaultResultsLimit
-		return
-	}
-
-	maxResults, ok := arguments[0].(int64) // Alt. non panicking version
-	if !ok {
-		panic(fmt.Sprintf(`invalid value passed as return results number to the "function-result-limit" rule; need int64 but got %T`, arguments[0]))
-	}
-	if maxResults < 0 {
-		panic(`the value passed as return results number to the "function-result-limit" rule cannot be negative`)
-	}
-
-	r.max = int(maxResults)
-}
-
 // Apply applies the rule to given file.
 func (r *FunctionResultsLimitRule) Apply(file *lint.File, arguments lint.Arguments) []lint.Failure {
 	r.configureOnce.Do(func() { r.configure(arguments) })
 
 	var failures []lint.Failure
+	for _, decl := range file.AST.Decls {
+		funcDecl, ok := decl.(*ast.FuncDecl)
+		if !ok {
+			continue
+		}
 
-	walker := lintFunctionResultsNum{
-		max: r.max,
-		onFailure: func(failure lint.Failure) {
-			failures = append(failures, failure)
-		},
-	}
+		num := 0
+		hasResults := funcDecl.Type.Results != nil
+		if hasResults {
+			num = funcDecl.Type.Results.NumFields()
+		}
+
+		if num <= r.max {
+			continue
+		}
 
-	ast.Walk(walker, file.AST)
+		failures = append(failures, lint.Failure{
+			Confidence: 1,
+			Failure:    fmt.Sprintf("maximum number of return results per function exceeded; max %d but got %d", r.max, num),
+			Node:       funcDecl.Type,
+		})
+	}
 
 	return failures
 }
@@ -57,29 +51,21 @@ func (*FunctionResultsLimitRule) Name() string {
 	return "function-result-limit"
 }
 
-type lintFunctionResultsNum struct {
-	max       int
-	onFailure func(lint.Failure)
-}
+const defaultResultsLimit = 3
 
-func (w lintFunctionResultsNum) Visit(n ast.Node) ast.Visitor {
-	node, ok := n.(*ast.FuncDecl)
-	if ok {
-		num := 0
-		hasResults := node.Type.Results != nil
-		if hasResults {
-			num = node.Type.Results.NumFields()
-		}
-		if num > w.max {
-			w.onFailure(lint.Failure{
-				Confidence: 1,
-				Failure:    fmt.Sprintf("maximum number of return results per function exceeded; max %d but got %d", w.max, num),
-				Node:       node.Type,
-			})
-		}
+func (r *FunctionResultsLimitRule) configure(arguments lint.Arguments) {
+	if len(arguments) < 1 {
+		r.max = defaultResultsLimit
+		return
+	}
 
-		return nil // skip visiting function's body
+	maxResults, ok := arguments[0].(int64) // Alt. non panicking version
+	if !ok {
+		panic(fmt.Sprintf(`invalid value passed as return results number to the "function-result-limit" rule; need int64 but got %T`, arguments[0]))
+	}
+	if maxResults < 0 {
+		panic(`the value passed as return results number to the "function-result-limit" rule cannot be negative`)
 	}
 
-	return w
+	r.max = int(maxResults)
 }