refactor: replace mutex with sync.Once for rule configuration (#1118)

Author: alexandear

rule/add_constant.go

@@ -36,12 +36,13 @@ type AddConstantRule struct {
 	allowList       allowList
 	ignoreFunctions []*regexp.Regexp
 	strLitLimit     int
-	sync.Mutex
+
+	configureOnce sync.Once
 }
 
 // Apply applies the rule to given file.
 func (r *AddConstantRule) Apply(file *lint.File, arguments lint.Arguments) []lint.Failure {
-	r.configure(arguments)
+	r.configureOnce.Do(func() { r.configure(arguments) })
 
 	var failures []lint.Failure
 
@@ -201,9 +202,6 @@ func (w *lintAddConstantRule) isStructTag(n *ast.BasicLit) bool {
 }
 
 func (r *AddConstantRule) configure(arguments lint.Arguments) {
-	r.Lock()
-	defer r.Unlock()
-
 	if r.allowList == nil {
 		r.strLitLimit = defaultStrLitLimit
 		r.allowList = newAllowList()

rule/argument_limit.go

@@ -11,18 +11,13 @@ import (
 // ArgumentsLimitRule lints given else constructs.
 type ArgumentsLimitRule struct {
 	max int
-	sync.Mutex
+
+	configureOnce sync.Once
 }
 
 const defaultArgumentsLimit = 8
 
 func (r *ArgumentsLimitRule) configure(arguments lint.Arguments) {
-	r.Lock()
-	defer r.Unlock()
-	if r.max != 0 {
-		return
-	}
-
 	if len(arguments) < 1 {
 		r.max = defaultArgumentsLimit
 		return
@@ -37,7 +32,7 @@ func (r *ArgumentsLimitRule) configure(arguments lint.Arguments) {
 
 // Apply applies the rule to given file.
 func (r *ArgumentsLimitRule) Apply(file *lint.File, arguments lint.Arguments) []lint.Failure {
-	r.configure(arguments)
+	r.configureOnce.Do(func() { r.configure(arguments) })
 
 	var failures []lint.Failure
 	onFailure := func(failure lint.Failure) {

rule/banned_characters.go

@@ -12,23 +12,22 @@ import (
 // BannedCharsRule checks if a file contains banned characters.
 type BannedCharsRule struct {
 	bannedCharList []string
-	sync.Mutex
+
+	configureOnce sync.Once
 }
 
 const bannedCharsRuleName = "banned-characters"
 
 func (r *BannedCharsRule) configure(arguments lint.Arguments) {
-	r.Lock()
-	defer r.Unlock()
-	if r.bannedCharList == nil && len(arguments) > 0 {
+	if len(arguments) > 0 {
 		checkNumberOfArguments(1, arguments, bannedCharsRuleName)
 		r.bannedCharList = r.getBannedCharsList(arguments)
 	}
 }
 
 // Apply applied the rule to the given file.
 func (r *BannedCharsRule) Apply(file *lint.File, arguments lint.Arguments) []lint.Failure {
-	r.configure(arguments)
+	r.configureOnce.Do(func() { r.configure(arguments) })
 
 	var failures []lint.Failure
 	onFailure := func(failure lint.Failure) {

rule/cognitive_complexity.go

@@ -13,18 +13,13 @@ import (
 // CognitiveComplexityRule lints given else constructs.
 type CognitiveComplexityRule struct {
 	maxComplexity int
-	sync.Mutex
+
+	configureOnce sync.Once
 }
 
 const defaultMaxCognitiveComplexity = 7
 
 func (r *CognitiveComplexityRule) configure(arguments lint.Arguments) {
-	r.Lock()
-	defer r.Unlock()
-	if r.maxComplexity != 0 {
-		return // already configured
-	}
-
 	if len(arguments) < 1 {
 		r.maxComplexity = defaultMaxCognitiveComplexity
 		return
@@ -40,7 +35,7 @@ func (r *CognitiveComplexityRule) configure(arguments lint.Arguments) {
 
 // Apply applies the rule to given file.
 func (r *CognitiveComplexityRule) Apply(file *lint.File, arguments lint.Arguments) []lint.Failure {
-	r.configure(arguments)
+	r.configureOnce.Do(func() { r.configure(arguments) })
 
 	var failures []lint.Failure
 

rule/comment_spacings.go

@@ -12,16 +12,11 @@ import (
 // the comment symbol( // ) and the start of the comment text
 type CommentSpacingsRule struct {
 	allowList []string
-	sync.Mutex
+
+	configureOnce sync.Once
 }
 
 func (r *CommentSpacingsRule) configure(arguments lint.Arguments) {
-	r.Lock()
-	defer r.Unlock()
-	if r.allowList != nil {
-		return // already configured
-	}
-
 	r.allowList = []string{}
 	for _, arg := range arguments {
 		allow, ok := arg.(string) // Alt. non panicking version
@@ -34,7 +29,7 @@ func (r *CommentSpacingsRule) configure(arguments lint.Arguments) {
 
 // Apply the rule.
 func (r *CommentSpacingsRule) Apply(file *lint.File, args lint.Arguments) []lint.Failure {
-	r.configure(args)
+	r.configureOnce.Do(func() { r.configure(args) })
 
 	var failures []lint.Failure
 

rule/comments_density.go

@@ -12,22 +12,13 @@ import (
 // CommentsDensityRule lints given else constructs.
 type CommentsDensityRule struct {
 	minimumCommentsDensity int64
-	configured             bool
-	sync.Mutex
+
+	configureOnce sync.Once
 }
 
 const defaultMinimumCommentsPercentage = 0
 
 func (r *CommentsDensityRule) configure(arguments lint.Arguments) {
-	r.Lock()
-	defer r.Unlock()
-
-	if r.configured {
-		return
-	}
-
-	r.configured = true
-
 	if len(arguments) < 1 {
 		r.minimumCommentsDensity = defaultMinimumCommentsPercentage
 		return
@@ -42,7 +33,7 @@ func (r *CommentsDensityRule) configure(arguments lint.Arguments) {
 
 // Apply applies the rule to given file.
 func (r *CommentsDensityRule) Apply(file *lint.File, arguments lint.Arguments) []lint.Failure {
-	r.configure(arguments)
+	r.configureOnce.Do(func() { r.configure(arguments) })
 
 	commentsLines := countDocLines(file.AST.Comments)
 	statementsCount := countStatements(file.AST)

rule/context_as_argument.go

@@ -12,32 +12,31 @@ import (
 // ContextAsArgumentRule lints given else constructs.
 type ContextAsArgumentRule struct {
 	allowTypesLUT map[string]struct{}
-	sync.Mutex
+
+	configureOnce sync.Once
 }
 
 // Apply applies the rule to given file.
 func (r *ContextAsArgumentRule) Apply(file *lint.File, args lint.Arguments) []lint.Failure {
-	r.Lock()
-	if r.allowTypesLUT == nil {
-		r.allowTypesLUT = getAllowTypesFromArguments(args)
-	}
-	r.Unlock()
+	r.configureOnce.Do(func() { r.configure(args) })
 
 	var failures []lint.Failure
-	r.Lock()
 	walker := lintContextArguments{
 		allowTypesLUT: r.allowTypesLUT,
 		onFailure: func(failure lint.Failure) {
 			failures = append(failures, failure)
 		},
 	}
-	r.Unlock()
 
 	ast.Walk(walker, file.AST)
 
 	return failures
 }
 
+func (r *ContextAsArgumentRule) configure(arguments lint.Arguments) {
+	r.allowTypesLUT = getAllowTypesFromArguments(arguments)
+}
+
 // Name returns the rule name.
 func (*ContextAsArgumentRule) Name() string {
 	return "context-as-argument"

rule/cyclomatic.go

@@ -14,18 +14,13 @@ import (
 // CyclomaticRule lints given else constructs.
 type CyclomaticRule struct {
 	maxComplexity int
-	sync.Mutex
+
+	configureOnce sync.Once
 }
 
 const defaultMaxCyclomaticComplexity = 10
 
 func (r *CyclomaticRule) configure(arguments lint.Arguments) {
-	r.Lock()
-	defer r.Unlock()
-	if r.maxComplexity != 0 {
-		return // already configured
-	}
-
 	if len(arguments) < 1 {
 		r.maxComplexity = defaultMaxCyclomaticComplexity
 		return
@@ -40,7 +35,7 @@ func (r *CyclomaticRule) configure(arguments lint.Arguments) {
 
 // Apply applies the rule to given file.
 func (r *CyclomaticRule) Apply(file *lint.File, arguments lint.Arguments) []lint.Failure {
-	r.configure(arguments)
+	r.configureOnce.Do(func() { r.configure(arguments) })
 
 	var failures []lint.Failure
 	fileAst := file.AST

rule/defer.go

@@ -11,22 +11,17 @@ import (
 // DeferRule lints unused params in functions.
 type DeferRule struct {
 	allow map[string]bool
-	sync.Mutex
+
+	configureOnce sync.Once
 }
 
 func (r *DeferRule) configure(arguments lint.Arguments) {
-	r.Lock()
-	defer r.Unlock()
-	if r.allow != nil {
-		return // already configured
-	}
-
 	r.allow = r.allowFromArgs(arguments)
 }
 
 // Apply applies the rule to given file.
 func (r *DeferRule) Apply(file *lint.File, arguments lint.Arguments) []lint.Failure {
-	r.configure(arguments)
+	r.configureOnce.Do(func() { r.configure(arguments) })
 
 	var failures []lint.Failure
 	onFailure := func(failure lint.Failure) {

rule/dot_imports.go

@@ -10,13 +10,14 @@ import (
 
 // DotImportsRule lints given else constructs.
 type DotImportsRule struct {
-	sync.Mutex
 	allowedPackages allowPackages
+
+	configureOnce sync.Once
 }
 
 // Apply applies the rule to given file.
 func (r *DotImportsRule) Apply(file *lint.File, arguments lint.Arguments) []lint.Failure {
-	r.configure(arguments)
+	r.configureOnce.Do(func() { r.configure(arguments) })
 
 	var failures []lint.Failure
 
@@ -41,13 +42,6 @@ func (*DotImportsRule) Name() string {
 }
 
 func (r *DotImportsRule) configure(arguments lint.Arguments) {
-	r.Lock()
-	defer r.Unlock()
-
-	if r.allowedPackages != nil {
-		return
-	}
-
 	r.allowedPackages = make(allowPackages)
 	if len(arguments) == 0 {
 		return

rule/enforce_map_style.go

@@ -39,20 +39,12 @@ func mapStyleFromString(s string) (enforceMapStyleType, error) {
 
 // EnforceMapStyleRule implements a rule to enforce `make(map[type]type)` over `map[type]type{}`.
 type EnforceMapStyleRule struct {
-	configured      bool
 	enforceMapStyle enforceMapStyleType
-	sync.Mutex
+
+	configureOnce sync.Once
 }
 
 func (r *EnforceMapStyleRule) configure(arguments lint.Arguments) {
-	r.Lock()
-	defer r.Unlock()
-
-	if r.configured {
-		return
-	}
-	r.configured = true
-
 	if len(arguments) < 1 {
 		r.enforceMapStyle = enforceMapStyleTypeAny
 		return
@@ -72,7 +64,7 @@ func (r *EnforceMapStyleRule) configure(arguments lint.Arguments) {
 
 // Apply applies the rule to given file.
 func (r *EnforceMapStyleRule) Apply(file *lint.File, arguments lint.Arguments) []lint.Failure {
-	r.configure(arguments)
+	r.configureOnce.Do(func() { r.configure(arguments) })
 
 	if r.enforceMapStyle == enforceMapStyleTypeAny {
 		// this linter is not configured

rule/enforce_repeated_arg_type_style.go

@@ -41,22 +41,13 @@ func repeatedArgTypeStyleFromString(s string) enforceRepeatedArgTypeStyleType {
 
 // EnforceRepeatedArgTypeStyleRule implements a rule to enforce repeated argument type style.
 type EnforceRepeatedArgTypeStyleRule struct {
-	configured      bool
 	funcArgStyle    enforceRepeatedArgTypeStyleType
 	funcRetValStyle enforceRepeatedArgTypeStyleType
 
-	sync.Mutex
+	configureOnce sync.Once
 }
 
 func (r *EnforceRepeatedArgTypeStyleRule) configure(arguments lint.Arguments) {
-	r.Lock()
-	defer r.Unlock()
-
-	if r.configured {
-		return
-	}
-	r.configured = true
-
 	r.funcArgStyle = enforceRepeatedArgTypeStyleTypeAny
 	r.funcRetValStyle = enforceRepeatedArgTypeStyleTypeAny
 
@@ -94,7 +85,7 @@ func (r *EnforceRepeatedArgTypeStyleRule) configure(arguments lint.Arguments) {
 
 // Apply applies the rule to a given file.
 func (r *EnforceRepeatedArgTypeStyleRule) Apply(file *lint.File, arguments lint.Arguments) []lint.Failure {
-	r.configure(arguments)
+	r.configureOnce.Do(func() { r.configure(arguments) })
 
 	if r.funcArgStyle == enforceRepeatedArgTypeStyleTypeAny && r.funcRetValStyle == enforceRepeatedArgTypeStyleTypeAny {
 		// This linter is not configured, return no failures.

rule/enforce_slice_style.go

@@ -43,20 +43,12 @@ func sliceStyleFromString(s string) (enforceSliceStyleType, error) {
 
 // EnforceSliceStyleRule implements a rule to enforce `make([]type)` over `[]type{}`.
 type EnforceSliceStyleRule struct {
-	configured        bool
 	enforceSliceStyle enforceSliceStyleType
-	sync.Mutex
+
+	configureOnce sync.Once
 }
 
 func (r *EnforceSliceStyleRule) configure(arguments lint.Arguments) {
-	r.Lock()
-	defer r.Unlock()
-
-	if r.configured {
-		return
-	}
-	r.configured = true
-
 	if len(arguments) < 1 {
 		r.enforceSliceStyle = enforceSliceStyleTypeAny
 		return
@@ -76,7 +68,7 @@ func (r *EnforceSliceStyleRule) configure(arguments lint.Arguments) {
 
 // Apply applies the rule to given file.
 func (r *EnforceSliceStyleRule) Apply(file *lint.File, arguments lint.Arguments) []lint.Failure {
-	r.configure(arguments)
+	r.configureOnce.Do(func() { r.configure(arguments) })
 
 	if r.enforceSliceStyle == enforceSliceStyleTypeAny {
 		// this linter is not configured