Add white & black lists for var-naming

This PR introduces a white & black lists of initialisms for the
`var-naming` rule.

Now the rule can be configured with:

```toml
[rule.var-naming]
  arguments = [["ID"], ["VM", "BAR"]]
```

This way, the linter will ignore `customId` but will throw on `customVm` or `customBar`.

Fix #41

README.md

@@ -243,7 +243,7 @@ List of all available rules. The rules ported from `golint` are left unchanged a
 | `exported`            |  n/a   | Naming and commenting conventions on exported symbols.           |   yes    |  no   |
 | `if-return`           |  n/a   | Redundant if when returning an error.                            |   yes    |  no   |
 | `increment-decrement` |  n/a   | Use `i++` and `i--` instead of `i += 1` and `i -= 1`.            |   yes    |  no   |
-| `var-naming`          |  n/a   | Naming rules.                                                    |   yes    |  no   |
+| `var-naming`          |  whitelist & blacklist of initialisms   | Naming rules.                                                    |   yes    |  no   |
 | `package-comments`    |  n/a   | Package commenting conventions.                                  |   yes    |  no   |
 | `range`               |  n/a   | Prevents redundant variables when iterating over a collection.   |   yes    |  no   |
 | `receiver-naming`     |  n/a   | Conventions around the naming of receivers.                      |   yes    |  no   |
@@ -270,6 +270,21 @@ List of all available rules. The rules ported from `golint` are left unchanged a
 | `bool-literal-in-expr`|  n/a   | Suggests removing Boolean literals from logic expressions        |    no    |  no   |
 | `redefines-builtin-id`|  n/a   | Warns on redefinitions of builtin identifiers                    |    no    |  no   |
 
+## Configurable rules
+
+Here you can find how you can configure some of the existing rules:
+
+### `var-naming`
+
+This rule accepts two slices of strings, a whitelist and a blacklist of initialisms. By default the rule behaves exactly as the alternative in `golint` but optionally, you can relax it (see [golint/lint/issues/89](https://github.com/golang/lint/issues/89))
+
+```toml
+[rule.var-naming]
+  arguments = [["ID"], ["VM"]]
+```
+
+This way, revive will not warn for identifier called `customId` but will warn that `customVm` should be called `customVM`.
+
 ## Available Formatters
 
 This section lists all the available formatters and provides a screenshot for each one.

defaults.toml

@@ -22,4 +22,4 @@ warningCode = 0
 [rule.time-naming]
 [rule.unexported-return]
 [rule.indent-error-flow]
-[rule.errorf]
+[rule.errorf]

fixtures/var-naming.go

@@ -0,0 +1,7 @@
+package fixtures
+
+func foo() string {
+	customId := "result"
+	customVm := "result" // MATCH /var customVm should be customVM/
+	return customId
+}

lint/utils.go

@@ -6,7 +6,7 @@ import (
 )
 
 // Name returns a different name if it should be different.
-func Name(name string) (should string) {
+func Name(name string, whitelist, blacklist []string) (should string) {
 	// Fast path for simple cases: "_" and all lowercase.
 	if name == "_" {
 		return name
@@ -56,7 +56,17 @@ func Name(name string) (should string) {
 
 		// [w,i) is a word.
 		word := string(runes[w:i])
-		if u := strings.ToUpper(word); commonInitialisms[u] {
+		ignoreInitWarnings := map[string]bool{}
+		for _, i := range whitelist {
+			ignoreInitWarnings[i] = true
+		}
+
+		extraInits := map[string]bool{}
+		for _, i := range blacklist {
+			extraInits[i] = true
+		}
+
+		if u := strings.ToUpper(word); (commonInitialisms[u] || extraInits[u]) && !ignoreInitWarnings[u] {
 			// Keep consistent case, which is lowercase only at the start.
 			if w == 0 && unicode.IsLower(runes[w]) {
 				u = strings.ToLower(u)

rule/bool-literal-in-expr.go

@@ -1,9 +1,10 @@
 package rule
 
 import (
-	"github.com/mgechev/revive/lint"
 	"go/ast"
 	"go/token"
+
+	"github.com/mgechev/revive/lint"
 )
 
 // BoolLiteralRule warns when logic expressions contains Boolean literals.

rule/utils.go

@@ -61,47 +61,6 @@ func isCgoExported(f *ast.FuncDecl) bool {
 	return false
 }
 
-var commonInitialisms = map[string]bool{
-	"ACL":   true,
-	"API":   true,
-	"ASCII": true,
-	"CPU":   true,
-	"CSS":   true,
-	"DNS":   true,
-	"EOF":   true,
-	"GUID":  true,
-	"HTML":  true,
-	"HTTP":  true,
-	"HTTPS": true,
-	"ID":    true,
-	"IP":    true,
-	"JSON":  true,
-	"LHS":   true,
-	"QPS":   true,
-	"RAM":   true,
-	"RHS":   true,
-	"RPC":   true,
-	"SLA":   true,
-	"SMTP":  true,
-	"SQL":   true,
-	"SSH":   true,
-	"TCP":   true,
-	"TLS":   true,
-	"TTL":   true,
-	"UDP":   true,
-	"UI":    true,
-	"UID":   true,
-	"UUID":  true,
-	"URI":   true,
-	"URL":   true,
-	"UTF8":  true,
-	"VM":    true,
-	"XML":   true,
-	"XMPP":  true,
-	"XSRF":  true,
-	"XSS":   true,
-}
-
 var allCapsRE = regexp.MustCompile(`^[A-Z0-9_]+$`)
 
 func isIdent(expr ast.Expr, ident string) bool {

rule/var-naming.go

@@ -16,10 +16,23 @@ type VarNamingRule struct{}
 func (r *VarNamingRule) Apply(file *lint.File, arguments lint.Arguments) []lint.Failure {
 	var failures []lint.Failure
 
+	var whitelist []string
+	var blacklist []string
+
+	if len(arguments) >= 1 {
+		whitelist = getList(arguments[0], "whitelist")
+	}
+
+	if len(arguments) >= 2 {
+		blacklist = getList(arguments[1], "blacklist")
+	}
+
 	fileAst := file.AST
 	walker := lintNames{
-		file:    file,
-		fileAst: fileAst,
+		file:      file,
+		fileAst:   fileAst,
+		whitelist: whitelist,
+		blacklist: blacklist,
 		onFailure: func(failure lint.Failure) {
 			failures = append(failures, failure)
 		},
@@ -87,7 +100,7 @@ func check(id *ast.Ident, thing string, w *lintNames) {
 		})
 	}
 
-	should := lint.Name(id.Name)
+	should := lint.Name(id.Name, w.whitelist, w.blacklist)
 	if id.Name == should {
 		return
 	}
@@ -117,6 +130,8 @@ type lintNames struct {
 	lastGen                *ast.GenDecl
 	genDeclMissingComments map[*ast.GenDecl]bool
 	onFailure              func(lint.Failure)
+	whitelist              []string
+	blacklist              []string
 }
 
 func (w *lintNames) Visit(n ast.Node) ast.Visitor {
@@ -202,3 +217,19 @@ func (w *lintNames) Visit(n ast.Node) ast.Visitor {
 	}
 	return w
 }
+
+func getList(arg interface{}, argName string) []string {
+	temp, ok := arg.([]interface{})
+	if !ok {
+		panic(fmt.Sprintf("Invalid argument to the var-naming rule. Expecting a %s of type slice with initialisms, got %T", argName, arg))
+	}
+	var list []string
+	for _, v := range temp {
+		if val, ok := v.(string); ok {
+			list = append(list, val)
+		} else {
+			panic(fmt.Sprintf("Invalid %s values of the var-naming rule. Expecting slice of strings but got element of type %T", val, arg))
+		}
+	}
+	return list
+}

test/utils.go

@@ -275,7 +275,7 @@ func TestLintName(t *testing.T) {
 		{"IEEE802_16Bit", "IEEE802_16Bit"},
 	}
 	for _, test := range tests {
-		got := lint.Name(test.name)
+		got := lint.Name(test.name, nil, nil)
 		if got != test.want {
 			t.Errorf("lintName(%q) = %q, want %q", test.name, got, test.want)
 		}

test/var-naming_test.go

@@ -0,0 +1,14 @@
+package test
+
+import (
+	"testing"
+
+	"github.com/mgechev/revive/lint"
+	"github.com/mgechev/revive/rule"
+)
+
+func TestVarNaming(t *testing.T) {
+	testRule(t, "var-naming", &rule.VarNamingRule{}, &lint.RuleConfig{
+		Arguments: []interface{}{[]interface{}{"ID"}, []interface{}{"VM"}},
+	})
+}