fix(eslint-plugin): [naming-convention] handle no options correctly (typescript-eslint#2095)

bradzacher · web-flow · commit fd7d02b31ebd · 2020-05-25T08:59:18.000-07:00
diff --git a/packages/eslint-plugin/src/rules/naming-convention.ts b/packages/eslint-plugin/src/rules/naming-convention.ts
@@ -360,15 +360,17 @@ export default util.createRule<Options, MessageIds>({
   },
   defaultOptions: defaultCamelCaseAllTheThingsConfig,
   create(contextWithoutDefaults) {
-    const context: Context = contextWithoutDefaults.options
-      ? contextWithoutDefaults
-      : // only apply the defaults when the user provides no config
-        Object.setPrototypeOf(
-          {
-            options: defaultCamelCaseAllTheThingsConfig,
-          },
-          contextWithoutDefaults,
-        );
+    const context: Context =
+      contextWithoutDefaults.options &&
+      contextWithoutDefaults.options.length > 0
+        ? contextWithoutDefaults
+        : // only apply the defaults when the user provides no config
+          Object.setPrototypeOf(
+            {
+              options: defaultCamelCaseAllTheThingsConfig,
+            },
+            contextWithoutDefaults,
+          );
 
     const validators = parseOptions(context);
 
@@ -748,7 +750,7 @@ type ValidatorFunction = (
   modifiers?: Set<Modifiers>,
 ) => void;
 type ParsedOptions = Record<SelectorsString, null | ValidatorFunction>;
-type Context = TSESLint.RuleContext<MessageIds, Options>;
+type Context = Readonly<TSESLint.RuleContext<MessageIds, Options>>;
 function parseOptions(context: Context): ParsedOptions {
   const normalizedOptions = context.options.map(opt => normalizeOption(opt));
   const parsedOptions = util.getEnumNames(Selectors).reduce((acc, k) => {
diff --git a/packages/eslint-plugin/tests/rules/naming-convention.test.ts b/packages/eslint-plugin/tests/rules/naming-convention.test.ts
@@ -607,7 +607,6 @@ const cases: Cases = [
 
 ruleTester.run('naming-convention', rule, {
   valid: [
-    'const x = 1;', // no options shouldn't crash
     ...createValidTestCases(cases),
     {
       code: `
@@ -794,6 +793,17 @@ ruleTester.run('naming-convention', rule, {
     },
   ],
   invalid: [
+    {
+      // make sure we handle no options and apply defaults
+      code: 'const x_x = 1;',
+      errors: [{ messageId: 'doesNotMatchFormat' }],
+    },
+    {
+      // make sure we handle empty options and apply defaults
+      code: 'const x_x = 1;',
+      options: [],
+      errors: [{ messageId: 'doesNotMatchFormat' }],
+    },
     ...createInvalidTestCases(cases),
     {
       code: `
