Enable linting for istanbul ignore comments

.eslintrc.yml

@@ -9,6 +9,7 @@ plugins:
   - graphql-internal
   - flowtype
   - node
+  - istanbul
   - import
 
 rules:
@@ -67,6 +68,14 @@ rules:
   flowtype/space-before-type-colon: off
   flowtype/union-intersection-spacing: off
 
+  ##############################################################################
+  # `eslint-plugin-istanbul` rule list based on `v0.1.1`
+  # https://github.com/istanbuljs/eslint-plugin-istanbul#rules
+  ##############################################################################
+
+  istanbul/no-ignore-file: error
+  istanbul/prefer-ignore-reason: error
+
   ##############################################################################
   # `eslint-plugin-node` rule list based on `v11.1.x`
   ##############################################################################

package.json

@@ -59,6 +59,7 @@
     "eslint-plugin-flowtype": "5.1.0",
     "eslint-plugin-graphql-internal": "file:./resources/eslint-rules",
     "eslint-plugin-import": "2.20.2",
+    "eslint-plugin-istanbul": "0.1.1",
     "eslint-plugin-node": "11.1.0",
     "flow-bin": "0.125.1",
     "mocha": "7.1.2",

src/__tests__/version-test.js

@@ -26,14 +26,14 @@ describe('Version', () => {
     expect(minor).to.be.a('number');
     expect(patch).to.be.a('number');
 
-    /* istanbul ignore next (Can't be verified on all versions) */
+    // istanbul ignore next (Can't be verified on all versions)
     if (preReleaseTag !== null) {
       expect(preReleaseTag).to.be.a('string');
     }
 
     expect(
       `${major}.${minor}.${patch}` +
-        /* istanbul ignore next (Can't be verified on all versions) */
+        // istanbul ignore next (Can't be verified on all versions)
         (preReleaseTag !== null ? '-' + preReleaseTag : ''),
     ).to.equal(version);
   });

src/error/GraphQLError.js

@@ -196,7 +196,7 @@ export class GraphQLError extends Error {
       return;
     }
 
-    /* istanbul ignore next (See: https://github.com/graphql/graphql-js/issues/2317) */
+    // istanbul ignore next (See: https://github.com/graphql/graphql-js/issues/2317)
     if (Error.captureStackTrace) {
       Error.captureStackTrace(this, GraphQLError);
     } else {

src/execution/execute.js

@@ -311,7 +311,7 @@ export function buildExecutionContext(
     return [new GraphQLError('Must provide an operation.')];
   }
 
-  /* istanbul ignore next (See https://github.com/graphql/graphql-js/issues/2203) */
+  // istanbul ignore next (See https://github.com/graphql/graphql-js/issues/2203)
   const variableDefinitions = operation.variableDefinitions ?? [];
 
   const coercedVariableValues = getVariableValues(

src/execution/values.js

@@ -170,7 +170,7 @@ export function getArgumentValues(
 ): { [argument: string]: mixed, ... } {
   const coercedValues = {};
 
-  /* istanbul ignore next (See https://github.com/graphql/graphql-js/issues/2203) */
+  // istanbul ignore next (See https://github.com/graphql/graphql-js/issues/2203)
   const argumentNodes = node.arguments ?? [];
   const argNodeMap = keyMap(argumentNodes, (arg) => arg.name.value);
 

src/jsutils/__tests__/inspect-test.js

@@ -37,11 +37,12 @@ describe('inspect', () => {
 
   it('function', () => {
     const unnamedFuncStr = inspect(
-      /* istanbul ignore next */ () => invariant(false),
+      // istanbul ignore next (never called and used as a placeholder)
+      () => invariant(false),
     );
     expect(unnamedFuncStr).to.equal('[function]');
 
-    /* istanbul ignore next */
+    // istanbul ignore next (never called and used as a placeholder)
     function namedFunc() {
       invariant(false);
     }
@@ -107,7 +108,7 @@ describe('inspect', () => {
 
   it('custom symbol inspect is take precedence', () => {
     const object = {
-      /* istanbul ignore next */
+      // istanbul ignore next (never called and use just as a placeholder)
       inspect() {
         invariant(false);
       },

src/jsutils/__tests__/isCollection-test.js

@@ -30,7 +30,7 @@ describe('isCollection', () => {
     const iterator = { [Symbol.iterator]: identityFunc };
     expect(isCollection(iterator)).to.equal(true);
 
-    // istanbul ignore next
+    // istanbul ignore next (never called and use just as a placeholder)
     function* generatorFunc() {
       /* do nothing */
     }

src/jsutils/dedent.js

@@ -21,7 +21,7 @@ export default function dedent(
   for (let i = 0; i < strings.length; ++i) {
     str += strings[i];
     if (i < values.length) {
-      /* istanbul ignore next (ignore else inside Babel generated code) */
+      // istanbul ignore next (ignore else inside Babel generated code)
       const value = values[i];
 
       str += value; // interpolation

src/jsutils/defineInspect.js

@@ -14,7 +14,7 @@ export default function defineInspect(
 
   classObject.prototype.inspect = fn;
 
-  /* istanbul ignore else (See: https://github.com/graphql/graphql-js/issues/2317) */
+  // istanbul ignore else (See: https://github.com/graphql/graphql-js/issues/2317)
   if (nodejsCustomInspectSymbol) {
     classObject.prototype[nodejsCustomInspectSymbol] = fn;
   }

src/jsutils/devAssert.js

@@ -2,7 +2,7 @@
 
 export default function devAssert(condition: mixed, message: string): void {
   const booleanCondition = Boolean(condition);
-  /* istanbul ignore else (see transformation done in './resources/inlineInvariant.js') */
+  // istanbul ignore else (see transformation done in './resources/inlineInvariant.js')
   if (!booleanCondition) {
     throw new Error(message);
   }

src/jsutils/instanceOf.js

@@ -12,7 +12,7 @@ declare function instanceOf(
 // See: https://expressjs.com/en/advanced/best-practice-performance.html#set-node_env-to-production
 // See: https://webpack.js.org/guides/production/
 export default process.env.NODE_ENV === 'production'
-  ? /* istanbul ignore next (See: https://github.com/graphql/graphql-js/issues/2317) */
+  ? // istanbul ignore next (See: https://github.com/graphql/graphql-js/issues/2317)
     // eslint-disable-next-line no-shadow
     function instanceOf(value: mixed, constructor: mixed) {
       return value instanceof constructor;

src/jsutils/invariant.js

@@ -2,7 +2,7 @@
 
 export default function invariant(condition: mixed, message?: string): void {
   const booleanCondition = Boolean(condition);
-  /* istanbul ignore else (see transformation done in './resources/inlineInvariant.js') */
+  // istanbul ignore else (see transformation done in './resources/inlineInvariant.js')
   if (!booleanCondition) {
     throw new Error(
       message != null ? message : 'Unexpected invariant triggered.',

src/jsutils/nodejsCustomInspectSymbol.js

@@ -1,6 +1,6 @@
 // @flow strict
 
-/* istanbul ignore next (See: https://github.com/graphql/graphql-js/issues/2317) */
+// istanbul ignore next (See: https://github.com/graphql/graphql-js/issues/2317)
 const nodejsCustomInspectSymbol =
   typeof Symbol === 'function' && typeof Symbol.for === 'function'
     ? Symbol.for('nodejs.util.inspect.custom')

src/language/__tests__/visitor-test.js

@@ -1132,7 +1132,7 @@ describe('Visitor', () => {
                 return BREAK;
               }
             },
-            /* istanbul ignore next */
+            // istanbul ignore next (never called and used as a placeholder)
             leave() {
               invariant(false);
             },

src/polyfills/arrayFrom.js

@@ -32,7 +32,7 @@ const arrayFrom =
         result.push(mapFn.call(thisArg, step.value, i));
         // Infinite Iterators could cause forEach to run forever.
         // After a very large number of iterations, produce an error.
-        /* istanbul ignore if */
+        // istanbul ignore if (too big to actually test)
         if (i > 9999999) {
           throw new TypeError('Near-infinite iteration.');
         }

src/polyfills/symbols.js

@@ -1,17 +1,17 @@
 // @flow strict
 
 // In ES2015 (or a polyfilled) environment, this will be Symbol.iterator
-/* istanbul ignore next (See: https://github.com/graphql/graphql-js/issues/2317) */
+// istanbul ignore next (See: https://github.com/graphql/graphql-js/issues/2317)
 export const SYMBOL_ITERATOR: string =
   typeof Symbol === 'function' ? Symbol.iterator : '@@iterator';
 
 // In ES2017 (or a polyfilled) environment, this will be Symbol.asyncIterator
-/* istanbul ignore next (See: https://github.com/graphql/graphql-js/issues/2317) */
+// istanbul ignore next (See: https://github.com/graphql/graphql-js/issues/2317)
 export const SYMBOL_ASYNC_ITERATOR: string =
   // $FlowFixMe Flow doesn't define `Symbol.asyncIterator` yet
   typeof Symbol === 'function' ? Symbol.asyncIterator : '@@asyncIterator';
 
-/* istanbul ignore next (See: https://github.com/graphql/graphql-js/issues/2317) */
+// istanbul ignore next (See: https://github.com/graphql/graphql-js/issues/2317)
 export const SYMBOL_TO_STRING_TAG: string =
   // $FlowFixMe Flow doesn't define `Symbol.toStringTag` yet
   typeof Symbol === 'function' ? Symbol.toStringTag : '@@toStringTag';

src/subscription/__tests__/mapAsyncIterator-test.js

@@ -96,7 +96,7 @@ describe('mapAsyncIterator', () => {
       yield 1;
       yield 2;
 
-      /* istanbul ignore next (shouldn't be reached) */
+      // istanbul ignore next (shouldn't be reached)
       yield 3;
     }
 
@@ -156,7 +156,7 @@ describe('mapAsyncIterator', () => {
         yield 1;
         yield 2;
 
-        /* istanbul ignore next (shouldn't be reached) */
+        // istanbul ignore next (shouldn't be reached)
         yield 3;
       } finally {
         yield 'Done';
@@ -223,7 +223,7 @@ describe('mapAsyncIterator', () => {
         yield 1;
         yield 2;
 
-        /* istanbul ignore next (shouldn't be reached) */
+        // istanbul ignore next (shouldn't be reached)
         yield 3;
       } catch (e) {
         yield e;
@@ -311,7 +311,7 @@ describe('mapAsyncIterator', () => {
         yield 1;
         yield 2;
 
-        /* istanbul ignore next (shouldn't be reached) */
+        // istanbul ignore next (shouldn't be reached)
         yield 3;
       } finally {
         didVisitFinally = true;

src/subscription/__tests__/subscribe-test.js

@@ -136,7 +136,7 @@ async function createSubscription(
 async function expectPromiseToThrow(promise, message) {
   try {
     await promise();
-    /* istanbul ignore next */
+    // istanbul ignore next(shouldn't be reached)
     expect.fail('promise should have thrown but did not');
   } catch (error) {
     expect(error).to.be.an.instanceOf(Error);
@@ -280,7 +280,7 @@ describe('Subscription Initialization Phase', () => {
         },
         nonImportantEmail: {
           type: EmailEventType,
-          /* istanbul ignore next (shouldn't be called) */
+          // istanbul ignore next (shouldn't be called)
           subscribe() {
             didResolveNonImportantEmail = true;
             return eventEmitterAsyncIterator(new EventEmitter(), 'event');

src/type/__tests__/definition-test.js

@@ -39,7 +39,7 @@ const NonNullScalarType = GraphQLNonNull(ScalarType);
 const ListOfNonNullScalarsType = GraphQLList(NonNullScalarType);
 const NonNullListOfScalars = GraphQLNonNull(ListOfScalarsType);
 
-/* istanbul ignore next */
+// istanbul ignore next (never called and used as a placeholder)
 const dummyFunc = () => {
   /* empty */
 };

src/type/__tests__/introspection-test.js

@@ -1476,7 +1476,7 @@ describe('Introspection', () => {
     const schema = new GraphQLSchema({ query: QueryRoot });
     const source = getIntrospectionQuery({ directiveIsRepeatable: true });
 
-    /* istanbul ignore next */
+    // istanbul ignore next (called only to fail test)
     function fieldResolver(_1, _2, _3, info) {
       invariant(false, `Called on ${info.parentType.name}::${info.fieldName}`);
     }

src/type/validate.js

@@ -588,7 +588,7 @@ function getAllSubNodes<T: ASTNode, K: ASTNode, L: ASTNode>(
   object: SDLDefinedObject<T, K>,
   getter: (T | K) => ?(L | $ReadOnlyArray<L>),
 ): $ReadOnlyArray<L> {
-  /* istanbul ignore next (See https://github.com/graphql/graphql-js/issues/2203) */
+  // istanbul ignore next (See https://github.com/graphql/graphql-js/issues/2203)
   return flatMap(getAllNodes(object), (item) => getter(item) ?? []);
 }
 

src/utilities/__tests__/stripIgnoredCharacters-test.js

@@ -66,8 +66,7 @@ function lexValue(str) {
   return value;
 }
 
-// Called only to make error messages for failing tests
-/* istanbul ignore next */
+// istanbul ignore next (called only to make error messages for failing tests)
 function inspectStr(str) {
   return (JSON.stringify(str) ?? '')
     .replace(/^"|"$/g, '`')

src/utilities/extendSchema.js

@@ -415,7 +415,7 @@ export function extendSchemaImpl(
   |} {
     const opTypes = {};
     for (const node of nodes) {
-      /* istanbul ignore next (See https://github.com/graphql/graphql-js/issues/2203) */
+      // istanbul ignore next (See https://github.com/graphql/graphql-js/issues/2203)
       const operationTypesNodes = node.operationTypes ?? [];
 
       for (const operationType of operationTypesNodes) {
@@ -474,7 +474,7 @@ export function extendSchemaImpl(
   ): GraphQLFieldConfigMap<mixed, mixed> {
     const fieldConfigMap = Object.create(null);
     for (const node of nodes) {
-      /* istanbul ignore next (See https://github.com/graphql/graphql-js/issues/2203) */
+      // istanbul ignore next (See https://github.com/graphql/graphql-js/issues/2203)
       const nodeFields = node.fields ?? [];
 
       for (const field of nodeFields) {
@@ -496,7 +496,7 @@ export function extendSchemaImpl(
   function buildArgumentMap(
     args: ?$ReadOnlyArray<InputValueDefinitionNode>,
   ): GraphQLFieldConfigArgumentMap {
-    /* istanbul ignore next (See https://github.com/graphql/graphql-js/issues/2203) */
+    // istanbul ignore next (See https://github.com/graphql/graphql-js/issues/2203)
     const argsNodes = args ?? [];
 
     const argConfigMap = Object.create(null);
@@ -523,7 +523,7 @@ export function extendSchemaImpl(
   ): GraphQLInputFieldConfigMap {
     const inputFieldMap = Object.create(null);
     for (const node of nodes) {
-      /* istanbul ignore next (See https://github.com/graphql/graphql-js/issues/2203) */
+      // istanbul ignore next (See https://github.com/graphql/graphql-js/issues/2203)
       const fieldsNodes = node.fields ?? [];
 
       for (const field of fieldsNodes) {
@@ -548,7 +548,7 @@ export function extendSchemaImpl(
   ): GraphQLEnumValueConfigMap {
     const enumValueMap = Object.create(null);
     for (const node of nodes) {
-      /* istanbul ignore next (See https://github.com/graphql/graphql-js/issues/2203) */
+      // istanbul ignore next (See https://github.com/graphql/graphql-js/issues/2203)
       const valuesNodes = node.values ?? [];
 
       for (const value of valuesNodes) {
@@ -572,7 +572,7 @@ export function extendSchemaImpl(
   ): Array<GraphQLInterfaceType> {
     const interfaces = [];
     for (const node of nodes) {
-      /* istanbul ignore next (See https://github.com/graphql/graphql-js/issues/2203) */
+      // istanbul ignore next (See https://github.com/graphql/graphql-js/issues/2203)
       const interfacesNodes = node.interfaces ?? [];
 
       for (const type of interfacesNodes) {
@@ -591,7 +591,7 @@ export function extendSchemaImpl(
   ): Array<GraphQLObjectType> {
     const types = [];
     for (const node of nodes) {
-      /* istanbul ignore next (See https://github.com/graphql/graphql-js/issues/2203) */
+      // istanbul ignore next (See https://github.com/graphql/graphql-js/issues/2203)
       const typeNodes = node.types ?? [];
 
       for (const type of typeNodes) {

src/validation/rules/KnownArgumentNamesRule.js

@@ -64,7 +64,7 @@ export function KnownArgumentNamesOnDirectivesRule(
   const astDefinitions = context.getDocument().definitions;
   for (const def of astDefinitions) {
     if (def.kind === Kind.DIRECTIVE_DEFINITION) {
-      /* istanbul ignore next (See https://github.com/graphql/graphql-js/issues/2203) */
+      // istanbul ignore next (See https://github.com/graphql/graphql-js/issues/2203)
       const argsNodes = def.arguments ?? [];
 
       directiveArgs[def.name.value] = argsNodes.map((arg) => arg.name.value);

src/validation/rules/OverlappingFieldsCanBeMergedRule.js

@@ -571,9 +571,9 @@ function findConflict(
       ];
     }
 
-    /* istanbul ignore next (See https://github.com/graphql/graphql-js/issues/2203) */
+    // istanbul ignore next (See https://github.com/graphql/graphql-js/issues/2203)
     const args1 = node1.arguments ?? [];
-    /* istanbul ignore next (See https://github.com/graphql/graphql-js/issues/2203) */
+    // istanbul ignore next (See https://github.com/graphql/graphql-js/issues/2203)
     const args2 = node2.arguments ?? [];
     // Two field calls must have the same arguments.
     if (!sameArguments(args1, args2)) {