Fix import/no-cycle perf regression

CHANGELOG.md

@@ -13,6 +13,7 @@ This change log adheres to standards from [Keep a CHANGELOG](http://keepachangel
 - [`no-extraneous-dependencies`]: Add package.json cache ([#1948], thanks @fa93hws)
 - [`prefer-default-export`]: handle empty array destructuring ([#1965], thanks @ljharb)
 - [`no-unused-modules`]: make type imports mark a module as used (fixes #1924) ([#1974], thanks [@cherryblossom000])
+- [`import/no-cycle`]: fix perf regression ([#1944], thanks [@Blasz])
 
 ## [2.22.1] - 2020-09-27
 ### Fixed
@@ -741,6 +742,7 @@ for info on changes for earlier releases.
 [`memo-parser`]: ./memo-parser/README.md
 
 [#1974]: https://github.com/benmosher/eslint-plugin-import/pull/1974
+[#1944]: https://github.com/benmosher/eslint-plugin-import/pull/1944
 [#1924]: https://github.com/benmosher/eslint-plugin-import/issues/1924
 [#1965]: https://github.com/benmosher/eslint-plugin-import/issues/1965
 [#1948]: https://github.com/benmosher/eslint-plugin-import/pull/1948
@@ -1293,3 +1295,4 @@ for info on changes for earlier releases.
 [@straub]: https://github.com/straub
 [@andreubotella]: https://github.com/andreubotella
 [@cherryblossom000]: https://github.com/cherryblossom000
+[@Blasz]: https://github.com/Blasz

src/ExportMap.js

@@ -22,6 +22,7 @@ let parseConfigFileTextToJson;
 const log = debug('eslint-plugin-import:ExportMap');
 
 const exportCache = new Map();
+const tsConfigCache = new Map();
 
 export default class ExportMap {
   constructor(path) {
@@ -438,9 +439,11 @@ ExportMap.parse = function (path, content, context) {
 
   const source = makeSourceCode(content, ast);
 
-  function isEsModuleInterop() {
+  function readTsConfig() {
     const tsConfigInfo = tsConfigLoader({
-      cwd: context.parserOptions && context.parserOptions.tsconfigRootDir || process.cwd(),
+      cwd:
+        (context.parserOptions && context.parserOptions.tsconfigRootDir) ||
+        process.cwd(),
       getEnv: (key) => process.env[key],
     });
     try {
@@ -450,12 +453,26 @@ ExportMap.parse = function (path, content, context) {
           // this is because projects not using TypeScript won't have typescript installed
           ({ parseConfigFileTextToJson } = require('typescript'));
         }
-        const tsConfig = parseConfigFileTextToJson(tsConfigInfo.tsConfigPath, jsonText).config;
-        return tsConfig.compilerOptions.esModuleInterop;
+        return parseConfigFileTextToJson(tsConfigInfo.tsConfigPath, jsonText).config;
       }
     } catch (e) {
-      return false;
+      // Catch any errors
     }
+
+    return null;
+  }
+
+  function isEsModuleInterop() {
+    const cacheKey = hashObject({
+      tsconfigRootDir: context.parserOptions && context.parserOptions.tsconfigRootDir,
+    }).digest('hex');
+    let tsConfig = tsConfigCache.get(cacheKey);
+    if (typeof tsConfig === 'undefined') {
+      tsConfig = readTsConfig();
+      tsConfigCache.set(cacheKey, tsConfig);
+    }
+
+    return tsConfig !== null ? tsConfig.compilerOptions.esModuleInterop : false;
   }
 
   ast.body.forEach(function (n) {

tests/files/typescript-export-assign-property.ts

@@ -0,0 +1,3 @@
+const AnalyticsNode = { Analytics: {} };
+
+export = AnalyticsNode.Analytics;

tests/src/core/getExports.js

@@ -1,6 +1,8 @@
 import { expect } from  'chai';
 import semver from 'semver';
+import sinon from 'sinon';
 import eslintPkg from 'eslint/package.json';
+import * as tsConfigLoader from 'tsconfig-paths/lib/tsconfig-loader';
 import ExportMap from '../../../src/ExportMap';
 
 import * as fs from 'fs';
@@ -51,7 +53,8 @@ describe('ExportMap', function () {
     const differentSettings = Object.assign(
       {},
       fakeContext,
-      { parserPath: 'espree' });
+      { parserPath: 'espree' },
+    );
 
     expect(ExportMap.get('./named-exports', differentSettings))
       .to.exist.and
@@ -338,11 +341,11 @@ describe('ExportMap', function () {
       // ['string form', { 'typescript-eslint-parser': '.ts' }],
     ];
 
-    if (semver.satisfies(eslintPkg.version, '>5.0.0')) {
+    if (semver.satisfies(eslintPkg.version, '>5')) {
       configs.push(['array form', { '@typescript-eslint/parser': ['.ts', '.tsx'] }]);
     }
 
-    if (semver.satisfies(eslintPkg.version, '<6.0.0')) {
+    if (semver.satisfies(eslintPkg.version, '<6')) {
       configs.push(['array form', { 'typescript-eslint-parser': ['.ts', '.tsx'] }]);
     }
 
@@ -358,8 +361,12 @@ describe('ExportMap', function () {
         let imports;
         before('load imports', function () {
           this.timeout(20000);  // takes a long time :shrug:
+          sinon.spy(tsConfigLoader, 'tsConfigLoader');
           imports = ExportMap.get('./typescript.ts', context);
         });
+        after('clear spies', function () {
+          tsConfigLoader.tsConfigLoader.restore();
+        });
 
         it('returns something for a TypeScript file', function () {
           expect(imports).to.exist;
@@ -388,9 +395,38 @@ describe('ExportMap', function () {
         it('has exported abstract class', function () {
           expect(imports.has('Bar')).to.be.true;
         });
+
+        it('should cache tsconfig until tsconfigRootDir parser option changes', function () {
+          const customContext = Object.assign(
+            {},
+            context,
+            {
+              parserOptions: {
+                tsconfigRootDir: null,
+              },
+            },
+          );
+          expect(tsConfigLoader.tsConfigLoader.callCount).to.equal(0);
+          ExportMap.parse('./baz.ts', 'export const baz = 5', customContext);
+          expect(tsConfigLoader.tsConfigLoader.callCount).to.equal(1);
+          ExportMap.parse('./baz.ts', 'export const baz = 5', customContext);
+          expect(tsConfigLoader.tsConfigLoader.callCount).to.equal(1);
+
+          const differentContext = Object.assign(
+            {},
+            context,
+            {
+              parserOptions: {
+                tsconfigRootDir: process.cwd(),
+              },
+            },
+          );
+
+          ExportMap.parse('./baz.ts', 'export const baz = 5', differentContext);
+          expect(tsConfigLoader.tsConfigLoader.callCount).to.equal(2);
+        });
       });
     });
-
   });
 
   // todo: move to utils