[Refactor] no-cycle: Add per-run caching of traversed paths

 - This leads to about a 5x speed up

Signed-off-by: Sebastian Malton <sebastian@malton.name>

CHANGELOG.md

@@ -26,6 +26,7 @@ This change log adheres to standards from [Keep a CHANGELOG](https://keepachange
 - [meta] replace git.io link in comments with the original URL ([#2444], thanks [@liby])
 - [Docs] remove global install in readme ([#2412], thanks [@aladdin-add])
 - [readme] clarify `eslint-import-resolver-typescript` usage ([#2503], thanks [@JounQin])
+- [Refactor] `no-cycle`: Add per-run caching of traversed paths ([#2419], thanks [@nokel81])
 
 ## [2.26.0] - 2022-04-05
 
@@ -1004,6 +1005,7 @@ for info on changes for earlier releases.
 [#2466]: https://github.com/import-js/eslint-plugin-import/pull/2466
 [#2440]: https://github.com/import-js/eslint-plugin-import/pull/2440
 [#2427]: https://github.com/import-js/eslint-plugin-import/pull/2427
+[#2419]: https://github.com/import-js/eslint-plugin-import/pull/2419
 [#2417]: https://github.com/import-js/eslint-plugin-import/pull/2417
 [#2411]: https://github.com/import-js/eslint-plugin-import/pull/2411
 [#2399]: https://github.com/import-js/eslint-plugin-import/pull/2399

src/rules/no-cycle.js

@@ -9,7 +9,8 @@ import { isExternalModule } from '../core/importType';
 import moduleVisitor, { makeOptionsSchema } from 'eslint-module-utils/moduleVisitor';
 import docsUrl from '../docsUrl';
 
-// todo: cache cycles / deep relationships for faster repeat evaluation
+const traversed = new Set();
+
 module.exports = {
   meta: {
     type: 'suggestion',
@@ -87,7 +88,6 @@ module.exports = {
       }
 
       const untraversed = [{ mget: () => imported, route:[] }];
-      const traversed = new Set();
       function detectCycle({ mget, route }) {
         const m = mget();
         if (m == null) return;
@@ -101,7 +101,7 @@ module.exports = {
             // Ignore only type imports
             !isOnlyImportingTypes,
           );
-          
+
           /*
           If cyclic dependency is allowed via dynamic import, skip checking if any module is imported dynamically
           */
@@ -138,7 +138,11 @@ module.exports = {
       }
     }
 
-    return moduleVisitor(checkSourceValue, context.options[0]);
+    return Object.assign(moduleVisitor(checkSourceValue, context.options[0]), {
+      'Program:exit': () => {
+        traversed.clear();
+      },
+    });
   },
 };