fix: remove detection of case-sensitivity at filesystem level

Note yarn under PnP does not create a `node_modules` directory, so files like `reSOLVE.js` file is served from a virtual filesystem, which is always case sensitive and not representative of the real underlying filesystem.

Author: charlessuh

src/rules/no-unresolved.js

@@ -3,7 +3,7 @@
  * @author Ben Mosher
  */
 
-import resolve, { CASE_SENSITIVE_FS, fileExistsWithCaseSync } from 'eslint-module-utils/resolve';
+import resolve, { fileExistsWithCaseSync } from 'eslint-module-utils/resolve';
 import ModuleCache from 'eslint-module-utils/ModuleCache';
 import moduleVisitor, { makeOptionsSchema } from 'eslint-module-utils/moduleVisitor';
 import docsUrl from '../docsUrl';
@@ -32,8 +32,8 @@ module.exports = {
         return;
       }
 
-      const caseSensitive = !CASE_SENSITIVE_FS && options.caseSensitive !== false;
-      const caseSensitiveStrict = !CASE_SENSITIVE_FS && options.caseSensitiveStrict;
+      const caseSensitive = options.caseSensitive !== false;
+      const caseSensitiveStrict = options.caseSensitiveStrict;
 
       const resolvedPath = resolve(source.value, context);
 

tests/src/core/resolve.js

@@ -2,7 +2,7 @@ import { expect } from 'chai';
 import eslintPkg from 'eslint/package.json';
 import semver from 'semver';
 
-import resolve, { CASE_SENSITIVE_FS, fileExistsWithCaseSync } from 'eslint-module-utils/resolve';
+import resolve, { fileExistsWithCaseSync } from 'eslint-module-utils/resolve';
 
 import * as path from 'path';
 import * as fs from 'fs';
@@ -315,7 +315,8 @@ describe('resolve', function () {
     });
   });
 
-  const caseDescribe = (!CASE_SENSITIVE_FS ? describe : describe.skip);
+  const caseInsensitive = fs.existsSync(utils.testFilePath('./MyUncoolComponent.jsx'));
+  const caseDescribe = (caseInsensitive ? describe : describe.skip);
   caseDescribe('case sensitivity', function () {
     let file;
     const testContext = utils.testContext({

tests/src/rules/default.js

@@ -1,9 +1,8 @@
+import fs from 'fs';
 import path from 'path';
-import { test, testVersion, SYNTAX_CASES, getTSParsers, parsers } from '../utils';
+import { test, testFilePath, testVersion, SYNTAX_CASES, getTSParsers, parsers } from '../utils';
 import { RuleTester } from 'eslint';
 
-import { CASE_SENSITIVE_FS } from 'eslint-module-utils/resolve';
-
 const ruleTester = new RuleTester();
 const rule = require('rules/default');
 
@@ -146,13 +145,19 @@ ruleTester.run('default', rule, {
 });
 
 // #311: import of mismatched case
-if (!CASE_SENSITIVE_FS) {
+if (fs.existsSync(testFilePath('./MyUncoolComponent.jsx'))) {
   ruleTester.run('default (path case-insensitivity)', rule, {
     valid: [
       test({
         code: 'import foo from "./jsx/MyUncoolComponent.jsx"',
       }),
     ],
+  });
+}
+
+if (fs.existsSync(testFilePath('./Named-Exports.js'))) {
+  ruleTester.run('default (path case-insensitivity)', rule, {
+    valid: [],
     invalid: [
       test({
         code: 'import bar from "./Named-Exports"',

tests/src/rules/named.js

@@ -1,9 +1,8 @@
+import fs from 'fs';
+
 import { test, SYNTAX_CASES, getTSParsers, testFilePath, testVersion, parsers } from '../utils';
 import { RuleTester } from 'eslint';
 
-import { CASE_SENSITIVE_FS } from 'eslint-module-utils/resolve';
-
-
 const ruleTester = new RuleTester();
 const rule = require('rules/named');
 
@@ -349,7 +348,7 @@ ruleTester.run('named', rule, {
 });
 
 // #311: import of mismatched case
-if (!CASE_SENSITIVE_FS) {
+if (fs.existsSync(testFilePath('./Named-Exports.js'))) {
   ruleTester.run('named (path case-insensitivity)', rule, {
     valid: [
       test({

tests/src/rules/no-unresolved.js

@@ -1,8 +1,7 @@
+import fs from 'fs';
 import path from 'path';
 
-import { getTSParsers, test, SYNTAX_CASES, testVersion, parsers } from '../utils';
-
-import { CASE_SENSITIVE_FS } from 'eslint-module-utils/resolve';
+import { getTSParsers, test, SYNTAX_CASES, testFilePath, testVersion, parsers } from '../utils';
 
 import { RuleTester } from 'eslint';
 
@@ -226,7 +225,8 @@ function runResolverTests(resolver) {
     ],
   });
 
-  if (!CASE_SENSITIVE_FS) {
+  const caseInsensitive = fs.existsSync(testFilePath('./MyUncoolComponent.jsx'));
+  if (caseInsensitive) {
     const relativePath = './tests/files/jsx/MyUnCoolComponent.jsx';
     const cwd = process.cwd();
     const mismatchedPath = path.join(cwd.toUpperCase(), relativePath).replace(/\\/g, '/');

utils/resolve.js

@@ -52,9 +52,6 @@ function tryRequire(target, sourceFile) {
 
 // https://stackoverflow.com/a/27382838
 exports.fileExistsWithCaseSync = function fileExistsWithCaseSync(filepath, cacheSettings, strict) {
-  // don't care if the FS is case-sensitive
-  if (CASE_SENSITIVE_FS) return true;
-
   // null means it resolved to a builtin
   if (filepath === null) return true;
   if (filepath.toLowerCase() === process.cwd().toLowerCase() && !strict) return true;