fix crash of wds when trying to follow emacs lock files by ignoring them

packages/react-dev-utils/__tests__/ignoredFiles.test.js

@@ -9,27 +9,33 @@
 
 const ignoredFiles = require('../ignoredFiles');
 
+const anymatch = require('anymatch');
+
 describe('ignore watch files regex', () => {
   it('normal file', () => {
     const appSrc = '/root/src/';
-    const isIgnored = ignoredFiles(appSrc).test('/foo');
-    const isIgnoredInSrc = ignoredFiles(appSrc).test('/root/src/foo');
+    const isIgnored = anymatch(ignoredFiles(appSrc), '/foo');
+    const isIgnoredInSrc = anymatch(ignoredFiles(appSrc), '/root/src/foo');
 
     expect(isIgnored).toBe(false);
     expect(isIgnoredInSrc).toBe(false);
   });
 
   it('node modules', () => {
     const appSrc = '/root/src/';
-    const isIgnored = ignoredFiles(appSrc).test('/root/node_modules/foo');
+    const isIgnored = anymatch(ignoredFiles(appSrc), '/root/node_modules/foo');
 
     expect(isIgnored).toBe(true);
   });
 
   it('node modules inside source directory', () => {
     const appSrc = '/root/src/';
-    const isIgnored = ignoredFiles(appSrc).test('/root/src/node_modules/foo');
-    const isIgnoredMoreThanOneLevel = ignoredFiles(appSrc).test(
+    const isIgnored = anymatch(
+      ignoredFiles(appSrc),
+      '/root/src/node_modules/foo'
+    );
+    const isIgnoredMoreThanOneLevel = anymatch(
+      ignoredFiles(appSrc),
       '/root/src/bar/node_modules/foo'
     );
 
@@ -39,7 +45,8 @@ describe('ignore watch files regex', () => {
 
   it('path contains source directory', () => {
     const appSrc = '/root/src/';
-    const isIgnored = ignoredFiles(appSrc).test(
+    const isIgnored = anymatch(
+      ignoredFiles(appSrc),
       '/bar/root/src/node_modules/foo'
     );
 
@@ -48,7 +55,31 @@ describe('ignore watch files regex', () => {
 
   it('path starts with source directory', () => {
     const appSrc = '/root/src/';
-    const isIgnored = ignoredFiles(appSrc).test('/root/src2/node_modules/foo');
+    const isIgnored = anymatch(
+      ignoredFiles(appSrc),
+      '/root/src2/node_modules/foo'
+    );
+
+    expect(isIgnored).toBe(true);
+  });
+
+  it('ignores emacs temporary files', () => {
+    const appSrc = '/root/src/';
+    const isIgnored = anymatch(ignoredFiles(appSrc), 'file.txt~');
+
+    expect(isIgnored).toBe(true);
+  });
+
+  it('ignores emacs lock files', () => {
+    const appSrc = '/root/src/';
+    const isIgnored = anymatch(ignoredFiles(appSrc), '.#file.txt');
+
+    expect(isIgnored).toBe(true);
+  });
+
+  it('ignores emacs backup files', () => {
+    const appSrc = '/root/src/';
+    const isIgnored = anymatch(ignoredFiles(appSrc), '.#file.txt#');
 
     expect(isIgnored).toBe(true);
   });

packages/react-dev-utils/ignoredFiles.js

@@ -11,10 +11,15 @@ const path = require('path');
 const escape = require('escape-string-regexp');
 
 module.exports = function ignoredFiles(appSrc) {
-  return new RegExp(
-    `^(?!${escape(
-      path.normalize(appSrc + '/').replace(/[\\]+/g, '/')
-    )}).+/node_modules/`,
-    'g'
-  );
+  return [
+    new RegExp(
+      `^(?!${escape(
+        path.normalize(appSrc + '/').replace(/[\\]+/g, '/'),
+      )}).+/node_modules/`,
+      'g',
+    ),
+    '**/.#*',
+    '**/*~',
+    '**/#*#',
+  ];
 };