Build: Switch to an alternative node:fs mocking system

code/lib/core-common/package.json

@@ -70,9 +70,7 @@
   },
   "devDependencies": {
     "@types/fs-extra": "^11.0.1",
-    "@types/mock-fs": "^4.13.1",
     "@types/picomatch": "^2.3.0",
-    "mock-fs": "^5.2.0",
     "slash": "^5.0.0",
     "type-fest": "~2.19",
     "typescript": "~4.9.3"

code/lib/core-common/src/mock.ts

@@ -0,0 +1,66 @@
+import path from 'node:path';
+import fs from 'node:fs';
+import os from 'node:os';
+
+const tempDir = os.tmpdir();
+
+let savedDir: string | null = null;
+
+interface Dir {
+  [key: string]: File;
+}
+type File = Dir | string;
+
+function mkdirpSync(nested: string): void {
+  const paths = [];
+  let curr = nested;
+  for (;;) {
+    paths.push(curr);
+    const { root, dir } = path.parse(curr);
+    if (root === dir) {
+      break;
+    }
+    curr = dir;
+  }
+  for (let i = paths.length - 1; i >= 0; i -= 1) {
+    try {
+      fs.mkdirSync(paths[i]);
+    } catch (error) {
+      if ((error as NodeJS.ErrnoException).code !== 'EEXIST') {
+        throw error;
+      }
+    }
+  }
+}
+
+function mock(root: Dir): void {
+  if (savedDir !== null) {
+    throw new Error(`A file system is already being mocked.`);
+  }
+  savedDir = fs.mkdtempSync(path.join(tempDir, 'storybook-'));
+  const visit = (curr: string, dir: Dir) => {
+    Object.entries(dir).forEach(([name, contents]) => {
+      const filepath = path.join(curr, name);
+      if (typeof contents === 'string') {
+        mkdirpSync(path.dirname(filepath));
+        fs.writeFileSync(filepath, contents, 'utf-8');
+      } else {
+        fs.mkdirSync(filepath);
+        visit(filepath, contents);
+      }
+    });
+  };
+  visit(savedDir, root);
+  process.chdir(savedDir);
+}
+
+mock.restore = () => {
+  if (savedDir === null) {
+    throw new Error(`There is no file system to restore.`);
+  }
+  process.chdir(savedDir);
+  // TODO rimraf the tmp directory
+  savedDir = null;
+};
+
+export default mock;

code/lib/core-common/src/utils/__tests__/interpret-files.test.ts

@@ -1,4 +1,4 @@
-import mock from 'mock-fs';
+import mock from '../../mock';
 import { getInterpretedFile } from '../interpret-files';
 
 describe('interpret-files', () => {

code/lib/core-common/src/utils/__tests__/template.test.ts

@@ -1,4 +1,4 @@
-import mock from 'mock-fs';
+import mock from '../../mock';
 import { getPreviewHeadTemplate, getPreviewBodyTemplate } from '../template';
 
 const HEAD_HTML_CONTENTS = '<script>console.log("custom script!");</script>';

code/yarn.lock

@@ -6386,7 +6386,6 @@ __metadata:
     "@storybook/types": "workspace:*"
     "@types/find-cache-dir": "npm:^3.2.1"
     "@types/fs-extra": "npm:^11.0.1"
-    "@types/mock-fs": "npm:^4.13.1"
     "@types/node": "npm:^18.0.0"
     "@types/node-fetch": "npm:^2.6.4"
     "@types/picomatch": "npm:^2.3.0"
@@ -6401,7 +6400,6 @@ __metadata:
     glob: "npm:^10.0.0"
     handlebars: "npm:^4.7.7"
     lazy-universal-dotenv: "npm:^4.0.0"
-    mock-fs: "npm:^5.2.0"
     node-fetch: "npm:^2.0.0"
     picomatch: "npm:^2.3.0"
     pkg-dir: "npm:^5.0.0"
@@ -9060,15 +9058,6 @@ __metadata:
   languageName: node
   linkType: hard
 
-"@types/mock-fs@npm:^4.13.1":
-  version: 4.13.2
-  resolution: "@types/mock-fs@npm:4.13.2"
-  dependencies:
-    "@types/node": "npm:*"
-  checksum: c589d8ba674e9d2279c6321841ee5b4e9ba3138a8790cbe2a61ea1da1e9d254188ef9f1a2f66539b225aaebcd56f746551f4723de24afc0c430d9e7c68344a7b
-  languageName: node
-  linkType: hard
-
 "@types/ms@npm:*":
   version: 0.7.32
   resolution: "@types/ms@npm:0.7.32"
@@ -22517,13 +22506,6 @@ __metadata:
   languageName: node
   linkType: hard
 
-"mock-fs@npm:^5.2.0":
-  version: 5.2.0
-  resolution: "mock-fs@npm:5.2.0"
-  checksum: e917e71295ee9d805c7d9ab0214a66658db0212f35731ba0c75dc1ccbb9964e6787a6d725561f05fcf569c64cf4a1176f5ce438f98b009227520f646f8abf174
-  languageName: node
-  linkType: hard
-
 "moo@npm:^0.5.0":
   version: 0.5.2
   resolution: "moo@npm:0.5.2"