Prevent --check-files from crossing symlinks

__tests__/commands/install/integration.js

@@ -48,6 +48,16 @@ async function mockConstants(base: Config, mocks: Object, cb: (config: Config) =
 beforeEach(request.__resetAuthedRequests);
 afterEach(request.__resetAuthedRequests);
 
+test.concurrent('packages installed through the link protocol should validate all peer dependencies', async () => {
+  await runInstall({checkFiles: true}, 'check-files-should-not-cross-symlinks', async (config): Promise<void> => {
+    expect(JSON.parse(await fs.readFile(`${config.cwd}/node_modules/.yarn-integrity`)).files).toEqual([
+      'some-missing-pkg',
+      'some-other-pkg',
+      'some-pkg/package.json',
+    ]);
+  });
+});
+
 test.concurrent('installing a package with a renamed file should not delete it', async () => {
   await runInstall({}, 'case-sensitivity', async (config, reporter): Promise<void> => {
     const pkgJson = await fs.readJson(`${config.cwd}/package.json`);

__tests__/fixtures/install/check-files-should-not-cross-symlinks/package.json

@@ -0,0 +1,7 @@
+{
+    "dependencies": {
+        "some-pkg": "file:./some-pkg/",
+        "some-other-pkg": "link:./some-other-pkg",
+        "some-missing-pkg": "link:./some-missing-pkg"
+    }
+}

__tests__/fixtures/install/check-files-should-not-cross-symlinks/some-other-pkg/package.json

@@ -0,0 +1,4 @@
+{
+    "name": "some-other-pkg",
+    "version": "1.0.0"
+}

__tests__/fixtures/install/check-files-should-not-cross-symlinks/some-pkg/package.json

@@ -0,0 +1,4 @@
+{
+    "name": "some-pkg",
+    "version": "1.0.0"
+}

__tests__/fixtures/install/check-files-should-not-cross-symlinks/yarn.lock

@@ -0,0 +1,14 @@
+# THIS IS AN AUTOGENERATED FILE. DO NOT EDIT THIS FILE DIRECTLY.
+# yarn lockfile v1
+
+
+"some-missing-pkg@link:./some-missing-pkg":
+  version "0.0.0"
+  uid ""
+
+"some-other-pkg@link:./some-other-pkg":
+  version "0.0.0"
+  uid ""
+
+"some-pkg@file:./some-pkg/":
+  version "1.0.0"

package.json

@@ -94,7 +94,7 @@
     "build-win-installer": "scripts\\build-windows-installer.bat",
     "check-lockfile": "./scripts/check-lockfile.sh",
     "lint": "eslint . && flow check",
-    "prettier": "eslint . --fix",
+    "prettier": "eslint src __tests__ --fix",
     "release-branch": "./scripts/release-branch.sh",
     "test": "yarn lint && yarn test-only",
     "test-ci": "yarn build && yarn test-only",

src/integrity-checker.js

@@ -124,7 +124,7 @@ export default class InstallationIntegrityChecker {
     async function getFilePaths(rootDir: string, files: Array<string>, currentDir: string = rootDir): Promise<void> {
       for (const file of await fs.readdir(currentDir)) {
         const entry = path.join(currentDir, file);
-        const stat = await fs.stat(entry);
+        const stat = await fs.lstat(entry);
         if (stat.isDirectory()) {
           await getFilePaths(rootDir, files, entry);
         } else {