fix: don't crash when fs.readFile returns promise from another realm (

#18416)

* fix: don't crash when `fs.readFile` returns promise from another realm

Fixes #18407

* update test case title

lib/eslint/eslint.js

@@ -9,8 +9,7 @@
 // Requirements
 //------------------------------------------------------------------------------
 
-// Note: Node.js 12 does not support fs/promises.
-const fs = require("fs").promises;
+const fs = require("fs/promises");
 const { existsSync } = require("fs");
 const path = require("path");
 const findUp = require("find-up");

package.json

@@ -72,7 +72,7 @@
     "@eslint/js": "9.2.0",
     "@humanwhocodes/config-array": "^0.13.0",
     "@humanwhocodes/module-importer": "^1.0.1",
-    "@humanwhocodes/retry": "^0.2.3",
+    "@humanwhocodes/retry": "^0.2.4",
     "@nodelib/fs.walk": "^1.2.8",
     "ajv": "^6.12.4",
     "chalk": "^4.0.0",

tests/lib/eslint/eslint.js

@@ -13,7 +13,7 @@
 const assert = require("assert");
 const util = require("util");
 const fs = require("fs");
-const fsp = fs.promises;
+const fsp = require("fs/promises");
 const os = require("os");
 const path = require("path");
 const timers = require("node:timers/promises");
@@ -1057,6 +1057,61 @@ describe("ESLint", () => {
             await assert.rejects(async () => await eslint.lintFiles(["lib/cli.js"]), /Expected object with parse\(\) or parseForESLint\(\) method/u);
         });
 
+        // https://github.com/eslint/eslint/issues/18407
+        it("should work in case when `fsp.readFile()` returns an object that is not an instance of Promise from this realm", async () => {
+
+            /**
+             * Promise wrapper
+             */
+            class PromiseLike {
+                constructor(promise) {
+                    this.promise = promise;
+                }
+                then(...args) {
+                    return new PromiseLike(this.promise.then(...args));
+                }
+                catch(...args) {
+                    return new PromiseLike(this.promise.catch(...args));
+                }
+                finally(...args) {
+                    return new PromiseLike(this.promise.finally(...args));
+                }
+            }
+
+            const spy = sinon.spy(
+                (...args) => new PromiseLike(fsp.readFile(...args))
+            );
+
+            const { ESLint: LocalESLint } = proxyquire("../../../lib/eslint/eslint", {
+                "fs/promises": {
+                    readFile: spy,
+                    "@noCallThru": false // allows calling other methods of `fs/promises`
+                }
+            });
+
+            const testDir = "tests/fixtures/simple-valid-project";
+            const expectedLintedFiles = [
+                path.resolve(testDir, "foo.js"),
+                path.resolve(testDir, "src", "foobar.js")
+            ];
+
+            eslint = new LocalESLint({
+                cwd: originalDir,
+                overrideConfigFile: path.resolve(testDir, "eslint.config.js")
+            });
+
+            const results = await eslint.lintFiles([`${testDir}/**/foo*.js`]);
+
+            assert.strictEqual(results.length, expectedLintedFiles.length);
+
+            expectedLintedFiles.forEach((file, index) => {
+                assert(spy.calledWith(file), `Spy was not called with ${file}`);
+                assert.strictEqual(results[index].filePath, file);
+                assert.strictEqual(results[index].messages.length, 0);
+                assert.strictEqual(results[index].suppressedMessages.length, 0);
+            });
+        });
+
         describe("Invalid inputs", () => {
 
             [
@@ -5513,13 +5568,10 @@ describe("ESLint", () => {
         });
 
         it("should call fs.writeFile() for each result with output", async () => {
-            const fakeFS = {
-                writeFile: sinon.spy(() => Promise.resolve())
-            };
-            const spy = fakeFS.writeFile;
+            const spy = sinon.spy(() => Promise.resolve());
             const { ESLint: localESLint } = proxyquire("../../../lib/eslint/eslint", {
-                fs: {
-                    promises: fakeFS
+                "fs/promises": {
+                    writeFile: spy
                 }
             });
 
@@ -5542,15 +5594,13 @@ describe("ESLint", () => {
         });
 
         it("should call fs.writeFile() for each result with output and not at all for a result without output", async () => {
-            const fakeFS = {
-                writeFile: sinon.spy(() => Promise.resolve())
-            };
-            const spy = fakeFS.writeFile;
+            const spy = sinon.spy(() => Promise.resolve());
             const { ESLint: localESLint } = proxyquire("../../../lib/eslint/eslint", {
-                fs: {
-                    promises: fakeFS
+                "fs/promises": {
+                    writeFile: spy
                 }
             });
+
             const results = [
                 {
                     filePath: path.resolve("foo.js"),