From 7692378aa60a5a4d12eb410711aecbf1d7265294 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Nicol=C3=B2=20Ribaudo?= <nicolo.ribaudo@gmail.com>
Date: Tue, 2 Nov 2021 09:26:18 +0100
Subject: [PATCH 1/2] Fix `parserOverride` support in `@babel/eslint-parser`

---
 .../src/worker/maybeParse.cjs                 |  7 ++-
 .../parser-override/babel.config.json         |  3 ++
 .../test/fixtures/parser-override/plugin.js   |  9 ++++
 .../test/integration/parser-override.js       | 47 +++++++++++++++++++
 4 files changed, 64 insertions(+), 2 deletions(-)
 create mode 100644 eslint/babel-eslint-tests/test/fixtures/parser-override/babel.config.json
 create mode 100644 eslint/babel-eslint-tests/test/fixtures/parser-override/plugin.js
 create mode 100644 eslint/babel-eslint-tests/test/integration/parser-override.js

diff --git a/eslint/babel-eslint-parser/src/worker/maybeParse.cjs b/eslint/babel-eslint-parser/src/worker/maybeParse.cjs
index 22c6fcaa7147..3b79a45c4030 100644
--- a/eslint/babel-eslint-parser/src/worker/maybeParse.cjs
+++ b/eslint/babel-eslint-parser/src/worker/maybeParse.cjs
@@ -15,7 +15,8 @@ module.exports = function maybeParse(code, options) {
       { dirname: __dirname, type: "plugin" },
     );
   }
-  options.plugins.push(extractParserOptionsConfigItem);
+  const { plugins } = options;
+  options.plugins = plugins.concat(extractParserOptionsConfigItem);
 
   try {
     return {
@@ -28,8 +29,10 @@ module.exports = function maybeParse(code, options) {
     }
   }
 
-  let ast;
+  // There was already a parserOverride, so remove our plugin.
+  options.plugins = plugins;
 
+  let ast;
   try {
     ast = babel.parseSync(code, options);
   } catch (err) {
diff --git a/eslint/babel-eslint-tests/test/fixtures/parser-override/babel.config.json b/eslint/babel-eslint-tests/test/fixtures/parser-override/babel.config.json
new file mode 100644
index 000000000000..1fbb7f264ff0
--- /dev/null
+++ b/eslint/babel-eslint-tests/test/fixtures/parser-override/babel.config.json
@@ -0,0 +1,3 @@
+{
+  "plugins": ["./plugin.js"]
+}
diff --git a/eslint/babel-eslint-tests/test/fixtures/parser-override/plugin.js b/eslint/babel-eslint-tests/test/fixtures/parser-override/plugin.js
new file mode 100644
index 000000000000..979051f29354
--- /dev/null
+++ b/eslint/babel-eslint-tests/test/fixtures/parser-override/plugin.js
@@ -0,0 +1,9 @@
+const parser = require("@babel/parser");
+
+module.exports = function () {
+  return {
+    parserOverride(code, opts) {
+      return parser.parse(`foo;`, opts);
+    },
+  };
+};
diff --git a/eslint/babel-eslint-tests/test/integration/parser-override.js b/eslint/babel-eslint-tests/test/integration/parser-override.js
new file mode 100644
index 000000000000..c2ed899f554a
--- /dev/null
+++ b/eslint/babel-eslint-tests/test/integration/parser-override.js
@@ -0,0 +1,47 @@
+import path from "path";
+import { fileURLToPath } from "url";
+import * as babelESLint from "@babel/eslint-parser";
+import * as babelESLintWorker from "@babel/eslint-parser/experimental-worker";
+
+describe("parserOverride", () => {
+  const expectedAST = {
+    type: "Program",
+    body: [
+      {
+        type: "ExpressionStatement",
+        expression: {
+          type: "Identifier",
+          name: "foo",
+        },
+      },
+    ],
+  };
+
+  it("works when parsing in the main thread", () => {
+    const { ast } = babelESLint.parseForESLint(`27`, {
+      filename: "input.js",
+      babelOptions: {
+        configFile: path.resolve(
+          path.dirname(fileURLToPath(import.meta.url)),
+          "../fixtures/parser-override/babel.config.json",
+        ),
+      },
+    });
+
+    expect(ast).toMatchObject(expectedAST);
+  });
+
+  it("works when parsing in a worker", () => {
+    const { ast } = babelESLintWorker.parseForESLint(`27`, {
+      filename: "input.js",
+      babelOptions: {
+        configFile: path.resolve(
+          path.dirname(fileURLToPath(import.meta.url)),
+          "../fixtures/parser-override/babel.config.json",
+        ),
+      },
+    });
+
+    expect(ast).toMatchObject(expectedAST);
+  });
+});

From e1a0f9b8c45a77e1de2686a3424b67cfdfe9b2f5 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Nicol=C3=B2=20Ribaudo?= <nicolo.ribaudo@gmail.com>
Date: Tue, 2 Nov 2021 09:39:56 +0100
Subject: [PATCH 2/2] Fix test

---
 .../test/integration/parser-override.js                   | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/eslint/babel-eslint-tests/test/integration/parser-override.js b/eslint/babel-eslint-tests/test/integration/parser-override.js
index c2ed899f554a..1091c40671a1 100644
--- a/eslint/babel-eslint-tests/test/integration/parser-override.js
+++ b/eslint/babel-eslint-tests/test/integration/parser-override.js
@@ -1,7 +1,7 @@
 import path from "path";
 import { fileURLToPath } from "url";
+import { createRequire } from "module";
 import * as babelESLint from "@babel/eslint-parser";
-import * as babelESLintWorker from "@babel/eslint-parser/experimental-worker";
 
 describe("parserOverride", () => {
   const expectedAST = {
@@ -31,7 +31,11 @@ describe("parserOverride", () => {
     expect(ast).toMatchObject(expectedAST);
   });
 
-  it("works when parsing in a worker", () => {
+  const babel7node12 = parseInt(process.versions.node) < 12 ? it.skip : it;
+  babel7node12("works when parsing in a worker", async () => {
+    const require = createRequire(import.meta.url);
+    const babelESLintWorker = require("@babel/eslint-parser/experimental-worker");
+
     const { ast } = babelESLintWorker.parseForESLint(`27`, {
       filename: "input.js",
       babelOptions: {