From 5e875382369a3017aa61ed47d43a4338fe23e066 Mon Sep 17 00:00:00 2001
From: 43081j <43081j@users.noreply.github.com>
Date: Mon, 26 Feb 2024 19:02:16 +0000
Subject: [PATCH] fix: support some virtual contexts in `toThrow`

This adds support for VM situations where we pass a `RegExp` from
another process.

Note that we don't have a full fix for this stuff until `check-error`
also supports `Error` being from another origin.
---
 lib/chai/core/assertions.js |  6 +++---
 lib/chai/utils/index.js     |  4 ++++
 test/assert.js              |  3 +++
 test/virtual-machines.js    | 31 +++++++++++++++++++++++++++++++
 web-test-runner.config.js   |  5 ++++-
 5 files changed, 45 insertions(+), 4 deletions(-)
 create mode 100644 test/virtual-machines.js

diff --git a/lib/chai/core/assertions.js b/lib/chai/core/assertions.js
index 7d72b068..db7b2a94 100644
--- a/lib/chai/core/assertions.js
+++ b/lib/chai/core/assertions.js
@@ -2676,7 +2676,7 @@ function assertThrows (errorLike, errMsgMatcher, msg) {
     , negate = flag(this, 'negate') || false;
   new Assertion(obj, flagMsg, ssfi, true).is.a('function');
 
-  if (errorLike instanceof RegExp || typeof errorLike === 'string') {
+  if (_.isRegExp(errorLike) || typeof errorLike === 'string') {
     errMsgMatcher = errorLike;
     errorLike = null;
   }
@@ -2709,7 +2709,7 @@ function assertThrows (errorLike, errMsgMatcher, msg) {
     }
 
     this.assert(
-        caughtErr
+        caughtErr !== undefined
       , 'expected #{this} to throw ' + errorLikeString
       , 'expected #{this} to not throw an error but #{act} was thrown'
       , errorLike && errorLike.toString()
@@ -2760,7 +2760,7 @@ function assertThrows (errorLike, errMsgMatcher, msg) {
   if (caughtErr && errMsgMatcher !== undefined && errMsgMatcher !== null) {
     // Here we check compatible messages
     var placeholder = 'including';
-    if (errMsgMatcher instanceof RegExp) {
+    if (_.isRegExp(errMsgMatcher)) {
       placeholder = 'matching'
     }
 
diff --git a/lib/chai/utils/index.js b/lib/chai/utils/index.js
index 0602997a..099c22ad 100644
--- a/lib/chai/utils/index.js
+++ b/lib/chai/utils/index.js
@@ -94,3 +94,7 @@ export {isNaN} from './isNaN.js';
 
 // getOperator method
 export {getOperator} from './getOperator.js';
+
+export function isRegExp(obj) {
+  return Object.prototype.toString.call(obj) === '[object RegExp]';
+}
diff --git a/test/assert.js b/test/assert.js
index c469dda1..d22998a7 100644
--- a/test/assert.js
+++ b/test/assert.js
@@ -1644,6 +1644,9 @@ describe('assert', function () {
       assert[throws](function() { throw new Error('bar'); }, Error, 'bar');
       assert[throws](function() { throw new Error(''); }, Error, '');
       assert[throws](function() { throw new Error('foo') }, '');
+      assert[throws](function() { throw ''; }, '');
+      assert[throws](function() { throw ''; }, /^$/);
+      assert[throws](function() { throw new Error(''); }, /^$/);
 
       var thrownErr = assert[throws](function() { throw new Error('foo'); });
       assert(thrownErr instanceof Error, 'assert.' + throws + ' returns error');
diff --git a/test/virtual-machines.js b/test/virtual-machines.js
new file mode 100644
index 00000000..92ac1978
--- /dev/null
+++ b/test/virtual-machines.js
@@ -0,0 +1,31 @@
+import vm from 'node:vm';
+import * as chai from '../index.js';
+
+const {assert} = chai;
+const vmContext = {assert};
+vm.createContext(vmContext);
+
+function runCodeInVm(code) {
+  vm.runInContext(code, vmContext);
+}
+
+describe('node virtual machines', function () {
+  it('throws', function() {
+    const shouldNotThrow = [
+      `assert.throws(function() { throw ''; }, /^$/);`,
+      `assert.throws(function() { throw new Error('bleepbloop'); });`,
+      `assert.throws(function() { throw new Error(''); });`,
+      // TODO (43081j): enable this test once check-error supports
+      // cross-vm `Error` objects
+      //`assert.throws(function() { throw new Error('swoosh'); }, /swoosh/);`
+    ];
+
+    for (const code of shouldNotThrow) {
+      assert.doesNotThrow(
+        () => {
+          runCodeInVm(code);
+        }
+      );
+    }
+  });
+});
diff --git a/web-test-runner.config.js b/web-test-runner.config.js
index 50d70191..b9b6cb25 100644
--- a/web-test-runner.config.js
+++ b/web-test-runner.config.js
@@ -5,7 +5,10 @@ const commonjs = fromRollup(rollupCommonjs);
 
 export default {
   nodeResolve: true,
-  files: ["test/*.js"],
+  files: [
+    "test/*.js",
+    "!test/virtual-machines.js"
+  ],
   plugins: [
     commonjs({
       include: [