From 0731b5f64311b168ac941ce3e547bb1a32766783 Mon Sep 17 00:00:00 2001
From: Jordan Harband <ljharb@gmail.com>
Date: Sun, 15 Jan 2023 13:49:01 -0800
Subject: [PATCH] [Fix] `throws`: avoid crashing on a nonconfigurable or
 nonextensible `expected`

---
 lib/test.js    | 10 ++++++----
 test/throws.js | 43 ++++++++++++++++++++++++++++++++++++++++---
 2 files changed, 46 insertions(+), 7 deletions(-)

diff --git a/lib/test.js b/lib/test.js
index 596f83a5..926da137 100644
--- a/lib/test.js
+++ b/lib/test.js
@@ -542,10 +542,12 @@ Test.prototype['throws'] = function (fn, expected, msg, extra) {
 		fn();
 	} catch (err) {
 		caught = { error: err };
-		if (Object(err) === err && (!isEnumerable(err, 'message') || !has(err, 'message'))) {
-			var message = err.message;
-			delete err.message;
-			err.message = message;
+		if (Object(err) === err && 'message' in err && (!isEnumerable(err, 'message') || !has(err, 'message'))) {
+			try {
+				var message = err.message;
+				delete err.message;
+				err.message = message;
+			} catch (e) { /**/ }
 		}
 	}
 
diff --git a/test/throws.js b/test/throws.js
index 9186d052..a39d3a4a 100644
--- a/test/throws.js
+++ b/test/throws.js
@@ -176,10 +176,19 @@ tap.test('failures', function (tt) {
 			'          at Test.<anonymous> ($TEST/throws.js:$LINE:$COL)',
 			'          [... stack stripped ...]',
 			'  ...',
+			'# non-extensible throw match',
+			'ok 15 error is non-extensible',
+			'ok 16 non-extensible error matches',
+			'ok 17 errorWithMessage is non-extensible',
+			'ok 18 non-extensible error with message matches',
+			'# frozen `message` property',
+			'ok 19 error is non-writable',
+			'ok 20 error is non-configurable',
+			'ok 21 non-writable error matches',
 			'',
-			'1..14',
-			'# tests 14',
-			'# pass  4',
+			'1..21',
+			'# tests 21',
+			'# pass  11',
 			'# fail  10',
 			''
 		]);
@@ -221,4 +230,32 @@ tap.test('failures', function (tt) {
 		t['throws'](function () { throw actual; }, TypeError, 'throws actual');
 		t.end();
 	});
+
+	test('non-extensible throw match', { skip: !Object.seal }, function (t) {
+		var error = { foo: 1 };
+		Object.seal(error);
+		t.throws(function () { error.x = 1; }, TypeError, 'error is non-extensible');
+
+		t.throws(function () { throw error; }, error, 'non-extensible error matches');
+
+		var errorWithMessage = { message: 'abc' };
+		Object.seal(errorWithMessage);
+		t.throws(function () { errorWithMessage.x = 1; }, TypeError, 'errorWithMessage is non-extensible');
+
+		t.throws(function () { throw errorWithMessage; }, error, 'non-extensible error with message matches');
+
+		t.end();
+	});
+
+	test('frozen `message` property', { skip: !Object.defineProperty }, function (t) {
+		var error = { message: 'abc' };
+		Object.defineProperty(error, 'message', { configurable: false, enumerable: false, writable: false });
+
+		t.throws(function () { error.message = 'def'; }, TypeError, 'error is non-writable');
+		t.throws(function () { delete error.message; }, TypeError, 'error is non-configurable');
+
+		t.throws(function () { throw error; }, { message: 'abc' }, 'non-writable error matches');
+
+		t.end();
+	});
 });