util: inspect: do not crash on an Error stack pointing to itself

SamVerschueren · aduh95 · commit db648b92c1fe · 2025-07-24T20:08:23.000+02:00
PR-URL: #58196 Reviewed-By: Jordan Harband <ljharb@gmail.com> Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de> Reviewed-By: Ethan Arrowood <ethan@arrowood.dev>
diff --git a/lib/internal/util/inspect.js b/lib/internal/util/inspect.js
@@ -1319,7 +1319,12 @@ function getStackString(ctx, error) {
     if (typeof error.stack === 'string') {
       return error.stack;
     }
-    return formatValue(ctx, error.stack);
+    ctx.seen.push(error);
+    ctx.indentationLvl += 4;
+    const result = formatValue(ctx, error.stack);
+    ctx.indentationLvl -= 4;
+    ctx.seen.pop();
+    return `${ErrorPrototypeToString(error)}\n    ${result}`;
   }
   return ErrorPrototypeToString(error);
 }
diff --git a/test/parallel/test-util-inspect.js b/test/parallel/test-util-inspect.js
@@ -770,14 +770,14 @@ assert.strictEqual(util.inspect(-5e-324), '-5e-324');
 // Note: Symbols are not supported by `Error#toString()` which is called by
 // accessing the `stack` property.
 [
-  [404, '404 [RangeError]: foo', '[404]'],
+  [404, '404 [RangeError]: foo', '[RangeError: foo\n    404]'],
   [0, '0 [RangeError]: foo', '[RangeError: foo]'],
   [0n, '0 [RangeError]: foo', '[RangeError: foo]'],
   [null, 'null: foo', '[RangeError: foo]'],
   [undefined, 'RangeError: foo', '[RangeError: foo]'],
   [false, 'false [RangeError]: foo', '[RangeError: foo]'],
   ['', 'foo', '[RangeError: foo]'],
-  [[1, 2, 3], '1,2,3 [RangeError]: foo', '[[\n  1,\n  2,\n  3\n]]'],
+  [[1, 2, 3], '1,2,3 [RangeError]: foo', '[RangeError: foo\n    [\n      1,\n      2,\n      3\n    ]]'],
 ].forEach(([value, outputStart, stack]) => {
   let err = new RangeError('foo');
   err.name = value;
@@ -3425,6 +3425,34 @@ ${error.stack.split('\n').slice(1).join('\n')}`,
 
   assert.strictEqual(
     inspect(error),
-    '[[\n  Symbol(foo)\n]]'
+    '[Error\n    [\n      Symbol(foo)\n    ]]'
   );
 }
+
+{
+  const prepareStackTrace = Error.prepareStackTrace;
+
+  Error.prepareStackTrace = (error) => error;
+
+  const error = new Error('foo');
+
+  assert.strictEqual(inspect(error), '[Error: foo\n    [Circular *1]]');
+
+  Error.prepareStackTrace = prepareStackTrace;
+}
+
+{
+  const error = new Error('foo');
+  error.stack = error;
+
+  assert.strictEqual(inspect(error), '[Error: foo\n    [Circular *1]]');
+}
+
+{
+  const error = new Error('foo');
+  const error2 = new Error('bar');
+  error.stack = error2;
+  error2.stack = error;
+
+  assert.strictEqual(inspect(error), '[Error: foo\n    [Error: bar\n        [Circular *1]]]');
+}

Original file line number	Diff line number	Diff line change
`@@ -1319,7 +1319,12 @@ function getStackString(ctx, error) {`
`1319`	`1319`	`if (typeof error.stack === 'string') {`
`1320`	`1320`	`return error.stack;`
`1321`	`1321`	`}`
`1322`		`- return formatValue(ctx, error.stack);`
	`1322`	`+ ctx.seen.push(error);`
	`1323`	`+ ctx.indentationLvl += 4;`
	`1324`	`+ const result = formatValue(ctx, error.stack);`
	`1325`	`+ ctx.indentationLvl -= 4;`
	`1326`	`+ ctx.seen.pop();`
	`1327`	+ return `${ErrorPrototypeToString(error)}\n ${result}`;
`1323`	`1328`	`}`
`1324`	`1329`	`return ErrorPrototypeToString(error);`
`1325`	`1330`	`}`