util: inspect objects with throwing Symbol.toStringTag

BridgeAR · targos · commit 3c62b3886f21 · 2025-09-24T09:03:34.000+02:00
`util.inspect()` should handle all kinds of input, even if it is not well defined. Throwing is something that is meant to be worked around in all known cases. This fixes issues inspecting objects where accessing the Symbol.toStringTag would cause an error. The symbol is just ignored in that case. Refs: #55539 Refs: #55544 PR-URL: #59860 Reviewed-By: Luigi Pinca <luigipinca@gmail.com> Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com> Reviewed-By: James M Snell <jasnell@gmail.com>
diff --git a/lib/internal/util/inspect.js b/lib/internal/util/inspect.js
@@ -935,7 +935,14 @@ function formatRaw(ctx, value, recurseTimes, typedArray) {
     protoProps = undefined;
   }
 
-  let tag = value[SymbolToStringTag];
+  let tag = '';
+
+  try {
+    tag = value[SymbolToStringTag];
+  } catch {
+    // Ignore error.
+  }
+
   // Only list the tag in case it's non-enumerable / not an own property.
   // Otherwise we'd print this twice.
   if (typeof tag !== 'string' ||
diff --git a/test/parallel/test-util-inspect.js b/test/parallel/test-util-inspect.js
@@ -1646,7 +1646,7 @@ util.inspect(process);
     }
   }
 
-  assert.throws(() => util.inspect(new ThrowingClass()), /toStringTag error/);
+  assert.strictEqual(util.inspect(new ThrowingClass()), 'ThrowingClass {}');
 
   const y = {
     get [Symbol.toStringTag]() {
@@ -1655,7 +1655,11 @@ util.inspect(process);
   };
   const x = { y };
   y.x = x;
-  assert.throws(() => util.inspect(x), /TypeError: Converting circular structure to JSON/);
+
+  assert.strictEqual(
+    util.inspect(x),
+    '<ref *1> {\n  y: { x: [Circular *1], Symbol(Symbol.toStringTag): [Getter] }\n}'
+  );
 
   class NotStringClass {
     get [Symbol.toStringTag]() {
