util: fix iterable types with special prototype

The fallback should only be taken for a null prototype. If an
iterable data type (e.g., Array) has a prototype without
`Symbol.iterator`, just try the best to visualize it as object.
PR-URL: #25457Fixes: #25451
Reviewed-By: Gus Caplan <me@gus.host>
Reviewed-By: Anto Aravinth <anto.aravinth.cse@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

Author: BridgeAR

lib/internal/util/inspect.js

@@ -463,28 +463,22 @@ function clazzWithNullPrototype(clazz, name) {
 functionnoPrototypeIterator(ctx,value,recurseTimes){
 letnewVal;
 if(isSet(value)){
-constclazz=Object.getPrototypeOf(value)||
-clazzWithNullPrototype(Set,'Set');
+constclazz=clazzWithNullPrototype(Set,'Set');
 newVal=newclazz(setValues(value));
 }elseif(isMap(value)){
-constclazz=Object.getPrototypeOf(value)||
-clazzWithNullPrototype(Map,'Map');
+constclazz=clazzWithNullPrototype(Map,'Map');
 newVal=newclazz(mapEntries(value));
 }elseif(Array.isArray(value)){
-constclazz=Object.getPrototypeOf(value)||
-clazzWithNullPrototype(Array,'Array');
+constclazz=clazzWithNullPrototype(Array,'Array');
 newVal=newclazz(value.length);
 }elseif(isTypedArray(value)){
-letclazz=Object.getPrototypeOf(value);
-if(!clazz){
-constconstructor=findTypedConstructor(value);
-clazz=clazzWithNullPrototype(constructor,constructor.name);
-}
+constconstructor=findTypedConstructor(value);
+constclazz=clazzWithNullPrototype(constructor,constructor.name);
 newVal=newclazz(value);
 }
-if(newVal){
+if(newVal!==undefined){
 Object.defineProperties(newVal,Object.getOwnPropertyDescriptors(value));
-returnformatValue(ctx,newVal,recurseTimes);
+returnformatRaw(ctx,newVal,recurseTimes);
 }
 }
 
@@ -728,9 +722,11 @@ function formatRaw(ctx, value, recurseTimes, typedArray) {
 }else{
 // The input prototype got manipulated. Special handle these. We have to
 // rebuild the information so we are able to display everything.
-constspecialIterator=noPrototypeIterator(ctx,value,recurseTimes);
-if(specialIterator){
-returnspecialIterator;
+if(constructor===null){
+constspecialIterator=noPrototypeIterator(ctx,value,recurseTimes);
+if(specialIterator){
+returnspecialIterator;
+}
 }
 if(isMapIterator(value)){
 braces=[`[${tag||'Map Iterator'}] {`,'}'];

test/parallel/test-util-inspect.js

@@ -1853,6 +1853,16 @@ assert.strictEqual(
 util.inspect(newStorageObject()),
 '<[Object: null prototype] {}> {}'
 );
+
+obj=[1,2,3];
+Object.setPrototypeOf(obj,Number.prototype);
+assert.strictEqual(inspect(obj),"Number { '0': 1, '1': 2, '2': 3 }");
+
+Object.setPrototypeOf(obj,Object.create(null));
+assert.strictEqual(
+inspect(obj),
+"<[Object: null prototype] {}> { '0': 1, '1': 2, '2': 3 }"
+);
 }
 
 // Check that the fallback always works.