util: fix nested proxy inspection

Fixes: #61061

Author: BridgeAR

lib/internal/util/inspect.js

@@ -173,6 +173,7 @@ const {
   isModuleNamespaceObject,
   isNativeError,
   isPromise,
+  isProxy,
   isSet,
   isSetIterator,
   isWeakMap,
@@ -1120,15 +1121,21 @@ function formatValue(ctx, value, recurseTimes, typedArray) {
   const context = value;
   // Always check for proxies to prevent side effects and to prevent triggering
   // any proxy handlers.
-  const proxy = getProxyDetails(value, !!ctx.showProxy);
+  let proxy = getProxyDetails(value, !!ctx.showProxy);
   if (proxy !== undefined) {
-    if (proxy === null || proxy[0] === null) {
-      return ctx.stylize('<Revoked Proxy>', 'special');
-    }
     if (ctx.showProxy) {
+      if (proxy[0] === null) {
+        return ctx.stylize('<Revoked Proxy>', 'special');
+      }
       return formatProxy(ctx, proxy, recurseTimes);
     }
-    value = proxy;
+    do {
+      if (proxy === null) {
+        return ctx.stylize('<Revoked Proxy>', 'special');
+      }
+      value = proxy;
+      proxy = getProxyDetails(value, false);
+    } while (proxy !== undefined);
   }
 
   // Provide a hook for user-specified inspect functions.
@@ -1144,7 +1151,7 @@ function formatValue(ctx, value, recurseTimes, typedArray) {
       // a counter internally.
       const depth = ctx.depth === null ? null : ctx.depth - recurseTimes;
       const isCrossContext =
-        proxy !== undefined || !FunctionPrototypeSymbolHasInstance(Object, context);
+        context !== value || !FunctionPrototypeSymbolHasInstance(Object, context);
       const ret = FunctionPrototypeCall(
         maybeCustom,
         context,
@@ -2691,7 +2698,7 @@ function hasBuiltInToString(value) {
     if (proxyTarget === null) {
       return true;
     }
-    value = proxyTarget;
+    return hasBuiltInToString(proxyTarget);
   }
 
   let hasOwnToString = ObjectPrototypeHasOwnProperty;

test/parallel/test-util-inspect-proxy.js

@@ -42,7 +42,11 @@ proxyObj = new Proxy(target, handler);
 util.inspect(proxyObj, opts);
 
 // Make sure inspecting object does not trigger any proxy traps.
-util.format('%s', proxyObj);
+// %i%f%d use Symbol.toPrimitive to convert the value to a string.
+// %j uses JSON.stringify, accessing the value's toJSON and toString method.
+util.format('%s%o%O%c', proxyObj, proxyObj, proxyObj, proxyObj);
+const nestedProxy = new Proxy(new Proxy({}, handler), {});
+util.format('%s%o%O%c', nestedProxy, nestedProxy, nestedProxy, nestedProxy);
 
 // getProxyDetails is an internal method, not intended for public use.
 // This is here to test that the internals are working correctly.
@@ -188,3 +192,21 @@ assert.strictEqual(
     ')\x1B[39m'
 );
 assert.strictEqual(util.format('%s', proxy12), 'Proxy([ 1, 2, 3 ])');
+
+{
+  // Nested proxies should not trigger any proxy handlers.
+  const nestedProxy = new Proxy(new Proxy(new Proxy({}, handler), {}), {});
+
+  util.inspect(nestedProxy, { showProxy: true });
+  util.inspect(nestedProxy, { showProxy: false });
+}
+
+{
+  // Nested revoked proxies should work as expected as well as custom inspection functions.
+  const revocable = Proxy.revocable({}, handler);
+  revocable.revoke();
+  const nestedProxy = new Proxy(revocable.proxy, {});
+
+  assert.strictEqual(util.inspect(nestedProxy, { showProxy: true }), 'Proxy [ <Revoked Proxy>, {} ]');
+  assert.strictEqual(util.inspect(nestedProxy, { showProxy: false }), '<Revoked Proxy>');
+}