worker: support more cases when (de)serializing errors

- error.cause is potentially an error, so is now handled recursively
- best effort to serialize thrown symbols
- handle thrown object with custom inspect

Author: MoLow

lib/internal/error_serdes.js

@@ -13,19 +13,27 @@ const {
   ObjectGetOwnPropertyNames,
   ObjectGetPrototypeOf,
   ObjectKeys,
+  ObjectPrototypeHasOwnProperty,
   ObjectPrototypeToString,
   RangeError,
   ReferenceError,
   SafeSet,
+  StringPrototypeSubstring,
   SymbolToStringTag,
   SyntaxError,
+  SymbolFor,
   TypeError,
   URIError,
 } = primordials;
+const { inspect: { custom: customInspectSymbol } } = require('util');
 
 const kSerializedError = 0;
 const kSerializedObject = 1;
 const kInspectedError = 2;
+const kInspectedSymbol = 3;
+const kCustomInspectedObject = 4;
+
+const kSymbolStringLength = 'Symbol('.length;
 
 const errors = {
   Error, TypeError, RangeError, URIError, SyntaxError, ReferenceError, EvalError,
@@ -52,7 +60,13 @@ function TryGetAllProperties(object, target = object) {
         // Continue regardless of error.
       }
     }
-    if ('value' in descriptor && typeof descriptor.value !== 'function') {
+    if (key === 'cause') {
+      delete descriptor.get;
+      delete descriptor.set;
+      descriptor.value = serializeError(descriptor.value);
+      all[key] = descriptor;
+    } else if ('value' in descriptor &&
+            typeof descriptor.value !== 'function' && typeof descriptor.value !== 'symbol') {
       delete descriptor.get;
       delete descriptor.set;
       all[key] = descriptor;
@@ -95,6 +109,10 @@ function inspect(...args) {
 let serialize;
 function serializeError(error) {
   if (!serialize) serialize = require('v8').serialize;
+  if (typeof error === 'symbol') {
+    return Buffer.concat([Buffer.from([kInspectedSymbol]),
+                          Buffer.from(inspect(error), 'utf8')]);
+  }
   try {
     if (typeof error === 'object' &&
         ObjectPrototypeToString(error) === '[object Error]') {
@@ -113,6 +131,15 @@ function serializeError(error) {
   } catch {
     // Continue regardless of error.
   }
+  try {
+    if (error != null &&
+      ObjectPrototypeHasOwnProperty(error, customInspectSymbol)) {
+      return Buffer.concat([Buffer.from([kCustomInspectedObject]),
+                            Buffer.from(inspect(error), 'utf8')]);
+    }
+  } catch {
+    // Continue regardless of error.
+  }
   try {
     const serialized = serialize(error);
     return Buffer.concat([Buffer.from([kSerializedObject]), serialized]);
@@ -123,6 +150,12 @@ function serializeError(error) {
                         Buffer.from(inspect(error), 'utf8')]);
 }
 
+function fromBuffer(error) {
+  return Buffer.from(error.buffer,
+                     error.byteOffset + 1,
+                     error.byteLength - 1);
+}
+
 let deserialize;
 function deserializeError(error) {
   if (!deserialize) deserialize = require('v8').deserialize;
@@ -132,19 +165,27 @@ function deserializeError(error) {
       const ctor = errors[constructor];
       ObjectDefineProperty(properties, SymbolToStringTag, {
         __proto__: null,
-        value: { value: 'Error', configurable: true },
+        value: { __proto__: null, value: 'Error', configurable: true },
         enumerable: true,
       });
+      if ('cause' in properties && 'value' in properties.cause) {
+        properties.cause.value = deserializeError(properties.cause.value);
+      }
       return ObjectCreate(ctor.prototype, properties);
     }
     case kSerializedObject:
       return deserialize(error.subarray(1));
-    case kInspectedError: {
-      const buf = Buffer.from(error.buffer,
-                              error.byteOffset + 1,
-                              error.byteLength - 1);
-      return buf.toString('utf8');
+    case kInspectedError:
+      return fromBuffer(error).toString('utf8');
+    case kInspectedSymbol: {
+      const buf = fromBuffer(error);
+      return SymbolFor(StringPrototypeSubstring(buf.toString('utf8'), kSymbolStringLength, buf.length - 1));
     }
+    case kCustomInspectedObject:
+      return {
+        __proto__: null,
+        [customInspectSymbol]: () => fromBuffer(error).toString('utf8'),
+      };
   }
   require('assert').fail('This should not happen');
 }

test/parallel/test-error-serdes.js

@@ -2,6 +2,7 @@
 'use strict';
 require('../common');
 const assert = require('assert');
+const { inspect } = require('util');
 const { ERR_INVALID_ARG_TYPE } = require('internal/errors').codes;
 const { serializeError, deserializeError } = require('internal/error_serdes');
 
@@ -15,6 +16,9 @@ assert.strictEqual(cycle(1.4), 1.4);
 assert.strictEqual(cycle(null), null);
 assert.strictEqual(cycle(undefined), undefined);
 assert.strictEqual(cycle('foo'), 'foo');
+assert.strictEqual(cycle(Symbol.for('foo')), Symbol.for('foo'));
+assert.strictEqual(cycle(Symbol('foo')).toString(), Symbol('foo').toString());
+
 
 let err = new Error('foo');
 for (let i = 0; i < 10; i++) {
@@ -43,6 +47,16 @@ assert.strictEqual(cycle(new SubError('foo')).name, 'Error');
 assert.deepStrictEqual(cycle({ message: 'foo' }), { message: 'foo' });
 assert.strictEqual(cycle(Function), '[Function: Function]');
 
+
+assert.strictEqual(cycle(new Error('Error with cause', { cause: 0 })).cause, 0);
+assert.strictEqual(cycle(new Error('Error with cause', { cause: -1 })).cause, -1);
+assert.strictEqual(cycle(new Error('Error with cause', { cause: 1.4 })).cause, 1.4);
+assert.strictEqual(cycle(new Error('Error with cause', { cause: null })).cause, null);
+assert.strictEqual(cycle(new Error('Error with cause', { cause: undefined })).cause, undefined);
+assert.strictEqual(cycle(new Error('Error with cause', { cause: 'foo' })).cause, 'foo');
+assert.deepStrictEqual(cycle(new Error('Error with cause', { cause: new Error('err') })).cause, new Error('err'));
+
+
 {
   const err = new ERR_INVALID_ARG_TYPE('object', 'Object', 42);
   assert.match(String(err), /^TypeError \[ERR_INVALID_ARG_TYPE\]:/);
@@ -66,3 +80,12 @@ assert.strictEqual(cycle(Function), '[Function: Function]');
   serializeError(new DynamicError());
   assert.strictEqual(called, true);
 }
+
+
+const data = {
+  foo: 'bar',
+  [inspect.custom]() {
+    return 'barbaz';
+  }
+};
+assert.strictEqual(inspect(cycle(data)), 'barbaz');