fix(core-base): key paths containing javascript built-ins are handled inconsistently

packages/core-base/src/resolver.ts

@@ -1,4 +1,4 @@
-import { isFunction, isObject } from '@intlify/shared'
+import { hasOwn, isFunction, isObject } from '@intlify/shared'
 import { AST_NODE_PROPS_KEYS, isMessageAST } from './ast'
 
 /** @VueI18nGeneral */
@@ -335,7 +335,8 @@ export function resolveValue(obj: unknown, path: Path): PathValue {
 
   // resolve path value
   const len = hit.length
-  let last = obj
+
+  let last: any = obj
   let i = 0
   while (i < len) {
     const key = hit[i]
@@ -350,6 +351,9 @@ export function resolveValue(obj: unknown, path: Path): PathValue {
     if (!isObject(last)) {
       return null
     }
+    if (!hasOwn(last as object, key)) {
+      return null
+    }
     const val = last[key]
     if (val === undefined) {
       return null

packages/core-base/test/resolver.test.ts

@@ -133,6 +133,39 @@ describe('resolveValue', () => {
     expect(resolveValue({ 'test.link': 'world' }, 'test.link')).toEqual(null)
   })
 
+  test('Object.prototype built-in key paths (issue #1838)', () => {
+    const builtins = [
+      'constructor',
+      'hasOwnProperty',
+      'isPrototypeOf',
+      'propertyIsEnumerable',
+      'toLocaleString',
+      'toString',
+      'valueOf',
+      '__proto__'
+    ]
+
+    // top-level: builtin name as key with value defined -> should resolve
+    for (const k of builtins) {
+      expect(resolveValue({ [k]: 'hi' }, k)).toEqual('hi')
+    }
+
+    // top-level: builtin name as key, NOT defined -> should return null
+    for (const k of builtins) {
+      expect(resolveValue({}, k)).toEqual(null)
+    }
+
+    // nested: a.<builtin>.c with value defined -> should resolve
+    for (const k of builtins) {
+      expect(resolveValue({ a: { [k]: { c: 'hi' } } }, `a.${k}.c`)).toEqual('hi')
+    }
+
+    // nested: a.<builtin>.c without value -> should return null
+    for (const k of builtins) {
+      expect(resolveValue({ a: {} }, `a.${k}.c`)).toEqual(null)
+    }
+  })
+
   test('ast', () => {
     expect(resolveValue(ast, 'language')).toEqual(ast.language)
     expect(resolveValue(ast, 'product')).toEqual(ast.product)