nodejs · XadillaX · Jun 20, 2017 · Jun 20, 2017 · Jun 20, 2017 · Jun 20, 2017
diff --git a/lib/repl.js b/lib/repl.js
@@ -57,6 +57,7 @@ const Module = require('module');
 const domain = require('domain');
 const debug = util.debuglog('repl');
 const errors = require('internal/errors');
+const Buffer = require('buffer').Buffer;
 
 const parentModule = module;
 const replMap = new WeakMap();
@@ -689,8 +690,31 @@ function intFilter(item) {
   return /^[A-Za-z_$]/.test(item);
 }
 
+const DEFAULT_PROPERTIES = {
+  ARRAY: Object.getOwnPropertyNames([]).filter(intFilter),
+  BUFFER: Object.getOwnPropertyNames(Buffer.alloc(1)).filter(intFilter)
+};
+
+function mayBeLargeObject(obj) {
+  return (Array.isArray(obj) || Buffer.isBuffer(obj));
+}
+
 function filteredOwnPropertyNames(obj) {
   if (!obj) return [];
+  if (mayBeLargeObject(obj) && obj.length > 1e6) {
+    this._writeToOutput('\r\n');
+    process.emitWarning(
+      'Instance is too large that the completion may missing ' +
+      'some customized properties.',
+      'REPLWarning',
+      undefined,
+      undefined,
+      true);
+
+    return Array.isArray(obj) ?
+      DEFAULT_PROPERTIES.ARRAY :
+      DEFAULT_PROPERTIES.BUFFER;
+  }
   return Object.getOwnPropertyNames(obj).filter(intFilter);
 }
 
@@ -732,6 +756,7 @@ function complete(line, callback) {
     }
   }
 
+  var self = this;
   var completions;
 
   // list of completion lists, one for each inheritance "level"
@@ -843,9 +868,11 @@ function complete(line, callback) {
         if (this.useGlobal || vm.isContext(this.context)) {
           var contextProto = this.context;
           while (contextProto = Object.getPrototypeOf(contextProto)) {
-            completionGroups.push(filteredOwnPropertyNames(contextProto));
+            completionGroups.push(
+              filteredOwnPropertyNames.call(this, contextProto));
           }
-          completionGroups.push(filteredOwnPropertyNames(this.context));
+          completionGroups.push(
+            filteredOwnPropertyNames.call(this, this.context));
           addStandardGlobals(completionGroups, filter);
           completionGroupsLoaded();
         } else {
@@ -871,7 +898,7 @@ function complete(line, callback) {
           if (obj != null) {
             if (typeof obj === 'object' || typeof obj === 'function') {
               try {
-                memberGroups.push(filteredOwnPropertyNames(obj));
+                memberGroups.push(filteredOwnPropertyNames.call(self, obj));
               } catch (ex) {
                 // Probably a Proxy object without `getOwnPropertyNames` trap.
                 // We simply ignore it here, as we don't want to break the
@@ -889,7 +916,7 @@ function complete(line, callback) {
                 p = obj.constructor ? obj.constructor.prototype : null;
               }
               while (p !== null) {
-                memberGroups.push(filteredOwnPropertyNames(p));
+                memberGroups.push(filteredOwnPropertyNames.call(self, p));
                 p = Object.getPrototypeOf(p);
                 // Circular refs possible? Let's guard against that.
                 sentinel--;

diff --git a/test/parallel/test-repl-tab-complete.js b/test/parallel/test-repl-tab-complete.js
@@ -23,6 +23,7 @@
 
 const common = require('../common');
 const assert = require('assert');
+const Buffer = require('buffer').Buffer;
 
 // We have to change the directory to ../fixtures before requiring repl
 // in order to make the tests for completion of node_modules work properly
@@ -305,6 +306,34 @@ testMe.complete('.b', common.mustCall((error, data) => {
   assert.deepStrictEqual(data, [['break'], 'b']);
 }));
 
+// tab completion for large buffer
+[ Array, Buffer ].forEach((type) => {
+  putIn.run(['.clear']);
+
+  if (type === Array) {
+    putIn.run(['var ele = []; for (let i = 0; i < 1e7; i++) ele.push(i);']);
+  } else {
+    putIn.run(['var ele = Buffer.alloc(1e8)']);
+  }
+
+  common.hijackStderr(common.mustCall((err) => {
+    process.nextTick(function() {
+      assert.ok(/REPLWarning: Instance is too large that the/.test(err));
+    });
+  }));
+  testMe.complete('ele.', common.mustCall((err, data) => {
+    common.restoreStderr();
+    assert.ifError(err);
+
+    const ele = (type === Array) ? [] : Buffer.alloc(1);
+
+    data[0].forEach((key) => {
+      if (!key) return;
+      assert.notStrictEqual(ele[key.substr(4)], undefined);
+    });
+  }));
+});
+
 const testNonGlobal = repl.start({
   input: putIn,
   output: putIn,