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repl: Prevent crash when tab-completed with Proxy
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If the proxy objects don't have a valid `hasOwnPropertyNames` trap,
REPL crashes with a `TypeError`, as per the bug report
#2119

    > var proxy = Proxy.create({ fix: function() { return {}; } });
    undefined
    > proxy.<tab>
    TypeError: Proxy handler #<Object> has no 'getOwnPropertyNames' trap
        at Function.getOwnPropertyNames (native)
        at repl.js:644:40
        at REPLServer.defaultEval (repl.js:169:5)
        at bound (domain.js:254:14)
        at REPLServer.runBound [as eval] (domain.js:267:12)
        at REPLServer.complete (repl.js:639:14)
        at REPLServer.complete [as completer] (repl.js:207:10)
        at REPLServer.Interface._tabComplete (readline.js:377:8)
        at REPLServer.Interface._ttyWrite (readline.js:845:14)
        at ReadStream.onkeypress (readline.js:105:10)

This patch traps the error thrown and suppresses it.

PR-URL: #2120
Fixes: #2119
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Evan Lucas <evanlucas@me.com>
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thefourtheye authored and evanlucas committed Jul 10, 2015
1 parent 47e2c5c commit 59f6b5d
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Showing 2 changed files with 24 additions and 1 deletion.
9 changes: 8 additions & 1 deletion lib/repl.js
Original file line number Diff line number Diff line change
Expand Up @@ -641,7 +641,14 @@ REPLServer.prototype.complete = function(line, callback) {

if (obj != null) {
if (typeof obj === 'object' || typeof obj === 'function') {
memberGroups.push(Object.getOwnPropertyNames(obj));
try {
memberGroups.push(Object.getOwnPropertyNames(obj));
} catch (ex) {
// Probably a Proxy object without `getOwnPropertyNames` trap.
// We simply ignore it here, as we don't want to break the
// autocompletion. Fixes the bug
// https://github.com/nodejs/io.js/issues/2119
}
}
// works for non-objects
try {
Expand Down
16 changes: 16 additions & 0 deletions test/parallel/test-repl-tab-complete.js
Original file line number Diff line number Diff line change
@@ -1,4 +1,7 @@
'use strict';

// Flags: --harmony-proxies

var common = require('../common');
var assert = require('assert');
var util = require('util');
Expand Down Expand Up @@ -232,3 +235,16 @@ putIn.run([
testMe.complete('cus', common.mustCall(function(error, data) {
assert.deepEqual(data, [['custom'], 'cus']);
}));

// Make sure tab completion doesn't crash REPL with half-baked proxy objects.
// See: https://github.com/nodejs/io.js/issues/2119
putIn.run(['.clear']);

putIn.run([
'var proxy = Proxy.create({});'
]);

testMe.complete('proxy.', common.mustCall(function(error, data) {
assert.strictEqual(error, null);
assert.deepEqual(data, [[], 'proxy.']);
}));

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