Bug 3293 – Object.prototype.hasOwnProperty() missing

• Status: RESOLVED
• Resolution: FIXED
• Component: JavaScriptCore

[Gavin Kistner]

The hasOwnProperty() method is specified in ECMAScript-262 rev3 section 15.2.4.5 (page 85), but is 
missing from Safari/JavascriptCore.

Test pages at http://phrogz.net/JS/hasOwnProperty.html and http://phrogz.net/JS/
hasOwnProperty_test.html

This bug is copied from Apple's Bug Reporter #3749342

[Gavin Kistner]

Created attachment 2126 [details]
Webpage with simple test case

[Gavin Kistner]

The severity of this bug is due to the fact that--without this feature--it is impossible to extend objects 
through the prototype without breaking the iteration of properties in an object using the
for ( var propName in myObj )
loop style.

A real-world case where this breaks is http://phrogz.net/JS/Object.prototype.toSourceCode.js (which was 
'hacked' to look for 'toSourceCode' as an explicit key, but which breaks if any other key is added to the 
prototype, such as http://phrogz.net/JS/Object.prototype.duplicate.js 

[Mark Rowe (bdash)]

Created attachment 2218 [details]
Implementation of Object.prototype.hasOwnProperty

[Mark Rowe (bdash)]

Created attachment 2219 [details]
Layout test

[Mark Rowe (bdash)]

Created attachment 2220 [details]
Expected layout test output

[Mark Rowe (bdash)]

Created attachment 2286 [details]
Updated implementation that handles special properties correctly

[Mark Rowe (bdash)]

Comment on attachment 2286 [details]
Updated implementation that handles special properties correctly

This patch adds a new hasOwnProperty method to ObjectImp, and alters
hasProperty to delegate to it.	Subclasses are updated to implement
hasOwnProperty rather than hasProperty where needed.

[Mark Rowe (bdash)]

Created attachment 2287 [details]
Updated layout test

[Mark Rowe (bdash)]

Created attachment 2288 [details]
Updated layout test output

[Darin Adler]

Comment on attachment 2286 [details]
Updated implementation that handles special properties correctly

ObjectImp::hasProperty that takes an integer needs to call through to
hasOwnProperty that takes an integer; it's important to stay in the integer
code path until you get to the array implementation of hasOwnProperty.

Other than that, this patch looks good.

[Mark Rowe (bdash)]

Created attachment 2483 [details]
Updated patch with Object::hasProperty improved for the integer case

[Maciej Stachowiak]

I have this in my tree and ready to commit, just need to complete ChangeLog entries.

[Maciej Stachowiak]

Landed.

[Adele Peterson]

This change has caused two failures in the layout-tests.  I'm rolling the fix out.

[Adele Peterson]

Comment on attachment 2483 [details]
Updated patch with Object::hasProperty improved for the integer case

Setting the review - flag.  We need a new patch that fixes the layout-test
issues.  When this gets fixed, we also need to re-add a few layout tests

[Adele Peterson]

Created attachment 2537 [details]
other layout test that uses hasOwnProperty that needs to be added

This is another layout test that we need to land when we fix this bug

[Maciej Stachowiak]

Created attachment 2747 [details]
Fixed version of patch - passes all layout tests.

[John Sullivan]

Comment on attachment 2747 [details]
Fixed version of patch - passes all layout tests.

Don't forget to commit the new layout test that Adele attached.

[Maciej Stachowiak]

*** Bug 4203 has been marked as a duplicate of this bug. ***

[Mark Rowe (bdash)]

*** Bug 5569 has been marked as a duplicate of this bug. ***