Add-on Compatibility for Firefox 35

Dec 18 2014

Firefox 35 will be released on January 13th. Here’s the list of changes that went into this version that can affect add-on compatibility. There is more information available in Firefox 35 for Developers, so you should also give it a look.

General

Implement ES6 “temporal dead zone” for let. If your add-on is affected by this, you were likely contacted by us before about this, since it affected many add-ons and caused their scripts not to work at all. This is due to certain types of redeclaration using let that weren’t detected before. There’s an extended discussion about how this in the newsgroups.
Truncate tag to a maximum length. Tags in bookmarks used to have no length restrictions, causing performance problems if they were too long. They are now restricted to to 100 characters.
Remove DOS encodings that aren’t Web-exposed. A number of old encodings that weren’t exposed to content have been removed.
Replace jschar typedef with char16_t.
Remove Navigator::MozisLocallyAvailable API.

New!

tabbrowser’s _getTabForBrowser is very slow with lots of tabs. The new bit here is that now there’s a public getTabForBrowser function in gBrowser, which is also more efficient when there are lots of tabs open. The private form of this function (_getTabForBrowser, with an underscore) is deprecated.

Please let me know in the comments if there’s anything missing or incorrect on these lists. If your add-on breaks on Firefox 35, I’d like to know.

The automatic compatibility validation and upgrade for add-ons on AMO will happen soon, so keep an eye on your email if you have an add-on listed on our site with its compatibility set to Firefox 34.

9 responses

Kohei Yoshino wrote on December 19, 2014 at 8:21 am:

Japanese translation, as always 🙂 https://dev.mozilla.jp/2014/12/firefox-35-addon-compatibility/
1. Jorge Villalobos wrote on December 22, 2014 at 12:27 pm :
  
  Yay!
Aris wrote on December 19, 2014 at 8:45 am:

Since “gBrowser” is mentioned, is there a documentation somewhere about all “gBrowser” functions and what they can do?

Where can we read about e.g. gBrowser.selectedTab, gBrowser.addTab, gBrowser.tabContainer
functions?
1. Jorge Villalobos wrote on December 22, 2014 at 12:29 pm :
  
  gBrowser is a tabbrowser node, so you can find some of this info in the tabbrowser element docs.
steve nicolas wrote on January 1, 2015 at 6:30 am:

Why don’t you give people the option of staying on there old versions. You changed the search engine to ASK which is a joke. I have tried to get Google back but it won’t let me. Your system changes is going to force me to change severs.
1. Jorge Villalobos wrote on January 8, 2015 at 12:32 pm :
  
  You can stay on old versions if you disable automatic updates. Also, the search engine was changed to Yahoo!. If you have Ask set, then it’s for a different reason (maybe an add-on or other software you installed).
mcdavis wrote on January 6, 2015 at 10:57 pm:

Bug 944836 – No longer possible to move the Firefox window when it happens to be busy – is one for theme developers to know about since it needs to be used in-theme and has to do with functionality rather than just styling. There’s a new CSS property -moz-window-dragging, intended for chrome use only, that on OS X is used instead of the older drag bindings on windowdragbox, some toolbars, some statusbars and the Firefox-drawn titlebar. The new property defines draggable areas for moving the window, and it’s required (again, on OS X only) for window dragging to work right in the case when the system-drawn window titlebar is hidden and also for dragging by (some) toolbars whether the system-drawn window titlebar is shown or hidden.
MaDonna wrote on January 14, 2015 at 4:18 pm:

colorPicker3.0 is not working with FF 35. The color codes do not read out. I am sorry I posted this remark on the FF 36 site. Couldn’t delete it.
1. Jorge Villalobos wrote on January 15, 2015 at 10:03 am :
  
  Seems to work okay for me.