The release cycle for WordPress 3.6 isn’t going to start until January, but we can of course start to drop in some early things before then. (This worked out nicely before the start of 3.5.)
With that in mind, I have added jQuery 1.9 Beta 1 to trunk. It comes with a migration plugin for deprecated/removed features, and this migration plugin issues warnings in the console so we may fix them. Yes, we are likely to ship the migration plugin in 3.6 final; that’s why it exists. But for now, we should aim to fix anything not only outright broken in core, but also any warnings. (There are a lot of them.)
For more, see the jQuery announcement post and the WordPress core Trac ticket, #22975.
A side note: If you are using the WordPress Beta Tester plugin and wish to go back to the 3.5 branch, you can do so by changing the update stream setting from “Bleeding edge nightlies” (which is currently 3.6-alpha) to “Point release nightlies” (which is currently 3.5.1-alpha) and then downgrade. Of course, we’re happy to have you testing the 3.6 branch, which will be kept fairly stable throughout its development.
Ashley, and 8 others are discussing. 
Papa Midnight, 
Eric Mann 2:51 am on December 18, 2012 Permalink | Log in to Reply
I like the idea of the migration plugin … but I’m hesitant shipping any library that includes “Beta” in its version number. What’s to say parts of the API won’t change by the time 1.9 is finalized? Not to mention the possibility of shipping bugs with our own release…
Japh 3:13 am on December 18, 2012 Permalink | Log in to Reply
Most likely something that’s beta now, will be stable by the time we’re ready to ship it. It makes more sense than going with the current stable and shipping that even after it’s out of date, or switching further through the dev cycle and not taking full advantage of new features.
Andrew Nacin 5:06 am on December 18, 2012 Permalink | Log in to Reply
Sorry, I should have mentioned that jQuery 1.9 is due out in January, well before 3.6 would even be in beta.
We strive to always ship the latest of packaged external libraries. By being good citizens and dropping pre-release packages into our own trunk, we contribute greatly to the upstream project while also ensuring there *won’t* be bugs with our own release.
moebiusmania 9:05 pm on December 27, 2012 Permalink | Log in to Reply
hi, there is any possibilities of having the $ alias for jQuery by default in 3.6?
Andrew Nacin 3:44 pm on January 10, 2013 Permalink | Log in to Reply
No, likely not. jQuery.noConflict() — used for historical reasons because of potential conflicts with other libraries, primarily Prototype — also happens to enforce better code. You can still use
$in code, you just have to be smarter about it:jQuery(document).ready( function($) { // You can use $ in here });Or:
(function($) { // You can use $ in here })(jQuery);