A library I wrote (http://github.com/nathansobo/space-pen) for a large internal project at GitHub allows you to build view objects that inherit from jQuery with prototypical inheritance. Unfortunately, there's 3 places in jQuery core where code references this.constructor when it could just reference the jQuery constructor directly to build new element sets.

I am able to build instances of my inheriting constructor correctly, but when I try to call methods on it like find, jQuery tries to call my constructor when it really wants to call the original jQuery constructor, which causes problems. The only way around it short of changing jQuery is to assign this.constructor = jQuery on my objects in their constructor, but this creates surprises when other code wants to inspect the inheriting object's constructor and it sees the wrong value.

The jQuery unit tests still pass when I replace the 3 references to this.constructor with a reference to the local jQuery variable in core.