Tabs are not working in current build

Using the current build (https://github.com/twbs/bootstrap/commit/721d948d949f783d3213f383d1ef97ff909a2249) the tabs seems broken for me. You can see a demo of this issue here: https://plnkr.co/edit/VBjPURJoPwCeQWuyt3OB?p=preview

I’ve included the JS (see bootstrap-721d948.min.js) from the master branch.

Clicking the tabs throws a Uncaught TypeError (Cannot read property 'nodeName' of undefined), looks like a regression from #23087 at this line https://github.com/twbs/bootstrap/pull/23087/commits/2eb1e687bd74d147145000b3971821cc890d7652#diff-02a6d2619ddbbd65ac148de3377674eeR154.

[kleisauke]

Update: Looks like when applying the base .nav class on the HTML <ul> tag:

--- index.html	Tue Aug 22 17:29:03 2017
+++ index.html	Tue Aug 22 17:28:39 2017
@@ -18,7 +18,7 @@
       </button>
 
       <div class="collapse navbar-collapse" id="navbar-header">
-        <ul class="navbar-nav mr-auto" role="tablist">
+        <ul class="nav navbar-nav mr-auto" role="tablist">
           <li class="nav-item">
             <a class="nav-link active" id="over-tab" href="over" data-toggle="tab" data-target="#over" aria-controls="over" role="tab"><span>Over mij</span></a>
           </li>

^{(https://plnkr.co/edit/lhm70q5YxdsHg10kYjjA?p=preview)}

That the error is gone.

To prevent confusion, should this class also be added on the starter-template? Or is it better that the class navbar-nav is added on Tab.js nav selector? Note that everything was working fine with alpha 6 (so without the base .nav class).

[k-funk]

Just ran into this after upgrading from Bootstrap4 Beta1 -> 2. Not sure why it just popped up now and not before, but these issues that depend on a parent css class to work are extremely difficult to debug. Would be nice if there weren’t these arbitrarily-required parent classes whose only purpose is for jquery to point at.