Vue: _directives.length ERROR: Cannot read property 'length' of null

[kvdmolen]

Using Vueify in an app (compiled in DEV) I get the following error:

Uncaught TypeError: Cannot read property 'length' of null

From script.js:7557

var originalDirCount = vm._directives.length

I use no custom directives. Error occurs only sometimes, very weird.

Any idea anyone?
Thanks!

More context on script.js:

/**
       * A linker function to be called on a already compiled
       * piece of DOM, which instantiates all directive
       * instances.
       *
       * @param {Vue} vm
       * @param {Element|DocumentFragment} el
       * @return {Function|undefined}
       */

      return function link (vm, el) {
        var originalDirCount = vm._directives.length
        if (paramsLinkFn) paramsLinkFn(vm, el)
        if (nodeLinkFn) nodeLinkFn(vm, el)
        if (childLinkFn) childLinkFn(vm, el.childNodes)

[mikend]

I'm experiencing the same error. Had to revert back to 0.11.3 to make my app work again. This is almost definitely a bug. Could try doing some further investigations.

[yyx990803]

This is actually pretty weird because it indicates the linker is called when the target vm is already destroyed. I would need a more isolated reproduction to identify the cause.

[agonbina]

@kvdmolen can you repro this issue in a jsfiddle so we can all look into it?

[kvdmolen]

@agonbina I will definitely try to pinpoint & isolate, but difficult because it happens only sometimes.
Though, it does happen right after an emit event:

var store = module.exports = new Emitter()
store.emit('...')

After which (at the receiver) the v-component should be updated (which is then not executed):

<div v-component="{{page}}"></div>

Perhaps that gives some first insight. It's according the hackernews-example. I'll be working on isolating the issue!

[jcoffland]

Please see my comment on issue #654 above. I believe these issue are not the same but are related.

Events can cause components to be added or removed by changing variables which effect v-if or v-component="{{someVar}}". This alters event propagation. In the case of #654, the list of event listeners may change while the event code is traversing that same list.

I think the event propagation code should make a copy of the event listener list when it begins processing the list. Then while iterating through the list it should check that each listener still exists before calling update().

[yyx990803]

Closing since this has most likely been fixed by v-if and transclusion refactor.