pattern.indexOf is not a function

[jerel]

I noticed an uncaught error when upgrading an app from 2.0.0-beta1 to canary: pattern.indexOf is not a function. I found that it came from https://github.com/emberjs/ember.js/blob/master/packages/ember-metal/lib/expand_properties.js#L37-L39 which has a docblock that specifies that pattern is a string but also checks if pattern is of type string after calling indexOf on it. All tests appear to test with a string.

So anyway, while I was debugging I edited the Ember source in my app and moved the pattern.indexOf(' ') call inside the conditional and then received Ember.observer called without a function. Seems reasonable, something must be calling observer wrong. However while I was looking for the cause (I only have about 3 observers in this app, all correct) I restarted ember serve and the error went away. I'm unable to replicate it now.

So, I'm happy to submit a patch to make the behavior more user friendly if that's what is needed. Alternatively maybe someone else will hit the same error and can add details to this issue.

[gpoitch]

That error can occur when an observer has its function before its dependent key arguments, which was deprecated. See: #11778

[krisselden]

@gdub22 @teddyzeenny @rwjblue unfortunately ember inspector throws the same error because it is using this form of observer(fn, key). It was fixed with emberjs/ember-inspector@3cb4460 but the released version I have throws this error.