Broken live-binding with can.compute if compute is updated with a can.Construct

[colinexl]

The first commit that shows the broken behavior is 3c386da

Here's a fiddle: http://jsfiddle.net/qYdwR/1182/

Before, we initialized an empty compute by using

can.compute()

Then after some async loading operations are done, it'll update the compute by calling passing in a new Construct with data:

can.compute(new ConstructOfSomeSort(data))

This would then cause the Mustache view to update itself due to live-binding.

However, after this commit, the Mustache doesn't update itself anymore. I dug around briefly and it looks like the "computed" function in compute.js is no longer being called after the can compute update.

I believe this issue is happening in the latest CanJS2 as well.

[andykant]

I've tested this a bit further, and this is an issue whenever the compute's value starts as undefined. It doesn't matter what type of new object you set it to (not can.Construct-specific)

[andykant]

In the meantime, here's a workaround... Initialize your empty can.compute with can.compute(null).

[colinexl]

@andykant Your solution worked perfectly and thanks for getting down to the root cause.