"unless" breaks when "each" value equals "null"

[jeremykentbgross]

When using "each" over either an object or an array and a null value is encountered, "unless" will destroy the context, replacing the null value with an empty object, and dropping parent access all together.

Here is a reproduction test case: https://jsfiddle.net/r33cjjb2/3/

To aid seeing the issue, the failing case renders the following inline: !!!FAIL!!!FAIL!!!FAIL!!!FAIL!!!FAIL!!!FAIL!!!FAIL!!!FAIL!!!FAIL!!!FAIL!!

Looking forward to seeing this fixed. It is a real pain in my @$$ atm. Otherwise thank you for a magnificent tool.

[jeremykentbgross]

It seems that if/else have the same bug. Updated test case: https://jsfiddle.net/r33cjjb2/4/

[nknapp]

I tried to reproduce this in a simpler jsfiddle https://jsfiddle.net/r33cjjb2/6/. What you mean is, that the first line of output of my jsfiddle should have parent="parent value" in it, right?

[jeremykentbgross]

Hey nknapp,

Sorry my example wasn't as simple as yours. It was a stripped down version of my actual use case, But yes that is correct, except that actually it's a bit worse than that. Yours only captures part of the issue.

I updated yours again:
https://jsfiddle.net/r33cjjb2/9/

Note that the first (relevant) line (after the 'unless' header) now reads as:
this="[object Object]" parent=""

(The object, as you will see if you catch it in a helper or something as I did for debugging my real project, contains no members.)

It should match the 'no unless' case (I think), which comes out correctly as:
this="" parent="parent value"

As it is, all context values:

• 'this',
• '.' (ie 'this' again via dot),
• '..' (parent)

are containing unexpected values that are inconsistent with all other cases. If the unless is not present, you would get the correct result (as the updated example, or my original shows). In every other case they match.

Also not included in this simpler version is the fact that {{else}} cases are also broken (if memory serves). I also have not tested {{#if}}{{else}}{{/if}}, but looking a bit at the handlebars source code (which I did on my phone on the train the day i submitted this), suggests it probably also has the same issue.

Thanks for your time.

-Jeremy

[jeremykentbgross]

Correction: I forgot that I DID test if/else case, the fiddle for it I had already posted above your first reply.

[jeremykentbgross]

Also I don't know if it is relevant or not, but my original one demonstrated that this was true for iterating over either objects or arrays. Your example only shows arrays. Perhaps this is enough test coverage for the problem, I don't know the internal implementation really so I error-ed on the side of caution and inclusiveness. Sorry if it was too much.

[nknapp]

My example did not cover all aspects, that's right. I just wanted to check if I understood the problem correctly. No problem.

I have to dig into the code as well. It seems like the "unless"-helper just calls the if-helper with flipped blocks.

[nknapp]

One thing I noticed is that for the null-context, in this line the context-parameter is not null but {}. However depths[0]=null which is why the context is added to the currentDepths. This is essentially the reason why the currentDepths are shifted and return the wrong value.

[nknapp]

The place where {} is passed to the function instead of null is here
The change was introduced due to #1093.

[jeremykentbgross]

Thanks for your attention on the matter.

Do you know how long it will take for the fix to turn up in the npm and bower packages? Do I need to wait for a version number increase? If so which one should I expect it will turn up in?