Extremely odd behavior with nested {{#if}} helpers

[workmanw]

We discovered a really bizarre issue today when using nested {{#if}} helpers that have a common condition. It seems that when two {{#if}} helpers have different conditions, but have a common nested condition, it causes a very unexpected rendering.

Example:

{{#if myCondition1}}
  {{#if showInnerSection}}
    Hello 1
  {{/if}}
{{/if}}
{{#if myCondition2}}
  {{#if showInnerSection}}
    Hello 2
  {{/if}}
{{/if}}

If you assume that all three of the above conditions are true (myCondition1, myCondition2 and showInnerSection are all true), the value should be: "Hello 1 Hello 2". However: with RC3 it is: "Hello 1 Hello 1". See this Fiddle: http://jsfiddle.net/DCrHG/15/

So by now you might be thinking, uh, WTF. Here is where I completely blow your mind, if you add a carriage return (newline) in between the nested statements, it WORKS as expected. See this Fiddle: http://jsfiddle.net/DCrHG/16/

Our app is currently on RC2. This problem exists on RC3 in a fiddle. Unfortunately, I can't say for sure how long this has been a problem. We just noticed it today.

CC: @jkoehl

[lukemelia]

I think this is a handlebars bug that was recently fixed: handlebars-lang/handlebars.js#514 / handlebars-lang/handlebars.js#428

Can you try it with latest handlebars and reopen if that does not fix the problem?

[workmanw]

Yea, I'd love to test and confirm, but it seems that the Handlebars.COMPILER_REVISION revision was changed to 3 (baccdb4c) before this was fixed (d6f146f). Ember-latest currently only supports compiler revision 2. Any advice on how to actually test it?

[lukemelia]

@workmanw ideally, you could add a failing test case, update to COMPILER_REVISION to 3 and pull in the new handlebars, verify that that fixes the problem, and then submit a PR with those changes.