feat(ngRepeat): use block separator comments

[jankuca]

This change allows the use of ngRepeat in combination with directives that use transclusion and directives that replace its original elements or add more elements to ngRepeat blocks.

[mary-poppins]

Thanks for the PR!

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[jeffbcross]

Tests passed on CI: http://ci.angularjs.org/job/angular.js-jeff/58/console

[jeffbcross]

Can you change the commit message to close the issues that this resolves? https://help.github.com/articles/closing-issues-via-commit-messages

Unfortunately, I tried applying the fix to issue #4002 but it didn't completely fix it. I think it may require a separate PR though. If you want to see the failing example, see this plnkr: http://plnkr.co/edit/Hjqpqbuy0nhrTOmCjk36?p=preview and swap out the angular.js src with http://ci.angularjs.org/job/angular.js-jeff/58/artifact/build/angular.js

[rodyhaddad]

There is a problem with multi-element directives: if they contain an element with a directive having transclude: 'element', they will fail to remove any node that that directive add:

<div ng-if-start="expr"></div>
<div ng-repeat="item in list">{{ item }}</div>
<div ng-if-end></div>

Anything that ngRepeat adds in the example above won't be removed by ngIf when expr evaluates to false

This PR solves the problem for ngRepeat, which is where multi-element directives are used the most. But a more generic solution implemented in $compile would be much better in the long run.

[vojtajina]

better to create a DSL, toBeComment()

[vojtajina]

I added some changes in https://github.com/vojtajina/angular.js/tree/pr-4157:

• take care of moving elements too
• remove block.elements as we don't use it anymore

@IgorMinar can you review that ?

[rodyhaddad]

While this does solve #3104, #3104 unveils an underlying problem that the changes in this PR don't address (and I tried to explain the problem in that issue a while ago)

This only works for ngRepeat, it's simply not generic!
Any directive that gets used in a multi-element fashion will face the exact same problem.
That's why it should be baked in $compile (or something similar), instead of having the individual directive solve the problem on its own.

It's like the whole multi-element implementation scenario again: The first PRs submitted on the subject worked just for ngRepeat (#1646, #2531), but then we had a PR (#2783) that made $compile support multi-element directives natively with -start/-end, and that's awesome because others can benefit from the progress.

I'm not saying that this PR is bad: if we're looking for a solution to include in the 1.2.0rc3 release, then this is great. But in the long run, it would be better to solve the problem in a way that will work for all directives, not just one. We will surely get new issues when people start using -start/-end with more than just ngRepeat.

[vojtajina]

@rodyhaddad you are right - $compile should take care of this in order to make it more general. That would be however a much bigger change, so for 1.2 I'm merging this fix. The future version of Angular will more likely have a re-designed "compiler" (similar to what angular.dart has now), that takes care of this stuff.

[vojtajina]

Landed as 9efa46a.