Missing assets using the additionalStreams option

[asselin]

If you use the additionalStreams option, gulp-useref may not stream through all of the assets. This is a timing dependent bug.

[asselin]

Updated an existing test to reliably repro the issue.

In debugging, there are a couple of problems I'm seeing:

1. es.wait (https://github.com/jonkemp/gulp-useref/blob/master/lib/streamManager.js#L175) is not waiting for both streams to finish. It looks like it's a bug in the es code (or maybe, since it works with old style streams, in combining old and new style streams).
2. The testcase makes an assumption on file ordering that is invalid

The testcase uses this fixture:

<!-- build:js scripts/combined.js -->
<script src="./scripts/this.js"></script>
<script src="./scripts/anotherone.js"></script>
<!-- endbuild -->

<script src="./scripts/renamedthat.js"></script>
<script src="./scripts/renamedyet.js"></script>

However, useref() won't include 'renamedthat.js' and 'renamedyet.js' in it's output, so as far as reorderTheStream is concerned, they are unsorted files (https://github.com/jonkemp/gulp-useref/blob/master/lib/reorderTheStream.js#L21). This means that whatever order the additionalStreams wind up resolving their files in will be the order they're added to gulp-useref's output stream.

I can take a crack at fixing this if you want, but my preferred way to fix the first issue would be to use a promise. Any objection to adding Q as a dependency?

For the second issue, what is the expected behavior in this scenario? How about if the 'renamed' block was surrounded by another build:js block?

[jonkemp]

Yes, I would prefer not to use Promises here.

[jonkemp]

I need more information here. The failing test in #185 passes once the file is added back to the stream. That seems to invalidate this claim that it is timing dependent. I also fixed the test so it is not order dependent because you are correct, the additional files are not being sent through in any particular order.

[asselin]

OK, I'll take a look at the updated code and see if I can reproduce the issue.