#968 - Fix the child deletion issue in many-to-one form

[pimpreneil]

Here is a fix for the Child deletion issue in many-to-one form issue.

Because this issue is caused mainly by Symfony not comparing the collection objects like Propel is made for, I unfortunately did not manage to provide any tests, though this fix does not break any existing ones...

[marcj]

Thanks! Can you also please add a failing unit tests that covers your changes? I'm not sure if this fixes really that issue. I think we had a issue with this approach (performance/memory) and changed it a bit. Not sure why it isn't working at the moment.

[pimpreneil]

Thanks @marcj , unfortunately, as mentioned I really am not capable to write the failing test (I did try!).
This PR does fix the issue, one of my projects was stuck because of this issue, and this fix really sorted the things out.
There must indeed be a reason for this code to be removed in Propel2.

As detailed in the related issue #968 , the problem originates from an object comparison in Symfony2 that fails when using Propel, and succeeds when using Doctrine

[pimpreneil]

@marcj Sorry, I fucked up a bit and pushed my modifs twice (forgot to merge master before pushing my branch)...
Anyway, here is the requested failing test.

[Maxooo]

Good test, thank you @pimpreneil 👍

[pimpreneil]

If you don't want to merge it, maybe change the tag? :)

[marcj]

Very nice, could you please squash your commits into one? :)

[pimpreneil]

@marcj Done. Thx 😀

[marcj]

Awesome, thanks =)