Break retain cycles and fix memory leaks

[5sw]

Added __weak and __unsafe_unretained at the appropriate places to break all retain cycles. So finally the git repository gets dealloced when the window is closed.

[tiennou]

Please note that __weak isn't compatible with some classes on 10.7 (see #208 for an example). So if you're reverting anything touched by 5a9bf26, that won't fly for 10.7 users ;-).

Just taking a quick look at the diff, it seems like this ought to be fine tough.

[5sw]

Sure. I was careful to use __unsafe_unretained instead of __weak for NSViewControllersubclasses. Still no guarantees that I didn’t miss some as I don‘t have 10.7 available for testing.

[rowanj]

Can anyone verify on 10.7?

[5sw]

Is 10.7 still relevant? Seems nobody here is using that anymore to test this.

It is still very important to break those retain cycles so things get properly released. Not just because of memory.

• Open a git repository in gitx
• Close the repo again, but leave gitx running
• Move the whole repository to the trash
• Try to empty trash

Doesn't work as some pack-index-files are still open.

[rowanj]

10.7 and 10.8 each have roughly half the market share of 10.9; so dropping 10.7 is potentially 25% of users capable of running the current version.

Weather that is relevant is debatable, but given the voracity with which bugs are reported when compatibility is broken, I'm leaning toward yes - however I have long said that 10.7 support in GitX won't be around forever unless somebody actually volunteers to maintain it.

The time is coming, I think it may be basically after the next round of bug fixes.

[rowanj]

I should note: I like these changes.