Freelist corruption issues

[finnschiermer]

This is an "overview issue" for various issues all related to/indicative of corruption of the in-memory freelist in the slab allocator.

• Double deallocation while clearing Table #6340
• Exception when adding multiple documents to Realm via loop #6399
• My app crashes when scene phase is changing from background to active #6536
• Realm Write Crash #6593
• Slab allocator crashes deleting a block #6922

The following are also fixed now, but was earlier wrongly attributed to a different bug.

• Crash on open Realm #5953
• Assert while trimming history (2) #5680

[aehlke]

Are there workarounds available such as avoiding shouldCompactOnLaunch?

[finnschiermer]

@aehlke I cannot answer conclusively at this point, since we still haven't identified the root cause. I can only say that we have reports indicating that avoiding compact on launch helps. If you implement this change, we'd be interested in the effect you observe.

[bmunkholm]

Fixed in #6962

[sync-by-unito]

➤ finnschiermer commented:

This issue has been edited to only reflect the bugs we're convinced was fixed.

Issues that are possibly related and may or may not be fixed are now in: #7006