* For some reason, if a null was recieved (indicating a missing asset), the code had stopped passing that on to the waiting lock, resulting in a perpetual freeze
* This change passes the null on correctly
* Many thanks to thomax for being insistent in presenting his analysis of the problem :)
This may break a lot of things, but it needs to go in. It was tested in standalone and the UCI grid, but it needs a lot more testing.
Known problems:
* HG asset transfers are borked for now
* missing texture is missing
* 3 unit tests commented out for now
* Not locking causes enumeration exceptions as described in this matis
* part.TaskInventory needs to be locked for every access as it's a dictionary
* Extra locking will hopefully not cause any major issues - in places where the enumeration of the dictionary performs other lock or long running operations, the dictionary is
cloned instead