Following d592bf9cb6, paths requested at turn N were set-up to be
computed between the end of turn N and the start of turn N+1 (which
would ultimately allow threading this computation), via calls to
'StartProcessingMoves' and 'FetchAsyncResultsAndSendMessages'.
However, the call to UpdateGrid() remained at the start of turn N+1,
between the 'start' and 'fetch' calls. Since all paths are currently
computed on the 'start' call, this means all paths are computed on a
(possibly) dirty pathfinder grid.
In particular, this leads to OOS on rejoin since the rejoiner will
recompute the grid before computing the outstanding paths.
This would also obviously be buggy in a threaded environment, since some
paths might be computed on the fresh and some on the dirty grid.
Finally, MT_TurnStart was sent before the paths were computed, which
might lead to further pathfinder grid changes (not a crashing problem
without threading, but still conceptually odd). The 'fetch' call is thus
moved before it.
This thus fixes d592bf9cb6/D1918, after 92ad6a61fa already fixed a first
issue.
Since the grid is now only updated at the end of a turn, we need to
ensure that it is correct on Turn 0, thus the pathfinder recomputes it
on InitGame.
Refs D14
Reported by: Itms
Fixes#5851
Differential Revision: https://code.wildfiregames.com/D3064
This was SVN commit r24142.