OOS on rejoin - a24 Pathfinder

[elexis]

As of r22958, there is an OOS on rejoin, apparently on every rejoin where a unit had moved.

Sample replay attached that reproduces the serializationtest failure using -rejointest=20 from commandline.

[elexis]

simstate difference

[wraitii]

Thanks for the replay, though I can only reproduce with -rejointest=21, not -rejointest=20 using r22961 (which ought to run identically) ?

[wraitii]

I think I get the issue, it's r22902. I failed to realised that I needed to keep the requests in the pathfinder in case of serialisation.

[elexis]

Replying to wraitii:

Thanks for the replay, though I can only reproduce with -rejointest=21, not -rejointest=20 using r22961 (which ought to run identically) ?

(I think it was turn 30 and I posted the wrong terminal line.)

[wraitii]

In 22979:

Fix OOS introduced by pathfinder threading preparation diff rP22902

Following rP22902, paths were computed at the end of turn N, and then messages were sent at the beginning of turn N+1. However, the path requests were removed at the end of turn N and so weren't serialised, and neither were computed paths. This meant rejoiners would OOS when the game was serialised with pending path results.

To fix this in preparation for threading, the architecture needs to change slightly so that requests are kept and serialised correctly, and rejoiners can compute the paths after deserialisation, in order to send the messages at the beginning of turn N+1.

Fixes #5604

Reported By: elexis

Differential Revision: ​https://code.wildfiregames.com/D2317