Editor: packet 'Immovable' incompatibility in B19

[toptopple]

I saved my map "Gold Rush 1.1" with build 8199 (post-B19). When I try to open this map in B19 (Debug) I receive an incompatibility message and it does not open. There was already 1 player who reported this bug in the "Maps" download gallery as a comment on this map.

The message reports an incompatibility of packet "immovable.cc:706", UnhandledVersionError, saved version 8, current version 7.

SirVer mentions in the forum that this should not happen.

[GunChleoc (gunchleoc)]

This is caused by the extra data that we need for former_building, so we can show a building name when a building is burning. This new data is only needed for game loading, not map loading.

We do need to load immovables into maps though, so not sure how to solve this one.

[TiborB (tiborb95)]

I dont know the code, but would it be viable to use something like "Unknown" as a replacement of missing information?

[GunChleoc (gunchleoc)]

No - the problem is the packet format. There is no way that I can tell a past version of Widelands not to read something.

I have had an idea though - We could have 2 packet numbers, one for with former_building, and one for without. When saving, the Immovable can detect whether former_building == nullptr and if so, use the old packet version - this will give us the old packet version for map saving and loading.

[GunChleoc (gunchleoc)]

Fixed in build20-rc1