Code review comment for lp:~widelands-dev/widelands/bug-1674243-crash_with_save_game

Mhh, ao the savegames caanot be fixed, as they already have the broken status.
So when or why is Player::rediscover_node called?

As of the code this is for the NoteFieldTerrainChanged Event raised
by Map::change_terrain, this should happen by the gameeditor or some
luascript only -> should happen in scenarios only?

And when the a fields vision changes from 0 to 1 (read the field becomes visible)
from see_node/see_area, but this is called in a regular manner.

please add a comment to that function.