When loading different worlds (save files), previously loaded map items remain loaded.
What I expected to happen was...:
Map items will display the appropriate content for the world.
What actually happened was...:
The first map item of a given ID I open in a world carried over to worlds I open afterwards. In order to view the appropriate map contents, Minecraft must be restarted. The map data is not actually copied to the second world, but appears on the screen as though it was.
Steps to Reproduce:
1. View the first map created in a world (save, not dimension. create a new one if needed)
2. Exit the world, but not Minecraft
3. Open or create a second world (save, not dimension), and open the first map in that world. the map from the first world will be displayed instead, same with the 2nd, 3rd ... 9000th map of a world. I used higher numbers for pictures in maps.
4. Maps that were not loaded in the first world, but were loaded in the first will generate as normal, but that bug will carry over to the first and any future worlds
5. restart Minecraft, it will clear the bug. The bug will occur again if you open a second world without restarting. Not tested with servers.
Linked issues
Attachments
Comments 6
Duplicate of MC-33193
Not a duplicate of MC-33193. This is about map data of the same ID being shared across save files, not map locations being shared across dimensions or worlds. The screenshots I've attached show the effects of opening one save after another, and the map data being left in cache. The contents of the map appear in the other save, misrepresenting terrain and images contained in maps.
Although I do not know any 1.7 servers to test this with, in theory loading a map in single player and going onto a 1.7 server would make it appear as though your single player maps were on the server, and vice versa.
As for Meta's comment, deleting the map data files does NOT fix this bug, but restarting Minecraft does. I agree that it sounds like a feature, saving time in loading maps. However, it sounds like that feature was poorly implemented.
Is this still a concern in the latest Minecraft version 13w48b? If so, please update the affected versions in order to best aid Mojang ensuring bugs are still valid in the latest releases/pre-releases.
Sounds like a feature.
As far as I know (or guess) there are files with the data for the maps. Go kill them.