OfflinePlayer#getPlayer causes weird behaviour if player was originally online but have re-logged since

[LichtHund]

Expected behavior

OfflinePlayer#getPlayer should return a valid Player instance at the moment it is called.

Observed/Actual behavior

OfflinePlayer#getPlayer created when the player was online and has since logged out and logged back in will return an outdated Player instance.

Steps/models to reproduce

• Bukkit.getOfflinePlayer when the player is online.
• Player logs out and logs back in.
• OfflinePlayer#getPlayer and try something like Player#openInventory.

Plugin and Datapack List

None.

Paper version

1.21.4-147-main@3bd69f2

Other

I'll start off by saying that I am not sure if this is intentional or not, so if it is then apologies.

Because Bukkit.getOfflinePlayer returns the Player instance itself when the player is online and Player#getPlayer returns this it can be an unexpected behavior. This makes it so if you are expecting an OfflinePlayer but want to do something extra if they are online, like sending a message, but they have since logged out and back again it'll simply not work making Bukkit.getPlayer(offlinePlayer.getUniqueId()) always the most reliable way of doing it.

[lynxplay]

The only way we could technically "fix" this is with a new offlineplayer implementation that implements Player as well but, instead of being a CraftPlayer, has a Weak ref and then delegates all player method to that.

Idk if that is worth it for us to maintain when plugins could just not keep an offline player reference around and instead use a uuid.

[masmc05]

I still wonder, why CraftPlayer even has an override of getPlayer, instead of letting it just get the player from CraftServer as per CraftOfflinePlayer impl? Player interface doesn't override the javadocs, indeed making it a conflicting undocumented behavior change when player object becomes invalid. While if player is online, it wouldn't have changed at all if it would have just request it from the player map and return the same instance

[LichtHund]

I think CraftPlayer returning a player from craft server would be an okay "fix", maintaining a new implementation definitely doesn't seem worth it.

But yeah plugins should be using uuids instead. I found this issue on a plugin because of a completely different problem where attempting to open an inventory on what turned out to be an outdated player instance overrides the inventory holder if they had another inventory opened at the time and now could take items from said inventory.

[lynxplay]

I don't think we can do that? That way Player#getPlayer would return the "updated" player too, which seems wrong.
The entire idea of keeping the OfflinePlayer of an online player around is just so wrong, I don't think we'd wanna encourage it by fixing things for that exact usecase.
I think this might just be on plugins to fix sadly.

Thank you for the report anyway, sorry if the resolution isn't what you were hoping for!