[Bug]: Cloning worlds with uppercase letters fails on linux

[henry-samulewitz]

/mv dumps output

[18:37:02 INFO]: Logs : https://mclo.gs/Ns619fc [18:37:02 INFO]: pastes.dev : https://pastes.dev/ZLjFRNMjFx

Server logs

https://gist.github.com/henry-samulewitz/7aaa011954c383e2fbd96ed4ee7fc3db

Server Version

[18:39:55 INFO]: Checking version, please wait...
[18:39:55 INFO]: This server is running Paper version 26.1.2-64-main@2186e1e (2026-05-16T22:33:57Z) (Implementing API version 26.1.2.build.64-stable)
You are running the latest version

Bug Description

When running /mv clone on the latest Minecraft version on Linux using a worldName containing at least 1 uppercase letter, it fails to copy the world and instead throws an error.
This bug could only be replicated on Linux, not on Windows.

Steps to reproduce

1. Start a Paper-Server for the latest version (at this time, 26.1.2) with Multiverse-core (latest version) installed on Linux (here tested with Linux Mint and Ubuntu)
2. Create a world with a name containing an uppercase letter (example: "/mv create Test")
3. Try cloning the newly created world (example: "/mv clone Test TestB")
4. The world will not be cloned, but instead an error is thrown

Agreements

• I have searched for and ensured there isn't already an open or resolved issue(s) regarding this.
• I was able to reproduce my issue on a freshly setup and up-to-date server with the latest version of Multiverse plugins with no other plugins and with no kinds of other server or client mods.

[henry-samulewitz]

Forgot to specify: The world-type (normal, nether, end) does not change the result.
The example-command should obviously be "/mv create Test normal"

[benwoo1110]

Yea it needs to be forced lowercase now, workaround for now is just create world with name that are all lowercased and use alias to change the display name