updated today adn minecraft suddenly said my save game was corrupted. did some trial and error and found out it was the new version of litho that caused this

I had a the same thing happen to me. Wouldn't load world saying it was corrupted, going back to previous version fixed the issue.
It also caused Minecraft to crash completely when clicking on Singleplayer with no saved worlds or deleting the last world in the single player list. Here are some crash reports for both scenarios.
crash-2025-01-09_19.53.40-client.txt
crash-2025-01-09_19.57.29-client.txt

You need to be more specific than "my save game was corrupted". Can you not enter your world anymore with a warning about safe mode or are there things like chunk errors?

Same, no idea about any technical details but ever since this update, I can no longer create worlds in my heavily modded modpack. Everything works fine on 1.3.10

CTOV is incompatible with Lithostitched 1.4 until they update to a new format for some internal files.

This breaking change was announced upon the release of 1.3.9 a month ago but it appears they never got around to actually updating :/

Yup, I can confirm this crash. I have been trying to fix this problem for 2 hours, and found out that
When I disabled (lithostitched-neoforge-1.21.1-1.4) and I revert to v1.3.10 the crash does not happen.

So because my particular world depends on the CTOV, I will revert back to v1.3.10 of Lithostitched,
until CTOV updates their mod. 2 hours of frustrations trying to figure out what it was. My head hurts. 🤦‍♂️

I forgot to add limit for lithostitched

Hello,
All of my datapacks and 5 of my content mods are also affected, as I recently added support for Lithostitched with the RPG series mods.
I respectfully ask for a migration guide (or at least some technical comparison that shows difference between version formats).

Moreover, it would be amazing to avoid such cases in the future. Recommended actions for such:

• handle data files in some optional manner, so unparsable files do not actually crash the game
• add some kind of file version field (often called schema version), and parse data files based on that

Hello, All of my datapacks and 5 of my content mods are also affected, as I recently added support for Lithostitched with the RPG series mods. I respectfully ask for a migration guide (or at least some technical comparison that shows difference between version formats).

A page on the wiki has now been made for that. It's a small change for consistency with other worldgen modifiers and I have no plans for future breaking changes right now.

Thank you for the information!

Can confirm this issue is present.

Hello @Apollounknowndev !

This breaking change puts me into a very difficult position.
Under normal circumstances players expect (and are recommended) that latest version from all mods should be installed.

If I do not upgrade for 1.4 -> players don't understand why latest version of everything crashes.
If I upgrade my content mods for 1.4 -> there is no way to play together with CTOV (until it updates).

I respectfully ask for a solution from your end. Options in my mind:

• Make the decoder optional, so it doesn't crash on malformed JSON.
• Make the decoder smarter, so it can parse a either a string or array of strings into an array of IDs.

The minor version number will be used for breaking changes and the patch version number for random fixes/additions moving forwards. In the future, please keep questions in separate issues.

CTOV has updated to work on Lithostitched 1.4. Issues with other mods not working with 1.4 should be moved to their own issue page(s).

@Apollounknowndev Why did you delete my comment? I was simply wondering if your project follows semantic versioning so I can watch out for these breaking changes in the future.