I've heard through the grapevine from a little birdy (firebelle) that ID shifting is not supposed to occur from 1.8 on. However, every time I remove a mod in any branch of Forge from 1.8 to 1.11.2 the world associated with the pack experiences what I call ID SHIFTING. Where blocks that might've been logs are now machines or some other block from some other mod in the pack.

 

I can agree with the little birdy that this should not be  happening because we went to actual names as IDs but then I also know that those names are mapped to internal actual ID numbers. So if you delete a mod, all of the associated ID slots associated with are now empty and Forge then to conserve precious memory compacts the ID map essentially reallocation those IDs to other mods that came below the one that was removed, thus causing what I call the ID SHIFT or world corruption as others might call it.

 

Is the the bird on the grapevine correct? If so, how do I tell Forge to stop compacting so that ID SHIFT doesn't occur? Other than not removing a mod is there any other way to protect against it with MCediting or some such.

On 6/4/2017 at 8:03 PM, diesieben07 said:

Forge specifically does not "compact unused IDs", i.e. IDs that were once in use are marked as "blocked" in the save file, even if the corresponding mod is removed.

However there are some mods that think it is a good idea to hack into the internals of FMLs registry system and break it in the process. If you post your FML log, we can tell you whether you have such a mod installer.

Here ya go.

 

https://gist.github.com/a52ec71c7cc694aa1578cfd15a62d62c