I am still getting this error on Foreman 1.4

Perhaps you could use snippets to get around the character limit?

i've change the size of the "layout" column in pgsql, so now, it work with long ptables.

not sure if it's the best way, but now it's working...

I had the same issue with an mysql backend.

The mysql column is defined as varchar(2048). My partition layout was being truncated without warning.

I edited my layout so it used up less space and fixed it like that.

The field in foreman should at least check for the same amount of max characters and throw an error if it has to many character.