So, just to give you a bit of an update, I'm using a Typescript, and my code was like this :

new objection.ValidationError({
    message: "...",
    type: "...",
    data: {...}
});

This is how it is mentioned in the documentation for the custom validation by the way.

Before 2.2.10 everything was fine, but now ValidationError requires a modelClass argument and without it Typescript compilation fails with the error about a missing required param.

I had to add this param to make builds work.

The new code may work with a pure JS, but it is Typescript compilation that is a problem, because the arguments for ValidationError now includes & {modelClass: ModelClass<Model>} which wasn't there before.

It is unexpected to encounter a code breaking change in the patch release, since most of us has the dependency specified as something like this: "objection": "^2.2.3", which will install the latest patch version by default.

Originally posted by @dryu in #1891 (comment)