OH3 Rules reload - Type cannot be derived

Setup, Configuration and Use Scripts & Rules
1

In Openhab 3, when rules are reloaded I’m getting:

2021-01-06 14:24:57.612 [INFO ] [el.core.internal.ModelRepositoryImpl] - Loading model ‘default.rules’
2021-01-06 14:25:10.630 [INFO ] [el.core.internal.ModelRepositoryImpl] - Validation issues found in configuration model ‘default.rules’, using it anyway:
Type cannot be derived

Can I verify somehow, what cause it?

2

This is a warning not an error so the rule probably is working as it should.

The warning is telling you that you have a variable somewhere that is defined in such a way that it cannot determine what type of Object it represents. For example

var myTimer = null

There is nothing there to tell the parser what type myTimer is. The correct way to define it would be

var Timer myTimer = null

That tells the parser that myTimer is of type Timer.

So start by looking for something like that.

3

Is it connected with strict null assignment or just general variable definition?
It’s outside rules or can be anywhere?

4

Any variable that is defined without assigning to it something with a type will cause this problem. So

var myVariable

would also cause the problem.

anywhere in the .rules file.

5

Can I change logging and verify where is it?
There are so many… :slight_smile:

6

No, but if you have any variables created without a type and without an assignment to something other than null you need to change them all.

7

Thanks !! It seems it was a problem when variable doesn’t have an assignment or value. Similar as in example above:

var myVariable