Slot usage of attributes in abstract class

[mszulcz-mitre]

I have an abstract class (Abstract) in which an attribute (custom) has the type of a custom class (Custom). In a child class of the abstract class (Implementation), I want to define the type of an attribute (attr3) in the custom class. However, I get an error when I try to validate. Here's the code (InheritanceTest.yaml):

id: https://example.org/InheritanceTest
name: InheritanceTest 
description: |-
  A test for how inheritance works in LinkML.
prefixes:
  linkml: https://w3id.org/linkml/
imports:
  - linkml:types
default_range: string

classes:
  
  Custom:
    abstract: true
    attributes:
      attr3:

  Abstract:
    abstract: true
    attributes:
      attr1:
      attr2:
      custom:
        range: Custom

  CustomImpl:
    is_a: Custom
    slot_usage:
      attr3: float

  Implementation:
    tree_root: true
    is_a: Abstract
    slot_usage:
      attr1:
        range: integer 
      custom:
          range: CustomImpl

Here's the instance I try to validate (InheritanceInstance.yaml):

attr1: 1
attr2: world
custom:
  attr3: 3.14

I validate with linkml-validate -s InheritanceTest.yaml InheritanceInstance.yaml. I get the error [ERROR] [InheritanceInstance.yaml/0] 3.14 is not of type 'string' in /custom/att3. Is what I'm trying to do possible in LinkML?

A related question. Is there a way to identify objects with prefixes in their names? For example, the file above imports linkml:types. Can I identify the types using a C++-like notation such as linkml::integer. Here's my use case: I'd like to be able to use the same class name in 2 different schema files and import 1 to use in the other. To distinguish them, it'd be useful to attach a prefix or a namespace to the imported class.

[sneakers-the-rat]

looks like just a syntax problem:

this:

  CustomImpl:
    is_a: Custom
    slot_usage:
      attr3: float

should be

  CustomImpl:
    is_a: Custom
    slot_usage:
      attr3: 
        range: float

That validates correctly with the above data, and other generated models seem to be right too.

You'll also see a warning that says slot_usage for undefined slot: attr3

Another way you could write the schema is like this:

id: https://example.org/InheritanceTest
name: InheritanceTest 
description: |-
  A test for how inheritance works in LinkML.
prefixes:
  linkml: https://w3id.org/linkml/
imports:
  - linkml:types
default_range: string

classes:
  
  Custom:
    abstract: true
    slots:
    - attr3

  Abstract:
    abstract: true
    slots:
    - attr1
    - attr2
    - custom

  CustomImpl:
    is_a: Custom
    slot_usage:
      attr3: 
        range: float

  Implementation:
    tree_root: true
    is_a: Abstract
    slot_usage:
      attr1:
        range: integer 
      custom:
        range: CustomImpl

slots:
  attr1:
  attr2:
  attr3:
  custom:
    range: Custom

which validates without warning :)

[sneakers-the-rat]

re: namespaced imports, it's an ongoing conversation! https://github.com/orgs/linkml/discussions/1739