[BUG]: Biovalidator can't detect local schema ID - "Empty schema `$id`"

Bug summary

Biovalidator complains about an empty $id in a local schema with a proper $id

Technical details

Biovalidator branch used for installation main
node v16.13.0
npm v8.6.0
OS: WSL2

To reproduce

Create a simple JSON Schema with a $id field as follows:

{
"$schema": "https://json-schema.org/draft/2019-09/schema",
"$id": "https://raw.githubusercontent.com/EbiEga/ega-metadata-schema/main/schemas/test.json",
"type": "object",
"$async": true,
"required": ["test" ],
"additionalProperties": false,
"properties": {
  "test": {
    "type": "string",
    "enum": ["test"]
  }
}      
}

Try to compile the schema using -r at launch of a Biovalidator server:

$ node biovalidator -r "schema_test/test.json"
2024-06-24T16:29:42.041Z [info] Custom keywords successfully added. Number of custom keywords: 5
2024-06-24T16:29:42.042Z [info] Compiling local schema from: schema_test/test.json
2024-06-24T16:29:42.048Z [info] Adding compiled local schema to cache: https://raw.githubusercontent.com/EbiEga/ega-metadata-schema/main/schemas/test.json
2024-06-24T16:29:42.090Z [info] ---------------------------------------------
2024-06-24T16:29:42.090Z [info] ------------ ELIXIR biovalidator ------------
2024-06-24T16:29:42.091Z [info] ---------------------------------------------
2024-06-24T16:29:42.091Z [info] Started server on port 3020 with base URL /
2024-06-24T16:29:42.091Z [info] Server available at http://localhost:3020/
2024-06-24T16:29:42.091Z [info] PID file is available at /mnt/c/Users/mcasado/Documents/GitHub/biovalidator/src/server.pid
2024-06-24T16:29:42.092Z [info] Writing logs to: /mnt/c/Users/mcasado/Documents/GitHub/biovalidator/src/logs/

Create a simple JSON document as follows. Notice how the referenced $id is the same as the one in the schema file.

{
"data": {
    "test": "test"
},
"schema": {
    "$ref": "https://raw.githubusercontent.com/EbiEga/ega-metadata-schema/main/schemas/test.json"
}
}

Execute the validation request:

$ curl --data @test_doc.json -H "Content-Type: application/json" -X POST "http://localhost:3020/validate"

Observe the logs from Biovalidator, displaying a warning about an empty schema $id and that it won't be cached.

2024-06-24T16:29:48.622Z [warn] Compiling schema with empty schema $id. Schema will not be cached.
2024-06-24T16:29:48.646Z [info] Returning referenced schema from cache: https://raw.githubusercontent.com/EbiEga/ega-metadata-schema/main/schemas/test.json
2024-06-24T16:29:48.649Z [info] New validation request: Processed successfully in 28ms.

Observed behaviour

Biovalidator complains about an empty schema $id. Error message sources from: https://github.com/elixir-europe/biovalidator/blob/d8fd80517f1df7621a3b7a4d0deada2a8ed4a186/src/core/biovalidator-core.js#L145

Expected behaviour

The schema's $id should be identified without a warning. It is retrieved successfully from cache and used for validation, but the warning seems misleading.

Additional context

No response

elixir-europe / biovalidator