Request: traversing into enum for failure message

[jamesbraza]

In astral-sh/ruff#11880 today with validate-pyproject==0.18, I am getting an error that says:

[ERROR] `tool.ruff.lint` cannot be validated by any definition:

The actual error was in an extend-select field whose JSON schema type is enum:

    "RuleSelector": {
      "type": "string",
      "enum": [
        "A",
        "A0",
        ...,
      ]
    },

The request here is to traverse into the enum for a better error message:

[ERROR] `tool.ruff.lint.extend-select` cannot be validated by any definition:

To show where the exact error lies

[abravalheri]

Hi @jamesbraza, sorry this issue slipped under my radar.
Right now we depend on the implementation of the fastjsonschema dependency, so I believe we cannot implement this directly in validate-pyproject.

[trim21]

Is it possible to use another json schema validator if they have better error message? Since the performance is not very critical in this case

Foe example horejsek/python-fastjsonschema#72

[abravalheri]

My policy for this repo is to use a JSON schema validator that allows 0 dependency (fastjsonschema allows that once you compile).