Convert error hash to object with helpful error rendering messages?

[robacarp]

Hello, and thanks for working on this project. I'm working to get some helpful error messages produced by schema validation and having to jump through some hoops:

  def steps_must_conform_to_schema
    steps.each.with_index do |step, index|
      schema_errors = SCHEMA.validate step

      if schema_errors.any?
        errors.add(
          "step #{index}",
          decode_schema_error(schema_errors.first)
        )
      end
    end
  end

  def decode_schema_error(error)
    messages = []

    error["details"].each do |error_type, details|
      case error_type
      when "missing_keys"
        messages << "is missing required keys #{details.join(", ")}"
      when "schema"
      end
    end

    messages.join ", "
  end

Would it be a useful enhancement to convert the error hash into an object which has rendering methods for building the plain text version of the error?

[robacarp]

Here's a more complete error rendering method. I'm sure it's incomplete, but it's a start:

  def decode_json_schemer_errors(error)
    messages = []

    formatted_data_pointer = format_data_pointer error["data_pointer"]

    case error["type"]
    when "required"
      if error["details"].key? "missing_keys"
        messages << "#{formatted_data_pointer}is missing required keys #{error["details"]["missing_keys"].join(", ")}"
      else
        messages << "#{formatted_data_pointer}is missing required keys"
      end

    when "schema"
      if error["schema_pointer"] == "/additionalProperties"
        messages << "contains unrecognized property '#{formatted_data_pointer}'"
      else
        messages << "does not validate: schema_pointer=#{error["schema_pointer"]}"
      end

    when "string"
      messages << "property '#{formatted_data_pointer}' should be a string"
    when "boolean"
      messages << "property '#{formatted_data_pointer}' should be a boolean"
    when "integer"
      messages << "property '#{formatted_data_pointer}' should be a number"
    when "object"
      messages << "property '#{formatted_data_pointer}' should be an object"
    when "pattern"
      messages << "property '#{formatted_data_pointer}' does not match pattern: #{error["schema"]["pattern"]}"
    else
      messages << "does not validate: error_type=#{error["type"]}"
    end

    messages.flatten.join ", "
  end

  def format_data_pointer(data_pointer)
    data_pointer = data_pointer
      .sub(%r|^/|, '')   # remove leading /
      .sub('/', '.')     # convert / into .

    unless data_pointer.blank?
      data_pointer = data_pointer + ' '
    end

    data_pointer
  end

[davishmcclurg]

Thanks for the issue! I'll keep this in mind when I get around to implementing the latest draft's "output formatting": #2

[davishmcclurg]

I'll likely leave the errors as hashes with a more useful default error message.