Reporting duplicate enum values when json schema is compiled?

[sebastien-rosset]

It would be useful to report a warning or error when the compiler finds duplicate enum values. For example, having the same foo enum value in a flat list of enums seems to be a mistake (such as a typo by the author of a JSON schema):

enum:
- foo
- foo
- bar

Technically, duplicate enum values are allowed by the spec, so I understand why the compiler cannot fail the compilation if it finds duplicate enums. The 2020-12 JSON schema states:

The value of this keyword MUST be an array. This array SHOULD have at least one element. Elements in the array SHOULD be unique.

(https://json-schema.org/draft/2020-12/json-schema-validation.html#name-enum )

Previously (in draft 4 - https://datatracker.ietf.org/doc/html/draft-fge-json-schema-validation-00#page-15), enum values MUST be unique.

Elements in the array MUST be unique.

[santhosh-tekuri]

schema validation is done by validating it with hyper-schema (see here. there is no explicit code for schema validation.

in hyper-schema https://json-schema.org/draft/2019-09/meta/validation enum has no uniqueItems see here

in hyper-schema https://json-schema.org/draft/2020-12/meta/validation enum has no uniqueItems see here

so making it error for above two drafts make it incompatible with the specification.

in earlier drafts, the hyper-schema has uniqueItems for enum keyword.

raising warnings is never considered in the library. the api is also not suitable for generating warnings. and more over the library never assumes to be as linter by users.

[sebastien-rosset]

thanks. I'm closing the issue.