Type checking: "unable to compile the schema: pattern must be a valid regex"

[anderseknert]

The JSON schema-backed type checker fails if it encounters a regex pattern that it can't compile, even though the pattern is valid in the ECMA regex dialect provided in JSON schemas. While we'll unlikely be able to support that regex dialect fully, there doesn't seem to be much point in compiling those patterns at all unless we're actually using them in our type checks, which as far as I can tell, we don't. If correct, I'd suggest ignoring pattern for the purpose of type checking, and don't compile the values.

Example schema and policy below, reduced from the AWS Cloudformation S3Bucket template schema.

schemas/name.json

{
    "properties": {
        "name": {
            "pattern": "^(?!aws:.*)[a-zA-Z0-9\\s\\_\\.\\/\\=\\+\\-]+$",
            "type": "string"
        }
    }
}

policy.rego

# METADATA
# schemas:
#   - input: schema.name
package policy

allow {
    input.name == "Jane"
}

opa eval -f raw -d policy.rego -s schemas data.policy.allow
1 error occurred: policy.rego:6: rego_type_error: unable to compile the schema: pattern must be a valid regex