# schema-enum-types

Source: https://apigenie.pl/docs/linter/asyncapi/rules/schema-enum-types

This rule ensures that the values listed in the `enum` of a schema are
allowed by the schema's `type`.

## Rule Details

An enum value whose type is not allowed by the schema can never be sent or
received: a message containing it would fail validation. Such values usually
come from a missing or wrong `type`, or from unquoted YAML values (e.g. `yes`,
`1.0`) that are parsed as something other than strings.

The `schema-enum-types` rule checks every schema of an AsyncAPI document that
has an `enum` list, and reports `Enum value type is not in the schema type`
when one of the values is not allowed by the schema's `type`:

- strings require `string`, booleans require `boolean`, `null` requires
  `null`, arrays require `array` and objects require `object`,
- integer values require `integer` or `number`,
- other numeric values require `number`.

A schema that has an `enum` but no `type` is reported as well, since none of
its values is allowed by an explicit type.

## Configuration

None.

## Examples

**Good**.

```yaml
asyncapi: 3.0.0
info:
  title: Pet Events
  version: 1.0.0
components:
  schemas:
    PetStatus:
      type: [string, "null"]
      enum: [AVAILABLE, ADOPTED, null]
    Rating:
      type: number
      enum: [1, 2.5, 5]
```

**Bad**. The values are integers, but the schema allows only strings.

```yaml
asyncapi: 3.0.0
info:
  title: Pet Events
  version: 1.0.0
components:
  schemas:
    Priority:
      type: string
      enum: [1, 2, 3]
```

## Automatic fixes

When invoked with `--fix`, this rule sets the `type` of a reported schema to
the type of its enum values, provided that all values have the same type and
the schema has no `format`. In the "Bad" example above, the type of
`Priority` is changed to `integer`. Schemas mixing values of different types
are not fixed.

## When Not to Use It

We recommend to always enable this rule.

## Compatibility

This rule is compatible with AsyncAPI 3.x documents. AsyncAPI 2.x documents
are rejected by the reader and are not linted.