# patch-request-body-partial

Source: https://apigenie.pl/docs/linter/openapi/rules/patch-request-body-partial

This rule checks that `PATCH` request bodies do not require properties.

## Rule Details

`PATCH` applies a partial modification to a resource (RFC 5789). With a merge patch
(RFC 7396) the client sends only the properties to change, so none of them should be
required. A `PATCH` body with required properties forces clients to resend values they do
not want to change, which is what `PUT` is for.

The rule checks object schemas of `PATCH` request bodies, including the properties
required by their `allOf` members. `application/json-patch+json` bodies are skipped: they
are arrays of operations, whose properties are rightly required.

## Configuration

This rule accepts an object with the following options:

- `allowedRequired`: names of properties which may be required, for example a version
  used for optimistic locking. Defaults to none.

```yaml
commands:
  lint:
    rules:
      patch-request-body-partial:
        - warning
        - allowedRequired: [version]
```

## Examples

**Good**.

```yaml
paths:
  /users/{id}:
    patch:
      requestBody:
        content:
          application/merge-patch+json:
            schema:
              type: object
              properties:
                name:
                  type: string
                email:
                  type: string
```

**Bad**. Clients must send `name` even to change only `email`.

```yaml
paths:
  /users/{id}:
    patch:
      requestBody:
        content:
          application/json:
            schema:
              type: object
              required: [name]
              properties:
                name:
                  type: string
                email:
                  type: string
```

## When Not to Use It

Many APIs use `PATCH` for an update whose only field is required, such as the body of
a comment. Disable the rule, or list those properties in `allowedRequired`, when `PATCH`
does not mean a partial update in your API.

## Compatibility

This rule is compatible with all OpenAPI 3.x versions.