no-empty-post-response

Id

@azure-tools/typespec-azure-resource-manager/no-empty-post-response

Synchronous ARM resource POST responses with status 200 must have a body.

Synchronous ARM resource POST operations returning 200 must return a response body. Use a 204 response when the operation completes without a payload. Response headers are metadata, not a response body. An explicitly declared empty model payload is still a body, but an explicit @body of type void carries no payload and must also use 204.

The rule reports one warning on an operation when any of its 200 response variants has no HTTP payload. It checks resource lifecycle and action operations, excluding long-running operations. Other rules check allowed status-code combinations and bodies forbidden on 202/204 responses.

This rule is available for explicit opt-in and is disabled in the Azure resource manager ruleset by default.

Incorrect

For an Employee ARM resource, the following response customization returns 200 without a payload:

@armResourceOperations
interface Employees {
  hire is ArmResourceActionSync<
    Employee,
    void,
    Response = {
      @statusCode _: 200;
    }
  >;
}

Correct

Use the same synchronous action template with a 204 response:

@armResourceOperations
interface Employees {
  hire is ArmResourceActionSync<Employee, void, Response = ArmNoContentResponse>;
}

Alternatively, retain 200 and provide a response payload.

Impact

• Area: API
• Impact: A 200 success response without the expected payload makes the response contract inconsistent and can confuse clients. A 204 response explicitly communicates that there is no content to consume.

Suppression

Suppress this rule only when preserving an existing API’s approved response contract requires a bodyless 200 response. For a new API, use 204 instead.

LintDiff Equivalent

This rule covers the synchronous resource POST missing-body check from PostResponseCodes. The mapping is partial: existing official rules retain status-code and async-body checks. This rule does not reproduce legacy LRO response representations or inspect provider actions outside the ARM resource-operation population.