AV0007: Invalid API version day

Cause

An API version expressed an invalid day.

Rule Description

When an API version is expressed as a date, the specified day must be valid.

Consider the following code:

[ApiController]
[ApiVersion(2026, 1, 32)]
[Route("[controller]")]
public class ExampleController : ControllerBase
{
    [HttpGet]
    public IActionResult Get() => Ok();
}

The day 32 is not a valid API version. The day must be between 1 and 31. This would not detected until runtime.

How to Fix Violations

Update the API version to be well-formed.

[ApiController]
[ApiVersion(2026, 1, 1)]
[Route("[controller]")]
public class ExampleController : ControllerBase
{
    [HttpGet]
    public IActionResult Get() => Ok();
}

When to Suppress Warnings

It is never safe to suppress this rule because a runtime exception will be thrown when the attribute is initialized.