Rule 6-6-5 A function shall have a single point of exit at the end of function.

[mishak]

Yes, this rule is a bit of a pain to live with at times. Unfortunately, functional safety standards (i.e. 61508 and derivatives) require that functions have a single point of exit - the rule is there to support that objective.

Personally, I see no issue with using a deviation supported with a "Reason" of code-quality.

It's worth noting that MISRA C:2012 has reduced the enforcement level of this rule to "Advisory", which makes it easier to manage as it could be set to "Disapplied" when using MISRA Compliance:2016.

There is also another compliant coding pattern that can be used which avoids the risk of failing to detect an error and that has better readability:

Code:

int CheckIsOk()
{
  int err = E_UNEXPECTED;
  
  if ( currentObject == NULL )
  {
    err = E_ERR_1;
  }
  else if ( !IsClassValid( id ) )
  {
    err = E_ERR_2;
  }
  else
  {
    currentObject->test();
    err = E_OK;
  }
  
  return err;
}