Make error reporting of Eloquent methods (or Laraval in general) more consistent

[nagmat84]

At the moment many Eloquent methods report errors inconsistently. (Probably, this is also true for Laravel in general, but I mostly use Eloquent and there it is specifically striking.)

For example, the methods \Illuminate\Database\Eloquent\Model::save() and \Illuminate\Database\Eloquent\Model::delete() return a nullable boolean and may throw exceptions. If save returns true or null, this indicates a success. If it returns false, this indicates a failure (without further information what went wrong). However, save may also throw exceptions.

To properly handle all error cases in one place, I typically write something like this

try {
  if ($model->save() === false) {
    // sic! we must explicitly check for === false, because save() may also return null on success
    throw new \RuntimeException('Model::save() returned false');
  }
} catch (\Throwable $e) {
  // ... error handling in one place
}

First, I would really like if Laravel would be consistent: either use a boolean return value to indicate success/fail or use exceptions, but not both at the same time. This should also be consistent across the whole API.

Second, I would recommend to use exceptions. Exceptions are around since PHP 5, I believe they are the "modern" way of error reporting and they allow to differentiate between different error cases. I would love to write something like that

try {
  $model->save();
} catch (EloquentError $e) {
  // something on the DB layer went wrong
}
} catch (InteruptedByObserver $e) {
  // some observer listing to the saving event decided to not save this model
}
} catch (\AbstractLaravelError $e) {
  // oops, something went completely sideways
}

This would mean that many methods (like save, delete, update) which return a boolean now would return void in the future.

Note: This idea is related to discussion #40020 as the above example would also imply that Laravel only throws specific exceptions.