In the `to_internal_value` method of the primary key and slug related fields, `TypeError`s and `ValueError`s are caught from `self.get_queryset().get(...)` and presented to the user. This works fine for most cases, but can cause problems if the exception is coming from `self.get_queryset()` rather than from the `.get(...)`.
It means errors in the `get_queryset` method can be hidden and presented back to the user as though, for example, the input provided to the `to_internal_value` was the wrong type, whereas in reality there's a bug in the `get_queryset` method and therefore it should bubble up and be exposed as a server error.
I've decided to fix this because twice now I've had to debug why I'm seeing `invalid_type` errors from my serializer (errors like `wrong pk type - int` when the `pk` type on my model is `int`) when the real problem was a bug in my custom `get_queryset` method.
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