mypy question

[Thomas Passin]

On 12/29/2023 10:02 AM, Karsten Hilbert via Python-list wrote:
> Am Fri, Dec 29, 2023 at 07:49:17AM -0700 schrieb Mats Wichmann via Python-list:
> 
>>> I am not sure why mypy thinks this
>>>
>>> gmPG2.py:554: error: Argument "queries" to "run_rw_queries" has incompatible type "List[Dict[str, str]]"; expected
>>> "List[Dict[str, Union[str, List[Any], Dict[str, Any]]]]"  [arg-type]
>>>                      rows, idx = run_rw_queries(link_obj = conn, queries = queries, return_data = True)
>>>                                                                            ^~~~~~~
>>>
>>> should be flagged. The intent is for "queries" to be
>>>
>>> a list
>>> 	of dicts
>>> 		with keys of str
>>> 		and values of
>>> 			str OR
>>> 			list of anything OR
>>> 			dict with
>>> 				keys of str
>>> 				and values of anything
>>>
>>> I'd have thunk list[dict[str,str]] matches that ?
>>
>> Dict[str, str] means the key type and value type should both be strings,
> 
> Indeed, I know that much, list[dict[str, str]] is what is getting
> passed in in this particular invocation of run_rw_queries().
> 
> For what it's worth here's the signature of that function:
> 
> 	def run_rw_queries (
> 		link_obj:_TLnkObj=None,
> 		queries:list[dict[str, str | list | dict[str, Any]]]=None,
> 		end_tx:bool=False,
> 		return_data:bool=None,
> 		get_col_idx:bool=False,
> 		verbose:bool=False
> 	) -> tuple[list[dbapi.extras.DictRow], dict[str, int] | None]:
> 
> Given that I would have thought that passing in
> list[dict[str, str]] for "queries" ought to be type safe.
> Mypy indicates otherwise which I am not grokking as to why.
> 
>> but in your
>> retelling above you indicate lots of possible value types... actually the mypy guess
>> seems to be a pretty good recreation of your psuedo-code description.
> 
> I agree that mypy's grasp of my intent from
> 
> 	queries:list[dict[str, str | list | dict[str, Any]]]=None,
> 
> into
> 
> 	"List[Dict[str, Union[str, List[Any], Dict[str, Any]]]]"
> 
> seems accurate. I just don't understand why list[dict[str,
> str]] should not pass that construct.

Maybe better to ask the mypy people directly.

> Karsten
> --
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