Narrow type of argmap from Mapping to Dict #682
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The `Mapping` case is meant to support passthrough to `Schema.from_dict`. However, only `Dict` is actually supported. Therefore, narrowing this from `Mapping` to `Dict` makes the annotation more accurate. In terms of runtime behavior, the check is changed from looking at `isinstance(argmap, collections.abc.Mapping)` to `isinstance(argmap, dict)`. This should not impact any users and harmonizes the logic with the declared types and documentation. Technically, it is possible to make a non-dict mapping type which is close enough to dict to be acceptable for `Schema.from_dict`. Such a usage is unlikely and was not supported intentionally in the first place. To avoid unclear and surprising behaviors, non-dict mapping types will now trigger a `TypeError`. The test case for this uses a UserDict, which is dict-like but not a subclass of dict, to demonstrate the sort of case this will catch. Additionally, fix some minor issues with some of the type annotations. In order for a decorator to preserve the type of the decorated function, it needs to be annotated with a type variable. There were a couple of cases of this in `Parser` which have been fixed.
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The
Mappingcase is meant to support passthrough toSchema.from_dict. However, onlyDictis actually supported.Therefore, narrowing this from
MappingtoDictmakes the annotation more accurate.In terms of runtime behavior, the check is changed from looking at
isinstance(argmap, collections.abc.Mapping)toisinstance(argmap, dict). This should not impact any users and harmonizes the logic with the declared types and documentation.Technically, it is possible to make a non-dict mapping type which is close enough to dict to be acceptable for
Schema.from_dict. Such a usage is unlikely and was not supported intentionally in the first place.To avoid unclear and surprising behaviors, non-dict mapping types will now trigger a
TypeError. The test case for this uses a UserDict, which is dict-like but not a subclass of dict, to demonstrate the sort of case this will catch.Additionally, fix some minor issues with some of the type annotations. In order for a decorator to preserve the type of the decorated function, it needs to be annotated with a type variable. There were a couple of cases of this in
Parserwhich have been fixed.resolves #679