Provide more precise type hints for Table.get

[alex-ball]

When working with pyright (at least), the return value from calls to Table.get is the declared type Document | list[Document] | None. To avoid type errors when using the return value, one therefore has do one of the following:

• Exclude the line from type checking
• Introduce an assertion, e.g. assert isinstance(obj, Document)
• Test, say, if instance(obj, Document) instead of if obj is not None or if obj

It would be highly convenient if static type checkers could understand the logic of the method, and knew that it returns a list if and only if doc_id is None and a list is passed to doc_ids.

Here are the typing overloads that do the trick. I've confirmed that pytest and mypy remain happy with these in place. I haven't covered the case that passing no arguments leads to a NoReturn return type, as that's adding more information than was already there, but I could if you wanted.

I could provide some assert_type tests if you like but I'm not so familiar with the best place to put them (and they would involve a typing_extensions dependency on older Pythons).

[msiemens]

Hey, thanks for the PR! It seems like the type checking unit tests fail:

381: error: All overload variants of "get" of "Table" require at least one argument  [call-overload]
381: note: Possible overload variants:
381: note:     def get(self, cond: QueryLike, doc_id: None = ..., doc_ids: None = ...) -> Optional[Document]
381: note:     def get(self, *, cond: QueryLike, doc_id: None = ..., doc_ids: None = ...) -> Optional[Document]
381: note:     def get(self, cond: Optional[QueryLike], doc_id: int, doc_ids: Optional[List[Any]] = ...) -> Optional[Document]
381: note:     def get(self, *, cond: Optional[QueryLike] = ..., doc_id: int, doc_ids: Optional[List[Any]] = ...) -> Optional[Document]
381: note:     def get(self, cond: Optional[QueryLike], doc_id: None, doc_ids: List[Any]) -> List[Document]
381: note:     def get(self, cond: Optional[QueryLike], *, doc_id: None = ..., doc_ids: List[Any]) -> List[Document]
381: note:     def get(self, *, cond: Optional[QueryLike] = ..., doc_id: None = ..., doc_ids: List[Any]) -> List[Document]

Can you take a closer look at that? See eg. https://github.com/msiemens/tinydb/actions/runs/20165183963/job/59009114221?pr=602

[alex-ball]

Ah, this looks like it relates to the comment I made:

I haven't covered the case that passing no arguments leads to a NoReturn return type, as that's adding more information than was already there, but I could if you wanted.

I've now added that missing case, and the error no longer occurs.

[msiemens]

Seems like the CI failures are unrelated to this PR. Thanks for contributing!