pip_api: type hints

[woodruffw]

I believe this covers the majority of the public API surface; will test these hints against my work in pip-audit.

Closes #96.

[woodruffw]

Turns out that this is a significant pain due to the vendored modules:

$ mypy pip_api
pip_api/_vendor/pyparsing.py:123: error: Module "itertools" has no attribute "ifilterfalse"; maybe "filterfalse"?
pip_api/_vendor/pyparsing.py:123: error: Name "filterfalse" already defined (possibly by an import)
pip_api/_vendor/pyparsing.py:126: error: Module "_thread" has no attribute "RLock"
pip_api/_vendor/pyparsing.py:143: error: Cannot find implementation or library stub for module named "ordereddict"
pip_api/_vendor/pyparsing.py:143: note: See https://mypy.readthedocs.io/en/stable/running_mypy.html#missing-imports
pip_api/_vendor/pyparsing.py:143: error: Name "_OrderedDict" already defined (possibly by an import)
pip_api/_vendor/pyparsing.py:145: error: Cannot assign to a type
pip_api/_vendor/pyparsing.py:145: error: Incompatible types in assignment (expression has type "None", variable has type "Type[OrderedDict[Any, Any]]")
pip_api/_vendor/pyparsing.py:150: error: Name "SimpleNamespace" already defined (possibly by an import)
pip_api/_vendor/pyparsing.py:233: error: Module has no attribute "maxint"
pip_api/_vendor/pyparsing.py:234: error: Name "xrange" is not defined
pip_api/_vendor/pyparsing.py:236: error: Name "_ustr" already defined on line 227
pip_api/_vendor/pyparsing.py:260: error: Cannot find implementation or library stub for module named "__builtin__"
pip_api/_vendor/pyparsing.py:1800: error: Name "_FifoCache" already defined on line 1771
pip_api/_vendor/pyparsing.py:1829: error: Need type annotation for "packrat_cache" (hint: "packrat_cache: Dict[<type>, <type>] = ...")
pip_api/_vendor/pyparsing.py:2902: error: "Type[ParserElement]" has no attribute "_literalStringClass"
pip_api/_vendor/pyparsing.py:5086: error: Not all arguments converted during string formatting
pip_api/_vendor/pyparsing.py:5944: error: "Callable[[VarArg(Any), KwArg(Any)], Any]" has no attribute "ANY_VALUE"
pip_api/_vendor/pyparsing.py:6730: error: Need type annotation for "_ranges" (hint: "_ranges: List[<type>] = ...")
pip_api/_vendor/pyparsing.py:6799: error: Need type annotation for "_ranges" (hint: "_ranges: List[<type>] = ...")
Found 19 errors in 1 file (checked 21 source files)

The CI will pass above, but the parent call to mypy in pip-audit will continue to fail because of these inner errors. I've tried to mark the imports for pyparsing with # type: ignore, but that doesn't seem to have done anything...

Edit: I've added mypy to the CI to (hopefully) demonstrate the failure.

[woodruffw]

Urgh, this might actually be fixable with py.typed. Will dig in further tomorrow.

[woodruffw]

Okay: in local testing, adding py.typed to the distribution allows pip-audit to typecheck against its usage of pip-api, since said usage is limited to the public APIs that we've annotated.

For the package itself, mypy in the CI still won't work, for the vendoring reasons mentioned above. If that's acceptable, this should be good to go 🙂

[di]

For the package itself, mypy in the CI still won't work, for the vendoring reasons mentioned above. If that's acceptable, this should be good to go 🙂

I think that's acceptable for now.

[woodruffw]

Okay, this should be good to go once the CI goes through!

A minor bump once it's merged would also be appreciated 🙂

[di]

Released in https://pypi.org/project/pip-api/0.0.21/