Switch back to upstream PyQt5-stubs for mypy

[The-Compiler]

Right now, qutebrowser is still running with its own outdated fork of PyQt5-stubs. We should switch back to the upstream project.

From a quick test, that results in 456 new mypy errors (some of them I don't quite understand), so that will likely need a bit more work first.

[The-Compiler]

Ah, right, I'll probably need to resolve python-qt-tools/PyQt5-stubs#15 first.

[rakanalh]

The PR for that issue: python-qt-tools/PyQt5-stubs#36 has been merged. Do you think it's possible to switch QB to use the latest package now?

[The-Compiler]

Those stubs aren't in the master branch yet: python-qt-tools/PyQt5-stubs#42

Even then, there's still a lot to be fixed in the stubs (and perhaps in qutebrowser's codebase) - right now, I see:

Found 174 errors in 61 files (checked 179 source files)

and with the new modules in, that number might raise.

[The-Compiler]

The new files are in master now, and things do look better:

Found 118 errors in 49 files (checked 179 source files)

I'll see if I can take a look at those.

[The-Compiler]

Almost there after some changes:

 43 files changed, 207 insertions(+), 133 deletions(-)

Todo:

• Can we improve the typing in keyutils.py?
• What to do about PyQIODevice?

qutebrowser/utils/qtutils.py:233: error: Argument 1 to "TextIOWrapper" has incompatible type "PyQIODevice"; expected "IO[bytes]"  [arg-type]
                new_f = io.TextIOWrapper(PyQIODevice(f),
                                         ^
qutebrowser/utils/qtutils.py:305: error: Argument 1 to "QtOSError" has incompatible type "QIODevice"; expected "QFileDevice"  [arg-type]
                raise QtOSError(self.dev)
                                ^
qutebrowser/utils/qtutils.py:328: error: Argument 1 to "QtOSError" has incompatible type "QIODevice"; expected "QFileDevice"  [arg-type]
                raise QtOSError(self.dev, msg="seek failed!")
                                ^
qutebrowser/utils/qtutils.py:350: error: Return type "QByteArray" of "readline" incompatible with return type "bytes" in supertype "IOBase"  [override]
        def readline(self, size: int = -1) -> QByteArray:
        ^
qutebrowser/utils/qtutils.py:365: error: Incompatible types in assignment (expression has type "QByteArray", variable has type "bytes")  [assignment]
                    buf = self.dev.readAll()
                          ^
qutebrowser/utils/qtutils.py:371: error: Incompatible return value type (got "bytes", expected "QByteArray")  [return-value]
            return buf
                   ^
qutebrowser/utils/qtutils.py:384: error: Argument 1 of "write" is incompatible with supertype "BufferedIOBase"; supertype defines the argument type as "Union[bytes, bytearray]"  [override]
        def write(self, data: str) -> int:
        ^
qutebrowser/utils/qtutils.py:387: error: Argument 1 to "write" of "QIODevice" has incompatible type "str"; expected "Union[QByteArray, bytes, bytearray]"  [arg-type]
            num = self.dev.write(data)
                                 ^
qutebrowser/utils/qtutils.py:389: error: Argument 1 to "QtOSError" has incompatible type "QIODevice"; expected "QFileDevice"  [arg-type]
                raise QtOSError(self.dev)
                                ^
qutebrowser/utils/qtutils.py:392: error: Return type "QByteArray" of "read" incompatible with return type "bytes" in supertype "BufferedIOBase"  [override]
        def read(self, size: typing.Optional[int] = None) -> QByteArray:
        ^
qutebrowser/utils/qtutils.py:399: error: Incompatible types in assignment (expression has type "bytes", variable has type "QByteArray")  [assignment]
                buf = self.dev.read(size)
                      ^
qutebrowser/utils/qtutils.py:399: error: Argument 1 to "read" of "QIODevice" has incompatible type "Optional[int]"; expected "int"  [arg-type]
                buf = self.dev.read(size)
                                    ^

• Is it a good idea that configtypes.QtFont inherits from configtypes.Font?

qutebrowser/config/configtypes.py:1347: error: Return type "Union[Unset, None, QFont]" of "to_py" incompatible with return type "Union[None, str, Unset]" in supertype "Font"  [override]
        def to_py(self, value: _StrUnset) -> typing.Union[usertypes.Unset,
        ^

• Is this intended?

qutebrowser/browser/hints.py:896: error: Argument 1 to "_hint_strings" of "HintManager" has incompatible type "List[HintLabel]"; expected "Sequence[AbstractWebElement]"  [arg-type]
                strings = self._hint_strings(visible)
                                             ^

• While we're at it, maybe also review type: ignore annotations, and perhaps switch to type: ignore[...] if we can.
• Broken unittests
• pylint: https://travis-ci.org/github/qutebrowser/qutebrowser/jobs/685090083