verify: format messages directly at the source

dirstate: update messages in verify to not use the old `state` API

dirstate: add narrow support to `verify` This will be called later in the series by the `verify` command.

dirstate: stop using `entry.state()` for logic in `verify` Use the new API instead of the deprecated one. The next changeset will remove the use of `state` in this method altogether (currently still in the messages)

dirstate-entry: add `modified` property This was already done in the Rust implementation and is a useful primitive. The C implementation had this called `merged`, but wasn't used anywhere. It will be used in the next changeset.

debug: add debug-revlog-stats command Display statistics about revlogs in the store. Useful to get an approximate size of a repository, etc. More statistics will be added in the future.

typing: attempt to remove @overloads in the platform module for stdlib methods This is mostly successful, as examining util.pyi, posix.pyi, and windows.pyi after a pytype run shows that the type overloads for `oslink`, `readlink`, `removedirs`, `rename`, `split`, and `unlink` have been removed. (Some of these still have an @overload, but the differences are the variable names, not the types.) However, @overloads remain for `abspath` and `normpath` for some reason. It's useful to redefine these methods for the type checking phase because in addition to excluding str and PathLike variants, some of these functions have optional args in stdlib that aren't implemented in the custom implementation on Windows, and we want the type checking to flag that instead of assuming it's an allowable overload everywhere. One last quirk I noticed that I can't explain- `pycompat.TYPE_CHECKING` is always False, so the conditionals need to check `typing.TYPE_CHECKING` directly. I tried dropping the custom code for assigning `pycompat.TYPE_CHECKING` and simply did `from typing import TYPE_CHECKING` directly in pycompat.py, and used `pycompat.TYPE_CHECKING` for the conditional here... and pytype complained that `pycompat` doesn't have the `TYPE_CHECKING` variable.

typing: add trivial type hints to rest of the windows platform module Skipping the file wrappers for now because there's interplay with C code, and making them subclass `typing.BinaryIO_Proxy` confuses PyCharm a bit.

typing: add type hints to the rest of the posix module These methods either don't have an analog in the windows module, or are aliased in the windows module from something else (like os.path.xxx).

typing: add type hints to the platform `cachestat` classes

util: fix the signature of observedbufferedinputpipe._fillbuffer() Flagged by PyCharm, since it didn't match the signature of the method being overridden. The default value in the superclass is also `_chunksize`, and I suspect that the amount read from `osread` should be limited to what is passed in. Only one caller (`bufferedinputpipe.unbufferedread()`) passes this argument, and it passes the max of `_chunksize` and whatever it was passed.

tests: drop some obsolete py2 handling in util.py doctest Flagged by PyCharm while inspecting imports from the platform modules.

typing: add type hints to the common posix/windows platform functions These are done in sync because some platforms have empty implementations, and it isn't obvious what the types should be without examining the other. We want the types aligned, so @overload definitions that differ aren't generated. The only differences here are the few methods that unconditionally raise an error are marked as `NoReturn`, which doesn't seem to bother pytype. A couple of the posix module functions needed to be updated with a modern ternary operator, because pytype seems to want to use the type of the second object in the old `return x and y` style.

typing: add type hints to the posix platform module matching win32.py

typing: add type hints to mercurial/win32.py These are the low level functions that are imported by the mercurial.windows module, which is in turn imported by mercurial.utils as the platform module. Pretty straightforward, but pytype inferred very little of it, likely because of the heavy ctypes usage. It also seems to trigger a pytype bug in procutil, now that it has an idea of the underlying function type, so disable that warning to maintain a working test.

windows: drop some py2 registry module importing The comment was actually backwards- `winreg` is importable on py3, and is already imported by mercurial/windows.py.

typing: add type hints to the platform specific scm modules Surprisingly, pytype struggled to figure out the return types in the posix functions.

typing: add type hints to most mercurial/pycompat.py functions The `rapply` methods are left out because it's not `rapply(f, xs: _T0) -> _T0` as I first thought- it's used somewhere to walk a collection and convert between bytes and str. Also, the `open()` call is partially untyped because I'm not sure what its purpose is at this point- both the name and mode can be either bytes or str as it is currently constituted. It might make sense to assert that the file is being opened in binary mode (like `namedtempfile()`) and cast the result to `BinaryIO`, but that shouldn't be smuggled in with these other changes. The return is currently typed as `Any` because something suddenly got smarter and a few uses in util.py (like readfile()) suddenly think it returns `IO[str]` instead of `IO[bytes]` (BinaryIO), and it flags the type mismatch there.

statprof: don't pass str `sys.argv` to a function expecting bytes Found by typing the global functions in mercurial.pycompat.

typing: drop an unnecessary warning disabling comment in match.py This stopped being necessary in d2e1dcd4490d, when the exception stopped being subscripted.

scmposix: don't subscript IOError This warning disabling has been in place since late 2019 in 667f56d73ceb. We should have had some py3 support at the time, but both pytype complains and subscripting a real FileNotFoundError generated in `hg debugshell` crashed, so maybe this fixes a problem. It looks like all other instances of subscripting exceptions have been replaced (at least as far as greping for `== errno.` revealed).

typing: add type hints to pycompat.bytestr The problem with leaving pytype to its own devices here was that for functions that returned a bytestr, pytype inferred `Union[bytes, int]`. It now accepts that it can be treated as plain bytes. I wasn't able to figure out the arg type for `__getitem__`- `SupportsIndex` (which PyCharm indicated is how the superclass function is typed) got flagged: File "/mnt/c/Users/Matt/hg/mercurial/pycompat.py", line 236, in __getitem__: unsupported operand type(s) for item retrieval: bytestr and SupportsIndex [unsupported-operands] Function __getitem__ on bytestr expects int But some caller got flagged when I marked it as `int`. There's some minor spillover problems elsewhere- pytype doesn't seem to recognize that `bytes.startswith()` can optionally take a 3rd and 4th arg, so those few places have the warning disabled. It also flags where the tar API is being abused, but that would be a tricky refactor (and would require typing extensions until py3.7 is dropped), so disable those too.

pycompat: explicitly prefix builtin attr usage with `builtins.` It doesn't seem like this would fix any bug, because the wrapped functions that take bytes instead of str are defined after these calls. But PyCharm was flagging the second and third uses, saying "Type 'str' doesn't have expected attribute 'decode'". It wasn't flagging the first, but I changed it for consistency.

typing: add type hints to global variables in mercurial/pycompat.py The way `osaltsep` and `sysexecutable` were defined, pytype determined them to be `Union[bytes, str]`. This was a problem because that cascaded to all of the callers, and also because it couldn't be annotated as bytes on the initial assignment. Therefore, we use a ternary operator. The documentation says that `sys.executable` can either be None or an empty string if the value couldn't be determined. We opt for an empty string here because there are places that blindly pass it to `os.path.xxx()` functions, which crash if given None. Other places test `if pycompat.sysexecutable`, so empty string works for both.

windows: drop an unused method The only caller was removed in 563eb25e079b.

typing: add type hints to the prompt methods in mercurial/ui.py The @overloads allow for the callers that pass a non-None `default` to not have to worry about handling a None return to appease pytype.

ui: split the `default` arg out of **kwargs for the internal prompt method This arg was required anyway, based on how it was accessed. Having it separate allows it to be typed though, and this will simplify things for the callers- if a non-None `default` is passed, the return can never be None. That can be expressed with `@overload` when the arg can be typed, but that's not possible when it is rolled up in **kwargs. The default value is simply copied from the public `prompt()` above it.

typing: add trivial type hints to mercurial/ui.py There's not really a pattern here; it's mostly obvious return types and in a few cases, obvious parameter types. Some other "obvious" functions are left out because of quirks in how the return value for the various config() functions are inferred cause pytype to complain.

doc: don't pass str to ui methods in check-seclevel.py

typing: add type hints related to message output in mercurial/ui.py This will shake loose some bytes vs str issues in the doc checker.