Use mypy 1.0 (#15052)

* Update mypy and mypy-zope
* Remove unused ignores

These used to suppress

```
synapse/storage/engines/__init__.py:28: error: "__new__" must return a
class instance (got "NoReturn")  [misc]
```

and

```
synapse/http/matrixfederationclient.py:1270: error: "BaseException" has no attribute "reasons"  [attr-defined]
```

(note that we check `hasattr(e, "reasons")` above)

* Avoid empty body warnings, sometimes by marking methods as abstract

E.g.

```
tests/handlers/test_register.py:58: error: Missing return statement  [empty-body]
tests/handlers/test_register.py:108: error: Missing return statement  [empty-body]
```

* Suppress false positive about `JaegerConfig`

Complaint was

```
synapse/logging/opentracing.py:450: error: Function "Type[Config]" could always be true in boolean context  [truthy-function]
```

* Fix not calling `is_state()`

Oops!

```
tests/rest/client/test_third_party_rules.py:428: error: Function "Callable[[], bool]" could always be true in boolean context  [truthy-function]
```

* Suppress false positives from ParamSpecs

````
synapse/logging/opentracing.py:971: error: Argument 2 to "_custom_sync_async_decorator" has incompatible type "Callable[[Arg(Callable[P, R], 'func'), **P], _GeneratorContextManager[None]]"; expected "Callable[[Callable[P, R], **P], _GeneratorContextManager[None]]"  [arg-type]
synapse/logging/opentracing.py:1017: error: Argument 2 to "_custom_sync_async_decorator" has incompatible type "Callable[[Arg(Callable[P, R], 'func'), **P], _GeneratorContextManager[None]]"; expected "Callable[[Callable[P, R], **P], _GeneratorContextManager[None]]"  [arg-type]
````

* Drive-by improvement to `wrapping_logic` annotation

* Workaround false "unreachable" positives

See https://github.com/Shoobx/mypy-zope/issues/91

```
tests/http/test_proxyagent.py:626: error: Statement is unreachable  [unreachable]
tests/http/test_proxyagent.py:762: error: Statement is unreachable  [unreachable]
tests/http/test_proxyagent.py:826: error: Statement is unreachable  [unreachable]
tests/http/test_proxyagent.py:838: error: Statement is unreachable  [unreachable]
tests/http/test_proxyagent.py:845: error: Statement is unreachable  [unreachable]
tests/http/federation/test_matrix_federation_agent.py:151: error: Statement is unreachable  [unreachable]
tests/http/federation/test_matrix_federation_agent.py:452: error: Statement is unreachable  [unreachable]
tests/logging/test_remote_handler.py:60: error: Statement is unreachable  [unreachable]
tests/logging/test_remote_handler.py:93: error: Statement is unreachable  [unreachable]
tests/logging/test_remote_handler.py:127: error: Statement is unreachable  [unreachable]
tests/logging/test_remote_handler.py:152: error: Statement is unreachable  [unreachable]
```

* Changelog

* Tweak DBAPI2 Protocol to be accepted by mypy 1.0

Some extra context in:
- https://github.com/matrix-org/python-canonicaljson/pull/57
- https://github.com/python/mypy/issues/6002
- https://mypy.readthedocs.io/en/latest/common_issues.html#covariant-subtyping-of-mutable-protocol-members-is-rejected

* Pull in updated canonicaljson lib

so the protocol check just works

* Improve comments in opentracing

I tried to workaround the ignores but found it too much trouble.

I think the corresponding issue is
https://github.com/python/mypy/issues/12909. The mypy repo has a PR
claiming to fix this (https://github.com/python/mypy/pull/14677) which
might mean this gets resolved soon?

* Better annotation for INTERACTIVE_AUTH_CHECKERS

* Drive-by AUTH_TYPE annotation, to remove an ignore

2 files changed, 15 insertions, 5 deletions

diff --git a/synapse/handlers/auth.py b/synapse/handlers/auth.py
index 57a6854b1e..cf12b55d21 100644
--- a/synapse/handlers/auth.py
+++ b/synapse/handlers/auth.py
@@ -201,7 +201,7 @@ class AuthHandler:
         for auth_checker_class in INTERACTIVE_AUTH_CHECKERS:
             inst = auth_checker_class(hs)
             if inst.is_enabled():
-                self.checkers[inst.AUTH_TYPE] = inst  # type: ignore
+                self.checkers[inst.AUTH_TYPE] = inst
 
         self.bcrypt_rounds = hs.config.registration.bcrypt_rounds
 
diff --git a/synapse/handlers/ui_auth/checkers.py b/synapse/handlers/ui_auth/checkers.py
index 332edcca24..78a75bfed6 100644
--- a/synapse/handlers/ui_auth/checkers.py
+++ b/synapse/handlers/ui_auth/checkers.py
@@ -13,7 +13,8 @@
 # limitations under the License.
 
 import logging
-from typing import TYPE_CHECKING, Any
+from abc import ABC, abstractmethod
+from typing import TYPE_CHECKING, Any, ClassVar, Sequence, Type
 
 from twisted.web.client import PartialDownloadError
 
@@ -27,19 +28,28 @@ if TYPE_CHECKING:
 logger = logging.getLogger(__name__)
 
 
-class UserInteractiveAuthChecker:
+class UserInteractiveAuthChecker(ABC):
     """Abstract base class for an interactive auth checker"""
 
-    def __init__(self, hs: "HomeServer"):
+    # This should really be an "abstract class property", i.e. it should
+    # be an error to instantiate a subclass that doesn't specify an AUTH_TYPE.
+    # But calling this a `ClassVar` is simpler than a decorator stack of
+    # @property @abstractmethod and @classmethod (if that's even the right order).
+    AUTH_TYPE: ClassVar[str]
+
+    def __init__(self, hs: "HomeServer"):  # noqa: B027
         pass
 
+    @abstractmethod
     def is_enabled(self) -> bool:
         """Check if the configuration of the homeserver allows this checker to work
 
         Returns:
             True if this login type is enabled.
         """
+        raise NotImplementedError()
 
+    @abstractmethod
     async def check_auth(self, authdict: dict, clientip: str) -> Any:
         """Given the authentication dict from the client, attempt to check this step
 
@@ -304,7 +314,7 @@ class RegistrationTokenAuthChecker(UserInteractiveAuthChecker):
             )
 
 
-INTERACTIVE_AUTH_CHECKERS = [
+INTERACTIVE_AUTH_CHECKERS: Sequence[Type[UserInteractiveAuthChecker]] = [
     DummyAuthChecker,
     TermsAuthChecker,
     RecaptchaAuthChecker,