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, 64 insertions, 14 deletions

diff --git a/synapse/storage/engines/__init__.py b/synapse/storage/engines/__init__.py
index a182e8a098..d1ccb7390a 100644
--- a/synapse/storage/engines/__init__.py
+++ b/synapse/storage/engines/__init__.py
@@ -25,7 +25,7 @@ try:
 except ImportError:
 
     class PostgresEngine(BaseDatabaseEngine):  # type: ignore[no-redef]
-        def __new__(cls, *args: object, **kwargs: object) -> NoReturn:  # type: ignore[misc]
+        def __new__(cls, *args: object, **kwargs: object) -> NoReturn:
             raise RuntimeError(
                 f"Cannot create {cls.__name__} -- psycopg2 module is not installed"
             )
@@ -36,7 +36,7 @@ try:
 except ImportError:
 
     class Sqlite3Engine(BaseDatabaseEngine):  # type: ignore[no-redef]
-        def __new__(cls, *args: object, **kwargs: object) -> NoReturn:  # type: ignore[misc]
+        def __new__(cls, *args: object, **kwargs: object) -> NoReturn:
             raise RuntimeError(
                 f"Cannot create {cls.__name__} -- sqlite3 module is not installed"
             )
diff --git a/synapse/storage/types.py b/synapse/storage/types.py
index 0031df1e06..56a0048539 100644
--- a/synapse/storage/types.py
+++ b/synapse/storage/types.py
@@ -12,7 +12,18 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 from types import TracebackType
-from typing import Any, Iterator, List, Mapping, Optional, Sequence, Tuple, Type, Union
+from typing import (
+    Any,
+    Callable,
+    Iterator,
+    List,
+    Mapping,
+    Optional,
+    Sequence,
+    Tuple,
+    Type,
+    Union,
+)
 
 from typing_extensions import Protocol
 
@@ -112,15 +123,35 @@ class DBAPI2Module(Protocol):
     #   extends from this hierarchy. See
     #     https://docs.python.org/3/library/sqlite3.html?highlight=sqlite3#exceptions
     #     https://www.postgresql.org/docs/current/errcodes-appendix.html#ERRCODES-TABLE
-    Warning: Type[Exception]
-    Error: Type[Exception]
+    #
+    # Note: rather than
+    #     x: T
+    # we write
+    #     @property
+    #     def x(self) -> T: ...
+    # which expresses that the protocol attribute `x` is read-only. The mypy docs
+    #     https://mypy.readthedocs.io/en/latest/common_issues.html#covariant-subtyping-of-mutable-protocol-members-is-rejected
+    # explain why this is necessary for safety. TL;DR: we shouldn't be able to write
+    # to `x`, only read from it. See also https://github.com/python/mypy/issues/6002 .
+    @property
+    def Warning(self) -> Type[Exception]:
+        ...
+
+    @property
+    def Error(self) -> Type[Exception]:
+        ...
 
     # Errors are divided into `InterfaceError`s (something went wrong in the database
     # driver) and `DatabaseError`s (something went wrong in the database). These are
     # both subclasses of `Error`, but we can't currently express this in type
     # annotations due to https://github.com/python/mypy/issues/8397
-    InterfaceError: Type[Exception]
-    DatabaseError: Type[Exception]
+    @property
+    def InterfaceError(self) -> Type[Exception]:
+        ...
+
+    @property
+    def DatabaseError(self) -> Type[Exception]:
+        ...
 
     # Everything below is a subclass of `DatabaseError`.
 
@@ -128,7 +159,9 @@ class DBAPI2Module(Protocol):
     # - An integer was too big for its data type.
     # - An invalid date time was provided.
     # - A string contained a null code point.
-    DataError: Type[Exception]
+    @property
+    def DataError(self) -> Type[Exception]:
+        ...
 
     # Roughly: something went wrong in the database, but it's not within the application
     # programmer's control. Examples:
@@ -138,28 +171,45 @@ class DBAPI2Module(Protocol):
     # - A serialisation failure occurred.
     # - The database ran out of resources, such as storage, memory, connections, etc.
     # - The database encountered an error from the operating system.
-    OperationalError: Type[Exception]
+    @property
+    def OperationalError(self) -> Type[Exception]:
+        ...
 
     # Roughly: we've given the database data which breaks a rule we asked it to enforce.
     # Examples:
     # - Stop, criminal scum! You violated the foreign key constraint
     # - Also check constraints, non-null constraints, etc.
-    IntegrityError: Type[Exception]
+    @property
+    def IntegrityError(self) -> Type[Exception]:
+        ...
 
     # Roughly: something went wrong within the database server itself.
-    InternalError: Type[Exception]
+    @property
+    def InternalError(self) -> Type[Exception]:
+        ...
 
     # Roughly: the application did something silly that needs to be fixed. Examples:
     # - We don't have permissions to do something.
     # - We tried to create a table with duplicate column names.
     # - We tried to use a reserved name.
     # - We referred to a column that doesn't exist.
-    ProgrammingError: Type[Exception]
+    @property
+    def ProgrammingError(self) -> Type[Exception]:
+        ...
 
     # Roughly: we've tried to do something that this database doesn't support.
-    NotSupportedError: Type[Exception]
+    @property
+    def NotSupportedError(self) -> Type[Exception]:
+        ...
 
-    def connect(self, **parameters: object) -> Connection:
+    # We originally wrote
+    # def connect(self, *args, **kwargs) -> Connection: ...
+    # But mypy doesn't seem to like that because sqlite3.connect takes a mandatory
+    # positional argument. We can't make that part of the signature though, because
+    # psycopg2.connect doesn't have a mandatory positional argument. Instead, we use
+    # the following slightly unusual workaround.
+    @property
+    def connect(self) -> Callable[..., Connection]:
         ...