Synapse does not take advantage of Pydantic 2.0

[matrixbot]

This issue has been migrated from #15858.

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Description

After upgrading the PIP packages, Synapse failed to launch.

Steps to reproduce

• install matrix-synapse using the "virtualenv" approach with the most recent dependency versions
• start Synapse

Homeserver

another homeserver

Synapse Version

1.87.0rc1

Installation Method

pip (from PyPI)

Database

PostgreSQL

Workers

Single process

Platform

Raspberry Pi OS (Debian)

Configuration

No response

Relevant log output

/usr/local/opt/venvs/matrix-synapse/lib/python3.9/site-packages/pydantic/_internal/_config.py:257: UserWarning: Valid config keys have changed in V2:                                                            
* 'allow_mutation' has been removed                                                
  warnings.warn(message, UserWarning)                                              
Traceback (most recent call last):                                                 
  File "/usr/lib/python3.9/runpy.py", line 197, in _run_module_as_main             
    return _run_code(code, main_globals, None,                                     
  File "/usr/lib/python3.9/runpy.py", line 87, in _run_code                        
    exec(code, run_globals)                                                        
  File "/usr/local/opt/venvs/matrix-synapse/lib/python3.9/site-packages/synapse/app/homeserver.py", line 37, in <module>                                                                                         
    from synapse.app import _base                                                  
  File "/usr/local/opt/venvs/matrix-synapse/lib/python3.9/site-packages/synapse/app/_base.py", line 68, in <module>                                                                                              
    from synapse.handlers.auth import load_legacy_password_auth_providers          
  File "/usr/local/opt/venvs/matrix-synapse/lib/python3.9/site-packages/synapse/handlers/auth.py", line 56, in <module>                                                                                          
    from synapse.api.ratelimiting import Ratelimiter                              
  File "/usr/local/opt/venvs/matrix-synapse/lib/python3.9/site-packages/synapse/api/ratelimiting.py", line 21, in <module>                                                                                       
    from synapse.storage.databases.main import DataStore                           
  File "/usr/local/opt/venvs/matrix-synapse/lib/python3.9/site-packages/synapse/storage/__init__.py", line 34, in <module>                                                                                       
    from synapse.storage.databases import Databases                                
  File "/usr/local/opt/venvs/matrix-synapse/lib/python3.9/site-packages/synapse/storage/databases/__init__.py", line 20, in <module>                                                                             
    from synapse.storage.databases.main.events import PersistEventsStore           
  File "/usr/local/opt/venvs/matrix-synapse/lib/python3.9/site-packages/synapse/storage/databases/main/__init__.py", line 27, in <module>                                                                        
    from synapse.storage.databases.main.stats import UserSortOrder                 
  File "/usr/local/opt/venvs/matrix-synapse/lib/python3.9/site-packages/synapse/storage/databases/main/stats.py", line 42, in <module>                                                                           
    from synapse.storage.databases.main.events_worker import InvalidEventError     
  File "/usr/local/opt/venvs/matrix-synapse/lib/python3.9/site-packages/synapse/storage/databases/main/events_worker.py", line 62, in <module>
    from synapse.replication.tcp.streams import BackfillStream, UnPartialStatedEventStream
  File "/usr/local/opt/venvs/matrix-synapse/lib/python3.9/site-packages/synapse/replication/tcp/streams/__init__.py", line 27, in <module>
    from synapse.replication.tcp.streams._base import (
  File "/usr/local/opt/venvs/matrix-synapse/lib/python3.9/site-packages/synapse/replication/tcp/streams/_base.py", line 32, in <module>
    from synapse.replication.http.streams import ReplicationGetStreamUpdates
  File "/usr/local/opt/venvs/matrix-synapse/lib/python3.9/site-packages/synapse/replication/http/__init__.py", line 18, in <module>
    from synapse.replication.http import (
  File "/usr/local/opt/venvs/matrix-synapse/lib/python3.9/site-packages/synapse/replication/http/account_data.py", line 21, in <module>
    from synapse.replication.http._base import ReplicationEndpoint
  File "/usr/local/opt/venvs/matrix-synapse/lib/python3.9/site-packages/synapse/replication/http/_base.py", line 31, in <module>
    from synapse.http.servlet import parse_json_object_from_request
  File "/usr/local/opt/venvs/matrix-synapse/lib/python3.9/site-packages/synapse/http/servlet.py", line 32, in <module>
    from pydantic import BaseModel, MissingError, PydanticValueError, ValidationError
ImportError: cannot import name 'MissingError' from 'pydantic' (/usr/local/opt/venvs/matrix-synapse/lib/python3.9/site-packages/pydantic/__init__.py)
systemd[1]: matrix-synapse.service: Control process exited, code=exited, status=1/FAILURE

Anything else that would be useful to know?

pydantic 2.0 was released yesterday