Add support for pydantic v2 via pydantic.v1 compat module

changelog.d/16332.feature

@@ -0,0 +1 @@
+Added support for pydantic v2 in addition to pydantic v1. Contributed by Maxwell G (@gotmax23).

pyproject.toml

@@ -210,10 +210,11 @@ cryptography = ">=3.4.7"
 ijson = ">=3.1.4"
 matrix-common = "^1.3.0"
 # We need packaging.requirements.Requirement, added in 16.1.
-packaging = ">=16.1"
-# This is the most recent version of Pydantic with available on common distros.
-# We are currently incompatible with >=2.0.0: (https://github.com/matrix-org/synapse/issues/15858)
-pydantic = "^1.7.4"
+# We need packaging.verison.Version(...).major added in 20.0.
+packaging = ">=20.0"
+# We support pydantic v1 and pydantic v2 via the pydantic.v1 compat module.
+# See https://github.com/matrix-org/synapse/issues/15858
+pydantic = ">=1.7.4, <3"
 
 # This is for building the rust components during "poetry install", which
 # currently ignores the `build-system.requires` directive (c.f.
@@ -321,6 +322,8 @@ all = [
 isort = ">=5.10.1"
 black = ">=22.7.0"
 ruff = "0.0.290"
+# Type checking only works with the pydantic.v1 compat module from pydantic v2
+pydantic = "^2"
 
 # Typechecking
 lxml-stubs = ">=0.4.0"

scripts-dev/check_pydantic_models.py

@@ -36,11 +36,41 @@
 import traceback
 import unittest.mock
 from contextlib import contextmanager
-from typing import Any, Callable, Dict, Generator, List, Set, Type, TypeVar
+from typing import (
+    TYPE_CHECKING,
+    Any,
+    Callable,
+    Dict,
+    Generator,
+    List,
+    Set,
+    Type,
+    TypeVar,
+)
 
 from parameterized import parameterized
-from pydantic import BaseModel as PydanticBaseModel, conbytes, confloat, conint, constr
-from pydantic.typing import get_args
+
+from synapse._pydantic_compat import HAS_PYDANTIC_V2
+
+if TYPE_CHECKING or HAS_PYDANTIC_V2:
+    from pydantic.v1 import (
+        BaseModel as PydanticBaseModel,
+        conbytes,
+        confloat,
+        conint,
+        constr,
+    )
+    from pydantic.v1.typing import get_args
+else:
+    from pydantic import (
+        BaseModel as PydanticBaseModel,
+        conbytes,
+        confloat,
+        conint,
+        constr,
+    )
+    from pydantic.typing import get_args
+
 from typing_extensions import ParamSpec
 
 logger = logging.getLogger(__name__)
@@ -251,7 +281,10 @@ def test_expression_without_strict_raises(self) -> None:
         with monkeypatch_pydantic(), self.assertRaises(ModelCheckerException):
             run_test_snippet(
                 """
-                from pydantic import constr
+                try:
+                    from pydantic.v1 import constr
+                except ImportError:
+                    from pydantic import constr
                 constr()
                 """
             )
@@ -269,7 +302,10 @@ def test_wildcard_import_raises(self) -> None:
         with monkeypatch_pydantic(), self.assertRaises(ModelCheckerException):
             run_test_snippet(
                 """
-                from pydantic import *
+                try:
+                    from pydantic.v1 import *
+                except ImportError:
+                    from pydantic import *
                 constr()
                 """
             )
@@ -278,7 +314,10 @@ def test_alternative_import_raises(self) -> None:
         with monkeypatch_pydantic(), self.assertRaises(ModelCheckerException):
             run_test_snippet(
                 """
-                from pydantic.types import constr
+                try:
+                    from pydantic.v1.types import constr
+                except ImportError:
+                    from pydantic.types import constr
                 constr()
                 """
             )
@@ -287,16 +326,22 @@ def test_alternative_import_attribute_raises(self) -> None:
         with monkeypatch_pydantic(), self.assertRaises(ModelCheckerException):
             run_test_snippet(
                 """
-                import pydantic.types
-                pydantic.types.constr()
+                try:
+                    from pydantic.v1 import types as pydantic_types
+                except ImportError:
+                    from pydantic import types as pydantic_types
+                pydantic_types.constr()
                 """
             )
 
     def test_kwarg_but_no_strict_raises(self) -> None:
         with monkeypatch_pydantic(), self.assertRaises(ModelCheckerException):
             run_test_snippet(
                 """
-                from pydantic import constr
+                try:
+                    from pydantic.v1 import constr
+                except ImportError:
+                    from pydantic import constr
                 constr(min_length=10)
                 """
             )
@@ -305,7 +350,10 @@ def test_kwarg_strict_False_raises(self) -> None:
         with monkeypatch_pydantic(), self.assertRaises(ModelCheckerException):
             run_test_snippet(
                 """
-                from pydantic import constr
+                try:
+                    from pydantic.v1 import constr
+                except ImportError:
+                    from pydantic import constr
                 constr(strict=False)
                 """
             )
@@ -314,7 +362,10 @@ def test_kwarg_strict_True_doesnt_raise(self) -> None:
         with monkeypatch_pydantic():
             run_test_snippet(
                 """
-                from pydantic import constr
+                try:
+                    from pydantic.v1 import constr
+                except ImportError:
+                    from pydantic import constr
                 constr(strict=True)
                 """
             )
@@ -323,7 +374,10 @@ def test_annotation_without_strict_raises(self) -> None:
         with monkeypatch_pydantic(), self.assertRaises(ModelCheckerException):
             run_test_snippet(
                 """
-                from pydantic import constr
+                try:
+                    from pydantic.v1 import constr
+                except ImportError:
+                    from pydantic import constr
                 x: constr()
                 """
             )
@@ -332,7 +386,10 @@ def test_field_annotation_without_strict_raises(self) -> None:
         with monkeypatch_pydantic(), self.assertRaises(ModelCheckerException):
             run_test_snippet(
                 """
-                from pydantic import BaseModel, conint
+                try:
+                    from pydantic.v1 import BaseModel, conint
+                except ImportError:
+                    from pydantic import BaseModel, conint
                 class C:
                     x: conint()
                 """
@@ -361,7 +418,10 @@ def test_field_holding_unwanted_type_raises(self, annotation: str) -> None:
             run_test_snippet(
                 f"""
                 from typing import *
-                from pydantic import *
+                try:
+                    from pydantic.v1 import *
+                except ImportError:
+                    from pydantic import *
                 class C(BaseModel):
                     f: {annotation}
                 """
@@ -388,7 +448,10 @@ def test_field_holding_accepted_type_doesnt_raise(self, annotation: str) -> None
             run_test_snippet(
                 f"""
                 from typing import *
-                from pydantic import *
+                try:
+                    from pydantic.v1 import *
+                except ImportError:
+                    from pydantic import *
                 class C(BaseModel):
                     f: {annotation}
                 """
@@ -398,7 +461,10 @@ def test_field_holding_str_raises_with_alternative_import(self) -> None:
         with monkeypatch_pydantic(), self.assertRaises(ModelCheckerException):
             run_test_snippet(
                 """
-                from pydantic.main import BaseModel
+                try:
+                    from pydantic.v1.main import BaseModel
+                except ImportError:
+                    from pydantic.main import BaseModel
                 class C(BaseModel):
                     f: str
                 """

synapse/_pydantic_compat.py

@@ -0,0 +1,26 @@
+# Copyright 2023 Maxwell G <maxwell@gtmx.me>
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from packaging.version import Version
+
+try:
+    from pydantic import __version__ as pydantic_version
+except ImportError:
+    import importlib.metadata
+
+    pydantic_version = importlib.metadata.version("pydantic")
+
+HAS_PYDANTIC_V2: bool = Version(pydantic_version).major == 2
+
+__all__ = ("HAS_PYDANTIC_V2",)

synapse/config/_util.py

@@ -11,10 +11,16 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-from typing import Any, Dict, Type, TypeVar
+from typing import TYPE_CHECKING, Any, Dict, Type, TypeVar
 
 import jsonschema
-from pydantic import BaseModel, ValidationError, parse_obj_as
+
+from synapse._pydantic_compat import HAS_PYDANTIC_V2
+
+if TYPE_CHECKING or HAS_PYDANTIC_V2:
+    from pydantic.v1 import BaseModel, ValidationError, parse_obj_as
+else:
+    from pydantic import BaseModel, ValidationError, parse_obj_as
 
 from synapse.config._base import ConfigError
 from synapse.types import JsonDict, StrSequence

synapse/config/workers.py

@@ -15,10 +15,16 @@
 
 import argparse
 import logging
-from typing import Any, Dict, List, Optional, Union
+from typing import TYPE_CHECKING, Any, Dict, List, Optional, Union
 
 import attr
-from pydantic import BaseModel, Extra, StrictBool, StrictInt, StrictStr
+
+from synapse._pydantic_compat import HAS_PYDANTIC_V2
+
+if TYPE_CHECKING or HAS_PYDANTIC_V2:
+    from pydantic.v1 import BaseModel, Extra, StrictBool, StrictInt, StrictStr
+else:
+    from pydantic import BaseModel, Extra, StrictBool, StrictInt, StrictStr
 
 from synapse.config._base import (
     Config,

synapse/events/validator.py

@@ -12,10 +12,16 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 import collections.abc
-from typing import List, Type, Union, cast
+from typing import TYPE_CHECKING, List, Type, Union, cast
 
 import jsonschema
-from pydantic import Field, StrictBool, StrictStr
+
+from synapse._pydantic_compat import HAS_PYDANTIC_V2
+
+if TYPE_CHECKING or HAS_PYDANTIC_V2:
+    from pydantic.v1 import Field, StrictBool, StrictStr
+else:
+    from pydantic import Field, StrictBool, StrictStr
 
 from synapse.api.constants import (
     MAX_ALIAS_LENGTH,

synapse/http/servlet.py

@@ -28,8 +28,15 @@
     overload,
 )
 
-from pydantic import BaseModel, MissingError, PydanticValueError, ValidationError
-from pydantic.error_wrappers import ErrorWrapper
+from synapse._pydantic_compat import HAS_PYDANTIC_V2
+
+if TYPE_CHECKING or HAS_PYDANTIC_V2:
+    from pydantic.v1 import BaseModel, MissingError, PydanticValueError, ValidationError
+    from pydantic.v1.error_wrappers import ErrorWrapper
+else:
+    from pydantic import BaseModel, MissingError, PydanticValueError, ValidationError
+    from pydantic.error_wrappers import ErrorWrapper
+
 from typing_extensions import Literal
 
 from twisted.web.server import Request

synapse/rest/client/account.py

@@ -18,7 +18,12 @@
 from typing import TYPE_CHECKING, List, Optional, Tuple
 from urllib.parse import urlparse
 
-from pydantic import StrictBool, StrictStr, constr
+from synapse._pydantic_compat import HAS_PYDANTIC_V2
+
+if TYPE_CHECKING or HAS_PYDANTIC_V2:
+    from pydantic.v1 import StrictBool, StrictStr, constr
+else:
+    from pydantic import StrictBool, StrictStr, constr
 from typing_extensions import Literal
 
 from twisted.web.server import Request

synapse/rest/client/devices.py

@@ -17,7 +17,12 @@
 from http import HTTPStatus
 from typing import TYPE_CHECKING, List, Optional, Tuple
 
-from pydantic import Extra, StrictStr
+from synapse._pydantic_compat import HAS_PYDANTIC_V2
+
+if TYPE_CHECKING or HAS_PYDANTIC_V2:
+    from pydantic.v1 import Extra, StrictStr
+else:
+    from pydantic import Extra, StrictStr
 
 from synapse.api import errors
 from synapse.api.errors import NotFoundError, SynapseError, UnrecognizedRequestError

synapse/rest/client/directory.py

@@ -15,7 +15,13 @@
 import logging
 from typing import TYPE_CHECKING, List, Optional, Tuple
 
-from pydantic import StrictStr
+from synapse._pydantic_compat import HAS_PYDANTIC_V2
+
+if TYPE_CHECKING or HAS_PYDANTIC_V2:
+    from pydantic.v1 import StrictStr
+else:
+    from pydantic import StrictStr
+
 from typing_extensions import Literal
 
 from twisted.web.server import Request

synapse/rest/client/models.py

@@ -13,7 +13,12 @@
 # limitations under the License.
 from typing import TYPE_CHECKING, Dict, Optional
 
-from pydantic import Extra, StrictInt, StrictStr, constr, validator
+from synapse._pydantic_compat import HAS_PYDANTIC_V2
+
+if TYPE_CHECKING or HAS_PYDANTIC_V2:
+    from pydantic.v1 import Extra, StrictInt, StrictStr, constr, validator
+else:
+    from pydantic import Extra, StrictInt, StrictStr, constr, validator
 
 from synapse.rest.models import RequestBodyModel
 from synapse.util.threepids import validate_email

synapse/rest/key/v2/remote_key_resource.py

@@ -16,7 +16,13 @@
 import re
 from typing import TYPE_CHECKING, Dict, Mapping, Optional, Set, Tuple
 
-from pydantic import Extra, StrictInt, StrictStr
+from synapse._pydantic_compat import HAS_PYDANTIC_V2
+
+if TYPE_CHECKING or HAS_PYDANTIC_V2:
+    from pydantic.v1 import Extra, StrictInt, StrictStr
+else:
+    from pydantic import StrictInt, StrictStr, Extra
+
 from signedjson.sign import sign_json
 
 from twisted.web.server import Request