import pydantic objects from the `_pydantic_compat` module (#17667)

This PR changes `from pydantic import BaseModel` to `from
synapse._pydantic_compat import BaseModel` (as well as `constr`,
`conbytes`, `conint`, `confloat`).

It allows `check_pydantic_models.py` to mock those pydantic objects only
in the synapse module, and not interfere with pydantic objects in
external dependencies.

This should solve the CI problems for #17144, which breaks because
`check_pydantic_models.py` patches pydantic models from
[scim2-models](https://scim2-models.readthedocs.io/).

/cc @DMRobertson @gotmax23
fixes #17659 


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1 files changed, 7 insertions, 9 deletions

diff --git a/synapse/http/servlet.py b/synapse/http/servlet.py

index 08b8ff7afd..0330f1c878 100644
--- a/synapse/http/servlet.py
+++ b/synapse/http/servlet.py
@@ -37,19 +37,17 @@ from typing import (
     overload,
 )
 
-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
 
+from synapse._pydantic_compat import (
+    BaseModel,
+    ErrorWrapper,
+    MissingError,
+    PydanticValueError,
+    ValidationError,
+)
 from synapse.api.errors import Codes, SynapseError
 from synapse.http import redact_uri
 from synapse.http.server import HttpServer