Be more consistent about validator temrinology

Use field validator or model validator explicitly instead of talking
about Pydantic validators. Remove the linter exclusion for the old
root_validator and validator functions, which are no longer used.

docs/user-guide/pydantic.rst

@@ -13,7 +13,7 @@ Normalizing datetime fields
 Pydantic supports several input formats for `~datetime.datetime` fields, but the resulting `~datetime.datetime` object may be timezone-naive.
 Best practice for Python code is to only use timezone-aware `~datetime.datetime` objects in the UTC time zone.
 
-Pydantic provides a utility function, `~safir.pydantic.normalize_datetime`, that can be used as a validator for a `~datetime.datetime` model field.
+Pydantic provides a utility function, `~safir.pydantic.normalize_datetime`, that can be used as a field validator for a `~datetime.datetime` model field.
 It ensures that any input is converted to UTC and is always timezone-aware.
 
 Here's an example of how to use it:
@@ -36,14 +36,14 @@ Here's an example of how to use it:
            normalize_datetime
        )
 
-Multiple attributes can be listed as the initial arguments of `~pydantic.validator` if there are multiple fields that need to be checked.
+Multiple attributes can be listed as the initial arguments of `~pydantic.field_validator` if there are multiple fields that need to be checked.
 
-This validator accepts all of the input formats that Pydantic accepts.
+This field validator accepts all of the input formats that Pydantic accepts.
 This includes some ambiguous formats, such as an ISO 8601 date without time zone information.
 All such dates are given a consistent interpretation as UTC, but the results may be surprising if the caller expected local time.
 In some cases, it may be desirable to restrict input to one unambiguous format.
 
-This can be done by using `~safir.pydantic.normalize_isodatetime` as the validator instead.
+This can be done by using `~safir.pydantic.normalize_isodatetime` as the field validator instead.
 This function only accepts ``YYYY-MM-DDTHH:MM[:SS]Z`` as the input format.
 The ``Z`` time zone prefix indicating UTC is mandatory.
 It is called the same way as `~safir.pydantic.normalize_datetime`.

pyproject.toml

@@ -265,12 +265,6 @@ builtins-ignorelist = [
 fixture-parentheses = false
 mark-parentheses = false
 
-[tool.ruff.pep8-naming]
-classmethod-decorators = [
-    "pydantic.root_validator",
-    "pydantic.validator",
-]
-
 [tool.ruff.pydocstyle]
 convention = "numpy"
 

src/safir/pydantic.py

@@ -21,12 +21,12 @@
 
 
 def normalize_datetime(v: int | datetime | None) -> datetime | None:
-    """Pydantic validator for datetime fields.
+    """Pydantic field validator for datetime fields.
 
     Supports `~datetime.datetime` fields given in either any format supported
     by Pydantic natively, or in seconds since epoch (which Pydantic doesn't
-    support).  This validator ensures that datetimes are always stored in the
-    model as timezone-aware UTC datetimes.
+    support).  This field validator ensures that datetimes are always stored
+    in the model as timezone-aware UTC datetimes.
 
     Parameters
     ----------
@@ -41,12 +41,12 @@ def normalize_datetime(v: int | datetime | None) -> datetime | None:
 
     Examples
     --------
-    Here is a partial model that uses this function as a validator.
+    Here is a partial model that uses this function as a field validator.
 
     .. code-block:: python
 
        class Info(BaseModel):
-           last_used: Optional[datetime] = Field(
+           last_used: datetime | None = Field(
                None,
                title="Last used",
                description="When last used in seconds since epoch",
@@ -68,12 +68,12 @@ class Info(BaseModel):
 
 
 def normalize_isodatetime(v: str | None) -> datetime | None:
-    """Pydantic validator for datetime fields in ISO format.
+    """Pydantic field validator for datetime fields in ISO format.
 
-    This validator requires the ISO 8601 date and time format with ``Z`` as
-    the time zone (``YYYY-MM-DDTHH:MM:SSZ``).  This format is compatible with
-    Kubernetes and the ISO UWS standard and is the same format produced by
-    `safir.datetime.isodatetime`.  It should be used when the ambiguous
+    This field validator requires the ISO 8601 date and time format with ``Z``
+    as the time zone (``YYYY-MM-DDTHH:MM:SSZ``). This format is compatible
+    with Kubernetes and the ISO UWS standard and is the same format produced
+    by `safir.datetime.isodatetime`. It should be used when the ambiguous
     formats supported by Pydantic by default (such as dates and times without
     time zone information) shouldn't be allowed.
 
@@ -90,12 +90,12 @@ def normalize_isodatetime(v: str | None) -> datetime | None:
 
     Examples
     --------
-    Here is a partial model that uses this function as a validator.
+    Here is a partial model that uses this function as a field validator.
 
     .. code-block:: python
 
        class Info(BaseModel):
-           last_used: Optional[datetime] = Field(
+           last_used: datetime | None = Field(
                None,
                title="Last used",
                description="Date and time last used",
@@ -216,13 +216,13 @@ def model_dump_json(self, **kwargs: Any) -> str:
 def validate_exactly_one_of(
     *settings: str,
 ) -> Callable[[BaseModel], BaseModel]:
-    """Generate a validator imposing a one and only one constraint.
+    """Generate a model validator imposing a one and only one constraint.
 
     Sometimes, models have a set of attributes of which one and only one may
     be set. Ideally this is represented properly in the type system, but
-    occasionally it's more convenient to use a validator. This is a validator
-    generator that can produce a validator function that ensures one and only
-    one of an arbitrary set of attributes must be set.
+    occasionally it's more convenient to use a model validator. This is a
+    model validator generator that can produce a model validator function that
+    ensures one and only one of an arbitrary set of attributes must be set.
 
     Parameters
     ----------
@@ -237,7 +237,7 @@ def validate_exactly_one_of(
 
     Examples
     --------
-    Use this inside a Pydantic class as a validator as follows:
+    Use this inside a Pydantic class as a model validator as follows:
 
     .. code-block:: python
 
@@ -250,9 +250,9 @@ class Foo(BaseModel):
                validate_exactly_one_of("foo", "bar", "baz")
            )
 
-    The attribute listed as the first argument to the ``validator`` call must
-    be the last attribute in the model definition so that any other attributes
-    have already been seen.
+    The attribute listed as the first argument to the ``model_validator`` call
+    must be the last attribute in the model definition so that any other
+    attributes have already been seen.
     """
     if len(settings) < 2:
         msg = "validate_exactly_one_of takes at least two field names"