Improve type safety of validators (#286)

* Improve type safety of validators

* Remove unused import

mreg_cli/api/fields.py

@@ -20,7 +20,7 @@ class MACAddressField(FrozenModel):
 
     address: str
 
-    @field_validator("address", mode="before")
+    @field_validator("address", mode="after")
     @classmethod
     def validate_and_format_mac(cls, v: str) -> str:
         """Validate and normalize MAC address to 'aa:bb:cc:dd:ee:ff' format.
@@ -49,8 +49,13 @@ class IPAddressField(FrozenModel):
 
     @classmethod
     def from_string(cls, address: str) -> IPAddressField:
-        """Create an IPAddressField from a string."""
-        return cls(address=address)  # type: ignore # validator handles this
+        """Create an IPAddressField from a string.
+
+        Shortcut for creating an IPAddressField from a string,
+        without having to convince the type checker that we can
+        pass in a string to the address field each time.
+        """
+        return cls(address=address)  # pyright: ignore[reportArgumentType] # validator handles this
 
     @field_validator("address", mode="before")
     @classmethod
@@ -69,11 +74,13 @@ def is_ipv6(self) -> bool:
         """Check if the IP address is IPv6."""
         return isinstance(self.address, ipaddress.IPv6Address)
 
+    @staticmethod
     def is_valid(value: str) -> bool:
+        """Check if the value is a valid IP address."""
         try:
             ipaddress.ip_address(value)
             return True
-        except:
+        except ValueError:
             return False
 
     def __str__(self) -> str:

mreg_cli/api/history.py

@@ -63,12 +63,14 @@ class HistoryItem(BaseModel):
     data: dict[str, Any]
 
     @field_validator("data", mode="before")
-    def parse_json_data(cls, v: Any) -> dict[str, Any]:
-        """Ensure that data is always treated as a dictionary."""
+    def parse_json_data(cls, v: Any) -> Any:
+        """Ensure that non-dict values are treated as JSON."""
         if isinstance(v, dict):
-            return v  # type: ignore
-        else:
+            return v  # pyright: ignore[reportUnknownVariableType]
+        try:
             return json.loads(v)
+        except json.JSONDecodeError as e:
+            raise ValueError("Failed to parse history data as JSON") from e
 
     def clean_timestamp(self) -> str:
         """Clean up the timestamp for output."""
@@ -89,8 +91,8 @@ def msg(self, basename: str) -> str:
             rel = self.data["relation"][:-1]
             cls = str(self.resource)
             if "." in cls:
-                cls = cls[cls.rindex(".")+1:]
-            cls = cls.replace("HostPolicy_","")
+                cls = cls[cls.rindex(".") + 1 :]
+            cls = cls.replace("HostPolicy_", "")
             cls = cls.lower()
             msg = f"{rel} {self.data['name']} {direction} {cls} {self.name}"
         elif action == "create":

mreg_cli/api/models.py

@@ -14,7 +14,6 @@
     Field,
     computed_field,
     field_validator,
-    model_validator,
 )
 from typing_extensions import Unpack
 
@@ -397,7 +396,7 @@ class Permission(FrozenModelWithTimestamps, APIMixin):
 
     @field_validator("range", mode="before")
     @classmethod
-    def validate_ip_or_network(cls, value: str) -> IP_NetworkT:
+    def validate_ip_or_network(cls, value: Any) -> IP_NetworkT:
         """Validate and convert the input to a network."""
         try:
             return ipaddress.ip_network(value)
@@ -1862,21 +1861,19 @@ class IPAddress(FrozenModelWithTimestamps, WithHost, APIMixin):
 
     @field_validator("macaddress", mode="before")
     @classmethod
-    def create_valid_macadress_or_none(cls, v: str) -> MACAddressField | None:
+    def create_valid_macadress_or_none(cls, v: Any) -> MACAddressField | None:
         """Create macaddress or convert empty strings to None."""
         if v:
             return MACAddressField(address=v)
-
         return None
 
-    @model_validator(mode="before")
+    @field_validator("ipaddress", mode="before")
     @classmethod
-    def convert_ip_address(cls, values: Any):
-        """Convert ipaddress string to IPAddressField if necessary."""
-        ip_address = values.get("ipaddress")
-        if isinstance(ip_address, str):
-            values["ipaddress"] = {"address": ip_address}
-        return values
+    def create_valid_ipaddress(cls, v: Any) -> IPAddressField:
+        """Create macaddress or convert empty strings to None."""
+        if isinstance(v, str):
+            return IPAddressField.from_string(v)
+        return v  # let Pydantic handle it
 
     @classmethod
     def get_by_ip(cls, ip: IP_AddressT) -> list[Self]:
@@ -2039,7 +2036,7 @@ class CNAME(FrozenModelWithTimestamps, WithHost, WithZone, WithTTL, APIMixin):
 
     @field_validator("name", mode="before")
     @classmethod
-    def validate_name(cls, value: str) -> HostT:
+    def validate_name(cls, value: Any) -> HostT:
         """Validate the hostname."""
         return HostT(hostname=value)
 
@@ -2502,17 +2499,16 @@ class Host(FrozenModelWithTimestamps, WithTTL, WithHistory, APIMixin):
 
     @field_validator("name", mode="before")
     @classmethod
-    def validate_name(cls, value: str) -> HostT:
+    def validate_name(cls, value: Any) -> HostT:
         """Validate the hostname."""
         return HostT(hostname=value)
 
     @field_validator("bacnetid", mode="before")
     @classmethod
-    def convert_bacnetid(cls, v: dict[str, int] | None) -> int | None:
-        """Convert json id field to int or None."""
-        if v and "id" in v:
-            return v["id"]
-
+    def convert_bacnetid(cls, v: Any) -> Any:
+        """Use nested ID value in bacnetid value."""
+        if isinstance(v, dict):
+            return v.get("id")  # pyright: ignore[reportUnknownVariableType, reportUnknownMemberType]
         return None
 
     @classmethod
@@ -3133,12 +3129,6 @@ def get_by_ip(cls, ip: IP_AddressT) -> HostList:
         """
         return cls.get(params={"ipaddresses__ipaddress": str(ip), "ordering": "name"})
 
-    @field_validator("results", mode="before")
-    @classmethod
-    def check_results(cls, v: list[dict[str, str]]) -> list[dict[str, str]]:
-        """Check that the results are valid."""
-        return v
-
     def __len__(self):
         """Return the number of results."""
         return len(self.results)

mreg_cli/utilities/api.py

@@ -428,8 +428,9 @@ class PaginatedResponse(BaseModel):
     def _none_count_is_0(cls, v: Any) -> Any:
         """Ensure `count` is never `None`."""
         # Django count doesn't seem to be guaranteed to be an integer.
-        # Ensures here that None is treated as 0.
         # https://github.com/django/django/blob/bcbc4b9b8a4a47c8e045b060a9860a5c038192de/django/core/paginator.py#L105-L111
+        # Theoretically any callable can be passed to the "count" attribute of the paginator.
+        # Ensures here that None (and any falsey value) is treated as 0.
         return v or 0
 
     @classmethod