refactor: use pygen warning

cognite/pygen/_core/models/fields/connections.py

@@ -16,6 +16,8 @@
     SingleReverseDirectRelation,
 )
 
+from cognite.pygen.warnings import MissingReverseDirectRelationTargetWarning
+
 from .base import Field
 
 if TYPE_CHECKING:
@@ -246,12 +248,9 @@ def load(
             )
             if target is None or prop.through.property not in target:
                 target_str = (
-                    f"{prop.through.source}.{prop.through.property}" if target is not None else prop.through.source
-                )
-                warnings.warn(
-                    f"Target {target_str} does not exists. " f"Skipping reverse direct relation {field_string}",
-                    stacklevel=2,
+                    f"{prop.through.source}.{prop.through.property}" if target is not None else str(prop.through.source)
                 )
+                warnings.warn(MissingReverseDirectRelationTargetWarning(target_str, field_string), stacklevel=2)
                 return None
         edge_type = prop.type if isinstance(prop, dm.EdgeConnection) else None
         direction: Literal["outwards", "inwards"]

cognite/pygen/warnings.py

@@ -59,3 +59,13 @@ def __str__(self) -> str:
             f"Name collision detected. The following filter parameter {self.word!r} name is used by pygen."
             "An underscore will be added to this parameter to avoid name collision."
         )
+
+
+class MissingReverseDirectRelationTargetWarning(PygenWarning, UserWarning):
+
+    def __init__(self, target: str, field: str) -> None:
+        self.target = target
+        self.field = field
+
+    def __str__(self) -> str:
+        return f"Target {self.target} does not exists. Skipping reverse direct relation {self.field}."