Move stableTargetId typehint to extractedData

mex/common/models/base.py

@@ -214,26 +214,13 @@ def __str__(self) -> str:
 class MExModel(BaseModel):
     """Abstract base model for extracted data, merged item and rule set classes.
 
-    This class defines an `identifier` field and gives type hints for `stableTargetId`
-    and the class variable `entityType`.
+    This class defines an `identifier` field and gives a type hint for the frozen class
+    variable `entityType`.
     """
 
     model_config = ConfigDict(extra="forbid")
 
     if TYPE_CHECKING:
-        # Sometimes multiple primary sources describe the same activity, resource, etc.
-        # and a complete metadata item can only be created by merging these fragments.
-        # The `stableTargetID` is part of all models in `mex.common.models` to allow
-        # MEx to identify which extracted items describe the same thing and should be
-        # merged to create a complete metadata item.
-        # The name might be a bit misleading (also due to historical reasons), but the
-        # "stability" is only guaranteed for one "real world" or "digital world" thing
-        # having the same ID in MEx over time. But not as a guarantee, that the same
-        # metadata sources contribute to the complete metadata item.
-        # Because we anticipate that items have to be merged, the `stableTargetID` is
-        # also used as the foreign key for all fields containing references.
-        stableTargetId: Any
-
         # We add the entityType as a final class variable to all `MExModel` subclasses.
         # This helps with assigning the correct class when reading raw JSON entities.
         # Simple duck-typing would not work, because some entity types have overlapping

mex/common/models/extracted_data.py

@@ -1,4 +1,4 @@
-from typing import Annotated, Any
+from typing import TYPE_CHECKING, Annotated, Any
 
 from pydantic import Field, model_validator, validate_call
 
@@ -23,6 +23,20 @@ class ExtractedData(MExModel):
     See below, for a full description.
     """
 
+    if TYPE_CHECKING:
+        # Sometimes multiple primary sources describe the same activity, resource, etc.
+        # and a complete metadata item can only be created by merging these fragments.
+        # The `stableTargetID` is part of all models in `mex.common.models` to allow
+        # MEx to identify which extracted items describe the same thing and should be
+        # merged to create a complete metadata item.
+        # The name might be a bit misleading (also due to historical reasons), but the
+        # "stability" is only guaranteed for one "real world" or "digital world" thing
+        # having the same ID in MEx over time. But not as a guarantee, that the same
+        # metadata sources contribute to the complete metadata item.
+        # Because we anticipate that items have to be merged, the `stableTargetID` is
+        # also used as the foreign key for all fields containing references.
+        stableTargetId: Any
+
     hadPrimarySource: Annotated[
         PrimarySourceID,
         Field(

mex/common/public_api/transform.py

@@ -6,6 +6,7 @@
     MERGED_MODEL_CLASSES_BY_NAME,
     MExModel,
 )
+from mex.common.models.extracted_data import ExtractedData
 from mex.common.public_api.models import (
     PublicApiField,
     PublicApiFieldValueTypes,
@@ -54,7 +55,11 @@ def transform_mex_model_to_public_api_item(model: MExModel) -> PublicApiItem:
             )
     return PublicApiItem(
         entityType=model.__class__.__name__,
-        businessId=model.stableTargetId,
+        businessId=(
+            model.stableTargetId
+            if isinstance(model, ExtractedData)
+            else model.identifier
+        ),
         values=api_values,
     )