feat: typed PK identifiers for Units/Subsections/Sections

src/openedx_content/applets/sections/api.py

@@ -8,7 +8,7 @@
 from typing import Iterable
 
 from ..containers import api as containers_api
-from ..containers.models import Container, ContainerVersion
+from ..containers.models import ContainerVersion
 from ..publishing.models import LearningPackage
 from ..subsections.models import Subsection, SubsectionVersion
 from .models import Section, SectionVersion
@@ -24,7 +24,7 @@
 ]
 
 
-def get_section(section_id: Container.PK, /):
+def get_section(section_id: Section.PK, /):
     """Get a section"""
     return Section.objects.select_related("container").get(pk=section_id)
 
@@ -61,7 +61,7 @@ def create_section_and_version(
 
 
 def create_next_section_version(
-    section: Section | Container.PK,
+    section: Section | Section.PK,
     *,
     title: str | None = None,
     subsections: Iterable[Subsection | SubsectionVersion] | None = None,

src/openedx_content/applets/sections/models.py

@@ -2,13 +2,13 @@
 Models that implement sections
 """
 
-from typing import override
+from typing import NewType, TypeAlias, cast, override
 
 from django.core.exceptions import ValidationError
 from django.db import models
 
 from ..containers.api import get_container_subclass_of
-from ..containers.models import Container, ContainerVersion
+from ..containers.models import Container, ContainerPK, ContainerVersion
 from ..publishing.models import PublishableEntity
 from ..subsections.models import Subsection
 
@@ -17,6 +17,8 @@
     "SectionVersion",
 ]
 
+SectionPK = NewType("SectionPK", ContainerPK)
+
 
 @Container.register_subclass
 class Section(Container):
@@ -27,6 +29,8 @@ class Section(Container):
     entities and can be added to other containers.
     """
 
+    PK: TypeAlias = SectionPK
+
     type_code = "section"
     olx_tag_name = "chapter"  # Serializes to OLX as `<chapter>...</chapter>`.
 
@@ -37,6 +41,10 @@ class Section(Container):
         primary_key=True,
     )
 
+    @property
+    def id(self) -> SectionPK:
+        return cast(SectionPK, self.publishable_entity_id)
+
     @override
     @classmethod
     def validate_entity(cls, entity: PublishableEntity) -> None:

src/openedx_content/applets/subsections/api.py

@@ -8,7 +8,7 @@
 from typing import Iterable
 
 from ..containers import api as containers_api
-from ..containers.models import Container, ContainerVersion
+from ..containers.models import ContainerVersion
 from ..publishing.models import LearningPackage
 from ..units.models import Unit, UnitVersion
 from .models import Subsection, SubsectionVersion
@@ -24,7 +24,7 @@
 ]
 
 
-def get_subsection(subsection_id: Container.PK, /):
+def get_subsection(subsection_id: Subsection.PK, /):
     """Get a subsection"""
     return Subsection.objects.select_related("container").get(pk=subsection_id)
 
@@ -61,7 +61,7 @@ def create_subsection_and_version(
 
 
 def create_next_subsection_version(
-    subsection: Subsection | Container.PK,
+    subsection: Subsection | Subsection.PK,
     *,
     title: str | None = None,
     units: Iterable[Unit | UnitVersion] | None = None,

src/openedx_content/applets/subsections/models.py

@@ -2,13 +2,13 @@
 Models that implement subsections
 """
 
-from typing import override
+from typing import NewType, TypeAlias, cast, override
 
 from django.core.exceptions import ValidationError
 from django.db import models
 
 from ..containers.api import get_container_subclass_of
-from ..containers.models import Container, ContainerVersion
+from ..containers.models import Container, ContainerPK, ContainerVersion
 from ..publishing.models import PublishableEntity
 from ..units.models import Unit
 
@@ -17,6 +17,8 @@
     "SubsectionVersion",
 ]
 
+SubsectionPK = NewType("SubsectionPK", ContainerPK)
+
 
 @Container.register_subclass
 class Subsection(Container):
@@ -27,6 +29,8 @@ class Subsection(Container):
     entities and can be added to other containers.
     """
 
+    PK: TypeAlias = SubsectionPK
+
     type_code = "subsection"
     olx_tag_name = "sequential"  # Serializes to OLX as `<sequential>...</sequential>`.
 
@@ -37,6 +41,10 @@ class Subsection(Container):
         primary_key=True,
     )
 
+    @property
+    def id(self) -> SubsectionPK:
+        return cast(SubsectionPK, self.publishable_entity_id)
+
     @override
     @classmethod
     def validate_entity(cls, entity: PublishableEntity) -> None:

src/openedx_content/applets/units/api.py

@@ -9,7 +9,7 @@
 
 from ..components.models import Component, ComponentVersion
 from ..containers import api as containers_api
-from ..containers.models import Container, ContainerVersion
+from ..containers.models import ContainerVersion
 from ..publishing.models import LearningPackage
 from .models import Unit, UnitVersion
 
@@ -24,7 +24,7 @@
 ]
 
 
-def get_unit(unit_id: Container.PK, /):
+def get_unit(unit_id: Unit.PK, /):
     """Get a unit"""
     return Unit.objects.select_related("container").get(pk=unit_id)
 
@@ -61,7 +61,7 @@ def create_unit_and_version(
 
 
 def create_next_unit_version(
-    unit: Unit | Container.PK,
+    unit: Unit | Unit.PK,
     *,
     title: str | None = None,
     components: Iterable[Component | ComponentVersion] | None = None,

src/openedx_content/applets/units/models.py

@@ -2,19 +2,21 @@
 Models that implement units
 """
 
-from typing import override
+from typing import NewType, TypeAlias, cast, override
 
 from django.core.exceptions import ValidationError
 from django.db import models
 
-from ..containers.models import Container, ContainerVersion
+from ..containers.models import Container, ContainerPK, ContainerVersion
 from ..publishing.models import PublishableEntity
 
 __all__ = [
     "Unit",
     "UnitVersion",
 ]
 
+UnitPK = NewType("UnitPK", ContainerPK)
+
 
 @Container.register_subclass
 class Unit(Container):
@@ -25,6 +27,8 @@ class Unit(Container):
     entities and can be added to other containers.
     """
 
+    PK: TypeAlias = UnitPK
+
     type_code = "unit"
     olx_tag_name = "vertical"  # Serializes to OLX as `<unit>...</unit>`.
 
@@ -35,6 +39,10 @@ class Unit(Container):
         primary_key=True,
     )
 
+    @property
+    def id(self) -> UnitPK:
+        return cast(UnitPK, self.publishable_entity_id)
+
     @override
     @classmethod
     def validate_entity(cls, entity: PublishableEntity) -> None:

tests/openedx_content/applets/sections/test_api.py

@@ -8,7 +8,7 @@
 from django.core.exceptions import ValidationError
 
 import openedx_content.api as content_api
-from openedx_content.models_api import Container, Section, SectionVersion, Subsection, SubsectionVersion
+from openedx_content.models_api import Section, SectionVersion, Subsection, SubsectionVersion
 
 from ..components.test_api import ComponentTestCase
 
@@ -140,14 +140,14 @@ def test_get_section(self) -> None:
 
     def test_get_section_nonexistent(self) -> None:
         """Test `get_section()` when the subsection doesn't exist"""
-        FAKE_ID = cast(Container.PK, -500)
+        FAKE_ID = cast(Section.PK, -500)
         with pytest.raises(Section.DoesNotExist):
             content_api.get_section(FAKE_ID)
 
     def test_get_section_other_container_type(self) -> None:
         """Test `get_section()` when the provided PK is for a non-Subsection container"""
         with pytest.raises(Section.DoesNotExist):
-            content_api.get_section(self.unit_1.id)
+            content_api.get_section(self.unit_1.id)  # type: ignore[arg-type]
 
     def test_section_queries(self) -> None:
         """

tests/openedx_content/applets/subsections/test_api.py

@@ -1,13 +1,14 @@
 """
 Basic tests for the subsections API.
 """
+
 from typing import cast
 
 import pytest
 from django.core.exceptions import ValidationError
 
 import openedx_content.api as content_api
-from openedx_content.models_api import Container, Subsection, SubsectionVersion, Unit, UnitVersion
+from openedx_content.models_api import Subsection, SubsectionVersion, Unit, UnitVersion
 
 from ..components.test_api import ComponentTestCase
 
@@ -117,14 +118,14 @@ def test_get_subsection(self) -> None:
 
     def test_get_subsection_nonexistent(self) -> None:
         """Test `get_subsection()` when the subsection doesn't exist"""
-        FAKE_ID = cast(Container.PK, -500)
+        FAKE_ID = cast(Subsection.PK, -500)
         with pytest.raises(Subsection.DoesNotExist):
             content_api.get_subsection(FAKE_ID)
 
     def test_get_subsection_other_container_type(self) -> None:
         """Test `get_subsection()` when the provided PK is for a non-Subsection container"""
         with pytest.raises(Subsection.DoesNotExist):
-            content_api.get_subsection(self.unit_1.id)
+            content_api.get_subsection(self.unit_1.id)  # type: ignore[arg-type]
 
     def test_subsection_queries(self) -> None:
         """

tests/openedx_content/applets/units/test_api.py

@@ -1,13 +1,14 @@
 """
 Basic tests for the units API.
 """
+
 from typing import cast
 
 import pytest
 from django.core.exceptions import ValidationError
 
 import openedx_content.api as content_api
-from openedx_content.models_api import Component, ComponentVersion, Container, Unit, UnitVersion
+from openedx_content.models_api import Component, ComponentVersion, Unit, UnitVersion
 from tests.test_django_app.models import TestContainer
 
 from ..components.test_api import ComponentTestCase
@@ -111,7 +112,7 @@ def test_get_unit(self) -> None:
 
     def test_get_unit_nonexistent(self) -> None:
         """Test `get_unit()` when the unit doesn't exist"""
-        FAKE_ID = cast(Container.PK, -500)
+        FAKE_ID = cast(Unit.PK, -500)
         with pytest.raises(Unit.DoesNotExist):
             content_api.get_unit(FAKE_ID)
 
@@ -125,7 +126,7 @@ def test_get_unit_other_container_type(self) -> None:
             container_cls=TestContainer,
         )
         with pytest.raises(Unit.DoesNotExist):
-            content_api.get_unit(other_container.id)
+            content_api.get_unit(other_container.id)  # type: ignore[arg-type]
 
     def test_unit_queries(self) -> None:
         """