✨ feat: Introduce optimization.variables.delete()

ixmp4/core/optimization/variable.py

@@ -14,7 +14,7 @@
 from ixmp4.data.abstract import OptimizationVariable as VariableModel
 from ixmp4.data.abstract import Run
 
-from .base import Lister, Retriever, Tabulator
+from .base import Deleter, Lister, Retriever, Tabulator
 
 
 class Variable(BaseModelFacade):
@@ -105,6 +105,7 @@ def __str__(self) -> str:
 
 
 class VariableRepository(
+    Deleter[Variable, VariableModel],
     Retriever[Variable, VariableModel],
     Lister[Variable, VariableModel],
     Tabulator[Variable, VariableModel],

ixmp4/data/abstract/optimization/variable.py

@@ -42,6 +42,7 @@ def __str__(self) -> str:
 class VariableRepository(
     BackendBaseRepository[Variable],
     base.Creator,
+    base.Deleter,
     base.Retriever,
     base.Enumerator,
     Protocol,
@@ -91,6 +92,23 @@ def create(
         """
         ...
 
+    def delete(self, id: int) -> None:
+        """Deletes a Variable.
+
+        Parameters
+        ----------
+        id : int
+            The unique integer id of the Variable.
+
+        Raises
+        ------
+        :class:`ixmp4.data.abstract.Variable.NotFound`:
+            If the Variable with `id` does not exist.
+        :class:`ixmp4.data.abstract.Variable.DeletionPrevented`:
+            If the Variable with `id` is used in the database, preventing it's deletion.
+        """
+        ...
+
     def get(self, run_id: int, name: str) -> Variable:
         """Retrieves a Variable.
 

ixmp4/data/api/optimization/variable.py

@@ -39,6 +39,7 @@ class VariableDocsRepository(DocsRepository):
 
 class VariableRepository(
     base.Creator[Variable],
+    base.Deleter[Variable],
     base.Retriever[Variable],
     base.Enumerator[Variable],
     abstract.OptimizationVariableRepository,
@@ -64,6 +65,9 @@ def create(
             column_names=column_names,
         )
 
+    def delete(self, id: int) -> None:
+        super().delete(id=id)
+
     def add_data(self, variable_id: int, data: dict[str, Any] | pd.DataFrame) -> None:
         if isinstance(data, pd.DataFrame):
             # data will always contain str, not only Hashable

ixmp4/data/db/optimization/variable/model.py

@@ -50,7 +50,11 @@ def validate_data(self, key: Any, data: dict[str, Any]) -> dict[str, Any]:
         return data
 
     _variable_indexset_associations: types.Mapped[list[VariableIndexsetAssociation]] = (
-        db.relationship(back_populates="variable", cascade="all, delete-orphan")
+        db.relationship(
+            back_populates="variable",
+            cascade="all, delete-orphan",
+            passive_deletes=True,
+        )
     )
 
     _indexsets: db.AssociationProxy[list[IndexSet]] = db.association_proxy(

ixmp4/data/db/optimization/variable/repository.py

@@ -23,6 +23,7 @@
 
 class VariableRepository(
     base.Creator[Variable],
+    base.Deleter[Variable],
     base.Retriever[Variable],
     base.Enumerator[Variable],
     abstract.VariableRepository,
@@ -125,6 +126,10 @@ def create(
             column_names=column_names,
         )
 
+    @guard("edit")
+    def delete(self, id: int) -> None:
+        super().delete(id=id)
+
     @guard("view")
     def list(self, **kwargs: Unpack["base.EnumerateKwargs"]) -> Iterable[Variable]:
         return super().list(**kwargs)

ixmp4/server/rest/optimization/variable.py

@@ -85,3 +85,12 @@ def create(
     backend: Backend = Depends(deps.get_backend),
 ) -> OptimizationVariable:
     return backend.optimization.variables.create(**variable.model_dump())
+
+
+@autodoc
+@router.delete("/{variable_id}/")
+def delete(
+    variable_id: int,
+    backend: Backend = Depends(deps.get_backend),
+) -> None:
+    backend.optimization.variables.delete(id=variable_id)

tests/core/test_optimization_variable.py

@@ -51,7 +51,7 @@ def test_create_variable(self, platform: ixmp4.Platform) -> None:
         assert variable.marginals == []
 
         # Test creation with indexset
-        indexset_1, indexset_2 = tuple(
+        indexset_1, _ = tuple(
             IndexSet(_backend=platform.backend, _model=model)
             for model in create_indexsets_for_run(platform=platform, run_id=run.id)
         )
@@ -121,6 +121,42 @@ def test_create_variable(self, platform: ixmp4.Platform) -> None:
         assert variable_4.column_names == ["Column 1", "Column 2"]
         assert variable_4.indexsets == [indexset_1.name, indexset_1.name]
 
+    def test_delete_variable(self, platform: ixmp4.Platform) -> None:
+        run = platform.runs.create("Model", "Scenario")
+
+        variable_1 = run.optimization.variables.create(name="Variable 1")
+
+        # Test deletion without linked IndexSets
+        run.optimization.variables.delete(item=variable_1.name)
+
+        assert run.optimization.variables.tabulate().empty
+
+        (indexset_1,) = create_indexsets_for_run(
+            platform=platform, run_id=run.id, amount=1
+        )
+        variable_2 = run.optimization.variables.create(
+            name="Variable 2", constrained_to_indexsets=[indexset_1.name]
+        )
+
+        # TODO How to check that DeletionPrevented is raised? No other object uses
+        # Variable.id, so nothing could prevent the deletion.
+
+        # Test unknown name raises
+        with pytest.raises(OptimizationVariable.NotFound):
+            run.optimization.variables.delete(item="does not exist")
+
+        # Test normal deletion
+        run.optimization.variables.delete(item=variable_2.name)
+
+        assert run.optimization.variables.tabulate().empty
+
+        # Confirm that IndexSet has not been deleted
+        assert not run.optimization.indexsets.tabulate().empty
+
+        # Test that association table rows are deleted
+        # If they haven't, this would raise DeletionPrevented
+        run.optimization.indexsets.delete(item=indexset_1.id)
+
     def test_get_variable(self, platform: ixmp4.Platform) -> None:
         run = platform.runs.create("Model", "Scenario")
         (indexset,) = create_indexsets_for_run(

tests/data/test_optimization_variable.py

@@ -127,6 +127,41 @@ def test_create_variable(self, platform: ixmp4.Platform) -> None:
         assert variable_4.column_names == ["Column 1", "Column 2"]
         assert variable_4.indexsets == [indexset_1.name, indexset_1.name]
 
+    def test_delete_variable(self, platform: ixmp4.Platform) -> None:
+        run = platform.backend.runs.create("Model", "Scenario")
+
+        # Test deletion without linked IndexSets
+        variable_1 = platform.backend.optimization.variables.create(
+            run_id=run.id, name="Variable 1"
+        )
+        platform.backend.optimization.variables.delete(id=variable_1.id)
+
+        assert platform.backend.optimization.variables.tabulate().empty
+
+        indexset_1, _ = create_indexsets_for_run(platform=platform, run_id=run.id)
+        variable_2 = platform.backend.optimization.variables.create(
+            run_id=run.id, name="Variable 2", constrained_to_indexsets=[indexset_1.name]
+        )
+
+        # TODO How to check that DeletionPrevented is raised? No other object uses
+        # Variable.id, so nothing could prevent the deletion.
+
+        # Test unknown id raises
+        with pytest.raises(OptimizationVariable.NotFound):
+            platform.backend.optimization.variables.delete(id=(variable_2.id + 1))
+
+        # Test normal deletion
+        platform.backend.optimization.variables.delete(id=variable_2.id)
+
+        assert platform.backend.optimization.variables.tabulate().empty
+
+        # Confirm that IndexSet has not been deleted
+        assert not platform.backend.optimization.indexsets.tabulate().empty
+
+        # Test that association table rows are deleted
+        # If they haven't, this would raise DeletionPrevented
+        platform.backend.optimization.indexsets.delete(id=indexset_1.id)
+
     def test_get_variable(self, platform: ixmp4.Platform) -> None:
         run = platform.backend.runs.create("Model", "Scenario")
         (indexset,) = create_indexsets_for_run(