feat(db): modifier la contrainte de clé étrangère pour linked_production_pdl_id afin d'utiliser ON DELETE SET NULL

Author: Clément VALENTIN

apps/api/alembic/versions/20251211_0100_005_fix_linked_production_pdl_fk.py

@@ -0,0 +1,64 @@
+"""Fix linked_production_pdl_id foreign key to SET NULL on delete
+
+Revision ID: 005
+Revises: 004
+Create Date: 2025-12-11 01:00:00
+
+Fixes IntegrityError when deleting a PDL that is referenced by another PDL
+via linked_production_pdl_id. The FK constraint now uses ON DELETE SET NULL
+so that deleting a production PDL automatically nullifies the reference
+in any consumption PDL that was linked to it.
+"""
+from typing import Sequence, Union
+
+from alembic import op
+
+
+# revision identifiers, used by Alembic.
+revision: str = "005"
+down_revision: Union[str, None] = "004"
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    bind = op.get_bind()
+    dialect = bind.dialect.name
+
+    if dialect == "postgresql":
+        # PostgreSQL - drop and recreate the FK constraint with ON DELETE SET NULL
+        op.execute("""
+            ALTER TABLE pdls
+            DROP CONSTRAINT IF EXISTS pdls_linked_production_pdl_id_fkey
+        """)
+        op.execute("""
+            ALTER TABLE pdls
+            ADD CONSTRAINT pdls_linked_production_pdl_id_fkey
+            FOREIGN KEY (linked_production_pdl_id) REFERENCES pdls(id)
+            ON DELETE SET NULL
+        """)
+    else:
+        # SQLite doesn't support ALTER CONSTRAINT, but it also doesn't
+        # enforce foreign keys by default, so this is a no-op for SQLite.
+        # If you need strict FK enforcement in SQLite, you'd need to
+        # recreate the table entirely.
+        pass
+
+
+def downgrade() -> None:
+    bind = op.get_bind()
+    dialect = bind.dialect.name
+
+    if dialect == "postgresql":
+        # Restore the original FK constraint without ON DELETE behavior
+        op.execute("""
+            ALTER TABLE pdls
+            DROP CONSTRAINT IF EXISTS pdls_linked_production_pdl_id_fkey
+        """)
+        op.execute("""
+            ALTER TABLE pdls
+            ADD CONSTRAINT pdls_linked_production_pdl_id_fkey
+            FOREIGN KEY (linked_production_pdl_id) REFERENCES pdls(id)
+        """)
+    else:
+        pass

apps/api/src/models/pdl.py

@@ -23,7 +23,7 @@ class PDL(Base, TimestampMixin):
     is_active: Mapped[bool] = mapped_column(Boolean, nullable=False, default=True)  # PDL is active/enabled
     oldest_available_data_date: Mapped[date | None] = mapped_column(Date, nullable=True)  # Oldest date where Enedis has data (meter activation date)
     activation_date: Mapped[date | None] = mapped_column(Date, nullable=True)  # Contract activation date (from Enedis)
-    linked_production_pdl_id: Mapped[str | None] = mapped_column(String(36), ForeignKey("pdls.id"), nullable=True)  # Link to production PDL for combined graphs
+    linked_production_pdl_id: Mapped[str | None] = mapped_column(String(36), ForeignKey("pdls.id", ondelete="SET NULL"), nullable=True)  # Link to production PDL for combined graphs
     selected_offer_id: Mapped[str | None] = mapped_column(String(36), ForeignKey("energy_offers.id", ondelete="SET NULL"), nullable=True)  # Selected energy offer
 
     # Relations