Protect referenced feeder structures from deletion

tests/external-object-row-assignment-project-command.repository.test.ts

@@ -533,6 +533,61 @@ describe("external object new-circuit project command", () => {
     }
   });
 
+  it("blocks history removal when the generated circuit became a feeder", () => {
+    const context = createFixture(null);
+    try {
+      const object = objectSnapshot(null);
+      const circuit = newExternalCircuit(context.db);
+      const command = createExternalObjectNewCircuitProjectCommand(
+        externalObjectAssignToNewCircuitCommandType,
+        {
+          circuit,
+          objects: [{
+            expected: object,
+            target: { ...object, circuitDeviceRowId: "row-new" },
+          }],
+          confirmedConflictObjectIds: [],
+        }
+      );
+      const repository = new ExternalObjectNewCircuitProjectCommandRepository(context.db);
+      const inserted = repository.execute({
+        projectId: "project-1",
+        expectedRevision: 0,
+        source: "user",
+        command,
+      });
+      context.db.insert(distributionBoards).values({
+        id: "board-2",
+        projectId: "project-1",
+        name: "Unterverteiler",
+        boardNumber: "UV-02",
+        feedingDistributionBoardId: "board-1",
+        feedingCircuitId: circuit.id,
+      }).run();
+
+      assert.throws(
+        () => repository.execute({
+          projectId: "project-1",
+          expectedRevision: 1,
+          source: "undo",
+          historyTargetChangeSetId: inserted.revision.changeSetId,
+          command: inserted.inverse,
+        }),
+        /Speist UV-02 – erst Einspeisung ändern\./
+      );
+      assert.ok(
+        context.db.select().from(circuits)
+          .where(eq(circuits.id, circuit.id)).get()
+      );
+      assert.equal(
+        context.db.select().from(externalModelObjects).get()!.circuitDeviceRowId,
+        "row-new"
+      );
+    } finally {
+      context.close();
+    }
+  });
+
   it("rolls back the complete circuit subtree when history persistence fails", () => {
     const context = createFixture(null);
     try {