check that we are not migrating tablets to ourselves (#15477)

Author: vporyadke

ydb/core/mind/hive/hive_impl.cpp

@@ -581,6 +581,10 @@ void THive::Handle(TEvPrivate::TEvBootTablets::TPtr&) {
 
 void THive::Handle(TEvHive::TEvInitMigration::TPtr& ev) {
     BLOG_D("Handle InitMigration " << ev->Get()->Record);
+    if (AreWeRootHive()) {
+        Send(ev->Sender, new TEvHive::TEvInitMigrationReply(NKikimrProto::ERROR));
+        return;
+    }
     if (MigrationState == NKikimrHive::EMigrationState::MIGRATION_READY || MigrationState == NKikimrHive::EMigrationState::MIGRATION_COMPLETE) {
         if (ev->Get()->Record.GetMigrationFilter().GetFilterDomain().GetSchemeShard() == 0 && GetMySubDomainKey().GetSchemeShard() == 0) {
             BLOG_ERROR("Migration ignored - unknown domain");

ydb/core/mind/hive/hive_ut.cpp

@@ -1581,6 +1581,27 @@ Y_UNIT_TEST_SUITE(THiveTest) {
         runtime.SetObserverFunc(prevObserverFunc);
     }
 
+    Y_UNIT_TEST(TestNoMigrationToSelf) {
+        TTestBasicRuntime runtime(2, false);
+        Setup(runtime, true);
+
+        const ui64 hiveTablet = MakeDefaultHiveID();
+        const ui64 testerTablet = MakeTabletID(false, 1);
+        TActorId sender = runtime.AllocateEdgeActor(0);
+        CreateTestBootstrapper(runtime, CreateTestTabletInfo(hiveTablet, TTabletTypes::Hive), &CreateDefaultHive);
+        MakeSureTabletIsUp(runtime, hiveTablet, 0);
+
+        THolder<TEvHive::TEvCreateTablet> createTablet = MakeHolder<TEvHive::TEvCreateTablet>(testerTablet, 1, TTabletTypes::Dummy, BINDED_CHANNELS);
+        SendCreateTestTablet(runtime, hiveTablet, testerTablet, std::move(createTablet), 0, true);
+
+        THolder<TEvHive::TEvInitMigration> migration = MakeHolder<TEvHive::TEvInitMigration>();
+        runtime.SendToPipe(hiveTablet, sender, migration.Release(), 0, GetPipeConfigWithRetries());
+        TAutoPtr<IEventHandle> handle;
+        auto initMigrationReply = runtime.GrabEdgeEventRethrow<TEvHive::TEvInitMigrationReply>(handle);
+        UNIT_ASSERT(initMigrationReply);
+        UNIT_ASSERT(initMigrationReply->Record.GetStatus() == NKikimrProto::ERROR);
+    }
+
     Y_UNIT_TEST(TestCheckSubHiveMigrationManyTablets) {
         TTestBasicRuntime runtime(2, false);
         Setup(runtime, true);

ydb/core/mind/hive/monitoring.cpp

@@ -3081,6 +3081,7 @@ class TTxMonEvent_InitMigration : public TTransactionBase<THive> {
     TAutoPtr<NMon::TEvRemoteHttpInfo> Event;
     const TActorId Source;
     bool Wait = true;
+    TString Error;
 
     TTxMonEvent_InitMigration(const TActorId& source, NMon::TEvRemoteHttpInfo::TPtr& ev, TSelf* hive)
         : TBase(hive)
@@ -3093,6 +3094,9 @@ class TTxMonEvent_InitMigration : public TTransactionBase<THive> {
     TTxType GetTxType() const override { return NHive::TXTYPE_MON_INIT_MIGRATION; }
 
     bool Execute(TTransactionContext&, const TActorContext& ctx) override {
+        if (Self->AreWeRootHive()) {
+            Error = "Cannot migrate to root hive";
+        }
         TActorId waitActorId;
         TInitMigrationWaitActor* waitActor = nullptr;
         if (Wait) {
@@ -3106,8 +3110,12 @@ class TTxMonEvent_InitMigration : public TTransactionBase<THive> {
     }
 
     void Complete(const TActorContext& ctx) override {
-        if (!Wait) {
-            ctx.Send(Source, new NMon::TEvRemoteJsonInfoRes("{}"));
+        if (Error) {
+            ctx.Send(Source, new NMon::TEvRemoteJsonInfoRes(TStringBuilder() << "{\"error\":\"" << Error << "\"}"));
+        } else {
+            if (!Wait) {
+                ctx.Send(Source, new NMon::TEvRemoteJsonInfoRes("{}"));
+            }
         }
     }
 };