keyspace: unexpect dead code in saveKeyspaceGroups

[lhy1024]

Enhancement Task

pd/pkg/keyspace/tso_keyspace_group.go

Lines 321 to 353 in 181e613

	func (m *GroupManager) saveKeyspaceGroups(keyspaceGroups []*endpoint.KeyspaceGroup, overwrite bool) error {
	return m.store.RunInTxn(m.ctx, func(txn kv.Txn) error {
	for _, keyspaceGroup := range keyspaceGroups {
	// Check if keyspace group has already existed.
	oldKG, err := m.store.LoadKeyspaceGroup(txn, keyspaceGroup.ID)
	if err != nil {
	return err
	}
	if oldKG != nil && !overwrite {
	return ErrKeyspaceGroupExists
	}
	if oldKG.IsSplitting() && overwrite {
	return ErrKeyspaceGroupInSplit
	}
	newKG := &endpoint.KeyspaceGroup{
	ID: keyspaceGroup.ID,
	UserKind: keyspaceGroup.UserKind,
	Members: keyspaceGroup.Members,
	Keyspaces: keyspaceGroup.Keyspaces,
	}
	if oldKG.IsSplitting() {
	newKG.SplitState = &endpoint.SplitState{
	SplitSource: oldKG.SplitState.SplitSource,
	}
	}
	err = m.store.SaveKeyspaceGroup(txn, newKG)
	if err != nil {
	return err
	}
	}
	return nil
	})
	}

when oldKG.IsSplitting() is true, it means oldKG != nil is also true, so

1. when overwrite is false, the code will return with ErrKeyspaceGroupExists
2. when overwrite is true, the code will return with ErrKeyspaceGroupInSplit

so we cannot touch

pd/pkg/keyspace/tso_keyspace_group.go

Lines 341 to 345 in 181e613

	if oldKG.IsSplitting() {
	newKG.SplitState = &endpoint.SplitState{
	SplitSource: oldKG.SplitState.SplitSource,
	}
	}

[lhy1024]

closed by #6584