git.delta.rocks / unique-network / refs/commits / bebe624eff63

difftreelog

feat prevent ouroboros creation during nest

Yaroslav Bolyukin2022-04-19parent: #07a6969.patch.diff
in: master

11 files changed

modifiedclient/rpc/src/lib.rsdiffbeforeafterboth
--- a/client/rpc/src/lib.rs
+++ b/client/rpc/src/lib.rs
@@ -77,11 +77,7 @@
 	) -> Result<Vec<u8>>;
 
 	#[rpc(name = "unique_totalSupply")]
-	fn total_supply(
-		&self,
-		collection: CollectionId,
-		at: Option<BlockHash>,
-	) -> Result<u32>;
+	fn total_supply(&self, collection: CollectionId, at: Option<BlockHash>) -> Result<u32>;
 	#[rpc(name = "unique_accountBalance")]
 	fn account_balance(
 		&self,
modifiedpallets/common/src/lib.rsdiffbeforeafterboth
--- a/pallets/common/src/lib.rs
+++ b/pallets/common/src/lib.rs
@@ -918,7 +918,7 @@
 	fn check_nesting(
 		&self,
 		sender: T::CrossAccountId,
-		from: CollectionId,
+		from: (CollectionId, TokenId),
 		under: TokenId,
 		budget: &dyn Budget,
 	) -> DispatchResult;
modifiedpallets/fungible/src/common.rsdiffbeforeafterboth
--- a/pallets/fungible/src/common.rs
+++ b/pallets/fungible/src/common.rs
@@ -237,7 +237,7 @@
 	fn check_nesting(
 		&self,
 		_sender: <T>::CrossAccountId,
-		_from: CollectionId,
+		_from: (CollectionId, TokenId),
 		_under: TokenId,
 		_budget: &dyn Budget,
 	) -> sp_runtime::DispatchResult {
modifiedpallets/fungible/src/lib.rsdiffbeforeafterboth
--- a/pallets/fungible/src/lib.rs
+++ b/pallets/fungible/src/lib.rs
@@ -224,7 +224,12 @@
 			let dispatch = T::CollectionDispatch::dispatch(handle);
 			let dispatch = dispatch.as_dyn();
 
-			dispatch.check_nesting(from.clone(), collection.id, target.1, nesting_budget)?;
+			dispatch.check_nesting(
+				from.clone(),
+				(collection.id, TokenId::default()),
+				target.1,
+				nesting_budget,
+			)?;
 		}
 
 		// =========
@@ -293,7 +298,12 @@
 				let dispatch = T::CollectionDispatch::dispatch(handle);
 				let dispatch = dispatch.as_dyn();
 
-				dispatch.check_nesting(sender.clone(), collection.id, target.1, nesting_budget)?;
+				dispatch.check_nesting(
+					sender.clone(),
+					(collection.id, TokenId::default()),
+					target.1,
+					nesting_budget,
+				)?;
 			}
 		}
 
@@ -386,10 +396,11 @@
 		if let Some(source) = T::CrossTokenAddressMapping::address_to_token(from) {
 			// TODO: should collection owner be allowed to perform this transfer?
 			ensure!(
-				<PalletStructure<T>>::indirectly_owned(
+				<PalletStructure<T>>::check_indirectly_owned(
 					spender.clone(),
 					source.0,
 					source.1,
+					None,
 					nesting_budget
 				)?,
 				<CommonError<T>>::ApprovedValueTooLow,
modifiedpallets/nonfungible/src/common.rsdiffbeforeafterboth
before · pallets/nonfungible/src/common.rs
1// Copyright 2019-2022 Unique Network (Gibraltar) Ltd.2// This file is part of Unique Network.34// Unique Network is free software: you can redistribute it and/or modify5// it under the terms of the GNU General Public License as published by6// the Free Software Foundation, either version 3 of the License, or7// (at your option) any later version.89// Unique Network is distributed in the hope that it will be useful,10// but WITHOUT ANY WARRANTY; without even the implied warranty of11// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the12// GNU General Public License for more details.1314// You should have received a copy of the GNU General Public License15// along with Unique Network. If not, see <http://www.gnu.org/licenses/>.1617use core::marker::PhantomData;1819use frame_support::{dispatch::DispatchResultWithPostInfo, ensure, fail, weights::Weight, BoundedVec};20use up_data_structs::{TokenId, CustomDataLimit, CreateItemExData, CollectionId, budget::Budget};21use pallet_common::{CommonCollectionOperations, CommonWeightInfo, with_weight};22use sp_runtime::DispatchError;23use sp_std::vec::Vec;2425use crate::{26	AccountBalance, Allowance, Config, CreateItemData, Error, NonfungibleHandle, Owned, Pallet,27	SelfWeightOf, TokenData, weights::WeightInfo, TokensMinted,28};2930pub struct CommonWeights<T: Config>(PhantomData<T>);31impl<T: Config> CommonWeightInfo<T::CrossAccountId> for CommonWeights<T> {32	fn create_item() -> Weight {33		<SelfWeightOf<T>>::create_item()34	}3536	fn create_multiple_items_ex(data: &CreateItemExData<T::CrossAccountId>) -> Weight {37		match data {38			CreateItemExData::NFT(t) => <SelfWeightOf<T>>::create_multiple_items_ex(t.len() as u32),39			_ => 0,40		}41	}4243	fn create_multiple_items(amount: u32) -> Weight {44		<SelfWeightOf<T>>::create_multiple_items(amount)45	}4647	fn burn_item() -> Weight {48		<SelfWeightOf<T>>::burn_item()49	}5051	fn transfer() -> Weight {52		<SelfWeightOf<T>>::transfer()53	}5455	fn approve() -> Weight {56		<SelfWeightOf<T>>::approve()57	}5859	fn transfer_from() -> Weight {60		<SelfWeightOf<T>>::transfer_from()61	}6263	fn burn_from() -> Weight {64		<SelfWeightOf<T>>::burn_from()65	}6667	fn set_variable_metadata(bytes: u32) -> Weight {68		<SelfWeightOf<T>>::set_variable_metadata(bytes)69	}70}7172fn map_create_data<T: Config>(73	data: up_data_structs::CreateItemData,74	to: &T::CrossAccountId,75) -> Result<CreateItemData<T>, DispatchError> {76	match data {77		up_data_structs::CreateItemData::NFT(data) => Ok(CreateItemData::<T> {78			const_data: data.const_data,79			variable_data: data.variable_data,80			owner: to.clone(),81		}),82		_ => fail!(<Error<T>>::NotNonfungibleDataUsedToMintFungibleCollectionToken),83	}84}8586impl<T: Config> CommonCollectionOperations<T> for NonfungibleHandle<T> {87	fn create_item(88		&self,89		sender: T::CrossAccountId,90		to: T::CrossAccountId,91		data: up_data_structs::CreateItemData,92		nesting_budget: &dyn Budget,93	) -> DispatchResultWithPostInfo {94		with_weight(95			<Pallet<T>>::create_item(96				self,97				&sender,98				map_create_data::<T>(data, &to)?,99				nesting_budget,100			),101			<CommonWeights<T>>::create_item(),102		)103	}104105	fn create_multiple_items(106		&self,107		sender: T::CrossAccountId,108		to: T::CrossAccountId,109		data: Vec<up_data_structs::CreateItemData>,110		nesting_budget: &dyn Budget,111	) -> DispatchResultWithPostInfo {112		let data = data113			.into_iter()114			.map(|d| map_create_data::<T>(d, &to))115			.collect::<Result<Vec<_>, DispatchError>>()?;116117		let amount = data.len();118		with_weight(119			<Pallet<T>>::create_multiple_items(self, &sender, data, nesting_budget),120			<CommonWeights<T>>::create_multiple_items(amount as u32),121		)122	}123124	fn create_multiple_items_ex(125		&self,126		sender: <T>::CrossAccountId,127		data: up_data_structs::CreateItemExData<<T>::CrossAccountId>,128		nesting_budget: &dyn Budget,129	) -> DispatchResultWithPostInfo {130		let weight = <CommonWeights<T>>::create_multiple_items_ex(&data);131		let data = match data {132			up_data_structs::CreateItemExData::NFT(nft) => nft,133			_ => fail!(Error::<T>::NotNonfungibleDataUsedToMintFungibleCollectionToken),134		};135136		with_weight(137			<Pallet<T>>::create_multiple_items(self, &sender, data.into_inner(), nesting_budget),138			weight,139		)140	}141142	fn burn_item(143		&self,144		sender: T::CrossAccountId,145		token: TokenId,146		amount: u128,147	) -> DispatchResultWithPostInfo {148		ensure!(amount <= 1, <Error<T>>::NonfungibleItemsHaveNoAmount);149		if amount == 1 {150			with_weight(151				<Pallet<T>>::burn(self, &sender, token),152				<CommonWeights<T>>::burn_item(),153			)154		} else {155			Ok(().into())156		}157	}158159	fn transfer(160		&self,161		from: T::CrossAccountId,162		to: T::CrossAccountId,163		token: TokenId,164		amount: u128,165		nesting_budget: &dyn Budget,166	) -> DispatchResultWithPostInfo {167		ensure!(amount <= 1, <Error<T>>::NonfungibleItemsHaveNoAmount);168		if amount == 1 {169			with_weight(170				<Pallet<T>>::transfer(self, &from, &to, token, nesting_budget),171				<CommonWeights<T>>::transfer(),172			)173		} else {174			Ok(().into())175		}176	}177178	fn approve(179		&self,180		sender: T::CrossAccountId,181		spender: T::CrossAccountId,182		token: TokenId,183		amount: u128,184	) -> DispatchResultWithPostInfo {185		ensure!(amount <= 1, <Error<T>>::NonfungibleItemsHaveNoAmount);186187		with_weight(188			if amount == 1 {189				<Pallet<T>>::set_allowance(self, &sender, token, Some(&spender))190			} else {191				<Pallet<T>>::set_allowance(self, &sender, token, None)192			},193			<CommonWeights<T>>::approve(),194		)195	}196197	fn transfer_from(198		&self,199		sender: T::CrossAccountId,200		from: T::CrossAccountId,201		to: T::CrossAccountId,202		token: TokenId,203		amount: u128,204		nesting_budget: &dyn Budget,205	) -> DispatchResultWithPostInfo {206		ensure!(amount <= 1, <Error<T>>::NonfungibleItemsHaveNoAmount);207208		if amount == 1 {209			with_weight(210				<Pallet<T>>::transfer_from(self, &sender, &from, &to, token, nesting_budget),211				<CommonWeights<T>>::transfer_from(),212			)213		} else {214			Ok(().into())215		}216	}217218	fn burn_from(219		&self,220		sender: T::CrossAccountId,221		from: T::CrossAccountId,222		token: TokenId,223		amount: u128,224		nesting_budget: &dyn Budget,225	) -> DispatchResultWithPostInfo {226		ensure!(amount <= 1, <Error<T>>::NonfungibleItemsHaveNoAmount);227228		if amount == 1 {229			with_weight(230				<Pallet<T>>::burn_from(self, &sender, &from, token, nesting_budget),231				<CommonWeights<T>>::burn_from(),232			)233		} else {234			Ok(().into())235		}236	}237238	fn set_variable_metadata(239		&self,240		sender: T::CrossAccountId,241		token: TokenId,242		data: BoundedVec<u8, CustomDataLimit>,243	) -> DispatchResultWithPostInfo {244		let len = data.len();245		with_weight(246			<Pallet<T>>::set_variable_metadata(self, &sender, token, data),247			<CommonWeights<T>>::set_variable_metadata(len as u32),248		)249	}250251	fn check_nesting(252		&self,253		sender: T::CrossAccountId,254		from: CollectionId,255		under: TokenId,256		budget: &dyn Budget,257	) -> sp_runtime::DispatchResult {258		<Pallet<T>>::check_nesting(self, sender, from, under, budget)259	}260261	fn account_tokens(&self, account: T::CrossAccountId) -> Vec<TokenId> {262		<Owned<T>>::iter_prefix((self.id, account))263			.map(|(id, _)| id)264			.collect()265	}266267	fn collection_tokens(&self) -> Vec<TokenId> {268		<TokenData<T>>::iter_prefix((self.id,))269			.map(|(id, _)| id)270			.collect()271	}272273	fn token_exists(&self, token: TokenId) -> bool {274		<Pallet<T>>::token_exists(self, token)275	}276277	fn last_token_id(&self) -> TokenId {278		TokenId(<TokensMinted<T>>::get(self.id))279	}280281	fn token_owner(&self, token: TokenId) -> Option<T::CrossAccountId> {282		<TokenData<T>>::get((self.id, token)).map(|t| t.owner)283	}284	fn const_metadata(&self, token: TokenId) -> Vec<u8> {285		<TokenData<T>>::get((self.id, token))286			.map(|t| t.const_data)287			.unwrap_or_default()288			.into_inner()289	}290	fn variable_metadata(&self, token: TokenId) -> Vec<u8> {291		<TokenData<T>>::get((self.id, token))292			.map(|t| t.variable_data)293			.unwrap_or_default()294			.into_inner()295	}296297	fn total_supply(&self) -> u32 {298		<Pallet<T>>::total_supply(self)299	}300301	fn account_balance(&self, account: T::CrossAccountId) -> u32 {302		<AccountBalance<T>>::get((self.id, account))303	}304305	fn balance(&self, account: T::CrossAccountId, token: TokenId) -> u128 {306		if <TokenData<T>>::get((self.id, token))307			.map(|a| a.owner == account)308			.unwrap_or(false)309		{310			1311		} else {312			0313		}314	}315316	fn allowance(317		&self,318		sender: T::CrossAccountId,319		spender: T::CrossAccountId,320		token: TokenId,321	) -> u128 {322		if <TokenData<T>>::get((self.id, token))323			.map(|a| a.owner != sender)324			.unwrap_or(true)325		{326			0327		} else if <Allowance<T>>::get((self.id, token)) == Some(spender) {328			1329		} else {330			0331		}332	}333}
modifiedpallets/nonfungible/src/lib.rsdiffbeforeafterboth
--- a/pallets/nonfungible/src/lib.rs
+++ b/pallets/nonfungible/src/lib.rs
@@ -296,7 +296,12 @@
 			let dispatch = T::CollectionDispatch::dispatch(handle);
 			let dispatch = dispatch.as_dyn();
 
-			dispatch.check_nesting(from.clone(), collection.id, target.1, nesting_budget)?;
+			dispatch.check_nesting(
+				from.clone(),
+				(collection.id, token),
+				target.1,
+				nesting_budget,
+			)?;
 		}
 
 		// =========
@@ -381,13 +386,18 @@
 			);
 		}
 
-		for (to, _) in balances.iter() {
-			if let Some(target) = T::CrossTokenAddressMapping::address_to_token(to) {
+		for (i, data) in data.iter().enumerate() {
+			let token = TokenId(first_token + i as u32 + 1);
+			if let Some(target) = T::CrossTokenAddressMapping::address_to_token(&data.owner) {
 				let handle = <CollectionHandle<T>>::try_get(target.0)?;
 				let dispatch = T::CollectionDispatch::dispatch(handle);
 				let dispatch = dispatch.as_dyn();
-
-				dispatch.check_nesting(sender.clone(), collection.id, target.1, nesting_budget)?;
+				dispatch.check_nesting(
+					sender.clone(),
+					(collection.id, token),
+					target.1,
+					nesting_budget,
+				)?;
 			}
 		}
 
@@ -535,10 +545,11 @@
 		if let Some(source) = T::CrossTokenAddressMapping::address_to_token(from) {
 			// TODO: should collection owner be allowed to perform this transfer?
 			ensure!(
-				<PalletStructure<T>>::indirectly_owned(
+				<PalletStructure<T>>::check_indirectly_owned(
 					spender.clone(),
 					source.0,
 					source.1,
+					None,
 					nesting_budget
 				)?,
 				<CommonError<T>>::ApprovedValueTooLow,
@@ -610,31 +621,40 @@
 	pub fn check_nesting(
 		handle: &NonfungibleHandle<T>,
 		sender: T::CrossAccountId,
-		from: CollectionId,
+		from: (CollectionId, TokenId),
 		under: TokenId,
 		nesting_budget: &dyn Budget,
 	) -> DispatchResult {
 		fn ensure_sender_allowed<T: Config>(
 			collection: CollectionId,
 			token: TokenId,
+			for_nest: (CollectionId, TokenId),
 			sender: T::CrossAccountId,
 			budget: &dyn Budget,
 		) -> DispatchResult {
 			ensure!(
-				<PalletStructure<T>>::indirectly_owned(sender, collection, token, budget)?,
+				<PalletStructure<T>>::check_indirectly_owned(
+					sender,
+					collection,
+					token,
+					Some(for_nest),
+					budget
+				)?,
 				<CommonError<T>>::OnlyOwnerAllowedToNest,
 			);
 			Ok(())
 		}
 		match handle.limits.nesting_rule() {
 			NestingRule::Disabled => fail!(<CommonError<T>>::NestingIsDisabled),
-			NestingRule::Owner => ensure_sender_allowed::<T>(handle.id, under, sender, nesting_budget)?,
+			NestingRule::Owner => {
+				ensure_sender_allowed::<T>(handle.id, under, from, sender, nesting_budget)?
+			}
 			NestingRule::OwnerRestricted(whitelist) => {
 				ensure!(
-					whitelist.contains(&from),
+					whitelist.contains(&from.0),
 					<CommonError<T>>::SourceCollectionIsNotAllowedToNest
 				);
-				ensure_sender_allowed::<T>(handle.id, under, sender, nesting_budget)?
+				ensure_sender_allowed::<T>(handle.id, under, from, sender, nesting_budget)?
 			}
 		}
 		Ok(())
modifiedpallets/refungible/src/common.rsdiffbeforeafterboth
--- a/pallets/refungible/src/common.rs
+++ b/pallets/refungible/src/common.rs
@@ -260,7 +260,7 @@
 	fn check_nesting(
 		&self,
 		_sender: <T>::CrossAccountId,
-		_from: CollectionId,
+		_from: (CollectionId, TokenId),
 		_under: TokenId,
 		_budget: &dyn Budget,
 	) -> sp_runtime::DispatchResult {
modifiedpallets/refungible/src/lib.rsdiffbeforeafterboth
--- a/pallets/refungible/src/lib.rs
+++ b/pallets/refungible/src/lib.rs
@@ -352,7 +352,12 @@
 			let dispatch = T::CollectionDispatch::dispatch(handle);
 			let dispatch = dispatch.as_dyn();
 
-			dispatch.check_nesting(from.clone(), collection.id, target.1, nesting_budget)?;
+			dispatch.check_nesting(
+				from.clone(),
+				(collection.id, token),
+				target.1,
+				nesting_budget,
+			)?;
 		}
 
 		// =========
@@ -455,7 +460,8 @@
 			}
 		}
 
-		for token in data.iter() {
+		for (i, token) in data.iter().enumerate() {
+			let token_id = TokenId(first_token_id + i as u32 + 1);
 			for (to, _) in token.users.iter() {
 				if let Some(target) = T::CrossTokenAddressMapping::address_to_token(to) {
 					let handle = <CollectionHandle<T>>::try_get(target.0)?;
@@ -464,7 +470,7 @@
 
 					dispatch.check_nesting(
 						sender.clone(),
-						collection.id,
+						(collection.id, token_id),
 						target.1,
 						nesting_budget,
 					)?;
@@ -575,10 +581,11 @@
 		if let Some(source) = T::CrossTokenAddressMapping::address_to_token(from) {
 			// TODO: should collection owner be allowed to perform this transfer?
 			ensure!(
-				<PalletStructure<T>>::indirectly_owned(
+				<PalletStructure<T>>::check_indirectly_owned(
 					spender.clone(),
 					source.0,
 					source.1,
+					None,
 					nesting_budget
 				)?,
 				<CommonError<T>>::ApprovedValueTooLow,
modifiedpallets/structure/src/lib.rsdiffbeforeafterboth
--- a/pallets/structure/src/lib.rs
+++ b/pallets/structure/src/lib.rs
@@ -71,7 +71,7 @@
 #[derive(PartialEq)]
 pub enum Parent<CrossAccountId> {
 	/// Token owned by normal account
-	Normal(CrossAccountId),
+	User(CrossAccountId),
 	/// Passed token not found
 	TokenNotFound,
 	/// Token owner is another token (target token still may not exist)
@@ -94,7 +94,7 @@
 		Ok(match handle.token_owner(token) {
 			Some(owner) => match T::CrossTokenAddressMapping::address_to_token(&owner) {
 				Some((collection, token)) => Parent::Token(collection, token),
-				None => Parent::Normal(owner),
+				None => Parent::User(owner),
 			},
 			None => Parent::TokenNotFound,
 		})
@@ -137,29 +137,46 @@
 	) -> Result<T::CrossAccountId, DispatchError> {
 		let owner = Self::parent_chain(collection, token)
 			.take_while(|_| budget.consume())
-			.find(|p| matches!(p, Ok(Parent::Normal(_) | Parent::TokenNotFound)))
+			.find(|p| matches!(p, Ok(Parent::User(_) | Parent::TokenNotFound)))
 			.ok_or(<Error<T>>::DepthLimit)??;
 
 		Ok(match owner {
-			Parent::Normal(v) => v,
+			Parent::User(v) => v,
 			_ => fail!(<Error<T>>::TokenNotFound),
 		})
 	}
 
 	/// Check if token indirectly owned by specified user
-	pub fn indirectly_owned(
+	pub fn check_indirectly_owned(
 		user: T::CrossAccountId,
 		collection: CollectionId,
 		token: TokenId,
+		for_nest: Option<(CollectionId, TokenId)>,
 		budget: &dyn Budget,
 	) -> Result<bool, DispatchError> {
 		let target_parent = match T::CrossTokenAddressMapping::address_to_token(&user) {
 			Some((collection, token)) => Parent::Token(collection, token),
-			None => Parent::Normal(user),
+			None => Parent::User(user),
 		};
 
-		Ok(Self::parent_chain(collection, token)
-			.take_while(|_| budget.consume())
-			.any(|parent| Ok(&target_parent) == parent.as_ref()))
+		// Tried to nest token in itself
+		if Some((collection, token)) == for_nest {
+			return Err(<Error<T>>::OuroborosDetected.into());
+		}
+
+		for parent in Self::parent_chain(collection, token).take_while(|_| budget.consume()) {
+			match parent? {
+				// Tried to nest token in chain, which has this token as one of parents
+				Parent::Token(collection, token) if Some((collection, token)) == for_nest => {
+					return Err(<Error<T>>::OuroborosDetected.into())
+				}
+				// Found needed parent, token is indirecty owned
+				v if v == target_parent => return Ok(true),
+				Parent::TokenNotFound => return Ok(false),
+				_ => {}
+			}
+		}
+
+		Err(<Error<T>>::DepthLimit.into())
 	}
 }
modifiedtests/src/eth/util/helpers.tsdiffbeforeafterboth
--- a/tests/src/eth/util/helpers.ts
+++ b/tests/src/eth/util/helpers.ts
@@ -23,7 +23,7 @@
 import usingApi, {submitTransactionAsync} from '../../substrate/substrate-api';
 import {IKeyringPair} from '@polkadot/types/types';
 import {expect} from 'chai';
-import {getGenericResult, UNIQUE} from '../../util/helpers';
+import {CrossAccountId, getGenericResult, UNIQUE} from '../../util/helpers';
 import * as solc from 'solc';
 import config from '../../config';
 import privateKey from '../../substrate/privateKey';
@@ -80,6 +80,11 @@
   ]);
   return Web3.utils.toChecksumAddress('0x' + buf.toString('hex'));
 }
+export function tokenIdToCross(collection: number, token: number): CrossAccountId {
+  return {
+    Ethereum: tokenIdToAddress(collection, token),
+  };
+}
 
 export function createEthAccount(web3: Web3) {
   const account = web3.eth.accounts.create();
addedtests/src/nesting/graphs.test.tsdiffbeforeafterboth
--- /dev/null
+++ b/tests/src/nesting/graphs.test.ts
@@ -0,0 +1,51 @@
+import {ApiPromise} from '@polkadot/api';
+import {IKeyringPair} from '@polkadot/types/types';
+import {expect} from 'chai';
+import {tokenIdToCross} from '../eth/util/helpers';
+import privateKey from '../substrate/privateKey';
+import usingApi, {executeTransaction} from '../substrate/substrate-api';
+import {getCreateCollectionResult, transferExpectSuccess} from '../util/helpers';
+
+/**
+ * ```dot
+ * 4 -> 3 -> 2 -> 1
+ * 7 -> 6 -> 5 -> 2
+ * 8 -> 5
+ * ```
+ */
+async function buildComplexObjectGraph(api: ApiPromise, sender: IKeyringPair): Promise<number> {
+  const events = await executeTransaction(api, sender, api.tx.unique.createCollectionEx({mode: 'NFT'}));
+  const {collectionId} = getCreateCollectionResult(events);
+
+  await executeTransaction(api, sender, api.tx.unique.createMultipleItemsEx(collectionId, {NFT: Array(8).fill({owner: {Substrate: sender.address}})}));
+
+  await transferExpectSuccess(collectionId, 8, sender, tokenIdToCross(collectionId, 5));
+
+  await transferExpectSuccess(collectionId, 7, sender, tokenIdToCross(collectionId, 6));
+  await transferExpectSuccess(collectionId, 6, sender, tokenIdToCross(collectionId, 5));
+  await transferExpectSuccess(collectionId, 5, sender, tokenIdToCross(collectionId, 2));
+
+  await transferExpectSuccess(collectionId, 4, sender, tokenIdToCross(collectionId, 3));
+  await transferExpectSuccess(collectionId, 3, sender, tokenIdToCross(collectionId, 2));
+  await transferExpectSuccess(collectionId, 2, sender, tokenIdToCross(collectionId, 1));
+
+  return collectionId;
+}
+
+describe('graphs', () => {
+  it('ouroboros can\'t be created in graph', async () => {
+    await usingApi(async api => {
+      const alice = privateKey('//Alice');
+      const collection = await buildComplexObjectGraph(api, alice);
+
+      // to self
+      await expect(executeTransaction(api, alice, api.tx.unique.transfer(tokenIdToCross(collection, 1), collection, 1, 1)))
+        .to.be.rejectedWith(/structure\.OuroborosDetected/);
+      // to nested part of graph
+      await expect(executeTransaction(api, alice, api.tx.unique.transfer(tokenIdToCross(collection, 5), collection, 1, 1)))
+        .to.be.rejectedWith(/structure\.OuroborosDetected/);
+      await expect(executeTransaction(api, alice, api.tx.unique.transfer(tokenIdToCross(collection, 8), collection, 2, 1)))
+        .to.be.rejectedWith(/structure\.OuroborosDetected/);
+    });
+  });
+});