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
--- a/pallets/nonfungible/src/common.rs
+++ b/pallets/nonfungible/src/common.rs
@@ -251,7 +251,7 @@
 	fn check_nesting(
 		&self,
 		sender: T::CrossAccountId,
-		from: CollectionId,
+		from: (CollectionId, TokenId),
 		under: TokenId,
 		budget: &dyn Budget,
 	) -> sp_runtime::DispatchResult {
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
before · pallets/structure/src/lib.rs
1#![cfg_attr(not(feature = "std"), no_std)]23use sp_std::collections::btree_set::BTreeSet;45use frame_support::dispatch::DispatchError;6use frame_support::fail;7pub use pallet::*;8use pallet_common::{dispatch::CollectionDispatch, CollectionHandle};9use up_data_structs::{CollectionId, TokenId, mapping::TokenAddressMapping, budget::Budget};1011#[cfg(feature = "runtime-benchmarks")]12pub mod benchmarking;13pub mod weights;1415pub type SelfWeightOf<T> = <T as crate::Config>::WeightInfo;1617#[frame_support::pallet]18pub mod pallet {19	use frame_support::Parameter;20	use frame_support::dispatch::{GetDispatchInfo, UnfilteredDispatchable};21	use frame_support::pallet_prelude::*;2223	use super::*;2425	#[pallet::error]26	pub enum Error<T> {27		/// While searched for owner, got already checked account28		OuroborosDetected,29		/// While searched for owner, encountered depth limit30		DepthLimit,31		/// While searched for owner, found token owner by not-yet-existing token32		TokenNotFound,33	}3435	#[pallet::event]36	pub enum Event<T> {37		/// Executed call on behalf of token38		Executed(DispatchResult),39	}4041	#[pallet::config]42	pub trait Config: frame_system::Config + pallet_common::Config {43		type WeightInfo: weights::WeightInfo;44		type Event: IsType<<Self as frame_system::Config>::Event> + From<Event<Self>>;45		type Call: Parameter + UnfilteredDispatchable<Origin = Self::Origin> + GetDispatchInfo;46	}4748	#[pallet::pallet]49	pub struct Pallet<T>(_);5051	#[pallet::call]52	impl<T: Config> Pallet<T> {53		// #[pallet::weight({54		// 	let dispatch_info = call.get_dispatch_info();5556		// 	(57		// 		dispatch_info.weight58		// 			// Cost of dereferencing parent59		// 			.saturating_add(T::DbWeight::get().reads(2 * *max_depth as Weight))60		// 			.saturating_add(4000 * *max_depth as Weight),61		// 		dispatch_info.class)62		// })]63		// pub fn execute(64		// 	origin: OriginFor<T>,65		// 	call: Box<<T as Config>::Call>,66		// 	max_depth: u32,67		// ) -> DispatchResult {68	}69}7071#[derive(PartialEq)]72pub enum Parent<CrossAccountId> {73	/// Token owned by normal account74	Normal(CrossAccountId),75	/// Passed token not found76	TokenNotFound,77	/// Token owner is another token (target token still may not exist)78	Token(CollectionId, TokenId),79}8081impl<T: Config> Pallet<T> {82	pub fn find_parent(83		collection: CollectionId,84		token: TokenId,85	) -> Result<Parent<T::CrossAccountId>, DispatchError> {86		// TODO: Reduce cost by not reading collection config87		let handle = match CollectionHandle::try_get(collection) {88			Ok(v) => v,89			Err(_) => return Ok(Parent::TokenNotFound),90		};91		let handle = T::CollectionDispatch::dispatch(handle);92		let handle = handle.as_dyn();9394		Ok(match handle.token_owner(token) {95			Some(owner) => match T::CrossTokenAddressMapping::address_to_token(&owner) {96				Some((collection, token)) => Parent::Token(collection, token),97				None => Parent::Normal(owner),98			},99			None => Parent::TokenNotFound,100		})101	}102103	pub fn parent_chain(104		mut collection: CollectionId,105		mut token: TokenId,106	) -> impl Iterator<Item = Result<Parent<T::CrossAccountId>, DispatchError>> {107		let mut finished = false;108		let mut visited = BTreeSet::new();109		visited.insert((collection, token));110		core::iter::from_fn(move || {111			if finished {112				return None;113			}114			let parent = Self::find_parent(collection, token);115			match parent {116				Ok(Parent::Token(new_collection, new_token)) => {117					collection = new_collection;118					token = new_token;119					if !visited.insert((new_collection, new_token)) {120						finished = true;121						return Some(Err(<Error<T>>::OuroborosDetected.into()));122					}123				}124				_ => finished = true,125			}126			Some(parent as Result<_, DispatchError>)127		})128	}129130	/// Try to dereference address, until finding top level owner131	///132	/// May return token address if parent token not yet exists133	pub fn find_topmost_owner(134		collection: CollectionId,135		token: TokenId,136		budget: &dyn Budget,137	) -> Result<T::CrossAccountId, DispatchError> {138		let owner = Self::parent_chain(collection, token)139			.take_while(|_| budget.consume())140			.find(|p| matches!(p, Ok(Parent::Normal(_) | Parent::TokenNotFound)))141			.ok_or(<Error<T>>::DepthLimit)??;142143		Ok(match owner {144			Parent::Normal(v) => v,145			_ => fail!(<Error<T>>::TokenNotFound),146		})147	}148149	/// Check if token indirectly owned by specified user150	pub fn indirectly_owned(151		user: T::CrossAccountId,152		collection: CollectionId,153		token: TokenId,154		budget: &dyn Budget,155	) -> Result<bool, DispatchError> {156		let target_parent = match T::CrossTokenAddressMapping::address_to_token(&user) {157			Some((collection, token)) => Parent::Token(collection, token),158			None => Parent::Normal(user),159		};160161		Ok(Self::parent_chain(collection, token)162			.take_while(|_| budget.consume())163			.any(|parent| Ok(&target_parent) == parent.as_ref()))164	}165}
after · pallets/structure/src/lib.rs
1#![cfg_attr(not(feature = "std"), no_std)]23use sp_std::collections::btree_set::BTreeSet;45use frame_support::dispatch::DispatchError;6use frame_support::fail;7pub use pallet::*;8use pallet_common::{dispatch::CollectionDispatch, CollectionHandle};9use up_data_structs::{CollectionId, TokenId, mapping::TokenAddressMapping, budget::Budget};1011#[cfg(feature = "runtime-benchmarks")]12pub mod benchmarking;13pub mod weights;1415pub type SelfWeightOf<T> = <T as crate::Config>::WeightInfo;1617#[frame_support::pallet]18pub mod pallet {19	use frame_support::Parameter;20	use frame_support::dispatch::{GetDispatchInfo, UnfilteredDispatchable};21	use frame_support::pallet_prelude::*;2223	use super::*;2425	#[pallet::error]26	pub enum Error<T> {27		/// While searched for owner, got already checked account28		OuroborosDetected,29		/// While searched for owner, encountered depth limit30		DepthLimit,31		/// While searched for owner, found token owner by not-yet-existing token32		TokenNotFound,33	}3435	#[pallet::event]36	pub enum Event<T> {37		/// Executed call on behalf of token38		Executed(DispatchResult),39	}4041	#[pallet::config]42	pub trait Config: frame_system::Config + pallet_common::Config {43		type WeightInfo: weights::WeightInfo;44		type Event: IsType<<Self as frame_system::Config>::Event> + From<Event<Self>>;45		type Call: Parameter + UnfilteredDispatchable<Origin = Self::Origin> + GetDispatchInfo;46	}4748	#[pallet::pallet]49	pub struct Pallet<T>(_);5051	#[pallet::call]52	impl<T: Config> Pallet<T> {53		// #[pallet::weight({54		// 	let dispatch_info = call.get_dispatch_info();5556		// 	(57		// 		dispatch_info.weight58		// 			// Cost of dereferencing parent59		// 			.saturating_add(T::DbWeight::get().reads(2 * *max_depth as Weight))60		// 			.saturating_add(4000 * *max_depth as Weight),61		// 		dispatch_info.class)62		// })]63		// pub fn execute(64		// 	origin: OriginFor<T>,65		// 	call: Box<<T as Config>::Call>,66		// 	max_depth: u32,67		// ) -> DispatchResult {68	}69}7071#[derive(PartialEq)]72pub enum Parent<CrossAccountId> {73	/// Token owned by normal account74	User(CrossAccountId),75	/// Passed token not found76	TokenNotFound,77	/// Token owner is another token (target token still may not exist)78	Token(CollectionId, TokenId),79}8081impl<T: Config> Pallet<T> {82	pub fn find_parent(83		collection: CollectionId,84		token: TokenId,85	) -> Result<Parent<T::CrossAccountId>, DispatchError> {86		// TODO: Reduce cost by not reading collection config87		let handle = match CollectionHandle::try_get(collection) {88			Ok(v) => v,89			Err(_) => return Ok(Parent::TokenNotFound),90		};91		let handle = T::CollectionDispatch::dispatch(handle);92		let handle = handle.as_dyn();9394		Ok(match handle.token_owner(token) {95			Some(owner) => match T::CrossTokenAddressMapping::address_to_token(&owner) {96				Some((collection, token)) => Parent::Token(collection, token),97				None => Parent::User(owner),98			},99			None => Parent::TokenNotFound,100		})101	}102103	pub fn parent_chain(104		mut collection: CollectionId,105		mut token: TokenId,106	) -> impl Iterator<Item = Result<Parent<T::CrossAccountId>, DispatchError>> {107		let mut finished = false;108		let mut visited = BTreeSet::new();109		visited.insert((collection, token));110		core::iter::from_fn(move || {111			if finished {112				return None;113			}114			let parent = Self::find_parent(collection, token);115			match parent {116				Ok(Parent::Token(new_collection, new_token)) => {117					collection = new_collection;118					token = new_token;119					if !visited.insert((new_collection, new_token)) {120						finished = true;121						return Some(Err(<Error<T>>::OuroborosDetected.into()));122					}123				}124				_ => finished = true,125			}126			Some(parent as Result<_, DispatchError>)127		})128	}129130	/// Try to dereference address, until finding top level owner131	///132	/// May return token address if parent token not yet exists133	pub fn find_topmost_owner(134		collection: CollectionId,135		token: TokenId,136		budget: &dyn Budget,137	) -> Result<T::CrossAccountId, DispatchError> {138		let owner = Self::parent_chain(collection, token)139			.take_while(|_| budget.consume())140			.find(|p| matches!(p, Ok(Parent::User(_) | Parent::TokenNotFound)))141			.ok_or(<Error<T>>::DepthLimit)??;142143		Ok(match owner {144			Parent::User(v) => v,145			_ => fail!(<Error<T>>::TokenNotFound),146		})147	}148149	/// Check if token indirectly owned by specified user150	pub fn check_indirectly_owned(151		user: T::CrossAccountId,152		collection: CollectionId,153		token: TokenId,154		for_nest: Option<(CollectionId, TokenId)>,155		budget: &dyn Budget,156	) -> Result<bool, DispatchError> {157		let target_parent = match T::CrossTokenAddressMapping::address_to_token(&user) {158			Some((collection, token)) => Parent::Token(collection, token),159			None => Parent::User(user),160		};161162		// Tried to nest token in itself163		if Some((collection, token)) == for_nest {164			return Err(<Error<T>>::OuroborosDetected.into());165		}166167		for parent in Self::parent_chain(collection, token).take_while(|_| budget.consume()) {168			match parent? {169				// Tried to nest token in chain, which has this token as one of parents170				Parent::Token(collection, token) if Some((collection, token)) == for_nest => {171					return Err(<Error<T>>::OuroborosDetected.into())172				}173				// Found needed parent, token is indirecty owned174				v if v == target_parent => return Ok(true),175				Parent::TokenNotFound => return Ok(false),176				_ => {}177			}178		}179180		Err(<Error<T>>::DepthLimit.into())181	}182}
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/);
+    });
+  });
+});