Unverified Commit 62915a68 authored by Sergey Pepyakin's avatar Sergey Pepyakin Committed by GitHub
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Impose new restrictions on paras init and cleanup (#4360)

* Impose new restrictions on paras init and cleanup

For upcoming PVF pre-checking feature we will need to impose a couple of
new restrictions for:

- `schedule_para_initialize`.
- `schedule_para_cleanup`.

Specifically, for the former we do not want to allow registration of
wasm blob that is empty, i.e. 0 bytes. While that currently already
does not make a lot of sense, it allows us to simplify the PVF
pre-checking logic: if this PR is deployed before the following changes
for PVF prechecking then we can be sure that no paras onboarding have to
have to go through the PVF pre-checking. In case, we deploy it
altogether this property will allow us to distingush paras that came in
before PVF pre-checking.

For `schedule_para_cleanup` we do not want to allow offboarding of paras
that are undergoing the upgrade process. While this is not a harsh
restriction this change allows us to avoid making the PVF prechecking
more complicated than it has to be.

* Add a test for schedule_para_initialize

* Link to `ParaLifecycle::is_stable` in docs.

* `schedule_para_{init,cleanup}` docs

Now they link to their original declarations in the pallet for more
parent 8d6c8826
Pipeline #168161 passed with stages
in 45 minutes and 1 second
......@@ -157,6 +157,8 @@ pub mod pallet {
/// The ID given for registration has not been reserved.
/// Registering parachain with empty code is not allowed.
/// Pending swap operations.
......@@ -547,6 +549,7 @@ impl<T: Config> Pallet<T> {
parachain: bool,
) -> Result<(ParaGenesisArgs, BalanceOf<T>), sp_runtime::DispatchError> {
let config = configuration::Pallet::<T>::config();
ensure!(validation_code.0.len() > 0, Error::<T>::EmptyCode);
ensure!(validation_code.0.len() <= config.max_code_size as usize, Error::<T>::CodeTooLarge);
genesis_head.0.len() <= config.max_head_data_size as usize,
......@@ -52,6 +52,8 @@ pub use paras::ParaLifecycle;
use primitives::v1::Id as ParaId;
/// Schedule a para to be initialized at the start of the next session with the given genesis data.
/// See [`paras::Pallet::schedule_para_initialize`] for more details.
pub fn schedule_para_initialize<T: paras::Config>(
id: ParaId,
genesis: paras::ParaGenesisArgs,
......@@ -60,6 +62,8 @@ pub fn schedule_para_initialize<T: paras::Config>(
/// Schedule a para to be cleaned up at the start of the next session.
/// See [`paras::Pallet::schedule_para_cleanup`] for more details.
pub fn schedule_para_cleanup<T: paras::Config>(id: primitives::v1::Id) -> Result<(), ()> {
<paras::Pallet<T>>::schedule_para_cleanup(id).map_err(|_| ())
......@@ -870,8 +870,10 @@ impl<T: Config> Pallet<T> {
pub(crate) fn schedule_para_initialize(id: ParaId, genesis: ParaGenesisArgs) -> DispatchResult {
let scheduled_session = Self::scheduled_session();
// Make sure parachain isn't already in our system.
// Make sure parachain isn't already in our system and that the onboarding parameters are
// valid.
ensure!(Self::can_schedule_para_initialize(&id, &genesis), Error::<T>::CannotOnboard);
ensure!(!genesis.validation_code.0.is_empty(), Error::<T>::CannotOnboard);
ParaLifecycles::<T>::insert(&id, ParaLifecycle::Onboarding);
UpcomingParasGenesis::<T>::insert(&id, genesis);
......@@ -886,10 +888,24 @@ impl<T: Config> Pallet<T> {
/// Schedule a para to be cleaned up at the start of the next session.
/// Will return error if para is not a stable parachain or parathread.
/// Will return error if either is true:
/// - para is not a stable parachain or parathread (i.e. [`ParaLifecycle::is_stable`] is `false`)
/// - para has a pending upgrade.
/// No-op if para is not registered at all.
pub(crate) fn schedule_para_cleanup(id: ParaId) -> DispatchResult {
// Disallow offboarding in case there is an upcoming upgrade.
// This is not a fundamential limitation but rather simplification: it allows us to get
// away without introducing additional logic for pruning and, more importantly, enacting
// ongoing PVF pre-checking votings. It also removes some nasty edge cases.
// This implicitly assumes that the given para exists, i.e. it's lifecycle != None.
if FutureCodeHash::<T>::contains_key(&id) {
return Err(Error::<T>::CannotOffboard.into())
let lifecycle = ParaLifecycles::<T>::get(&id);
match lifecycle {
// If para is not registered, nothing to do!
......@@ -1178,12 +1194,12 @@ impl<T: Config> Pallet<T> {
mod tests {
use super::*;
use frame_support::assert_ok;
use frame_support::{assert_err, assert_ok};
use primitives::v1::BlockNumber;
use crate::{
mock::{new_test_ext, Configuration, MockGenesisConfig, Paras, ParasShared, System},
mock::{new_test_ext, Configuration, MockGenesisConfig, Paras, ParasShared, System, Test},
fn run_to_block(to: BlockNumber, new_session: Option<Vec<BlockNumber>>) {
......@@ -1335,6 +1351,32 @@ mod tests {
fn schedule_para_init_rejects_empty_code() {
new_test_ext(MockGenesisConfig::default()).execute_with(|| {
ParaGenesisArgs {
parachain: false,
genesis_head: Default::default(),
validation_code: ValidationCode(vec![]),
ParaGenesisArgs {
parachain: false,
genesis_head: Default::default(),
validation_code: ValidationCode(vec![1]),
fn para_past_code_pruning_in_initialize() {
let code_retention_period = 10;
......@@ -1817,55 +1859,51 @@ mod tests {
// Cannot offboard while an upgrade is pending.
assert_err!(Paras::schedule_para_cleanup(para_id), Error::<Test>::CannotOffboard);
// Just scheduling cleanup shouldn't change anything.
<Paras as Store>::ActionsQueue::get(Paras::scheduled_session()),
assert_eq!(Paras::parachains(), vec![para_id]);
assert_eq!(<Paras as Store>::FutureCodeUpgrades::get(&para_id), Some(expected_at));
assert_eq!(<Paras as Store>::FutureCodeHash::get(&para_id), Some(new_code.hash()));
assert_eq!(Paras::current_code(&para_id), Some(original_code.clone()));
// Enact the upgrade.
// For that run to block #7 and submit a new head.
assert_eq!(expected_at, 7);
run_to_block(7, None);
assert_eq!(<frame_system::Pallet<Test>>::block_number(), 7);
Paras::note_new_head(para_id, Default::default(), expected_at);
assert_eq!(<Paras as Store>::Heads::get(&para_id), Some(Default::default()));
// run to block #4, with a 2 session changes at the end of the block 2 & 3.
run_to_block(4, Some(vec![3, 4]));
// run to block #10, with a 2 session changes at the end of the block 7 & 8 (so 8 and 9
// observe the new sessions).
run_to_block(10, Some(vec![8, 9]));
// cleaning up the parachain should place the current parachain code
// into the past code buffer & schedule cleanup.
assert_eq!(Paras::past_code_meta(&para_id).most_recent_change(), Some(3));
<Paras as Store>::PastCodeHash::get(&(para_id, 3)),
assert_eq!(<Paras as Store>::PastCodePruning::get(), vec![(para_id, 3)]);
// Why 7 and 8? See above, the clean up scheduled above was processed at the block 8.
// The initial upgrade was enacted at the block 7.
assert_eq!(Paras::past_code_meta(&para_id).most_recent_change(), Some(8));
assert_eq!(<Paras as Store>::PastCodeHash::get(&(para_id, 8)), Some(new_code.hash()));
assert_eq!(<Paras as Store>::PastCodePruning::get(), vec![(para_id, 7), (para_id, 8)]);
// any future upgrades haven't been used to validate yet, so those
// are cleaned up immediately.
assert!(<Paras as Store>::FutureCodeUpgrades::get(&para_id).is_none());
assert!(<Paras as Store>::FutureCodeHash::get(&para_id).is_none());
// run to do the final cleanup
let cleaned_up_at = 3 + code_retention_period + 1;
let cleaned_up_at = 8 + code_retention_period + 1;
run_to_block(cleaned_up_at, None);
// now the final cleanup: last past code cleaned up, and this triggers meta cleanup.
assert_eq!(Paras::past_code_meta(&para_id), Default::default());
assert!(<Paras as Store>::PastCodeHash::get(&(para_id, 3)).is_none());
assert!(<Paras as Store>::PastCodeHash::get(&(para_id, 7)).is_none());
assert!(<Paras as Store>::PastCodeHash::get(&(para_id, 8)).is_none());
assert!(<Paras as Store>::PastCodePruning::get().is_empty());
......@@ -777,7 +777,7 @@ mod tests {
ParaGenesisArgs {
genesis_head: Vec::new().into(),
validation_code: Vec::new().into(),
validation_code: vec![1, 2, 3].into(),
parachain: is_chain,
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