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randomness_config_seqnum - [mainnet]

Randomness stall recovery utils.

When randomness generation is stuck due to a bug, the chain is also stuck. Below is the recovery procedure.

  1. Ensure more than 2/3 stakes are stuck at the same version.
  2. Every validator restarts with randomness_override_seq_num set to X+1 in the node config file, where X is the current RandomnessConfigSeqNum on chain.
  3. The chain should then be unblocked.
  4. Once the bug is fixed and the binary + framework have been patched, a governance proposal is needed to set RandomnessConfigSeqNum to be X+2.
use 0x1::config_buffer;
use 0x1::system_addresses;

Resources

RandomnessConfigSeqNum

If this seqnum is smaller than a validator local override, the on-chain RandomnessConfig will be ignored. Useful in a chain recovery from randomness stall.

struct RandomnessConfigSeqNum has drop, store, key
Fields
seq_num: u64

Functions

set_for_next_epoch

Update RandomnessConfigSeqNum. Used when re-enable randomness after an emergency randomness disable via local override.

public fun set_for_next_epoch(framework: &signer, seq_num: u64)
Implementation 
public fun set_for_next_epoch(framework: &signer, seq_num: u64) {
    system_addresses::assert_aptos_framework(framework);
    config_buffer::upsert(RandomnessConfigSeqNum { seq_num });
}

initialize

Initialize the configuration. Used in genesis or governance.

public fun initialize(framework: &signer)
Implementation 
public fun initialize(framework: &signer) {
    system_addresses::assert_aptos_framework(framework);
    if (!exists<RandomnessConfigSeqNum>(@aptos_framework)) {
        move_to(framework, RandomnessConfigSeqNum { seq_num: 0 })
    }
}

on_new_epoch

Only used in reconfigurations to apply the pending RandomnessConfig, if there is any.

public(friend) fun on_new_epoch(framework: &signer)
Implementation 
public(friend) fun on_new_epoch(framework: &signer) acquires RandomnessConfigSeqNum {
    system_addresses::assert_aptos_framework(framework);
    if (config_buffer::does_exist<RandomnessConfigSeqNum>()) {
        let new_config = config_buffer::extract_v2<RandomnessConfigSeqNum>();
        if (exists<RandomnessConfigSeqNum>(@aptos_framework)) {
            *borrow_global_mut<RandomnessConfigSeqNum>(@aptos_framework) = new_config;
        } else {
            move_to(framework, new_config);
        }
    }
}

Specification

on_new_epoch

public(friend) fun on_new_epoch(framework: &signer)
requires @aptos_framework == std::signer::address_of(framework);
include config_buffer::OnNewEpochRequirement<RandomnessConfigSeqNum>;
aborts_if false;