Don't include stakers with expired stakes in the missing_stakers results for StakingEscrowAgent.partition_stakers_by_activity()

[derekpierre]

Type of PR:

• Bugfix
• Feature
• Documentation
• Other

Required reviews:

• 1
• 2
• 3

What this does:
Ignores stakers with expired stakes.

Issues fixed/closed:
Fixes #2760 .

Why it's needed:
Including stakers with expired stakes causes an overstating of the number of inactive stakers on the network i.e. stakers who haven't committed to the current period.

[derekpierre]

@vzotova does the StakingEscrow contract need to be updated to really fix this i.e. the contract should do the pruning of its stakers list from time to time? Otherwise, with this agent-specific fix, we end up with some inconsistencies eg.

>>> active_stakers, pending_stakers, missing_stakers = staking_agent.partition_stakers_by_activity()
>>> staking_agent.get_staker_population()
2129
>>> len(active_stakers) + len(pending_stakers) + len(missing_stakers)
638

2129 != 638.

It is also inefficient to do the pruning on the agent side, since every call to the partition function requires excessive staker checks for expired stakes, as opposed to the list in the contract being already correct/corrected.

Interested to get your thoughts here.

[vzotova]

I'd prefer not to spend gas from anyone to make state clearer - just have this stakers and calculate real numbers offline. But it definitely possible

[derekpierre]

@vzotova some times for you 😅 :

Using infura:

# partition function before checking for expired stakes on mainnet
473.30053091049194 s
493.7947690486908 s

# partition function when checking for expired stakes on mainnet
875.4592299461365 s
820.4715950489044 s
768.975784778595 s

[derekpierre]

Ignore the numbers above, I was using the wrong web3 provider:

Using infura:

# before fix
262.1745069026947 s
266.5320801734924 s

# after fix
480.71446204185486 s
455.59283089637756 s