[EFM] Update Epoch Lookup Component

[jordanschalm]

The Epoch Lookup acts as a cache supporting queries for the epoch counter corresponding to a given view.

Changes:

• Add EpochExtended event handler:
  • Set epochRange.finalView to final view of extension
• Add EpochRecovered event handler:
  • Add epochRange for RecoveryEpoch (Note: will be similar to handler for EpochCommittedPhaseStarted)
• Remove/revisit [this sanity check](

  flow-go/module/epochs/epoch_lookup.go

  Lines 84 to 87 in 7364a43

  	// sanity check: ensure counters/views are sequential
  	if epoch.counter != latestCachedEpoch.counter+1 {
  	return fmt.Errorf("non-sequential epoch counters: adding epoch %d when latest cached epoch is %d", epoch.counter, latestCachedEpoch.counter)
  	}

  ) that counters are sequential

Depends on

Beta Give feedback

1. [EFM] Add EpochExtension to Epoch Data Model #5717
   S-BFT S-Epochs +2
   
2. [EFM] Dynamic Protocol State injects EpochExtension when entering EFM #5724
   S-BFT S-Epochs +2
   
3. [EFM] Dynamic Protocol State maintains EFM by injecting EpochExtensions #5726
   S-BFT S-Epochs +2