simulation stop early with no proposers

x/distribution/keeper/allocation.go

@@ -13,6 +13,7 @@ func (k Keeper) AllocateTokens(ctx sdk.Context, percentVotes sdk.Dec, proposer s
 
 	// get the proposer of this block
 	proposerValidator := k.stakeKeeper.ValidatorByConsAddr(ctx, proposer)
+
 	proposerDist := k.GetValidatorDistInfo(ctx, proposerValidator.GetOperator())
 
 	// get the fees which have been getting collected through all the

x/distribution/keeper/hooks.go

@@ -104,7 +104,6 @@ func (h Hooks) OnDelegationRemoved(ctx sdk.Context, delAddr sdk.AccAddress, valA
 func (h Hooks) OnValidatorBeginUnbonding(ctx sdk.Context, _ sdk.ConsAddress, addr sdk.ValAddress) {
 	h.k.onValidatorModified(ctx, addr)
 }
-
 func (h Hooks) OnValidatorBonded(ctx sdk.Context, _ sdk.ConsAddress, addr sdk.ValAddress) {
 	h.k.onValidatorModified(ctx, addr)
 }

x/mock/simulation/random_simulate_blocks.go

@@ -176,6 +176,12 @@ func SimulateFromSeed(tb testing.TB, app *baseapp.BaseApp,
 			app.Commit()
 		}
 
+		if header.ProposerAddress == nil {
+			fmt.Printf("\nSimulation stopped early as all validators have been unbonded, there is nobody left propose a block!\n")
+			stopEarly = true
+			break
+		}
+
 		// Generate a random RequestBeginBlock with the current validator set for the next block
 		request = RandomRequestBeginBlock(r, validators, livenessTransitionMatrix, evidenceFraction, pastTimes, pastVoteInfos, event, header)