Merge pull request #11159 from filecoin-project/asr/fix-frc-0051

fix: chainstore: do not get stuck in unhappy equivocation cases

chain/store/store.go

@@ -446,13 +446,15 @@ func (cs *ChainStore) RefreshHeaviestTipSet(ctx context.Context, newTsHeight abi
 			}
 		}
 
-		if newHeaviest == nil {
-			return xerrors.Errorf("failed to refresh to a new valid tipset")
-		}
-
-		errTake := cs.takeHeaviestTipSet(ctx, newHeaviest)
-		if errTake != nil {
-			return xerrors.Errorf("failed to take newHeaviest tipset as head: %w", err)
+		// if we've found something, we know it's the heaviest equivocation-free head, take it IMMEDIATELY
+		if newHeaviest != nil {
+			errTake := cs.takeHeaviestTipSet(ctx, newHeaviest)
+			if errTake != nil {
+				return xerrors.Errorf("failed to take newHeaviest tipset as head: %w", err)
+			}
+		} else {
+			// if we haven't found something, just stay with our equivocation-y head
+			newHeaviest = cs.heaviest
 		}
 	}
 

chain/store/store_test.go

@@ -396,8 +396,9 @@ func TestEquivocations(t *testing.T) {
 	require.Nil(t, tryTs2)
 	require.True(t, tryTsWeight2.IsZero())
 
-	// now we "notify" at this height -- it should fail, because we cannot refresh our head due to equivocation and nulls
-	require.ErrorContains(t, cg.ChainStore().RefreshHeaviestTipSet(ctx, blkAfterNulls.Height), "failed to refresh to a new valid tipset")
+	// now we "notify" at this height -- it should lead to no head change because there's no formable head in near epochs
+	require.NoError(t, cg.ChainStore().RefreshHeaviestTipSet(ctx, blkAfterNulls.Height))
+	require.True(t, headAfterNulls.TipSet.TipSet().Equals(cg.ChainStore().GetHeaviestTipSet()))
 }
 
 func addBlockToTracker(t *testing.T, cs *store.ChainStore, blk *types.BlockHeader) {