Extract a helper method for finding the next epoch

src/consensus/upgrades.cpp

@@ -114,20 +114,28 @@ bool IsActivationHeightForAnyUpgrade(
     return false;
 }
 
-boost::optional<int> NextActivationHeight(
-    int nHeight,
-    const Consensus::Params& params)
-{
+boost::optional<int> NextEpoch(int nHeight, const Consensus::Params& params) {
     if (nHeight < 0) {
         return boost::none;
     }
 
-    // Don't count Sprout as an activation height
+    // Sprout is never pending
     for (auto idx = Consensus::BASE_SPROUT + 1; idx < Consensus::MAX_NETWORK_UPGRADES; idx++) {
         if (NetworkUpgradeState(nHeight, params, Consensus::UpgradeIndex(idx)) == UPGRADE_PENDING) {
-            return params.vUpgrades[idx].nActivationHeight;
+            return idx;
         }
     }
 
     return boost::none;
 }
+
+boost::optional<int> NextActivationHeight(
+    int nHeight,
+    const Consensus::Params& params)
+{
+    auto idx = NextEpoch(nHeight, params);
+    if (idx) {
+        return params.vUpgrades[idx.get()].nActivationHeight;
+    }
+    return boost::none;
+}