Update epoch processing

src/gateway/GatewayGetterFacet.sol

@@ -157,4 +157,19 @@ contract GatewayGetterFacet {
     function majorityPercentage() public view returns (uint64) {
         return LibVoting.majorityPercentage();
     }
+
+    /// @notice returns the list of registered subnets in IPC
+    /// @return subnet - the list of subnets
+    function listSubnets() external view returns (Subnet[] memory) {
+        uint256 size = s.subnetKeys.length;
+        Subnet[] memory out = new Subnet[](size);
+        for (uint256 i = 0; i < size; ) {
+            bytes32 key = s.subnetKeys[i];
+            out[i] = s.subnets[key];
+            unchecked {
+                ++i;
+            }
+        }
+        return out;
+    }
 }

src/gateway/GatewayManagerFacet.sol

@@ -31,7 +31,7 @@ contract GatewayManagerFacet is GatewayActorModifiers, ReentrancyGuard {
         s.initialized = true;
     }
 
-    /// @notice register a subnet in the gateway. called by a subnet when it reaches the threshold stake
+    /// @notice register a subnet in the gateway. It is called by a subnet when it reaches the threshold stake
     function register() external payable {
         if (msg.value < s.minStake) {
             revert NotEnoughFunds();
@@ -49,6 +49,9 @@ contract GatewayManagerFacet is GatewayActorModifiers, ReentrancyGuard {
         subnet.stake = msg.value;
         subnet.status = Status.Active;
         subnet.genesisEpoch = block.number;
+
+        s.subnetKeys.push(subnetId.toHash());
+
         s.totalSubnets += 1;
     }
 

src/lib/ExecutableQueueHelper.sol

@@ -5,14 +5,14 @@ import {ExecutableQueue} from "../structs/ExecutableQueue.sol";
 
 library ExecutableQueueHelper {
     function push(ExecutableQueue storage queue, uint64 epoch) public {
-        if (epoch == 0) {
+        if (epoch == queue.genesisEpoch) {
             return;
         }
 
-        if (queue.first == 0 || queue.first > epoch) {
+        if (queue.first == queue.genesisEpoch || queue.first > epoch) {
             queue.first = epoch;
         }
-        if (queue.last == 0 || queue.last < epoch) {
+        if (queue.last == queue.genesisEpoch || queue.last < epoch) {
             queue.last = epoch;
         }
 

src/lib/LibGatewayActorStorage.sol

@@ -28,6 +28,8 @@ struct GatewayActorStorage {
     /// @notice List of subnets
     /// SubnetID => Subnet
     mapping(bytes32 => Subnet) subnets;
+    /// @notice Keys of the registered subnets. Useful to iterate through them
+    bytes32[] subnetKeys;
     /// @notice bottom-up period in number of epochs for the subnet
     uint64 bottomUpCheckPeriod;
     /// @notice Postbox keeps track of all the cross-net messages triggered by

src/lib/LibVoting.sol

@@ -13,7 +13,9 @@ struct VotingStorage {
     uint64 lastVotingExecutedEpoch;
     /// @notice Initial epoch number
     uint64 genesisEpoch;
+    /// @notice Percentage of majority
     uint8 majorityPercentage;
+    /// @notice Checkpoint submission period
     uint64 submissionPeriod;
     /// @notice Contains the executable epochs that are ready to be executed, but has yet to be executed.
     /// This usually happens when previous submission epoch has not executed, but the next submission
@@ -51,10 +53,11 @@ library LibVoting {
         if (epoch <= s.lastVotingExecutedEpoch) {
             revert EpochAlreadyExecuted();
         }
-        if (epoch > s.genesisEpoch) {
-            if ((epoch - s.genesisEpoch) % s.submissionPeriod != 0) {
-                revert EpochNotVotable();
-            }
+        if (epoch < s.genesisEpoch) {
+            revert EpochNotVotable();
+        }
+        if ((epoch - s.genesisEpoch) % s.submissionPeriod != 0) {
+            revert EpochNotVotable();
         }
     }
 
@@ -73,6 +76,7 @@ library LibVoting {
     function initGenesisEpoch(uint64 genesisEpoch) internal {
         VotingStorage storage s = votingStorage();
         s.genesisEpoch = genesisEpoch;
+        s.executableQueue.genesisEpoch = genesisEpoch;
     }
 
     /// @notice method that gives the epoch for a given block number and checkpoint period

src/structs/ExecutableQueue.sol

@@ -2,6 +2,7 @@
 pragma solidity 0.8.19;
 
 struct ExecutableQueue {
+    uint64 genesisEpoch; // genesis epoch
     uint64 period; // number of blocks per epoch
     uint64 first; // next epoch
     uint64 last; // last epoch

test/ExecutableQueueHelper.t.sol

@@ -19,6 +19,7 @@ contract ExecutableQueueHelperTest is Test {
 
     function setUp() public {
         queue.period = BLOCKS_PER_EPOCH;
+        queue.genesisEpoch = 0;
     }
 
     function test_Push_Works_ZeroEpoch() public {
@@ -27,6 +28,20 @@ contract ExecutableQueueHelperTest is Test {
         require(queue.epochs[0] == false);
     }
 
+    function test_Push_Works_GenesisEpochInvalid() public {
+        queue.genesisEpoch = 10;
+        queue.push(10);
+
+        require(queue.epochs[10] == false);
+    }
+
+    function test_Push_Works_NonGenesisEpochValid() public {
+        queue.genesisEpoch = 10;
+        queue.push(11);
+
+        require(queue.epochs[11]);
+    }
+
     function test_Push_Works_OneEpoch() public {
         _assertPush(EPOCH_ONE);