Version Skipping

src/AtomicAuctionHouse.sol

@@ -46,6 +46,13 @@ contract AtomicAuctionHouse is IAtomicAuctionHouse, AuctionHouse {
         address permit2_
     ) AuctionHouse(owner_, protocol_, permit2_) {}
 
+    // ========== VERSIONING ========== //
+
+    /// @inheritdoc IAuctionHouse
+    function VERSION() external pure returns (uint8 major, uint8 minor) {
+        return (1, 1);
+    }
+
     // ========== AUCTION MANAGEMENT ========== //
 
     /// @inheritdoc AuctionHouse

src/BatchAuctionHouse.sol

@@ -53,6 +53,13 @@ contract BatchAuctionHouse is IBatchAuctionHouse, AuctionHouse {
         address permit2_
     ) AuctionHouse(owner_, protocol_, permit2_) {}
 
+    // ========== VERSIONING ========== //
+
+    /// @inheritdoc IAuctionHouse
+    function VERSION() external pure returns (uint8 major, uint8 minor) {
+        return (1, 1);
+    }
+
     // ========== AUCTION MANAGEMENT ========== //
 
     /// @inheritdoc AuctionHouse

src/interfaces/IAuctionHouse.sol

@@ -115,6 +115,11 @@ interface IAuctionHouse {
         uint48 referrerFee; // 6 bytes
     }
 
+    // ========== VERSIONING ========== //
+
+    /// @notice     The version of the AuctionHouse
+    function VERSION() external view returns (uint8 major, uint8 minor);
+
     // ========== AUCTION MANAGEMENT ========== //
 
     /// @notice     Creates a new auction lot

src/modules/Modules.sol

@@ -63,7 +63,7 @@ abstract contract WithModules is Owned {
     /// @dev        - The module is not a contract
     /// @dev        - The module has an invalid Veecode
     /// @dev        - The module (or other versions) is already installed
-    /// @dev        - The module version is not one greater than the latest version
+    /// @dev        - The module version is not greater than the latest version
     ///
     /// @param      newModule_  The new module
     function installModule(
@@ -75,17 +75,18 @@ abstract contract WithModules is Owned {
         ensureValidVeecode(veecode);
         (Keycode keycode, uint8 version) = unwrapVeecode(veecode);
 
-        // Validate that the module version is one greater than the latest version
+        // Validate that the module version is greater than the latest version
         ModStatus storage status = getModuleStatus[keycode];
-        if (version != status.latestVersion + 1) revert InvalidModuleInstall(keycode, version);
+        uint8 currentVersion = status.latestVersion;
+        if (version <= currentVersion) revert InvalidModuleInstall(keycode, version);
 
         // Store module data and remove sunset if applied
         status.latestVersion = version;
         if (status.sunset) status.sunset = false;
         getModuleForVeecode[veecode] = newModule_;
 
         // If the module is not already installed, add it to the list of modules
-        if (version == uint8(1)) {
+        if (currentVersion == uint8(0)) {
             modules.push(keycode);
             modulesCount++;
         }

test/modules/Modules/installModule.t.sol

@@ -78,26 +78,44 @@ contract InstallModuleTest is Test {
         _withModules.installModule(moduleZero);
     }
 
-    function testReverts_whenInitialVersionIncorrect() external {
-        Module upgradedModule = new MockModuleV2(address(_withModules));
-
-        bytes memory err =
-            abi.encodeWithSelector(WithModules.InvalidModuleInstall.selector, toKeycode("MOCK"), 2);
-        vm.expectRevert(err);
+    function test_whenInitialVersionSkips() external {
+        Module initialModule = new MockModuleV2(address(_withModules));
 
         // Install version 2 (skips version 1)
-        _withModules.installModule(upgradedModule);
+        _withModules.installModule(initialModule);
+
+        // Check that the module is installed
+        Module module = _withModules.getModuleForVeecode(initialModule.VEECODE());
+        assertEq(address(module), address(initialModule));
+
+        // Check that the latest version is recorded
+        (uint8 moduleLatestVersion,) = _withModules.getModuleStatus(toKeycode("MOCK"));
+        assertEq(moduleLatestVersion, 2);
+
+        // Check that the modules array is updated
+        uint256 modulesCount = _withModules.modulesCount();
+        assertEq(modulesCount, 1);
+        assertEq(fromKeycode(_withModules.modules(0)), "MOCK");
     }
 
-    function testReverts_whenNewerVersionSkips() external whenVersion1IsInstalled {
+    function test_whenNewerVersionSkips() external whenVersion1IsInstalled {
         Module upgradedModule = new MockModuleV3(address(_withModules));
 
-        bytes memory err =
-            abi.encodeWithSelector(WithModules.InvalidModuleInstall.selector, toKeycode("MOCK"), 3);
-        vm.expectRevert(err);
-
-        // Install version 3
+        // Upgrade from version 1 to version 3 (skips version 2)
         _withModules.installModule(upgradedModule);
+
+        // Check that the module is installed
+        Module module = _withModules.getModuleForVeecode(upgradedModule.VEECODE());
+        assertEq(address(module), address(upgradedModule));
+
+        // Check that the latest version is recorded
+        (uint8 moduleLatestVersion,) = _withModules.getModuleStatus(toKeycode("MOCK"));
+        assertEq(moduleLatestVersion, 3);
+
+        // Check that the modules array is updated
+        uint256 modulesCount = _withModules.modulesCount();
+        assertEq(modulesCount, 1);
+        assertEq(fromKeycode(_withModules.modules(0)), "MOCK");
     }
 
     function testReverts_invalidVeecode() external {