feat: mock stable debt token

Author: sakulstra

src/contracts/instances/PoolInstance.sol

@@ -6,7 +6,7 @@ import {IPoolAddressesProvider} from '../interfaces/IPoolAddressesProvider.sol';
 import {Errors} from '../protocol/libraries/helpers/Errors.sol';
 
 contract PoolInstance is Pool {
-  uint256 public constant POOL_REVISION = 5;
+  uint256 public constant POOL_REVISION = 6;
 
   constructor(IPoolAddressesProvider provider) Pool(provider) {}
 

src/contracts/protocol/pool/Pool.sol

@@ -450,6 +450,10 @@ abstract contract Pool is VersionedInitializable, PoolStorage, IPool {
     res.accruedToTreasury = reserve.accruedToTreasury;
     res.unbacked = reserve.unbacked;
     res.isolationModeTotalDebt = reserve.isolationModeTotalDebt;
+    // This is a temporary workaround for integrations that are broken by Aave 3.2
+    // While the new pool data provider is backward compatible, some integrations hard-code an old implementation
+    // To allow them to unlock the funds, the pool address provider is setting a stable debt token, so balanceOf() and totalSupply() will return zero instead of reverting
+    res.stableDebtTokenAddress = ADDRESSES_PROVIDER.getAddress(bytes32('MOCK_STABLE_DEBT'));
     return res;
   }