[FAB-15720] prevent duplicate transactions

Throw an exception a transaction is defined with the same name more than once, either by ovewloading methods, or by specifying a name in the Transaction annotation

Change-Id: I5c2371e3efaafc26ccd68a5e97ee9b59a40946fb
Signed-off-by: James Taylor <[email protected]>

Author: jt-nti

fabric-chaincode-shim/src/main/java/org/hyperledger/fabric/contract/routing/impl/ContractDefinitionImpl.java

@@ -90,7 +90,13 @@ public ContractInterface getContractImpl() {
     public TxFunction addTxFunction(Method m) {
         logger.debug(() -> "Adding method " + m.getName());
         TxFunction txFn = new TxFunctionImpl(m, this);
-        txFunctions.put(txFn.getName(), txFn);
+        TxFunction previousTxnFn = txFunctions.put(txFn.getName(), txFn);
+        if (previousTxnFn != null) {
+            String message = String.format("Duplicate transaction method %s", previousTxnFn.getName());
+            ContractRuntimeException cre = new ContractRuntimeException(message);
+            logger.severe(() -> logger.formatError(cre));
+            throw cre;
+        }
         return txFn;
     }
 

fabric-chaincode-shim/src/test/java/org/hyperledger/fabric/contract/routing/ContractDefinitionTest.java

@@ -9,8 +9,11 @@
 import static org.hamcrest.Matchers.startsWith;
 import static org.junit.Assert.assertThat;
 
+import java.lang.reflect.Method;
 import java.security.Permission;
 
+import org.hyperledger.fabric.contract.ContractInterface;
+import org.hyperledger.fabric.contract.ContractRuntimeException;
 import org.hyperledger.fabric.contract.annotation.Contract;
 import org.hyperledger.fabric.contract.routing.impl.ContractDefinitionImpl;
 import org.junit.Before;
@@ -89,4 +92,18 @@ public void checkPermission(Permission perm) {
             System.setSecurityManager(null);
         }
     }
+
+    @Test
+    public void duplicateTransaction() throws NoSuchMethodException, SecurityException {
+        ContractDefinition cf = new ContractDefinitionImpl(SampleContract.class);
+
+        ContractInterface contract = new SampleContract();
+        Method m = contract.getClass().getMethod("t2", new Class[] {});
+
+        thrown.expect(ContractRuntimeException.class);
+        thrown.expectMessage("Duplicate transaction method t2");
+
+        cf.addTxFunction(m);
+        cf.addTxFunction(m);
+    }
 }