fix(api): homogenize error messages when required parameters are set to null (#822)

Signed-off-by: Adrian Sutton <adrian.sutton@consensys.net>

ethereum/jsonrpc/src/main/java/tech/pegasys/pantheon/ethereum/jsonrpc/internal/JsonRpcRequest.java

@@ -74,12 +74,28 @@ public class JsonRpcRequest {
 
   @JsonIgnore
   public int getParamLength() {
-    return params.length;
+    return hasParams() ? params.length : 0;
+  }
+
+  @JsonIgnore
+  public boolean hasParams() {
+
+    // Null Object: "params":null
+    if (params == null) {
+      return false;
+    }
+
+    // Null Array: "params":[null]
+    if (params.length == 0 || params[0] == null) {
+      return false;
+    }
+
+    return true;
   }
 
   @JsonSetter("id")
   protected void setId(final JsonRpcRequestId id) {
-    // If an id is explicitly set, its not a notification
+    // If an id is explicitly set, it is not a notification
     isNotification = false;
     this.id = id;
   }

ethereum/jsonrpc/src/main/java/tech/pegasys/pantheon/ethereum/jsonrpc/internal/parameters/JsonRpcParameter.java

@@ -57,7 +57,7 @@ public class JsonRpcParameter {
   @SuppressWarnings("unchecked")
   public <T> Optional<T> optional(
       final Object[] params, final int index, final Class<T> paramClass) {
-    if (params == null || params.length <= index) {
+    if (params == null || params.length <= index || params[index] == null) {
       return Optional.empty();
     }
 

ethereum/jsonrpc/src/test/java/tech/pegasys/pantheon/ethereum/jsonrpc/internal/methods/AdminAddPeerTest.java

@@ -55,6 +55,28 @@ public class AdminAddPeerTest {
     assertThat(actualResponse).isEqualToComparingFieldByField(expectedResponse);
   }
 
+  @Test
+  public void requestHasNullObjectParameter() {
+    final JsonRpcRequest request = new JsonRpcRequest("2.0", "admin_addPeer", null);
+    final JsonRpcResponse expectedResponse =
+        new JsonRpcErrorResponse(request.getId(), JsonRpcError.INVALID_PARAMS);
+
+    final JsonRpcResponse actualResponse = method.response(request);
+
+    assertThat(actualResponse).isEqualToComparingFieldByField(expectedResponse);
+  }
+
+  @Test
+  public void requestHasNullArrayParameter() {
+    final JsonRpcRequest request = new JsonRpcRequest("2.0", "admin_addPeer", new String[] {null});
+    final JsonRpcResponse expectedResponse =
+        new JsonRpcErrorResponse(request.getId(), JsonRpcError.INVALID_PARAMS);
+
+    final JsonRpcResponse actualResponse = method.response(request);
+
+    assertThat(actualResponse).isEqualToComparingFieldByField(expectedResponse);
+  }
+
   @Test
   public void requestHasInvalidEnode() {
     final JsonRpcRequest request =

ethereum/jsonrpc/src/test/java/tech/pegasys/pantheon/ethereum/jsonrpc/internal/methods/EthSendRawTransactionTest.java

@@ -64,6 +64,31 @@ public class EthSendRawTransactionTest {
     assertThat(actualResponse).isEqualToComparingFieldByField(expectedResponse);
   }
 
+  @Test
+  public void requestHasNullObjectParameter() {
+    final JsonRpcRequest request = new JsonRpcRequest("2.0", "eth_sendRawTransaction", null);
+
+    final JsonRpcResponse expectedResponse =
+        new JsonRpcErrorResponse(request.getId(), JsonRpcError.INVALID_PARAMS);
+
+    final JsonRpcResponse actualResponse = method.response(request);
+
+    assertThat(actualResponse).isEqualToComparingFieldByField(expectedResponse);
+  }
+
+  @Test
+  public void requestHasNullArrayParameter() {
+    final JsonRpcRequest request =
+        new JsonRpcRequest("2.0", "eth_sendRawTransaction", new String[] {null});
+
+    final JsonRpcResponse expectedResponse =
+        new JsonRpcErrorResponse(request.getId(), JsonRpcError.INVALID_PARAMS);
+
+    final JsonRpcResponse actualResponse = method.response(request);
+
+    assertThat(actualResponse).isEqualToComparingFieldByField(expectedResponse);
+  }
+
   @Test
   public void invalidTransactionRlpDecoding() {
     final String rawTransaction = "0x00";

ethereum/jsonrpc/src/test/java/tech/pegasys/pantheon/ethereum/jsonrpc/internal/methods/privacy/EeaSendRawTransactionTest.java

@@ -106,6 +106,31 @@ public class EeaSendRawTransactionTest {
     assertThat(actualResponse).isEqualToComparingFieldByField(expectedResponse);
   }
 
+  @Test
+  public void requestHasNullObjectParameter() {
+    final JsonRpcRequest request = new JsonRpcRequest("2.0", "eea_sendRawTransaction", null);
+
+    final JsonRpcResponse expectedResponse =
+        new JsonRpcErrorResponse(request.getId(), JsonRpcError.INVALID_PARAMS);
+
+    final JsonRpcResponse actualResponse = method.response(request);
+
+    assertThat(actualResponse).isEqualToComparingFieldByField(expectedResponse);
+  }
+
+  @Test
+  public void requestHasNullArrayParameter() {
+    final JsonRpcRequest request =
+        new JsonRpcRequest("2.0", "eea_sendRawTransaction", new String[] {null});
+
+    final JsonRpcResponse expectedResponse =
+        new JsonRpcErrorResponse(request.getId(), JsonRpcError.INVALID_PARAMS);
+
+    final JsonRpcResponse actualResponse = method.response(request);
+
+    assertThat(actualResponse).isEqualToComparingFieldByField(expectedResponse);
+  }
+
   @Test
   public void invalidTransactionRlpDecoding() {
     final String rawTransaction = "0x00";