THRIFT-5835 Allow exceptions to be used as regular struct datatype

Initial feature testcase added, compiler checks disabled.
Patch: Jens Geyer

compiler/cpp/src/thrift/parse/t_function.h

@@ -85,17 +85,23 @@ class t_function : public t_doc {
 
   void validate() const {
     get_returntype()->validate();
+
+#ifndef ALLOW_EXCEPTIONS_AS_TYPE
     if (get_returntype()->get_true_type()->is_xception()) {
       failure("method %s(): exception type \"%s\" cannot be used as function return", get_name().c_str(), get_returntype()->get_name().c_str());
     }
+#endif
 
     std::vector<t_field*>::const_iterator it;
     std::vector<t_field*> list = get_arglist()->get_members();
     for(it=list.begin(); it != list.end(); ++it) {
       (*it)->get_type()->validate();
+
+#ifndef ALLOW_EXCEPTIONS_AS_TYPE
       if( (*it)->get_type()->get_true_type()->is_xception()) {
         failure("method %s(): exception type \"%s\" cannot be used as function argument %s", get_name().c_str(), (*it)->get_type()->get_name().c_str(), (*it)->get_name().c_str());
       }
+#endif
     }
   }
 

compiler/cpp/src/thrift/parse/t_list.h

@@ -35,9 +35,11 @@ class t_list : public t_container {
   bool is_list() const override { return true; }
 
   void validate() const {
+#ifndef ALLOW_EXCEPTIONS_AS_TYPE
     if( get_elem_type()->get_true_type()->is_xception()) {
       failure("exception type \"%s\" cannot be used inside a list", get_elem_type()->get_name().c_str());
     }
+#endif
   }
 
 private:

compiler/cpp/src/thrift/parse/t_map.h

@@ -38,12 +38,14 @@ class t_map : public t_container {
   bool is_map() const override { return true; }
 
   void validate() const {
+#ifndef ALLOW_EXCEPTIONS_AS_TYPE
     if( get_key_type()->get_true_type()->is_xception()) {
       failure("exception type \"%s\" cannot be used inside a map", get_key_type()->get_name().c_str());
     }
     if( get_val_type()->get_true_type()->is_xception()) {
       failure("exception type \"%s\" cannot be used inside a map", get_val_type()->get_name().c_str());
     }
+#endif
   }
 
 private:

compiler/cpp/src/thrift/parse/t_set.h

@@ -37,9 +37,11 @@ class t_set : public t_container {
   bool is_set() const override { return true; }
 
   void validate() const {
+#ifndef ALLOW_EXCEPTIONS_AS_TYPE
     if( get_elem_type()->get_true_type()->is_xception()) {
       failure("exception type \"%s\" cannot be used inside a set", get_elem_type()->get_name().c_str());
     }
+#endif
   }
 
 private:

compiler/cpp/src/thrift/parse/t_struct.h

@@ -112,9 +112,8 @@ class t_struct : public t_type {
   const members_type& get_sorted_members() const { return members_in_id_order_; }
 
   bool is_struct() const override { return !is_xception_; }
-
   bool is_xception() const override { return is_xception_; }
-
+  bool is_method_xcepts() const override { return is_method_xcepts_; }
   bool is_union() const { return is_union_; }
 
   t_field* get_field_by_name(std::string field_name) {
@@ -144,11 +143,14 @@ class t_struct : public t_type {
     std::vector<t_field*> list = get_members();
     for(it=list.begin(); it != list.end(); ++it) {
       (*it)->get_type()->validate();
+
+#ifndef ALLOW_EXCEPTIONS_AS_TYPE
       if (!is_method_xcepts_) {  // this is in fact the only legal usage for any exception type
         if( (*it)->get_type()->get_true_type()->is_xception()) {
           failure("%s %s: exception type \"%s\" cannot be used as member field type %s", what.c_str(), get_name().c_str(), (*it)->get_type()->get_name().c_str(), (*it)->get_name().c_str());
         }
       }
+#endif
     }
   }
 

compiler/cpp/src/thrift/parse/t_type.h

@@ -26,6 +26,8 @@
 #include <stdint.h>
 #include <string>
 
+#define ALLOW_EXCEPTIONS_AS_TYPE
+
 class t_program;
 
 /**
@@ -54,6 +56,7 @@ class t_type : public t_doc {
   virtual bool is_enum() const { return false; }
   virtual bool is_struct() const { return false; }
   virtual bool is_xception() const { return false; }
+  virtual bool is_method_xcepts() const { return false; }
   virtual bool is_container() const { return false; }
   virtual bool is_list() const { return false; }
   virtual bool is_set() const { return false; }

test/ExceptionStruct.thrift

@@ -0,0 +1,56 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied. See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+namespace * test.ExceptionStruct
+
+enum ErrorCode {
+  GenericError,
+  ServerOverload,
+  InvalidData
+}
+
+struct GetRequest {
+  1: string id
+  2: binary data     // some arbitrary data
+}
+
+struct GetResponse {
+  1: i32 job_nr
+  2: binary data     // some arbitrary data
+}
+
+struct BatchGetRequest {
+  1: list<GetRequest> requests
+}
+
+struct BatchGetResponse {
+  1: map<string, GetRequest> responses,  // key is id
+  2: map<string, SomeException> errors,  // key is id
+}
+
+exception SomeException {
+  2: ErrorCode error
+}
+
+service Foo {
+  GetResponse get(1: GetRequest request) throws(1: SomeException error);
+  BatchGetResponse batchGet(1: BatchGetRequest request) throws(1: SomeException error); // may or may not be the same exception type, only throw exception when full request failed
+}
+
+# eof