THRIFT-5459: Fix breaking issue when adding a new exception
Client: go
Currently in the compiler generated go code, adding a new exception to
an existing endpoint can cause unexpected behaviors when the client
isn't updated. Fix the issue.
Will be cherry-picked into 0.15.0 after merged.
diff --git a/CHANGES.md b/CHANGES.md
index 5254682..adee1dd 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -16,6 +16,7 @@
- [THRIFT-5389](https://issues.apache.org/jira/browse/THRIFT-5389) - The compiler now generates correct go code with thrift constant defined on optional enum/typedef fields
- [THRIFT-4797](https://issues.apache.org/jira/browse/THRIFT-4797) - The compiler now correctly auto renames import thrift namespaces when they collide with system imports
- [THRIFT-5453](https://issues.apache.org/jira/browse/THRIFT-5453) - Defer DNS lookups from NewTSocketConf (without any timeout check) to TSocket.Open (subject to ConnectTimeout set in TConfiguration)
+- [THRIFT-5459](https://issues.apache.org/jira/browse/THRIFT-5459) - Client calls will return TApplicationException with MISSING_RESULT when the result is a struct but is unset, and no other error is known.
## 0.14.2
diff --git a/compiler/cpp/src/thrift/generate/t_go_generator.cc b/compiler/cpp/src/thrift/generate/t_go_generator.cc
index afed5ac..910eed3 100644
--- a/compiler/cpp/src/thrift/generate/t_go_generator.cc
+++ b/compiler/cpp/src/thrift/generate/t_go_generator.cc
@@ -2295,7 +2295,23 @@
f_types_ << indent() << "}" << endl << endl;
}
- if (!(*f_iter)->get_returntype()->is_void()) {
+ if ((*f_iter)->get_returntype()->is_struct()) {
+ // Check if the result is nil, which likely means we have a new
+ // exception added but unknown to the client yet
+ // (e.g. client hasn't updated the thrift file).
+ // Sadly this check can only be reliable done when the return type is a
+ // struct in go.
+ std::string retName = tmp("_ret");
+ f_types_ << indent() << "if " << retName << " := " << resultName
+ << ".GetSuccess(); " << retName << " != nil {" << endl;
+ indent_up();
+ f_types_ << indent() << "return " << retName << ", nil" << endl;
+ indent_down();
+ f_types_ << indent() << "}" << endl;
+ f_types_ << indent() << "return nil, "
+ << "thrift.NewTApplicationException(thrift.MISSING_RESULT, \""
+ << method << " failed: unknown result\")" << endl;
+ } else if (!(*f_iter)->get_returntype()->is_void()) {
f_types_ << indent() << "return " << resultName << ".GetSuccess(), nil" << endl;
} else {
f_types_ << indent() << "return nil" << endl;