protoc-gen-lua enum默认值解析错误分析与解决

测试用例：

package tutorial;

enum PhoneType {
    MOBILE = 0;
    HOME = 1;
    WORK = 2;
}

message PhoneNumber {
    optional PhoneType type = 1 [default = HOME];
}

下图左边是未修正前转换出来的lua文件，右边是修正之后转换出的lua文件。

修正方法：调整protoc-gen-lua生成文件中代码的顺序,改动diff如下：

diff --git a/plugin/protoc-gen-lua b/plugin/protoc-gen-lua
index 81f90f1..e0b8f19 100644
--- a/plugin/protoc-gen-lua
+++ b/plugin/protoc-gen-lua
@@ -131,6 +131,7 @@ class Env(object):
     extend = None
     descriptor = None
     message = None
+    enum = None
     context = None
     register = None
     def __init__(self):
@@ -196,6 +197,7 @@ class Env(object):
         self.descriptor = []
         self.context = []
         self.message = []
+        self.enum = []
         self.register = []

     def _build_nodes(self, node, names):
@@ -404,8 +406,7 @@ def code_gen_file(proto_file, env, is_gen):
     for enum_desc in proto_file.enum_type:
         code_gen_enum(enum_desc, env)
         for enum_value in enum_desc.value:
-            env.message.append('%s = %d\n' % (enum_value.name,
-                                              enum_value.number))
+            env.enum.append('%s = %d\n' % (enum_value.name, enum_value.number))

     for msg_desc in proto_file.message_type:
         code_gen_message(msg_desc, env)
@@ -422,9 +423,10 @@ def code_gen_file(proto_file, env, is_gen):
         lua("local localTable = {}\n")
         map(lua, env.descriptor)
         lua('\n')
+        map(lua, env.enum)
+        lua('\n')
         map(lua, env.context)
         lua('\n')
-        env.message.sort()
         map(lua, env.message)
         lua('\n')
         map(lua, env.register)