THRIFT-5046: Better struct tag overrides
Custom go.tag in an IDL no longer removes the existing "db" and "json"
tags but can override them.
This allows us to change default tags in the future without affecting
user defined ones.
Client: go
This closes #1963.
diff --git a/compiler/cpp/src/thrift/generate/t_go_generator.cc b/compiler/cpp/src/thrift/generate/t_go_generator.cc
index 2093841..a5d55d7 100644
--- a/compiler/cpp/src/thrift/generate/t_go_generator.cc
+++ b/compiler/cpp/src/thrift/generate/t_go_generator.cc
@@ -240,6 +240,8 @@
void generate_go_docstring(std::ostream& out, t_doc* tdoc);
+ void parse_go_tags(map<string,string>* tags, const string in);
+
/**
* Helper rendering functions
*/
@@ -1377,7 +1379,9 @@
t_type* fieldType = (*m_iter)->get_type();
string goType = type_to_go_type_with_opt(fieldType, is_pointer_field(*m_iter));
- string gotag = "db:\"" + escape_string((*m_iter)->get_name()) + "\" ";
+
+ map<string,string>tags;
+ tags["db"]=escape_string((*m_iter)->get_name());
// Only add the `omitempty` tag if this field is optional and has no default value.
// Otherwise a proper value like `false` for a bool field will be ommitted from
@@ -1385,16 +1389,25 @@
bool has_default = (*m_iter)->get_value();
bool is_optional = (*m_iter)->get_req() == t_field::T_OPTIONAL;
if (is_optional && !has_default) {
- gotag += "json:\"" + escape_string((*m_iter)->get_name()) + ",omitempty\"";
+ tags["json"]=escape_string((*m_iter)->get_name())+",omitempty";
} else {
- gotag += "json:\"" + escape_string((*m_iter)->get_name()) + "\"";
+ tags["json"]=escape_string((*m_iter)->get_name());
}
- // Check for user override of db and json tags using "go.tag"
+ // Check for user defined tags and them if there are any. User defined tags
+ // can override the above db and json tags.
std::map<string, string>::iterator it = (*m_iter)->annotations_.find("go.tag");
if (it != (*m_iter)->annotations_.end()) {
- gotag = it->second;
+ parse_go_tags(&tags, it->second);
}
+
+ string gotag;
+ for (auto it = tags.begin(); it != tags.end(); ++it) {
+ gotag += it->first + ":\"" + it->second + "\" ";
+ }
+ // Trailing whitespace
+ gotag.resize(gotag.size()-1);
+
indent(out) << publicize((*m_iter)->get_name()) << " " << goType << " `thrift:\""
<< escape_string((*m_iter)->get_name()) << "," << sorted_keys_pos;
if ((*m_iter)->get_req() == t_field::T_REQUIRED) {
@@ -3735,6 +3748,48 @@
throw "INVALID TYPE IN type_to_spec_args: " + ttype->get_name();
}
+// parses a string of struct tags into key/value pairs and writes them to the given map
+void t_go_generator::parse_go_tags(map<string,string>* tags, const string in) {
+ string key;
+ string value;
+
+ size_t mode=0; // 0/1/2 for key/value/whitespace
+ size_t index=0;
+ for (auto it=in.begin(); it<in.end(); ++it, ++index) {
+ // Normally we start in key mode because the IDL is expected to be in
+ // (go.tag="key:\"value\"") format, but if there is leading whitespace
+ // we need to start in whitespace mode.
+ if (index==0 && mode==0 && in[index]==' ') {
+ mode=2;
+ }
+
+ if (mode==2) {
+ if (in[index]==' ') {
+ continue;
+ }
+ mode=0;
+ }
+
+ if (mode==0) {
+ if (in[index]==':') {
+ mode=1;
+ index++;
+ it++;
+ continue;
+ }
+ key+=in[index];
+ } else if (mode==1) {
+ if (in[index]=='"') {
+ (*tags)[key]=value;
+ key=value="";
+ mode=2;
+ continue;
+ }
+ value+=in[index];
+ }
+ }
+}
+
bool format_go_output(const string& file_path) {
// formatting via gofmt deactivated due to THRIFT-3893
diff --git a/lib/go/test/GoTagTest.thrift b/lib/go/test/GoTagTest.thrift
index 5667c6e..4b6ac31 100644
--- a/lib/go/test/GoTagTest.thrift
+++ b/lib/go/test/GoTagTest.thrift
@@ -19,7 +19,7 @@
struct tagged {
1: string string_thing,
- 2: i64 int_thing (go.tag = "json:\"int_thing,string\""),
+ 2: i64 int_thing (go.tag = "json:\"custom_thing\" mykey:\"myvalue\""),
3: optional i64 optional_int_thing
4: optional bool optional_bool_thing = false
}
diff --git a/lib/go/test/tests/gotag_test.go b/lib/go/test/tests/gotag_test.go
index ff2f14e..4cbea56 100644
--- a/lib/go/test/tests/gotag_test.go
+++ b/lib/go/test/tests/gotag_test.go
@@ -38,8 +38,16 @@
s := gotagtest.Tagged{}
st := reflect.TypeOf(s)
field, ok := st.FieldByName("IntThing")
- if !ok || field.Tag.Get("json") != "int_thing,string" {
- t.Error("Unexpected custom tag value")
+ if !ok {
+ t.Error("Missing field IntThing")
+ return
+ }
+
+ if v := field.Tag.Get("json"); v != "custom_thing" {
+ t.Errorf("Expected custom_thing for tag json, got %s", v)
+ }
+ if v := field.Tag.Get("mykey"); v != "myvalue" {
+ t.Errorf("Expected myvalue for tag mykey, got %s", v)
}
}