From 883c28fe29293dc2af66b2541a79462b03a172ea Mon Sep 17 00:00:00 2001
From: Raphael Simon <simon.raphael@gmail.com>
Date: Sat, 9 Mar 2024 17:55:17 -0800
Subject: [PATCH] Correctly handle union to union transforms (#3491)

* Correctly handle union to union transforms

These happen when using views and `OneOf`.

* Remove unused code
---
 codegen/go_transform.go                  |  3 ++-
 codegen/go_transform_union_test.go       | 12 ++++++------
 codegen/service/testdata/service_code.go | 20 ++++++++++----------
 3 files changed, 18 insertions(+), 17 deletions(-)

diff --git a/codegen/go_transform.go b/codegen/go_transform.go
index 805ea43ed5..821d477ea0 100644
--- a/codegen/go_transform.go
+++ b/codegen/go_transform.go
@@ -698,7 +698,8 @@ for key, val := range {{ .SourceVar }} {
 {{ end }}switch actual := {{ .SourceVar }}.(type) {
 	{{- range $i, $ref := .SourceTypeRefs }}
 	case {{ $ref }}:
-		{{- transformAttribute (index $.SourceTypes $i).Attribute (index $.TargetTypes $i).Attribute "actual" $.TargetVar false $.TransformAttrs -}}
+		{{- transformAttribute (index $.SourceTypes $i).Attribute (index $.TargetTypes $i).Attribute "actual" "obj" true $.TransformAttrs -}}
+		{{ $.TargetVar }} = obj
 	{{- end }}
 }
 `
diff --git a/codegen/go_transform_union_test.go b/codegen/go_transform_union_test.go
index c864b3d6f0..4d02aec1a6 100644
--- a/codegen/go_transform_union_test.go
+++ b/codegen/go_transform_union_test.go
@@ -91,8 +91,8 @@ const unionToUnionCode = `func transform() {
 	var target *UnionString2
 	switch actual := source.(type) {
 	case UnionStringString:
-		target = UnionString2String(actual)
-
+		obj := UnionString2String(actual)
+		target = obj
 	}
 }
 `
@@ -101,11 +101,11 @@ const unionMultiToUnionMultiCode = `func transform() {
 	var target *UnionStringInt2
 	switch actual := source.(type) {
 	case UnionStringIntString:
-		target = UnionStringInt2String(actual)
-
+		obj := UnionStringInt2String(actual)
+		target = obj
 	case UnionStringIntInt:
-		target = UnionStringInt2Int(actual)
-
+		obj := UnionStringInt2Int(actual)
+		target = obj
 	}
 }
 `
diff --git a/codegen/service/testdata/service_code.go b/codegen/service/testdata/service_code.go
index 353cc1176c..26b9a9bd04 100644
--- a/codegen/service/testdata/service_code.go
+++ b/codegen/service/testdata/service_code.go
@@ -1516,16 +1516,16 @@ func newResultOneof(vres *resultwithoneoftypeviews.ResultOneofView) *ResultOneof
 	if vres.Result != nil {
 		switch actual := vres.Result.(type) {
 		case *resultwithoneoftypeviews.TView:
-			res.Result = &T{
+			obj := &T{
 				Message: actual.Message,
 			}
-
+			res.Result = obj
 		case *resultwithoneoftypeviews.UView:
-			res.Result = &U{}
+			obj := &U{}
 			if actual.Item != nil {
-				res.Result.(*U).Item = transformResultwithoneoftypeviewsItemViewToItem(actual.Item)
+				obj.(*U).Item = transformResultwithoneoftypeviewsItemViewToItem(actual.Item)
 			}
-
+			res.Result = obj
 		}
 	}
 	return res
@@ -1538,16 +1538,16 @@ func newResultOneofView(res *ResultOneof) *resultwithoneoftypeviews.ResultOneofV
 	if res.Result != nil {
 		switch actual := res.Result.(type) {
 		case *T:
-			vres.Result = &resultwithoneoftypeviews.TView{
+			obj := &resultwithoneoftypeviews.TView{
 				Message: actual.Message,
 			}
-
+			vres.Result = obj
 		case *U:
-			vres.Result = &resultwithoneoftypeviews.UView{}
+			obj := &resultwithoneoftypeviews.UView{}
 			if actual.Item != nil {
-				vres.Result.(*resultwithoneoftypeviews.UView).Item = transformItemToResultwithoneoftypeviewsItemView(actual.Item)
+				obj.(*resultwithoneoftypeviews.UView).Item = transformItemToResultwithoneoftypeviewsItemView(actual.Item)
 			}
-
+			vres.Result = obj
 		}
 	}
 	return vres