GOSDK-25: Unmarshaling optional enums in response payloads causes panic. Changing how we instantiate nullable enums in go sdk to use constructors to properly preserve nil on empty xml tag.

Author: RachelTucker

ds3-autogen-go/src/main/kotlin/com/spectralogic/ds3autogen/go/models/parser/ParseChildNodeImpls.kt

@@ -171,8 +171,7 @@ data class ParseChildNodeAsNullableEnum(
         val paramType: String) : ParseElement {
 
     override val parsingCode: String
-        get() { return "$modelName.$paramName = new($paramType)\n" +
-                goIndent(3) + "parseNullableEnum(child.Content, $modelName.$paramName, aggErr)" }
+        get() { return "$modelName.$paramName = new${paramType}FromContent(child.Content, aggErr)" }
 }
 
 data class ParseChildNodeAsCommonPrefix(

ds3-autogen-go/src/main/resources/tmpls/go/type/checksum_type_enum.ftl

@@ -8,3 +8,13 @@ const (
 )
 
 <#include "enum_unmarshal_to_string.ftl" />
+
+func new${name}FromContent(content []byte, aggErr *AggregateError) *${name} {
+    if len(content) == 0 {
+        // no value
+        return nil
+    }
+    result := new(${name})
+    parseEnum(content, result, aggErr)
+    return result
+}

ds3-autogen-go/src/main/resources/tmpls/go/type/enum_type.ftl

@@ -7,3 +7,13 @@ const (
 )
 
 <#include "enum_unmarshal_to_string.ftl" />
+
+func new${name}FromContent(content []byte, aggErr *AggregateError) *${name} {
+    if len(content) == 0 {
+        // no value
+        return nil
+    }
+    result := new(${name})
+    parseEnum(content, result, aggErr)
+    return result
+}

ds3-autogen-go/src/test/java/com/spectralogic/ds3autogen/go/models/parser/ParseChildNodeImpls_Test.java

@@ -109,8 +109,7 @@ public void ParseChildNodeAsEnumTest() {
 
     @Test
     public void ParseChildNodeAsNullableEnumTest() {
-        final String expected = String.format("%s.%s = new(%s)\n" +
-                "            parseNullableEnum(child.Content, %s.%s, aggErr)", MODEL_NAME, PARAM_NAME, PARAM_TYPE, MODEL_NAME, PARAM_NAME);
+        final String expected = String.format("%s.%s = new%sFromContent(child.Content, aggErr)", MODEL_NAME, PARAM_NAME, PARAM_TYPE);
 
         final ParseElement parseElement = new ParseChildNodeAsNullableEnum(XML_TAG, MODEL_NAME, PARAM_NAME, PARAM_TYPE);
         assertThat(parseElement.getXmlTag(), is(XML_TAG));