Issue #2725: added condition to import json based on return type

modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/GoClientCodegen.java

@@ -375,6 +375,15 @@ public class GoClientCodegen extends DefaultCodegen implements CodegenConfig {
             if (_import.startsWith(apiPackage()))
                 iterator.remove();
         }
+        // if the return type is not primitive, import encoding/json
+        for (CodegenOperation operation : operations) {
+            if(operation.returnBaseType != null && needToImport(operation.returnBaseType)) {
+                Map<String, String> newImportMap2 = new HashMap<String, String>();
+                newImportMap2.put("import", "encoding/json");
+                imports.add(newImportMap2);
+                break; //just need to import once
+            }
+        }
 
         // recursivly add import for mapping one type to multipe imports
         List<Map<String, String>> recursiveImports = (List<Map<String, String>>) objs.get("imports");

modules/swagger-codegen/src/main/resources/go/api.mustache

@@ -4,7 +4,6 @@ package {{packageName}}
 import (
     "strings"
     "fmt"
-    "encoding/json"
     "errors"
 {{#imports}}    "{{import}}"
 {{/imports}}