[GO] fix: stops adding imports for nested structs (#13833)

Author: NickUfer

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractGoCodegen.java

@@ -627,11 +627,39 @@ public ModelsMap postProcessModels(ModelsMap objs) {
                 iterator.remove();
         }
 
-        boolean addedTimeImport = false;
-        boolean addedOSImport = false;
         for (ModelMap m : objs.getModels()) {
+            boolean addedTimeImport = false;
+            boolean addedOSImport = false;
             CodegenModel model = m.getModel();
-            for (CodegenProperty cp : model.vars) {
+
+            List<CodegenProperty> inheritedProperties = new ArrayList<>();
+            if (model.getComposedSchemas() != null) {
+                if (model.getComposedSchemas().getAllOf() != null) {
+                    inheritedProperties.addAll(model.getComposedSchemas().getAllOf());
+                }
+                if (model.getComposedSchemas().getAnyOf() != null) {
+                    inheritedProperties.addAll(model.getComposedSchemas().getAnyOf());
+                }
+                if (model.getComposedSchemas().getOneOf() != null) {
+                    inheritedProperties.addAll(model.getComposedSchemas().getOneOf());
+                }
+            }
+
+            List<CodegenProperty> codegenProperties = new ArrayList<>();
+            if(model.getIsModel() || model.getComposedSchemas() == null) {
+                // If the model is a model, use model.vars as it only
+                // contains properties the generated struct will own itself.
+                // If model is no model and it has no composed schemas use
+                // model.vars.
+                codegenProperties.addAll(model.vars);
+            } else {
+                // If the model is no model, but is a
+                // allOf, anyOf or oneOf, add all first level options
+                // from allOf, anyOf or oneOf.
+                codegenProperties.addAll(inheritedProperties);
+            }
+
+            for (CodegenProperty cp : codegenProperties) {
                 if (!addedTimeImport && ("time.Time".equals(cp.dataType) ||
                         (cp.items != null && "time.Time".equals(cp.items.dataType)))) {
                     imports.add(createMapping("import", "time"));
@@ -651,7 +679,6 @@ public ModelsMap postProcessModels(ModelsMap objs) {
             // if oneOf contains "time.Time" type
             if (!addedTimeImport && model.oneOf != null && model.oneOf.contains("time.Time")) {
                 imports.add(createMapping("import", "time"));
-                addedTimeImport = true;
             }
 
             // if oneOf contains "null" type