OCM-7117 | add capability of list resource with a scalar items

Issue: The LoadBalncerQuotaValues returns a list of scalar items. Because of
this the metamodel started generating not valid sdk.

Sample of the model:
```
resource LoadBalancerQuotaValues {
	method List {
            in out Page Integer = 1
            in out Size Integer = 100
            out Total Integer
            out Items []Integer
	}
}
```

When generating the go sdk from teh model we get a error:
```
output/clustersmgmt/v1/load_balancer_quota_values_client.go:162:12: expected type, found '.'
output/clustersmgmt/v1/load_balancer_quota_values_client.go:191:59: expected type, found '.'
output/clustersmgmt/v1/load_balancer_quota_values_client.go:194:6: expected declaration, found '}'
E: Can't format generated sources: exit status 2
```

This is caused by the metamodel not handeling the list scalar items
properly. Because the metamodel generates the reposnse struct and some
other struct in following format:
```
type  LoadBalancerQuotaValuesListResponse struct {
	status int
	header http.Header
	err    *errors.Error
	items  *.IntegerList
	page   *int
	size   *int
	total  *int
}
```

I have added a fix so it would generate the sdk structs with the list
scalars.
```
// LoadBalancerQuotaValuesListResponse is the response for the 'list' method.
type LoadBalancerQuotaValuesListResponse struct {
	status int
	header http.Header
	err    *errors.Error
	items  []int
	page   *int
	size   *int
	total  *int
}
```

Signed-off-by: Martin Necas <[email protected]>

pkg/concepts/type.go

@@ -158,6 +158,9 @@ func (t *Type) IsMap() bool {
 // IsScalar returns true iff this type is an scalar type. Note that interface types are also considered
 // scalar types due to their opaque nature in the SDK.
 func (t *Type) IsScalar() bool {
+	if t == nil {
+		return false
+	}
 	return t.kind == ScalarType || t.kind == EnumType || t.kind == InterfaceType
 }
 

pkg/generators/golang/clients_generator.go

@@ -935,7 +935,11 @@ func (g *ClientsGenerator) generateResponseSource(method *concepts.Method) {
 			header http.Header
 			err    *errors.Error
 			{{ range $responseParameters }}
-				{{ fieldName . }} {{ fieldType . }}
+				{{ if and .Type.IsList .Type.Element.IsScalar }}
+					{{ fieldName . }} []{{ valueType .Type.Element }}
+				{{ else }}
+					{{ fieldName . }} {{ fieldType . }}
+				{{ end }}
 			{{ end }}
 		}
 
@@ -1086,6 +1090,8 @@ func (g *ClientsGenerator) accessorType(parameter *concepts.Parameter) *TypeRefe
 	var ref *TypeReference
 	typ := parameter.Type()
 	switch {
+	case typ.IsList() && typ.Element().IsScalar():
+		ref = g.types.NullableReference(typ)
 	case parameter.IsItems():
 		ref = g.types.ListReference(typ)
 	case typ.IsScalar():

pkg/generators/golang/json_generator.go

@@ -979,10 +979,14 @@ func (g *JSONSupportGenerator) generateListMethodSource(method *concepts.Method)
 					{{ end }}
 				{{ end }}
 				case "items":
-					{{ generateReadValue "items" .Items.Type false }}
+				{{ generateReadValue "items" .Items.Type false }}
+				{{ if and .Items.Type.IsList .Items.Type.Element.IsScalar }}
+					response.items = items
+				{{ else }}
 					response.items = &{{ structName .Items.Type }}{
 						items: items,
 					}
+				{{ end }}
 				default:
 					iterator.ReadAny()
 				}
@@ -1107,9 +1111,13 @@ func (g *JSONSupportGenerator) generateSearchMethodSource(method *concepts.Metho
 				{{ end }}
 				case "items":
 					{{ generateReadValue "items" .Items.Type false }}
-					response.items = &{{ structName .Items.Type }}{
-						items: items,
-					}
+					{{ if and .Items.Type.IsList .Items.Type.Element.IsScalar }}
+						response.items = items
+					{{ else }}
+						response.items = &{{ structName .Items.Type }}{
+							items: items,
+						}
+					{{ end }}
 				default:
 					iterator.ReadAny()
 				}

tests/go/clients_test.go

@@ -613,4 +613,28 @@ var _ = Describe("Client", func() {
 		Expect(ok).To(BeTrue())
 		Expect(value).To(BeTrue())
 	})
+
+	It("Can get a resource list with scalar items", func() {
+		server.AppendHandlers(RespondWith(http.StatusOK, `{
+		  "kind": "LoadBalancerQuotaValueList",
+		  "size": 5,
+		  "page": 1,
+		  "total": 5,
+		  "items": [
+			 1,
+			 2,
+			 3,
+			 4,
+			 5
+		  ]
+		}
+		`))
+		client := cmv1.NewClient(transport, "/api/clusters_mgmt/v1")
+		response, err := client.LoadBalancerQuotaValues().List().Send()
+		Expect(err).ToNot(HaveOccurred())
+		Expect(response).ToNot(BeNil())
+		items := response.Items()
+		Expect(items).ToNot(BeNil())
+		Expect(items[0]).To(Equal(1))
+	})
 })

tests/model/clusters_mgmt/v1/load_balancer_quota_values_resource.model

@@ -0,0 +1,33 @@
+/*
+Copyright (c) 2024 Red Hat, Inc.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+  http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+// Manages load balancer quota values.
+resource LoadBalancerQuotaValues {
+    // Retrieves the list of Load Balancer Quota Values.
+    method List {
+        // Index of the requested page, where one corresponds to the first page.
+        in out Page Integer = 1
+
+        // Number of items contained in the returned page.
+        in out Size Integer = 100
+
+        // Total number of items of the collection.
+        out Total Integer
+
+        // Retrieved list of values.
+        out Items []Integer
+    }
+}

tests/model/clusters_mgmt/v1/root_resource.model

@@ -37,4 +37,9 @@ resource Root {
 	locator Nil {
 		target Nil
 	}
+
+	// Reference to the resource that manages the load balancer quota values.
+	locator LoadBalancerQuotaValues{
+		target LoadBalancerQuotaValues
+	}
 }