Fix conversion of non-object results declared in Tasks

Prior to this commit, conversion between v1beta1 and v1 Tasks
would create an empty map for task.spec.results.properties,
even if the Task result was not an object result.

Currently, if Task result properties are a nil map, the result is treated
as a string result. If Task result properties are an empty map, the result
is treated as an object result. This commit only updates the conversion logic
of Task results to match the conversion logic of task params; it creates
a non-nil Properties map only if Properties was already non-nil.

Addressing the differences in how nil vs empty Properties are treated
will be handled in a separate commit.

pkg/apis/pipeline/v1beta1/result_conversion.go

@@ -26,20 +26,24 @@ func (r TaskResult) convertTo(ctx context.Context, sink *v1.TaskResult) {
 	sink.Name = r.Name
 	sink.Type = v1.ResultsType(r.Type)
 	sink.Description = r.Description
-	properties := make(map[string]v1.PropertySpec)
-	for k, v := range r.Properties {
-		properties[k] = v1.PropertySpec{Type: v1.ParamType(v.Type)}
+	if r.Properties != nil {
+		properties := make(map[string]v1.PropertySpec)
+		for k, v := range r.Properties {
+			properties[k] = v1.PropertySpec{Type: v1.ParamType(v.Type)}
+		}
+		sink.Properties = properties
 	}
-	sink.Properties = properties
 }
 
 func (r *TaskResult) convertFrom(ctx context.Context, source v1.TaskResult) {
 	r.Name = source.Name
 	r.Type = ResultsType(source.Type)
 	r.Description = source.Description
-	properties := make(map[string]PropertySpec)
-	for k, v := range source.Properties {
-		properties[k] = PropertySpec{Type: ParamType(v.Type)}
+	if source.Properties != nil {
+		properties := make(map[string]PropertySpec)
+		for k, v := range source.Properties {
+			properties[k] = PropertySpec{Type: ParamType(v.Type)}
+		}
+		r.Properties = properties
 	}
-	r.Properties = properties
 }

pkg/apis/pipeline/v1beta1/task_conversion_test.go

@@ -66,6 +66,11 @@ func TestTaskConversion(t *testing.T) {
 					Type:        v1beta1.ParamTypeString,
 					Description: "My first param",
 				}},
+				Results: []v1beta1.TaskResult{{
+					Name:        "result-1",
+					Type:        v1beta1.ResultsTypeString,
+					Description: "a result",
+				}},
 			},
 		},
 	}, {