Fixing error with non-public serialized fields on randomizers (#211)

* Fixing bug in UIElementsEditorUtilities and adding tests

* Adding error message when missing scripts are detected

* Update com.unity.perception/CHANGELOG.md

Co-authored-by: Mohsen K <mohsen.kamalzadeh@unity3d.com>

Co-authored-by: Mohsen K <mohsen.kamalzadeh@unity3d.com>

com.unity.perception/CHANGELOG.md

 
 ### Added
 
+Added error message when missing Randomizer scripts are detected
+
 Scenario serialization has been updated to include scalar values on randomizers and parameters.
 
 Added new ScenarioBase virtual lifecycle hooks: OnAwake, OnStart, OnComplete, and OnIdle.
 Fixed a null reference error that appeared when adding options to categorical parameters.
 
 Fixed ground truth not properly produced when there are other disabled PerceptionCameras present. Note: this does not yet add support for multiple enabled PerceptionCameras.
+
+Fixed exception when rendering inspector for randomizers with private serialized fields
 
 Fixed an issue preventing a user from adding more options to a Categorical Parameter's list of options with the 'Add Folder' button. 'Add Folder' now correctly appends the contents of the new folder on the list.
 

com.unity.perception/Editor/Randomization/Uss/Styles.uss

     margin: 3px 3px 3px 3px;
 }
 
+.scenario__error-box {
+    color: #FF4040;
+}
+
 .scenario__dark-viewport {
     border-radius: 5px;
     background-color: #191919;

com.unity.perception/Editor/Randomization/Utilities/UIElementsEditorUtilities.cs

 using System;
 using System.Linq;
+using System.Reflection;
 using UnityEditor.UIElements;
 using UnityEngine;
 using UnityEngine.Perception.Randomization.Randomizers.SampleRandomizers;
     /// <summary>
     /// This class contains a set of helper functions for simplifying the creation of UI Elements editors
     /// </summary>
-    public static class UIElementsEditorUtilities
+    static class UIElementsEditorUtilities
     {
         /// <summary>
         /// Creates a list of PropertyFields from the class fields of the given SerializedObject
         {
             var propertyField = new PropertyField(iterator.Copy());
             propertyField.Bind(iterator.serializedObject);
-            var originalField = parentPropertyType.GetField(iterator.name);
+            var originalField = parentPropertyType.GetField(iterator.name, BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance );
             var tooltipAttribute = originalField.GetCustomAttributes(true)
                 .ToList().Find(att => att.GetType() == typeof(TooltipAttribute));
             if (tooltipAttribute != null)

com.unity.perception/Editor/Randomization/VisualElements/Randomizer/RandomizerElement.cs

         {
             m_Property = property;
             this.randomizerList = randomizerList;
+
             m_Collapsed = property.FindPropertyRelative("collapsed");
             collapsed = m_Collapsed.boolValue;
 
 
         public bool collapsed
         {
-            get => m_Collapsed.boolValue;
+            get => m_Collapsed?.boolValue ?? true;
+                if (m_Collapsed == null)
+                    return;
+
                 m_Collapsed.boolValue = value;
                 m_Property.serializedObject.ApplyModifiedPropertiesWithoutUndo();
                 if (value)

com.unity.perception/Editor/Randomization/VisualElements/Randomizer/RandomizerList.cs

         void RefreshList()
         {
             m_Container.Clear();
+            if (m_Property.arraySize > 0 &&
+                string.IsNullOrEmpty(m_Property.GetArrayElementAtIndex(0).managedReferenceFullTypename))
+            {
+                var textElement = new TextElement()
+                {
+                    text = "One or more randomizers have missing scripts. See console for more info."
+                };
+                textElement.AddToClassList("scenario__info-box");
+                textElement.AddToClassList("scenario__error-box");
+                m_Container.Add(textElement);
+                return;
+            }
+
             for (var i = 0; i < m_Property.arraySize; i++)
                 m_Container.Add(new RandomizerElement(m_Property.GetArrayElementAtIndex(i), this));
         }

com.unity.perception/Tests/Editor/UIElementsEditorUtilitiesTests.cs

+using System;
+using NUnit.Framework;
+using UnityEditor;
+using UnityEngine;
+using Object = UnityEngine.Object;
+
+public class UIElementsEditorUtilitiesTests
+{
+    //ScriptableObject so we can use ScriptableObject.CreateInstance()
+    [Serializable]
+    class TestType : ScriptableObject
+    {
+        public string publicField;
+        [Tooltip("A tooltip")]
+        public string publicFieldWithTooltip;
+        [Tooltip("A tooltip")]
+        [SerializeField]
+        private string privateField;
+        [Tooltip("A tooltip")]
+        [SerializeField]
+        protected string protectedField;
+        [Tooltip("A tooltip")]
+        [SerializeField]
+        protected internal string protectedInternalField;
+        [Tooltip("A tooltip")]
+        [SerializeField]
+        internal string internalField;
+    }
+    [Test]
+    [TestCase(typeof(TestType), nameof(TestType.publicField))]
+    [TestCase(typeof(TestType), nameof(TestType.publicFieldWithTooltip), "A tooltip")]
+    [TestCase(typeof(TestType), "privateField", "A tooltip")]
+    [TestCase(typeof(TestType), "protectedField", "A tooltip")]
+    [TestCase(typeof(TestType), "protectedInternalField", "A tooltip")]
+    [TestCase(typeof(TestType), "internalField", "A tooltip")]
+    public void CreatePropertyField_ReturnsCorrectPropertyField_ForTypeAndField(Type type, string field,
+        string tooltipExpected = "")
+    {
+        var testType = ScriptableObject.CreateInstance<TestType>();
+        var serializedObject = new SerializedObject(testType);
+        var serializedProperty = serializedObject.FindProperty(field);
+        Assert.IsNotNull(serializedProperty);
+        var propertyField = UnityEditor.Perception.Randomization.UIElementsEditorUtilities.CreatePropertyField(serializedProperty, type);
+        Assert.IsNotNull(propertyField);
+        Assert.AreEqual(tooltipExpected, propertyField.tooltip);
+    }
+}

com.unity.perception/Tests/Editor/UIElementsEditorUtilitiesTests.cs.meta

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