Access Violation (Read from location 00000000 caused an access violation)

Question

I have a editor script I call FastSceneCreator which converts scenes into a prefab.
Here is the script:

   public class FastSceneCreator : EditorWindow
     {
         [MenuItem("UNDERUNITY/Convert to Fast Scene %#.", false, 0)]
         public static void Convert()
         {
             // EditorUtility.DisplayDialog("Convert to Fast Scene", "Converting...", "Okay");
             CreateScenePrefab(new GameObject(SceneManager.GetActiveScene().name).transform);
         }
     
         public static void CreateScenePrefab(Transform p)
         {
             p.gameObject.AddComponent<FastScene>();
             GameObject[] gameobjects = GameObject.FindObjectsOfType<GameObject>();
             for (int i = 0; i < gameobjects.Length + 1; i++)
             {
                 if (i < gameobjects.Length)
                 {
                     if (gameobjects[i].transform.parent == null)
                     {
                         gameobjects[i].transform.SetParent(p);
                         continue;
                     }
                 }
                 else
                 {
                     if (AssetDatabase.LoadAssetAtPath<GameObject>(SceneManager.GetActiveScene().path.Replace(".unity", "") + ".prefab") != true)
                     {
                         PrefabUtility.CreatePrefab(SceneManager.GetActiveScene().path.Replace(".unity", "") + ".prefab", p.gameObject);
                     }
                     else
                     {
                         p.GetComponent<FastScene>().Additive = AssetDatabase.LoadAssetAtPath<GameObject>(SceneManager.GetActiveScene().path.Replace(".unity", "") + ".prefab").GetComponent<FastScene>().Additive;
                         PrefabUtility.ReplacePrefab(p.gameObject, AssetDatabase.LoadAssetAtPath<GameObject>(SceneManager.GetActiveScene().path.Replace(".unity", "") + ".prefab"), ReplacePrefabOptions.ReplaceNameBased);
                     }
                     RemoveChildrenAndDelete(p);
                     break;
                 }
             }
         }
     
         public static void RemoveChildrenAndDelete(Transform p)
         {
             EditorUtility.DisplayDialog("Convert to Fast Scene", "Finishing things up...", "...");
             p.DetachChildren();
             if (Resources.Load<FastSceneSettings>("fastsettings").NotifySceneConvert == true)
             {
                 EditorUtility.DisplayDialog("Convert to Fast Scene", "Scene successfuly converted.", "Okay");
             }
         }
     }

When I use the Convert to Fast Scene menu item, the editor hangs without going into "Not Responding", then it crashes.
If you need the error log, tell me!

Answer 1

Answer by christoph_r · Aug 20, 2017 at 10:40 PM

I'd say for (int i = 0; i < gameobjects.Length + 1; i++) in line 14 appears to be the issue.

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BlockFade · Aug 20, 2017 at 10:55 PM 0

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Oh! Thanks! You made me realize that the Array "gameobjects" was filled by the children of the parent object, and when I set the parent of the child to another one, the gameobject in the array was set to null, so the loop was still iterating over the null! That's just a theory though, I'll go test out the new code, and tell you if it worked!

christoph_r · Aug 21, 2017 at 12:37 AM 0

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If you iterate until i is equal to gameobjects.Length (which you are doing according to that line), you will read beyond the array, which causes an access violation.

adrienPlayerium christoph_r · Aug 21, 2017 at 12:59 AM 2

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@christoph_r if you read the for loop he does some weird stuff when reaching the length of the array, he doesn't iterate on gameobjects beyond its length.

bobisgod234 adrienPlayerium · Aug 21, 2017 at 01:15 AM 2

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On top of that, accessing an array with an out of bounds index should only throw a managed IndexOutOfRangeException, certainly not result in an access violation or unity crashing.

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Access Violation (Read from location 00000000 caused an access violation)

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