improved handling of Reimport All and some other weird asset import cases

spine-unity/Assets/spine-unity/Editor/AssetDatabaseAvailabilityDetector.cs

@@ -0,0 +1,21 @@
+using UnityEngine;
+
+namespace Spine {
+	public static class AssetDatabaseAvailabilityDetector {
+		const string MARKER_RESOURCE_NAME = "SpineAssetDatabaseMarker";
+		private static bool _isMarkerLoaded;
+
+		public static bool IsAssetDatabaseAvailable (bool forceCheck = false) {
+			if (!forceCheck && _isMarkerLoaded)
+				return true;
+
+			TextAsset markerTextAsset = Resources.Load<TextAsset>(MARKER_RESOURCE_NAME);
+			_isMarkerLoaded = markerTextAsset != null;
+			if (markerTextAsset != null) {
+				Resources.UnloadAsset(markerTextAsset);
+			}
+
+			return _isMarkerLoaded;
+		}
+	}
+}

spine-unity/Assets/spine-unity/Editor/AssetDatabaseAvailabilityDetector.cs.meta

@@ -0,0 +1,12 @@
+fileFormatVersion: 2
+guid: 25086cd81e3158b439761b73d7366c47
+timeCreated: 1444587791
+licenseType: Pro
+MonoImporter:
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 

spine-unity/Assets/spine-unity/Editor/Resources.meta

@@ -0,0 +1,9 @@
+fileFormatVersion: 2
+guid: 24903fdac57ee784b9597fcb751ec22f
+folderAsset: yes
+timeCreated: 1444565388
+licenseType: Pro
+DefaultImporter:
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 

spine-unity/Assets/spine-unity/Editor/Resources/SpriteSharpPersistentMarker.txt

@@ -0,0 +1 @@
+DO NOT MOVE OR DELETE THIS FILE

spine-unity/Assets/spine-unity/Editor/Resources/SpriteSharpPersistentMarker.txt.meta

@@ -0,0 +1,8 @@
+fileFormatVersion: 2
+guid: 57281c00bdd90ad4392f811f2b9f0da1
+timeCreated: 1444565392
+licenseType: Pro
+TextScriptImporter:
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 

spine-unity/Assets/spine-unity/Editor/SpineEditorUtilities.cs

@@ -149,6 +149,7 @@ public class SpineEditorUtilities : AssetPostprocessor {
 
 	public static string editorPath = "";
 	public static string editorGUIPath = "";
+	static HashSet<string> assetsImportedInWrongState;
 	static Dictionary<int, GameObject> skeletonRendererTable;
 	static Dictionary<int, SkeletonUtilityBone> skeletonUtilityBoneTable;
 	static Dictionary<int, BoundingBoxFollower> boundingBoxFollowerTable;
@@ -173,6 +174,7 @@ public class SpineEditorUtilities : AssetPostprocessor {
 
 		Icons.Initialize();
 
+		assetsImportedInWrongState = new HashSet<string>();
 		skeletonRendererTable = new Dictionary<int, GameObject>();
 		skeletonUtilityBoneTable = new Dictionary<int, SkeletonUtilityBone>();
 		boundingBoxFollowerTable = new Dictionary<int, BoundingBoxFollower>();
@@ -254,8 +256,34 @@ public class SpineEditorUtilities : AssetPostprocessor {
 	}
 
 	static void OnPostprocessAllAssets (string[] imported, string[] deleted, string[] moved, string[] movedFromAssetPaths) {
-		ImportSpineContent(imported, false);
+		if (imported.Length == 0)
+			return;
+
+		// In case user used "Assets -> Reimport All", during the import process,
+		// asset database is not initialized until some point. During that period,
+		// all attempts to load any assets using API (i.e. AssetDatabase.LoadAssetAtPath)
+		// will return null, and as result, assets won't be loaded even if they actually exists,
+		// which may lead to numerous importing errors.
+		// This situation also happens if Library folder is deleted from the project, which is a pretty
+		// common case, since when using version control systems, the Library folder must be excluded.
+		// 
+		// So to avoid this, in case asset database is not available, we delay loading the assets
+		// until next time.
+		//
+		// Unity *always* reimports some internal assets after the process is done, so this method
+		// is always called once again in a state when asset database is available.
+		//
+		// Checking whether AssetDatabase is initialized is done by attempting to load
+		// a known "marker" asset that should always be available. Failing to load this asset
+		// means that AssetDatabase is not initialized.
+		assetsImportedInWrongState.UnionWith(imported);
+		if (AssetDatabaseAvailabilityDetector.IsAssetDatabaseAvailable()) {
+			string[] combinedAssets = assetsImportedInWrongState.ToArray();
+			assetsImportedInWrongState.Clear();
+			ImportSpineContent(combinedAssets);
+		}
 	}
+
 	public static void ImportSpineContent (string[] imported, bool reimport = false) {
 		List<string> atlasPaths = new List<string>();
 		List<string> imagePaths = new List<string>();
@@ -408,14 +436,34 @@ public class SpineEditorUtilities : AssetPostprocessor {
 					skeletonDataAsset.Reset();
 
 					string guid = AssetDatabase.AssetPathToGUID(AssetDatabase.GetAssetPath(skeletonDataAsset));
-					string lastHash = EditorPrefs.GetString(guid + "_hash");
+					string lastHash = EditorPrefs.GetString(guid + "_hash");
-
+					
-					if (lastHash != skeletonDataAsset.GetSkeletonData(true).Hash) {
+					// For some weird reason sometimes Unity loses the internal Object pointer,
+					// and as a result, all comparisons with null returns true.
+					// But the C# wrapper is still alive, so we can "restore" the object
+					// by reloading it from its Instance ID.
+					AtlasAsset[] skeletonDataAtlasAssets = skeletonDataAsset.atlasAssets;
+					if (skeletonDataAtlasAssets != null) {
+						for (int i = 0; i < skeletonDataAtlasAssets.Length; i++) {
+							if (!ReferenceEquals(null, skeletonDataAtlasAssets[i]) &&
+								skeletonDataAtlasAssets[i].Equals(null) &&
+								skeletonDataAtlasAssets[i].GetInstanceID() != 0
+								) {
+								skeletonDataAtlasAssets[i] = EditorUtility.InstanceIDToObject(skeletonDataAtlasAssets[i].GetInstanceID()) as AtlasAsset;
+							}
+						}
+					}
+
+					SkeletonData skeletonData = skeletonDataAsset.GetSkeletonData(true);
+					string currentHash = skeletonData != null ? skeletonData.Hash : null;
+					if (currentHash == null || lastHash != currentHash) {
 						//do any upkeep on synchronized assets
 						UpdateMecanimClips(skeletonDataAsset);
 					}
 
-					EditorPrefs.SetString(guid + "_hash", skeletonDataAsset.GetSkeletonData(true).Hash);
+					if (currentHash != null) {
+						EditorPrefs.SetString(guid + "_hash", currentHash);
+					}
 				}
 			}
 		}