Don't destroy the script wrapper on reload

Instead, the script wrapper now handles the AboutToReload and Reloaded
signals, in order to detach relevant script objects and to update its
object reference.

src/tiled/editablemap.cpp

@@ -698,6 +698,16 @@ void EditableMap::setDocument(Document *document)
 void EditableMap::documentChanged(const ChangeEvent &change)
 {
     switch (change.type) {
+    case ChangeEvent::DocumentAboutToReload:
+        for (Layer *layer : map()->layers())
+            detachLayer(layer);
+
+        mRenderer.reset();
+        setObject(nullptr);
+        break;
+    case ChangeEvent::DocumentReloaded:
+        setObject(mapDocument()->map());
+        break;
     case ChangeEvent::MapChanged:
         if (static_cast<const MapChangeEvent&>(change).property == Map::OrientationProperty)
             mRenderer.reset();

src/tiled/editabletileset.cpp

@@ -22,6 +22,7 @@
 
 #include "addremovetiles.h"
 #include "addremovewangset.h"
+#include "changeevents.h"
 #include "editabletile.h"
 #include "editablewangset.h"
 #include "scriptimage.h"
@@ -402,6 +403,7 @@ void EditableTileset::setDocument(Document *document)
 
     if (auto doc = tilesetDocument()) {
         connect(doc, &Document::fileNameChanged, this, &EditableAsset::fileNameChanged);
+        connect(doc, &Document::changed, this, &EditableTileset::documentChanged);
         connect(doc, &TilesetDocument::tilesAdded, this, &EditableTileset::attachTiles);
         connect(doc, &TilesetDocument::tilesRemoved, this, &EditableTileset::detachTiles);
         connect(doc, &TilesetDocument::tileObjectGroupChanged, this, &EditableTileset::tileObjectGroupChanged);
@@ -429,6 +431,23 @@ bool EditableTileset::tilesFromEditables(const QList<QObject *> &editableTiles,
     return true;
 }
 
+void EditableTileset::documentChanged(const ChangeEvent &event)
+{
+    switch (event.type) {
+    case ChangeEvent::DocumentAboutToReload:
+        detachTiles(tileset()->tiles());
+        detachWangSets(tileset()->wangSets());
+
+        setObject(nullptr);
+        break;
+    case ChangeEvent::DocumentReloaded:
+        setObject(tilesetDocument()->tileset().data());
+        break;
+    default:
+        break;
+    }
+}
+
 void EditableTileset::attachTiles(const QList<Tile *> &tiles)
 {
     for (Tile *tile : tiles) {

src/tiled/editabletileset.h

@@ -25,6 +25,7 @@
 
 namespace Tiled {
 
+class ChangeEvent;
 class EditableTile;
 class EditableWangSet;
 class ScriptImage;
@@ -179,6 +180,7 @@ public slots:
 private:
     bool tilesFromEditables(const QList<QObject*> &editableTiles, QList<Tile *> &tiles);
 
+    void documentChanged(const ChangeEvent &event);
     void attachTiles(const QList<Tile*> &tiles);
     void detachTiles(const QList<Tile*> &tiles);
     void detachWangSets(const QList<WangSet*> &wangSets);

src/tiled/mapdocument.cpp

@@ -1607,7 +1607,6 @@ void MapDocument::swapMap(std::unique_ptr<Map> &other)
     setHoveredMapObject(nullptr);
     setCurrentLayer(nullptr);
     setCurrentObject(nullptr);
-    mEditable.reset();
 
     emit changed(AboutToReloadEvent());
 

src/tiled/tilesetdocument.cpp

@@ -258,7 +258,6 @@ void TilesetDocument::swapTileset(SharedTileset &tileset)
     // Bring pointers to safety
     setSelectedTiles(QList<Tile*>());
     setCurrentObject(mTileset.data());
-    mEditable.reset();
     mWangColorModels.clear();
 
     emit changed(AboutToReloadEvent());