Delay loading of tile stamps until after initializing the session

The tilesets referenced by stored tile stamps may rely on custom
types defined in the project and possibly even on custom tileset formats
added by extensions. Hence, it is better to wait with loading them until
after the project has been loaded and script manager is initialized.

The user will still run into issues when the project isn't loaded on
startup, but this at least makes running into issues less likely. It could
help to force reloading of the stamps when switching projects.

src/tiled/mainwindow.cpp

@@ -68,6 +68,7 @@
 #include "tilesetdocument.h"
 #include "tileseteditor.h"
 #include "tilesetmanager.h"
+#include "tilestampmanager.h"
 #include "tmxmapformat.h"
 #include "utils.h"
 #include "world.h"
@@ -1017,6 +1018,11 @@ void MainWindow::initializeSession()
     // adding the project's extension path.
     ScriptManager::instance().ensureInitialized();
 
+    // Load tile stamps (delayed so that potential custom types and file
+    // formats can be supported by stamps - which isn't perfect since there
+    // will still be issues when the project isn't open on startup)
+    TileStampManager::instance()->loadStamps();
+
     if (projectLoaded || Preferences::instance()->restoreSessionOnStartup())
         restoreSession();
 }

src/tiled/projectmanager.cpp

@@ -37,6 +37,11 @@ ProjectManager::ProjectManager(QObject *parent)
     ourInstance = this;
 }
 
+ProjectManager::~ProjectManager()
+{
+    ourInstance = nullptr;
+}
+
 /**
  * Replaces the current project with the given \a project.
  */

src/tiled/projectmanager.h

@@ -40,6 +40,7 @@ class TILED_EDITOR_EXPORT ProjectManager : public QObject
 
 public:
     explicit ProjectManager(QObject *parent = nullptr);
+    ~ProjectManager() override;
 
     static ProjectManager *instance();
 

src/tiled/tilestampmanager.cpp

@@ -29,10 +29,6 @@
 #include "preferences.h"
 #include "savefile.h"
 #include "stampbrush.h"
-#include "tilelayer.h"
-#include "tileselectiontool.h"
-#include "tileset.h"
-#include "tilesetmanager.h"
 #include "tilestampmodel.h"
 #include "toolmanager.h"
 #include "utils.h"
@@ -46,6 +42,8 @@
 
 using namespace Tiled;
 
+TileStampManager *TileStampManager::ourInstance;
+
 TileStampManager::TileStampManager(const ToolManager &toolManager,
                                    QObject *parent)
     : QObject(parent)
@@ -54,6 +52,9 @@ TileStampManager::TileStampManager(const ToolManager &toolManager,
     , mTileStampModel(new TileStampModel(this))
     , mToolManager(toolManager)
 {
+    Q_ASSERT(!ourInstance);
+    ourInstance = this;
+
     mRegisteredCb = stampsDirectory.onChange([this] { stampsDirectoryChanged(); });
 
     connect(mTileStampModel, &TileStampModel::stampAdded,
@@ -64,15 +65,15 @@ TileStampManager::TileStampManager(const ToolManager &toolManager,
             this, &TileStampManager::saveStamp);
     connect(mTileStampModel, &TileStampModel::stampRemoved,
             this, &TileStampManager::deleteStamp);
-
-    loadStamps();
 }
 
 TileStampManager::~TileStampManager()
 {
     // needs to be over here where the TileStamp type is complete
 
     stampsDirectory.unregister(mRegisteredCb);
+
+    ourInstance = nullptr;
 }
 
 static TileStamp stampFromContext(AbstractTool *selectedTool)

src/tiled/tilestampmanager.h

@@ -51,12 +51,16 @@ class TileStampManager : public QObject
     TileStampManager(const ToolManager &toolManager, QObject *parent = nullptr);
     ~TileStampManager() override;
 
+    static TileStampManager *instance();
+
     static QList<Qt::Key> quickStampKeys();
 
     TileStampModel *tileStampModel() const;
 
     SessionOption<QString> stampsDirectory;
 
+    void loadStamps();
+
 public slots:
     TileStamp createStamp();
     void addVariation(const TileStamp &targetStamp);
@@ -76,8 +80,6 @@ public slots:
     void eraseQuickStamp(int index);
     void setQuickStamp(int index, TileStamp stamp);
 
-    void loadStamps();
-
 private:
     void stampAdded(TileStamp stamp);
     void stampRenamed(TileStamp stamp);
@@ -93,9 +95,16 @@ public slots:
     Session::CallbackIterator mRegisteredCb;
 
     const ToolManager &mToolManager;
+
+    static TileStampManager *ourInstance;
 };
 
 
+inline TileStampManager *TileStampManager::instance()
+{
+    return ourInstance;
+}
+
 /**
  * Returns the keys used for quickly accessible tile stamps.
  * Note: To store a tile layer <Ctrl> is added. The given keys will work