Save dock panel position on quit

* Restore the details dialog dock position if it was previously docked (i.e. not floating).
* Since the details_dialog instance was not deleted after closing by default, the previous instances were still saving their own geometry. We now delete them explicitely if we have to recreate a new instance to avoid the signal triggering the callback to save the geometry.
* Since restoreGeometry() and saveGeometry() are only called in our QDockWidget, it should be safe to modify the methods for the Preferences class (in qtlib).

qt/app.py

@@ -285,16 +285,18 @@ class DupeGuru(QObject):
         """Creates resultWindow and details_dialog depending on the selected ``app_mode``.
         """
         if self.details_dialog is not None:
+            # The object is not deleted entirely, avoid saving its geometry in the future
+            # self.willSavePrefs.disconnect(self.details_dialog.appWillSavePrefs)
+            # or simply delete it on close which is probably cleaner:
+            self.details_dialog.setAttribute(Qt.WA_DeleteOnClose)
             self.details_dialog.close()
-            self.details_dialog.setParent(None)
+            # self.details_dialog.setParent(None)  # seems unnecessary
         if self.resultWindow is not None:
             self.resultWindow.close()
             self.resultWindow.setParent(None)
         self.resultWindow = ResultWindow(self.directories_dialog, self)
         self.directories_dialog._updateActionsState()
         self.details_dialog = self._get_details_dialog_class()(self.resultWindow, self)
-        self.resultWindow.addDockWidget(
-            Qt.BottomDockWidgetArea, self.details_dialog)
 
     def show_results_window(self):
         self.showResultsWindow()

qt/details_dialog.py

@@ -24,18 +24,22 @@ class DetailsDialog(QDockWidget):
         # To avoid saving uninitialized geometry on appWillSavePrefs, we track whether our dialog
         # has been shown. If it has, we know that our geometry should be saved.
         self._shown_once = False
-        self.app.prefs.restoreGeometry("DetailsWindowRect", self)
+        self._wasDocked, area = self.app.prefs.restoreGeometry("DetailsWindowRect", self)
         self.tableModel = DetailsModel(self.model, app)
         # tableView is defined in subclasses
         self.tableView.setModel(self.tableModel)
         self.model.view = self
-
         self.app.willSavePrefs.connect(self.appWillSavePrefs)
+        # self.setAttribute(Qt.WA_DeleteOnClose)
+        parent.addDockWidget(
+            area if self._wasDocked else Qt.BottomDockWidgetArea, self)
 
     def _setupUi(self):  # Virtual
         pass
 
     def show(self):
+        if not self._shown_once and self._wasDocked:
+            self.setFloating(False)
         self._shown_once = True
         super().show()
         self.update_options()
@@ -63,7 +67,7 @@ class DetailsDialog(QDockWidget):
 
     # --- Events
     def appWillSavePrefs(self):
-        if self._shown_once and self.isFloating():
+        if self._shown_once:
             self.app.prefs.saveGeometry("DetailsWindowRect", self)
 
     # --- model --> view

qtlib/preferences.py

@@ -7,6 +7,7 @@
 # http://www.gnu.org/licenses/gpl-3.0.html
 
 from PyQt5.QtCore import Qt, QSettings, QRect, QObject, pyqtSignal
+from PyQt5.QtWidgets import QDockWidget
 
 from hscommon.trans import trget
 from hscommon.util import tryint
@@ -123,16 +124,22 @@ class Preferences(QObject):
         # We save geometry under a 5-sized int array: first item is a flag for whether the widget
         # is maximized and the other 4 are (x, y, w, h).
         m = 1 if widget.isMaximized() else 0
+        d = 1 if isinstance(widget, QDockWidget) and not widget.isFloating() else 0
+        area = widget.parent.dockWidgetArea(widget) if d else 0
         r = widget.geometry()
         rectAsList = [r.x(), r.y(), r.width(), r.height()]
-        self.set_value(name, [m] + rectAsList)
+        self.set_value(name, [m, d, area] + rectAsList)
 
     def restoreGeometry(self, name, widget):
         geometry = self.get_value(name)
-        if geometry and len(geometry) == 5:
-            m, x, y, w, h = geometry
+        if geometry and len(geometry) == 7:
+            m, d, area, x, y, w, h = geometry
             if m:
                 widget.setWindowState(Qt.WindowMaximized)
             else:
                 r = QRect(x, y, w, h)
                 widget.setGeometry(r)
+                if isinstance(widget, QDockWidget):
+                    # Inform of the previous dock state and the area used
+                    return bool(d), area
+        return False, 0