Make upstream window and app references weak to avoid reference cycles

.github/workflows/ci.yml

@@ -207,10 +207,15 @@ jobs:
           - backend: linux
             runs-on: ubuntu-22.04
             # The package list should be the same as in tutorial-0.rst, and the BeeWare
-            # tutorial, plus flwm to provide a window manager
+            # tutorial, plus blackbox to provide a window manager. We need a window
+            # manager that is reasonably lightweight, honors full screen mode, and
+            # treats the window position as the top-left corner of the *window*, not the
+            # top-left corner of the window *content*. The default GNOME window managers of
+            # most distros meet these requirementt, but they're heavyweight; flwm doesn't
+            # work either. Blackbox is the lightest WM we've found that works.
             pre-command: |
               sudo apt update -y
-              sudo apt install -y flwm pkg-config python3-dev libgirepository1.0-dev libcairo2-dev gir1.2-webkit2-4.0
+              sudo apt install -y blackbox pkg-config python3-dev libgirepository1.0-dev libcairo2-dev gir1.2-webkit2-4.0
 
               # Start Virtual X server
               echo "Start X server..."
@@ -219,7 +224,7 @@ jobs:
 
               # Start Window manager
               echo "Start window manager..."
-              DISPLAY=:99 flwm &
+              DISPLAY=:99 blackbox &
               sleep 1
 
             briefcase-run-prefix: 'DISPLAY=:99'

1215.bugfix.rst

@@ -0,0 +1 @@
+A memory leak associated with creation and deletion of windows has been resolved.

android/src/toga_android/app.py

@@ -1,4 +1,5 @@
 import asyncio
+import weakref
 
 from rubicon.java import android_events
 
@@ -173,7 +174,6 @@ def native(self):
 class App:
     def __init__(self, interface):
         self.interface = interface
-        self.interface._impl = self
         self._listener = None
 
         self.loop = android_events.AndroidEventLoop()
@@ -182,6 +182,14 @@ def __init__(self, interface):
     def native(self):
         return self._listener.native if self._listener else None
 
+    @property
+    def interface(self):
+        return self._interface()
+
+    @interface.setter
+    def interface(self, value):
+        self._interface = weakref.ref(value)
+
     def create(self):
         # The `_listener` listens for activity event callbacks. For simplicity,
         # the app's `.native` is the listener's native Java class.

android/src/toga_android/window.py

@@ -1,3 +1,5 @@
+import weakref
+
 from decimal import ROUND_UP
 
 from .container import Container
@@ -23,9 +25,16 @@ class Window(Container):
     def __init__(self, interface, title, position, size):
         super().__init__()
         self.interface = interface
-        self.interface._impl = self
         # self.set_title(title)
 
+    @property
+    def interface(self):
+        return self._interface()
+
+    @interface.setter
+    def interface(self, value):
+        self._interface = weakref.ref(value)
+
     def set_app(self, app):
         self.app = app
         native_parent = app.native.findViewById(R__id.content)

changes/2058.feature.rst

@@ -0,0 +1 @@
+Window and MainWindow now have 100% test coverage, and complete API documentation.

changes/2058.removal.1.rst

@@ -0,0 +1 @@
+Windows no longer need to be explicitly added to the app's window list. When a window is shown, it will be automatically added to the windows for the currently running app.

changes/2058.removal.2.rst

@@ -0,0 +1 @@
+The ``multiselect`` argument to Open File and Select Folder dialogs has been renamed ``multiple_select``, for consistency with other widgets that have multiple selection capability.

changes/2058.removal.3.rst

@@ -0,0 +1 @@
+``Window.resizeable`` and ``Window.closeable`` have been renamed ``Window.resizable`` and ``Window.closable``, to adhere to US spelling conventions.

cocoa/src/toga_cocoa/app.py

@@ -2,6 +2,7 @@
 import inspect
 import os
 import sys
+import weakref
 from urllib.parse import unquote, urlparse
 
 from rubicon.objc.eventloop import CocoaLifecycle, EventLoopPolicy
@@ -112,13 +113,20 @@ class App:
 
     def __init__(self, interface):
         self.interface = interface
-        self.interface._impl = self
 
         self._cursor_visible = True
 
         asyncio.set_event_loop_policy(EventLoopPolicy())
         self.loop = asyncio.new_event_loop()
 
+    @property
+    def interface(self):
+        return self._interface()
+
+    @interface.setter
+    def interface(self, value):
+        self._interface = weakref.ref(value)
+
     def create(self):
         self.native = NSApplication.sharedApplication
         self.native.setActivationPolicy(NSApplicationActivationPolicyRegular)
@@ -135,12 +143,21 @@ def create(self):
         self.appDelegate.native = self.native
         self.native.setDelegate_(self.appDelegate)
 
-        formal_name = self.interface.formal_name
+        self._create_app_commands()
 
+        # Call user code to populate the main window
+        self.interface._startup()
+
+        # Create the lookup table of menu items,
+        # then force the creation of the menus.
+        self.create_menus()
+
+    def _create_app_commands(self):
+        formal_name = self.interface.formal_name
         self.interface.commands.add(
             # ---- App menu -----------------------------------
             toga.Command(
-                lambda _: self.interface.about(),
+                self._menu_about,
                 "About " + formal_name,
                 group=toga.Group.APP,
             ),
@@ -176,12 +193,35 @@ def create(self):
             ),
             # Quit should always be the last item, in a section on its own
             toga.Command(
-                lambda _: self.interface.exit(),
+                self._menu_exit,
                 "Quit " + formal_name,
                 shortcut=toga.Key.MOD_1 + "q",
                 group=toga.Group.APP,
                 section=sys.maxsize,
             ),
+            # ---- File menu ----------------------------------
+            # This is a bit of an oddity. Safari has 2 distinct "Close Window" and
+            # "Close All Windows" menu items (partially to differentiate from "Close
+            # Tab"). Most other Apple HIG apps have a "Close" item that becomes
+            # "Close All" when you press Option (MOD_2). That behavior isn't something
+            # we're currently set up to implement, so we live with a separate menu item
+            # for now.
+            toga.Command(
+                self._menu_close_window,
+                "Close Window",
+                shortcut=toga.Key.MOD_1 + "W",
+                group=toga.Group.FILE,
+                order=1,
+                section=50,
+            ),
+            toga.Command(
+                self._menu_close_all_windows,
+                "Close All Windows",
+                shortcut=toga.Key.MOD_2 + toga.Key.MOD_1 + "W",
+                group=toga.Group.FILE,
+                order=2,
+                section=50,
+            ),
             # ---- Edit menu ----------------------------------
             toga.Command(
                 NativeHandler(SEL("undo:")),
@@ -244,26 +284,39 @@ def create(self):
                 section=10,
                 order=60,
             ),
+            # ---- Window menu ----------------------------------
+            toga.Command(
+                self._menu_minimize,
+                "Minimize",
+                shortcut=toga.Key.MOD_1 + "m",
+                group=toga.Group.WINDOW,
+            ),
             # ---- Help menu ----------------------------------
             toga.Command(
-                lambda _: self.interface.visit_homepage(),
+                lambda _, **kwargs: self.interface.visit_homepage(),
                 "Visit homepage",
                 enabled=self.interface.home_page is not None,
                 group=toga.Group.HELP,
             ),
         )
-        self._create_app_commands()
 
-        # Call user code to populate the main window
-        self.interface._startup()
+    def _menu_about(self, app, **kwargs):
+        self.interface.about()
 
-        # Create the lookup table of menu items,
-        # then force the creation of the menus.
-        self.create_menus()
+    def _menu_exit(self, app, **kwargs):
+        self.interface.exit()
 
-    def _create_app_commands(self):
-        # No extra commands
-        pass
+    def _menu_close_window(self, app, **kwargs):
+        if self.interface.current_window:
+            self.interface.current_window._impl.native.performClose(None)
+
+    def _menu_close_all_windows(self, app, **kwargs):
+        for window in self.interface.windows:
+            window._impl.native.performClose(None)
+
+    def _menu_minimize(self, app, **kwargs):
+        if self.interface.current_window:
+            self.interface.current_window._impl.native.miniaturize(None)
 
     def create_menus(self):
         # Recreate the menu
@@ -427,6 +480,7 @@ def select_file(self, **kwargs):
 
 class DocumentApp(App):
     def _create_app_commands(self):
+        super()._create_app_commands()
         self.interface.commands.add(
             toga.Command(
                 lambda _: self.select_file(),

cocoa/src/toga_cocoa/container.py

@@ -1,3 +1,5 @@
+import weakref
+
 from rubicon.objc import objc_method
 
 from .libs import (
@@ -32,7 +34,7 @@ def __init__(
         min_width=100,
         min_height=100,
         layout_native=None,
-        on_refresh=None,
+        parent=None,
     ):
         """A container for layouts.
 
@@ -45,11 +47,11 @@ def __init__(
             itself; however, for widgets like ScrollContainer where the layout needs to
             be computed based on a different size to what will be rendered, the source
             of the size can be different.
-        :param on_refresh: The callback to be notified when this container's layout is
-            refreshed.
+        :param parent: The parent of this container; this is the object that will be
+            notified when this container's layout is refreshed.
         """
         self._content = None
-        self.on_refresh = on_refresh
+        self.parent = weakref.ref(parent)
 
         self.native = TogaView.alloc().init()
         self.layout_native = self.native if layout_native is None else layout_native
@@ -103,8 +105,7 @@ def content(self, widget):
             widget.container = self
 
     def refreshed(self):
-        if self.on_refresh:
-            self.on_refresh(self)
+        self.parent().content_refreshed(self)
 
     @property
     def width(self):