Disable hiding window while in MINIMIZED, FULLSCREEN or PRESENTATION state and ignore no-op visibility requests

changes/3109.removal.rst

@@ -0,0 +1 @@
+The `show()` and `hide()` APIs can no longer be used on a window while it is in a `MINIMIZED`, `FULLSCREEN` or `PRESENTATION` state.

core/src/toga/window.py

@@ -312,7 +312,8 @@ def closed(self) -> bool:
     def show(self) -> None:
         """Show the window. If the window is already visible, this method has no
         effect."""
-        self._impl.show()
+        if not self.visible:
+            self._impl.show()
 
     ######################################################################
     # Window content and resources
@@ -436,8 +437,20 @@ def screen_position(self, position: PositionT) -> None:
 
     def hide(self) -> None:
         """Hide the window. If the window is already hidden, this method has no
-        effect."""
-        self._impl.hide()
+        effect.
+
+        :raises ValueError: If the window is currently in a minimized, full screen or
+            presentation state.
+        """
+        if self.state in {
+            WindowState.MINIMIZED,
+            WindowState.FULLSCREEN,
+            WindowState.PRESENTATION,
+        }:
+            raise ValueError(f"A window in {self.state} state cannot be hidden.")
+        else:
+            if self.visible:
+                self._impl.hide()
 
     @property
     def visible(self) -> bool:

core/tests/window/test_window.py

@@ -264,6 +264,7 @@ def test_show_hide(window, app):
 
 def test_hide_show(window, app):
     """The window can be hidden then shown."""
+    window.show()
     assert window.app == app
     window.hide()
 
@@ -304,6 +305,69 @@ def test_visibility(window, app):
     assert not window.visible
 
 
+def test_visibility_no_op(window, app):
+    """Changing visibility when already in that visibility state is a no-op."""
+    # Show the window
+    window.show()
+    assert window.visible
+    assert_action_performed(window, "show")
+    EventLog.reset()
+
+    window.show()
+    assert window.visible
+    assert_action_not_performed(window, "show")
+
+    window.visible = True
+    assert window.visible
+    assert_action_not_performed(window, "show")
+
+    # Hide the window
+    window.hide()
+    assert not window.visible
+    assert_action_performed(window, "hide")
+    EventLog.reset()
+
+    window.hide()
+    assert not window.visible
+    assert_action_not_performed(window, "hide")
+
+    window.visible = False
+    assert not window.visible
+    assert_action_not_performed(window, "hide")
+
+
+@pytest.mark.parametrize(
+    "state",
+    [
+        WindowState.MINIMIZED,
+        WindowState.FULLSCREEN,
+        WindowState.PRESENTATION,
+    ],
+)
+def test_hide_disallowed_on_window_state(window, app, state):
+    """A window in MINIMIZED, FULLSCREEN or PRESENTATION state cannot be
+    set to hidden."""
+    window.show()
+
+    window.state = state
+    assert window.state == state
+    assert window.visible is True
+
+    with pytest.raises(
+        ValueError,
+        match=f"A window in {state} state cannot be hidden.",
+    ):
+        window.hide()
+        assert_action_not_performed(window, "hide")
+
+    with pytest.raises(
+        ValueError,
+        match=f"A window in {state} state cannot be hidden.",
+    ):
+        window.visible = False
+        assert_action_not_performed(window, "hide")
+
+
 @pytest.mark.parametrize(
     "initial_state, final_state",
     [

dummy/src/toga_dummy/window.py

@@ -58,6 +58,7 @@ def __init__(self, interface, title, position, size):
         self.set_size(size)
 
         self._state = WindowState.NORMAL
+        self._visible = False
 
     ######################################################################
     # Window properties
@@ -82,7 +83,7 @@ def set_app(self, app):
 
     def show(self):
         self._action("show")
-        self._set_value("visible", True)
+        self._visible = True
 
     ######################################################################
     # Window content and resources
@@ -122,11 +123,14 @@ def set_position(self, position):
     ######################################################################
 
     def get_visible(self):
-        return self._get_value("visible", False)
+        # We cannot store the visibility value on the EventLog, since the value
+        # would be cleared on EventLog.reset(), thereby preventing us from
+        # testing no-op condition of requesting the same visibility as current.
+        return self._visible
 
     def hide(self):
         self._action("hide")
-        self._set_value("visible", False)
+        self._visible = False
 
     ######################################################################
     # Window state

testbed/tests/window/test_window.py

@@ -917,10 +917,9 @@ async def test_window_state_content_size_increase(
         "state",
         [
             WindowState.NORMAL,
-            WindowState.MINIMIZED,
             WindowState.MAXIMIZED,
-            WindowState.FULLSCREEN,
-            WindowState.PRESENTATION,
+            # Window cannot be hidden while in MINIMIZED, FULLSCREEN or
+            # PRESENTATION. So, those states are excluded from this test.
         ],
     )
     @pytest.mark.parametrize(