In the GTK3 days, HdyPreferencesRow (and GtkListBoxRow) did not
automatically unparent children.
In GTK4, AdwPreferencesRow (and GtkListBoxRow) do, so stop manually
unparenting child widgets.
This is just unfortunate. It’s an aliasing violation to cast a pointer
to a pointer (and there’s no way round that), although in practice it
will not cause a problem. People do quite often compile with
`-Werror=strict-aliasing`, though, so fixing the warnings is helpful.
Warnings are of the form:
```
../../source/gnome-control-center/panels/keyboard/cc-keyboard-shortcut-dialog.c: In function ‘cc_keyboard_shortcut_dialog_finalize’:
../../source/gnome-control-center/panels/keyboard/cc-keyboard-shortcut-dialog.c:518:20: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing]
518 | g_clear_pointer ((GtkWindow**)&self->shortcut_editor, gtk_window_destroy);
/opt/gnome/install/include/glib-2.0/glib/gmacros.h:871:47: note: in definition of macro ‘G_STATIC_ASSERT’
871 | #define G_STATIC_ASSERT(expr) _Static_assert (expr, "Expression evaluates to false")
| ^~~~
../../source/gnome-control-center/panels/keyboard/cc-keyboard-shortcut-dialog.c:518:3: note: in expansion of macro ‘g_clear_pointer’
518 | g_clear_pointer ((GtkWindow**)&self->shortcut_editor, gtk_window_destroy);
| ^~~~~~~~~~~~~~~
In file included from /opt/gnome/install/include/glib-2.0/glib/gatomic.h:30,
from /opt/gnome/install/include/glib-2.0/glib/gthread.h:34,
from /opt/gnome/install/include/glib-2.0/glib/gasyncqueue.h:34,
from /opt/gnome/install/include/glib-2.0/glib.h:34:
../../source/gnome-control-center/panels/keyboard/cc-keyboard-shortcut-dialog.c:518:20: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing]
518 | g_clear_pointer ((GtkWindow**)&self->shortcut_editor, gtk_window_destroy);
/opt/gnome/install/include/glib-2.0/glib/glib-typeof.h:39:36: note: in definition of macro ‘glib_typeof’
39 | #define glib_typeof(t) __typeof__ (t)
| ^
../../source/gnome-control-center/panels/keyboard/cc-keyboard-shortcut-dialog.c:518:3: note: in expansion of macro ‘g_clear_pointer’
518 | g_clear_pointer ((GtkWindow**)&self->shortcut_editor, gtk_window_destroy);
| ^~~~~~~~~~~~~~~
cc1: all warnings being treated as errors
```
I believe it’s better to fix these by expanding out the
`g_clear_pointer()` call, than by changing the types of variables — the
latter approach means everything becomes a `GtkWidget` or a `GtkWindow`,
which loses type specificity. So this approach is in contrast to that
taken in commit 1bafd46ea3, for example.
Alternative approaches would be:
1. Add internal `cc_clear_window()` and `cc_clear_widget()` helpers
which do this in a single line without aliasing violations.
2. Enforce compiling with `-Wno-strict-aliasing` if strict aliasing is
not something that g-c-c maintainers want to care about (which would
be fine, aliasing checks probably won’t catch any bugs in this kind
of code).
Signed-off-by: Philip Withnall <pwithnall@gnome.org>
Fixes: #2563
