st-bin: Disallow st_bin_set_child with already-parented children

Not checking for this would result in `clutter_actor_add_child`
failing, but StBin keeping a copy in `priv->child`. So later on,
`st_bin_remove` would never be called on it and this assertion
would fail and crash the whole shell:

```
static void
st_bin_destroy (ClutterActor *actor)
{
  StBinPrivate *priv = st_bin_get_instance_private (ST_BIN (actor));

  if (priv->child)
    clutter_actor_destroy (priv->child);
  g_assert (priv->child == NULL);

```

By disallowing spurious `st_bin_set_child` calls we now prevent StBin
from entering such a corrupt state and the above assertion won't fail
anymore.

Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/1507>
This commit is contained in:
Daniel van Vugt 2020-11-24 17:34:08 +08:00 committed by Florian Müllner
parent ee0f250662
commit 244c266c9f

View File

@ -358,6 +358,19 @@ st_bin_set_child (StBin *bin,
if (priv->child == child)
return;
if (child)
{
ClutterActor *parent = clutter_actor_get_parent (child);
if (parent)
{
g_warning ("%s: The provided 'child' actor %p already has a "
"(different) parent %p and can't be made a child of %p.",
G_STRFUNC, child, parent, bin);
return;
}
}
if (priv->child)
clutter_actor_remove_child (CLUTTER_ACTOR (bin), priv->child);