st/theme: Unref CRStylesheet after removing old theme nodes

Since we now remove all theme nodes on a stylesheet change (ie.
StTheme's "custom-stylesheets-changed" signal) instead of only
invalidating them, those nodes may not be accessed anymore as soon as
"custom-stylesheets-changed" is emitted.

It turned out though that when comparing them to the newly generated
nodes in `st_widget_recompute_style()` using the
`st_theme_node_paint/geometry_equal()` functions, the properties of the
old nodes will still be accessed, causing a crash since the
CRDeclarations are already freed.

To fix that, keep the reference to the CRStylesheet, which owns the
CRDeclarations used by the theme nodes, around a bit longer, so it's
still possible to access the CRDeclarations inside the
"custom-stylesheets-changed" signal handler. This allows us to compare
the old theme nodes to the new ones since the CSS properties of both are
still valid.

Fixes https://gitlab.gnome.org/GNOME/gnome-shell/-/issues/2709


(cherry picked from commit e06109c23c)
This commit is contained in:
Jonas Dreßler 2020-04-30 20:23:52 +00:00 committed by Florian Müllner
parent dff855942e
commit 118676bffb

View File

@ -287,8 +287,10 @@ st_theme_unload_stylesheet (StTheme *theme,
theme->custom_stylesheets = g_slist_remove (theme->custom_stylesheets, stylesheet);
g_hash_table_remove (theme->stylesheets_by_file, file);
g_hash_table_remove (theme->files_by_stylesheet, stylesheet);
cr_stylesheet_unref (stylesheet);
g_signal_emit (theme, signals[STYLESHEETS_CHANGED], 0);
cr_stylesheet_unref (stylesheet);
}
/**