[gnome-software] updates section: Fix critical warnings destroying the section header

[Kalev Lember <klember src gnome org>]

commit 12ca693720fe78f68c4d5f48982c3e2de7bacea2
Author: Kalev Lember <klember redhat com>
Date:   Sat Dec 1 19:12:03 2018 +0100

    updates section: Fix critical warnings destroying the section header
    
    Simplify the section header creation, changing it so that the header is
    created in init() and destroyed in dispose() and tie the header
    lifetime to the section lifetime. This makes the object lifetime much
    easier to understand and fixes various criticals removing the last row
    (which triggers header destruction) that appeared after commit 1af0015.
    
    15:06:04:0981 GLib-GObject invalid unclassed pointer in cast to 'GsProgressButton'
    15:06:04:0982 Gtk gtk_css_provider_load_from_data: assertion 'GTK_IS_CSS_PROVIDER (css_provider)' failed
    15:06:04:0982 Gtk gtk_stack_set_visible_child_name: assertion 'GTK_IS_STACK (stack)' failed
    15:06:04:0982 GLib-GObject invalid unclassed pointer in cast to 'GtkWidget'
    15:06:04:0982 Gtk gtk_widget_show: assertion 'GTK_IS_WIDGET (widget)' failed
    15:06:04:0982 GLib-GObject invalid unclassed pointer in cast to 'GtkButton'
    15:06:04:0982 Gtk gtk_button_set_label: assertion 'GTK_IS_BUTTON (button)' failed

 src/gs-updates-page.c    |  6 ------
 src/gs-updates-section.c | 40 +++++++++++++++++++++++++---------------
 2 files changed, 25 insertions(+), 21 deletions(-)
---
diff --git a/src/gs-updates-page.c b/src/gs-updates-page.c
index 72c1c067..7a19d8ad 100644
--- a/src/gs-updates-page.c
+++ b/src/gs-updates-page.c
@@ -543,12 +543,6 @@ gs_updates_page_get_updates_cb (GsPluginLoader *plugin_loader,
                gs_updates_section_add_app (GS_UPDATES_SECTION (self->sections[section]), app);
        }
 
-       /* invalidate the headers */
-       for (guint i = 0; i < GS_UPDATES_SECTION_KIND_LAST; i++) {
-               if (self->sections[i] != NULL)
-                       gtk_list_box_invalidate_headers (self->sections[i]);
-       }
-
        /* update the counter in headerbar */
        refresh_headerbar_updates_counter (self);
 
diff --git a/src/gs-updates-section.c b/src/gs-updates-section.c
index 7d08bb9e..132642d0 100644
--- a/src/gs-updates-section.c
+++ b/src/gs-updates-section.c
@@ -49,6 +49,7 @@ struct _GsUpdatesSection
        GtkWidget               *button_update;
        GtkWidget               *button_cancel;
        GtkStack                *button_stack;
+       GtkWidget               *section_header;
 };
 
 G_DEFINE_TYPE (GsUpdatesSection, gs_updates_section, GTK_TYPE_LIST_BOX)
@@ -129,15 +130,6 @@ gs_updates_section_remove_all (GsUpdatesSection *self)
                GtkWidget *w = GTK_WIDGET (l->data);
                gtk_container_remove (GTK_CONTAINER (self), w);
        }
-
-       /* the following are set in _build_section_header(); clear these so
-        * that they don't become dangling pointers once all items are removed
-        * from self->list */
-       self->button_download = NULL;
-       self->button_update = NULL;
-       self->button_cancel = NULL;
-       self->button_stack = NULL;
-
        gs_app_list_remove_all (self->list);
        gtk_widget_hide (GTK_WIDGET (self));
 }
@@ -462,7 +454,6 @@ _build_section_header (GsUpdatesSection *self)
 
        /* create header */
        header = gtk_box_new (GTK_ORIENTATION_HORIZONTAL, 3);
-       gtk_size_group_add_widget (self->sizegroup_header, header);
        context = gtk_widget_get_style_context (header);
        gtk_style_context_add_class (context, "app-listbox-header");
 
@@ -480,7 +471,6 @@ _build_section_header (GsUpdatesSection *self)
        self->button_stack = GTK_STACK (gtk_stack_new ());
        gtk_container_add (GTK_CONTAINER (header), GTK_WIDGET (self->button_stack));
        gtk_container_child_set (GTK_CONTAINER (header), GTK_WIDGET (self->button_stack), "pack-type", 
GTK_PACK_END, NULL);
-       gtk_size_group_add_widget (self->sizegroup_button, GTK_WIDGET (self->button_stack));
 
        /* add download button */
        self->button_download = gs_progress_button_new ();
@@ -516,8 +506,6 @@ _build_section_header (GsUpdatesSection *self)
        gtk_stack_add_named (self->button_stack, self->button_cancel, "cancel");
        gtk_widget_set_visible (self->button_cancel, TRUE);
 
-       _update_buttons (self);
-
        /* success */
        return header;
 }
@@ -530,7 +518,10 @@ _list_header_func (GtkListBoxRow *row, GtkListBoxRow *before, gpointer user_data
 
        /* section changed */
        if (before == NULL) {
-               header = _build_section_header (self);
+               GtkWidget *parent;
+               if ((parent = gtk_widget_get_parent (GTK_WIDGET (self->section_header))) != NULL)
+                       gtk_container_remove (GTK_CONTAINER (parent), GTK_WIDGET (self->section_header));
+               header = self->section_header;
        } else {
                header = gtk_separator_new (GTK_ORIENTATION_HORIZONTAL);
        }
@@ -557,6 +548,14 @@ _app_row_activated_cb (GtkListBox *list_box, GtkListBoxRow *row, GsUpdatesSectio
                                  G_CALLBACK (gtk_widget_destroy), dialog);
 }
 
+static void
+gs_updates_section_show (GtkWidget *widget)
+{
+       _update_buttons (GS_UPDATES_SECTION (widget));
+
+       GTK_WIDGET_CLASS (gs_updates_section_parent_class)->show (widget);
+}
+
 static void
 gs_updates_section_dispose (GObject *object)
 {
@@ -566,12 +565,16 @@ gs_updates_section_dispose (GObject *object)
        g_clear_object (&self->list);
        g_clear_object (&self->plugin_loader);
        g_clear_object (&self->page);
-
        g_clear_object (&self->sizegroup_image);
        g_clear_object (&self->sizegroup_name);
        g_clear_object (&self->sizegroup_desc);
        g_clear_object (&self->sizegroup_button);
        g_clear_object (&self->sizegroup_header);
+       self->button_download = NULL;
+       self->button_update = NULL;
+       self->button_cancel = NULL;
+       self->button_stack = NULL;
+       g_clear_object (&self->section_header);
 
        G_OBJECT_CLASS (gs_updates_section_parent_class)->dispose (object);
 }
@@ -580,7 +583,10 @@ static void
 gs_updates_section_class_init (GsUpdatesSectionClass *klass)
 {
        GObjectClass *object_class = G_OBJECT_CLASS (klass);
+       GtkWidgetClass *widget_class = GTK_WIDGET_CLASS (klass);
+
        object_class->dispose = gs_updates_section_dispose;
+       widget_class->show = gs_updates_section_show;
 }
 
 void
@@ -596,6 +602,9 @@ gs_updates_section_set_size_groups (GsUpdatesSection *self,
        g_set_object (&self->sizegroup_desc, desc);
        g_set_object (&self->sizegroup_button, button);
        g_set_object (&self->sizegroup_header, header);
+
+       gtk_size_group_add_widget (self->sizegroup_button, GTK_WIDGET (self->button_stack));
+       gtk_size_group_add_widget (self->sizegroup_header, self->section_header);
 }
 
 static void
@@ -650,6 +659,7 @@ gs_updates_section_new (GsUpdatesSectionKind kind,
        self->kind = kind;
        self->plugin_loader = g_object_ref (plugin_loader);
        self->page = g_object_ref (page);
+       self->section_header = g_object_ref_sink (_build_section_header (self));
        return GTK_LIST_BOX (self);
 }