[gnome-builder] rustup: avoid modifying preferences after unloading

[Christian Hergert <chergert src gnome org>]

commit ddccdac1b6bd37f99afedf85e94b8a6a7f265ed3
Author: Christian Hergert <chergert redhat com>
Date:   Sun Jan 14 17:59:51 2018 -0800

    rustup: avoid modifying preferences after unloading
    
    This should probably be refactored before long to properly use cancellables
    across the async function boundary. But for now, just track once we've
    unloaded and avoid doing work in those conditions.
    
    This fixes a gtk_widget_destroy() warning after unloading.

 src/plugins/rustup/rustup_plugin.py | 25 +++++++++++++++----------
 1 file changed, 15 insertions(+), 10 deletions(-)
---
diff --git a/src/plugins/rustup/rustup_plugin.py b/src/plugins/rustup/rustup_plugin.py
index 477f6e264..94476e358 100644
--- a/src/plugins/rustup/rustup_plugin.py
+++ b/src/plugins/rustup/rustup_plugin.py
@@ -441,6 +441,8 @@ class RustupPreferencesAddin(GObject.Object, Ide.PreferencesAddin):
        PreferencesAddin to display the installed rustup version and to change the rustup installation
     """
     def do_load(self, preferences):
+        self.unloaded = False
+
         preferences.add_list_group('sdk', 'rustup', _('Rustup'), Gtk.SelectionMode.NONE, 100)
         preferences.add_group('sdk', 'rustup_toolchains_edit', _('Rustup Toolchains'), 100)
 
@@ -465,6 +467,7 @@ class RustupPreferencesAddin(GObject.Object, Ide.PreferencesAddin):
         ]
 
     def do_unload(self, preferences):
+        self.unloaded = True
         if self.ids:
             for id in self.ids:
                 preferences.remove_id(id)
@@ -536,13 +539,14 @@ class RustupPreferencesAddin(GObject.Object, Ide.PreferencesAddin):
 
         # reload toolchains
         def has_rustup_callback(applicationAddin, preferenceAddin):
-            toolchains = RustupApplicationAddin.instance.get_toolchains()
-            self.toolchain_listbox.set_visible(len(toolchains) != 0)
-            tcs = []
-            for toolchain in toolchains:
-                tcs.append(ModelItem(toolchain[0], toolchain[1]))
-            old_len = self.store.get_n_items()
-            self.store.splice(0, old_len, tcs)
+            if not self.unloaded:
+                toolchains = RustupApplicationAddin.instance.get_toolchains()
+                self.toolchain_listbox.set_visible(len(toolchains) != 0)
+                tcs = []
+                for toolchain in toolchains:
+                    tcs.append(ModelItem(toolchain[0], toolchain[1]))
+                old_len = self.store.get_n_items()
+                self.store.splice(0, old_len, tcs)
         RustupApplicationAddin.instance.connect('rustup_changed', has_rustup_callback, self)
         has_rustup_callback(RustupApplicationAddin.instance, self)
         return self.toolchain_listbox
@@ -581,9 +585,10 @@ class RustupPreferencesAddin(GObject.Object, Ide.PreferencesAddin):
 
         # reload toolchains
         def has_rustup_callback(applicationAddin):
-            add_toolchain.set_sensitive(applicationAddin.has_rustup)
-            toolchains = applicationAddin.get_toolchains()
-            list_control.set_visible(applicationAddin.has_rustup and len(toolchains) != 0)
+            if not self.unloaded:
+                add_toolchain.set_sensitive(applicationAddin.has_rustup)
+                toolchains = applicationAddin.get_toolchains()
+                list_control.set_visible(applicationAddin.has_rustup and len(toolchains) != 0)
         RustupApplicationAddin.instance.connect('rustup_changed', has_rustup_callback)
         has_rustup_callback(RustupApplicationAddin.instance)