[gnome-shell/issue369] endSessionDialog: Check for PackageKit before considering updates/upgrades

[Mario Sanchez Prada <msanchez src gnome org>]

commit 4e59e28c44ee0a9ff7a22a72e5e6032dd0bfc05d
Author: Mario Sanchez Prada <mario igalia com>
Date:   Mon Jul 8 08:51:36 2019 +0200

    endSessionDialog: Check for PackageKit before considering updates/upgrades
    
    GNOME Shell is spitting out some errors in the journal due to its attempts
    to speak to PackageKit, which is not present on Endless OS, so let's add
    some runtime checks to make sure that PackageKit is actually available
    before assuming so and using its proxy to decide which kind of UI to
    show to the user when ending the session.
    
    https://gitlab.gnome.org/GNOME/gnome-shell/issues/369

 js/ui/endSessionDialog.js | 63 +++++++++++++++++++++++++++++++++++++----------
 1 file changed, 50 insertions(+), 13 deletions(-)
---
diff --git a/js/ui/endSessionDialog.js b/js/ui/endSessionDialog.js
index a7db08807..f4950ba84 100644
--- a/js/ui/endSessionDialog.js
+++ b/js/ui/endSessionDialog.js
@@ -231,14 +231,13 @@ class EndSessionDialog extends ModalDialog.ModalDialog {
         this._loginManager = LoginManager.getLoginManager();
         this._userManager = AccountsService.UserManager.get_default();
         this._user = this._userManager.get_user(GLib.get_user_name());
+        this._updatesPermission = null;
 
         this._pkOfflineProxy = new PkOfflineProxy(Gio.DBus.system,
                                                   'org.freedesktop.PackageKit',
                                                   '/org/freedesktop/PackageKit',
-                                                  (proxy, error) => {
-                                                      if (error)
-                                                          log(error.message);
-                                                  });
+                                                  this._onPkOfflineProxyCreated.bind(this));
+
         this._powerProxy = new UPowerProxy(Gio.DBus.system,
                                            'org.freedesktop.UPower',
                                            '/org/freedesktop/UPower',
@@ -333,14 +332,31 @@ class EndSessionDialog extends ModalDialog.ModalDialog {
         this._inhibitorSection.add_actor(this._sessionHeader);
         this._inhibitorSection.add_actor(this._sessionList);
 
+        this._dbusImpl = Gio.DBusExportedObject.wrapJSObject(EndSessionDialogIface, this);
+        this._dbusImpl.export(Gio.DBus.session, '/org/gnome/SessionManager/EndSessionDialog');
+    }
+
+    _onPkOfflineProxyCreated(proxy, error) {
+        if (error) {
+            log(error.message);
+            return;
+        }
+
+        // Creating a D-Bus proxy won't propagate SERVICE_UNKNOWN or NAME_HAS_NO_OWNER
+        // errors if PackageKit is not available, but the GIO implementation will make
+        // sure in that case that the proxy's g-name-owner is set to null, so check that.
+        if (this._pkOfflineProxy.g_name_owner === null) {
+            this._pkOfflineProxy = null;
+            return;
+        }
+
+        // It only makes sense to check for this permission if PackageKit is available.
         try {
-            this._updatesPermission = 
Polkit.Permission.new_sync("org.freedesktop.packagekit.trigger-offline-update", null, null);
-        } catch (e) {
+            this._updatesPermission = Polkit.Permission.new_sync(
+                "org.freedesktop.packagekit.trigger-offline-update", null, null);
+        } catch(e) {
             log('No permission to trigger offline updates: %s'.format(e.toString()));
         }
-
-        this._dbusImpl = Gio.DBusExportedObject.wrapJSObject(EndSessionDialogIface, this);
-        this._dbusImpl.export(Gio.DBus.session, '/org/gnome/SessionManager/EndSessionDialog');
     }
 
     _onDestroy() {
@@ -387,7 +403,8 @@ class EndSessionDialog extends ModalDialog.ModalDialog {
         }
 
         // Use a different description when we are installing a system upgrade
-        if (dialogContent.upgradeDescription) {
+        // if the PackageKit proxy is available (i.e. PackageKit is available).
+        if (this._pkOfflineProxy && dialogContent.upgradeDescription) {
             let name = this._pkOfflineProxy.PreparedUpgrade['name'].deep_unpack();
             let version = this._pkOfflineProxy.PreparedUpgrade['version'].deep_unpack();
 
@@ -496,6 +513,12 @@ class EndSessionDialog extends ModalDialog.ModalDialog {
     }
 
     _triggerOfflineUpdateReboot(callback) {
+        // Handle this gracefully if PackageKit is not available.
+        if (!this._pkOfflineProxy) {
+            callback();
+            return;
+        }
+
         this._pkOfflineProxy.TriggerRemote('reboot', (result, error) => {
             if (error)
                 log(error.message);
@@ -505,6 +528,12 @@ class EndSessionDialog extends ModalDialog.ModalDialog {
     }
 
     _triggerOfflineUpdateShutdown(callback) {
+        // Handle this gracefully if PackageKit is not available.
+        if (!this._pkOfflineProxy) {
+            callback();
+            return;
+        }
+
         this._pkOfflineProxy.TriggerRemote('power-off', (result, error) => {
             if (error)
                 log(error.message);
@@ -514,6 +543,12 @@ class EndSessionDialog extends ModalDialog.ModalDialog {
     }
 
     _triggerOfflineUpdateCancel(callback) {
+        // Handle this gracefully if PackageKit is not available.
+        if (!this._pkOfflineProxy) {
+            callback();
+            return;
+        }
+
         this._pkOfflineProxy.CancelRemote((result, error) => {
             if (error)
                 log(error.message);
@@ -676,7 +711,8 @@ class EndSessionDialog extends ModalDialog.ModalDialog {
         this._totalSecondsToStayOpen = totalSecondsToStayOpen;
         this._type = type;
 
-        if (this._type == DialogType.RESTART) {
+        // Only consider updates and upgrades if PackageKit is available.
+        if (this._pkOfflineProxy && this._type == DialogType.RESTART) {
             if (this._pkOfflineProxy.UpdateTriggered)
                 this._type = DialogType.UPDATE_RESTART;
             else if (this._pkOfflineProxy.UpgradeTriggered)
@@ -708,8 +744,9 @@ class EndSessionDialog extends ModalDialog.ModalDialog {
         if (dialogContent.showOtherSessions)
             this._loadSessions();
 
-        let updateTriggered = this._pkOfflineProxy.UpdateTriggered;
-        let updatePrepared = this._pkOfflineProxy.UpdatePrepared;
+        // Only consider updates and upgrades if PackageKit is available.
+        let updateTriggered = this._pkOfflineProxy ? this._pkOfflineProxy.UpdateTriggered : false;
+        let updatePrepared = this._pkOfflineProxy ? this._pkOfflineProxy.UpdatePrepared : false;
         let updatesAllowed = this._updatesPermission && this._updatesPermission.allowed;
 
         _setCheckBoxLabel(this._checkBox, dialogContent.checkBoxText || '');