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GNOME 3

Summary

Include GNOME 3

Owner

Current status

  • Targeted release: Fedora 15
  • Last updated: 2010-02-07
  • Percentage of completion: 90%

GNOME has been mostly updated to 2.91.6 in rawhide. dconf, gtk3 and yelp-xsl and other new components are in rawhide. The dbus a11y stack is now the default. gtk3 modules have been added for at-spi2-atk, PackageKit and gtk-themes-standard. The GNOME 3 visual appearance is being defined in the new theme packages gnome-icon-theme-symbolic and gnome-themes-standard. The first Fedora15 GNOME3 test day has happened on Febuary 3.

Detailed Description

GNOME 3 is the next major version of the GNOME desktop. After many years of a largely unchanged GNOME 2.x experience, GNOME 3 brings a fresh look and feel with gnome-shell. There are also many changes under the surfaces, like the move from CORBA-based technologies such as GConf, Bonobo and at-spi to dbus-based successors.

The user experience of GNOME 3 is largely defined by gnome-shell, which is a compositing window manager and desktop shell. It replaces the GNOME 2 desktop shell, which consisted of metacity, gnome-panel, notification-daemon and nautilus.

Apart from pure window management, gnome-shell provides the top bar on the screen, which hosts the 'system status' area in the top right, a clock in the center, and a hot corner that switches to the so-called 'overview' mode, which provides easy access to applications and windows (and in the future, documents).

In gnome-shell, notifications are displayed in the 'messaging area' which is an automatically hiding bar at the bottom of the screen. This is also where integrated chat functionality is provided.

Since the requirements of gnome-shell on the graphics system may not be met by certain hardware / driver combinations, GNOME 3 also support as 'fallback mode' in which we run gnome-panel, metacity and notification-daemon instead of gnome-shell. Note that this mode is not a 'Classic GNOME' mode; the panel configuration will be adjusted to be similar to the shell.

The fallback will be handled automatically by gnome-session, which will detect insufficient graphics capabilities and run a different session.

Benefit to Fedora

Fedora stays in sync with upstream, and gains a modern user experience. Some long-standing problems with the CORBA-based accessibility stack will hopefully be solved as a side-effect of the move to D-Bus

Scope

A successful GNOME 3 and Fedora 15 release does include:

  1. Runs on a reasonable range of graphics hardware
  2. Offers a graceful fallback for the rest
  3. Has working controls for common things like keyboards, monitors, network, sound and power
  4. All desktop applications work. 'core gnome' applications follow somewhat higher standards for integration and appearance, including

A successful GNOME 3 release does not include:

  1. A 1-1 equivalent of every feature or UI that was present in GNOME 2.32. GNOME 2 has had 16 major revisions to grow bells and whistles, while GNOME 3 is just starting out.

Details

  • Package new components
  • Build packages which provide gtk modules for gtk2 and gtk3 (tracked [upstream]):
    • librsvg2 (Done)
    • ibus-gtk [bug] (Done)
    • at-spi2-atk (Done)
    • PackageKit-gtk-module (Done)
  • Make GTK-using libraries parallel-installable, or port them to GTK3, or drop their GTK dependency:
    • libnotify (done, dependency now implicit)
    • gnome-desktop (done, parallel-installable gnome-desktop3)
    • libunique ([done], parallel-installable libunique3)
    • gtksourceview ([done], parallel-installable gtksourceview3)
    • webkitgtk ([done], parallel-installable webkitgtk3)
    • vte ([bug], parallel-installable vte3)
    • libwnck ([bug], parallel-installable libwnck3)
    • libmetacity-private ([bug])
    • clutter-gtk (done, parallel-installable clutter-gtk010)
    • libchamplain-gtk
    • gtkimageview
    • cheese-gtk
    • polkit-gtk
    • gnome-media (library has been split off as libgnome-media-profiles, ported to GTK3)
  • Switch to the dbus-based accessibility stack (Done)
  • Implement data migration for applications that are ported from GConf2 to dconf
    • done for evince
    • done for gedit
    • done for brasero
    • done for gnome-bluetooth
    • done for nautilus-sendto
    • done for gnome-color-manager
    • done for gnome-packagekit
    • done for gnome-power-manager
    • done deja-dup
    • done for eog
    • done for epiphany
    • done for file-roller
    • done for gnome-screenshot
    • done for gnome-settings-daemon
    • done for gvfs
    • done for gnome-system-log
    • done for nautilus
    • done for gnome-screensaver
    • done for gnome-session
  • Implement fallback from the shell to gnome-panel+metacity for unsupported hardware (in progress)
  • All system status indicators must use symbolic icons, others are optional
    • power (Done)
    • sound (Done)
    • bluetooth (Done)
    • updates (not a system status indicator anymore)
    • network
    • keyboard (Done)
    • bluetooth (Done)
  • Make sure applications keep working and don't run into mixed linkage against both gtk2 and gtk3 via gtk-using libraries. Currently known problems:
    • solang (uses gtk2, but needs libbrasero-burn/media which has moved to gtk3)
  • Current mixed linkage problems that need to be addressed:
    • gnome-volume-control-applet
    • gnomeradio (via gnome-media-profiles) [bug]
    • emerillon (via libclutter-gtk) [bug]
    • seahorse-plugins [bug]
    • gnome-user-share [bug]
    • claws-mail-plugins (via libclutter-gtk) [bug]
    • gnome-phone-manager [bug]
    • meego-panel-devices (via libclutter-gtk)
    • meego-panel-zones (via libclutter-gtk)
    • moblin-app-installer (via libclutter-gtk)
  • Upgrades need to ensure that all new components of GNOME 3 get installed when upgrading from an earlier Fedora release including GNOME 2.x. This includes in particular
    • gnome-shell (handled by a gnome-panel -> gnome-shell dependency now)
    • gnome-themes-standard

How To Test

See also ...
In conjunction with the Desktop team, the QA team is drafting test cases intended for several Fedora Test Days. Additional test scenarios are available at Category:GNOME3_acceptance_test_cases.
How to test basic gnome-shell functionality
  1. Use a system with supported graphics card
  2. Log in to a GNOME session
  3. Verify that your desktop has:
    1. A black panel at the top
    2. Your name on the top right
    3. Next to it, a system status area, with icons for sound, universal access, network, battery, etc, in symbolic style
    4. in the center of the panel, a clock that brings up a calendar popup when clicked
    5. on the left, an 'Activities' item that brings up the 'overview' when clicked
    6. the top left corner of the screen also functions as a hot corner to bring up the overview
  4. Notifications (ie 'bubbles') appear centered at the bottom of the screen, and are still available afterwards in the auto-hide 'messaging area' at the bottom right
How to test control-center functionality
  1. Log in to a GNOME session
  2. Start the control-center by going to the user menu and selecting 'System Settings'
  3. Verify that search functionality in the control-center works. E.g. typing 'batt' should find the Power panel (assuming English UI)
  4. Test the functionality of various panels; settings should generally be immediate-apply, unless the panel has an 'Apply' button
  5. Several panel offer privileged operations (such as creating user accounts or installing software). Verify that the PolicyKit integration for these works
How to test the accessibility stack
  1. Make sure at-spi2-core, at-spi2-atk, pyatspi are installed
  2. Turn accessibility support on, with the command: 
    gsettings set org.gnome.desktop.interface accessibility false
  3. Log in again
  4. Use the 'Universal access' menu in the system status area to turn various accessibility technologies on and off
  5. Verify that accessibility technologies work as expected
  6. Bring up the Universal Access settings, and make various changes
  7. Verify that the changes take effect
How to test fallback
  1. Use a system with supported graphics card
  2. Log in to a GNOME session
  3. Verify that you end up with gnome-shell
  4. Switch to a system with a graphics card on which we don't have 3d support (e.g. a VM)
  5. Log in to a GNOME session again
  6. Verify that you end up with the 'fallback' desktop
  7. Repeat the same test with a supported graphics card, but uninstall gnome-shell. You should again get the 'fallback' desktop
How to test multi-monitor functionality
  1. Use a system with 2 monitors
  2. Log in to a GNOME session
  3. Open the control-center Display panel, e.g. by running the command: 
    gnome-control-center display
  4. Verify that the monitor on which the panel resides appears with a black bar in the panel
  5. Drag the bar to the other monitor representation until it 'snaps over'
  6. Observe that the panel moves to the other monitor

User Experience

The user experience (on supported hardware) will be defined by gnome-shell. If graphics hardware (and/or drivers) do not support gnome-shell, GNOME 3 starts in a 'fallback mode' where we run gnome-panel and metacity instead of gnome-shell. Note that this is not a 'GNOME 2' mode, the panel configuration will be adjusted to give a similar look-and-feel to the shell.

In GNOME 3, nautilus is no longer part of the desktop shell, but just a regular application, and it is no longer started by default.

Accessibility tools will work as well as (or hopefully better than) they used to. The onscreen keyboard will no longer be gok, but caribou, which may offer a slightly different user experience.

Dependencies

  • gnome-shell uses clutter, which relies on 3D hardware and drivers. In F13, the shell is known to work ok with Intel and ATI graphics, and work somewhat with the nouveau driver for NVidia graphics. For F14, we want the shell to work well with all three of
    • xorg-x11-drv-ati
    • xorg-x11-drv-intel
    • xorg-x11-drv-nouveau
  • Any packages that install modules for gtk2 (such as image loaders, input methods or theme engines) need to do extra work to make their functionality available to gtk3 too.
  • The libnotify 0.7.0 version removes some APIs that were available in 0.6. All packages that use libnotify to show notification bubbles and attach them to status icons will need some (minor) updates. (mostly done in rawhide)
  • The GDesktopAppInfoLookup extension mechanism has been disabled in GIO (it is still installed to mainain API stability, but GIO now determines default handlers by looking for x-scheme-handler mimetypes (see recent xdg-list discussion about this). Only very few packages in other GTK+-based desktops are affected by this.
  • To make default applications work, applications need to add suitable x-scheme-handler entries to the mimetype field in their desktop files. (mostly done in rawhide)

Contingency Plan

If gnome-shell is not complete or stable enough, keep it experimental and use the 'fallback mode'. If there are problems with certain combinations of graphics hardware and drivers, use gnome-shell only on known good combinations, and use fallback mode everywhere else.

If the dbus-based accessibility stack is not sufficiently functional, we switch back to the CORBA-based stack.

Applications can be ported from GConf to dconf and from gtk2 to gtk3 one-by-one, so if the porting work is not complete (and it is very unlikely that it will be), we can just ship with some applications using the new technology, while others still use the old one.

Documentation

Release Notes

  • Fedora 15 includes GNOME 3. It brings the first major overhaul of the GNOME user experience in 10 years.

Comments and Discussion

General

When is the upstream decision made as to whether 2.91.x will become 3.0?
See http://live.gnome.org/action/edit/TwoPointNinetyone/ for the schedule
How is the upstream decision made as to whether 2.91.x will become 3.0? Is it dependent on blocker bug resolution, or release criteria?
Release readiness is monitored by the release team, based on information from various sources such as weekly blocker bug summaries (http://mail.gnome.org/archives/desktop-devel-list/2011-January/msg00170.html), buildability (http://build.gnome.org), etc. There are no fixed criteria.
Where is the upstream GNOME 3 blocker bug list?
https://bugzilla.gnome.org/buglist.cgi?bug_status=UNCONFIRMED&bug_status=NEW&bug_status=ASSIGNED&bug_status=REOPENED&bug_status=NEEDINFO&cf_gnome_target=3.0
If GNOME 3 isn't considered ready by upstream, how will Fedora proceed?
There are various options, of which the third one seems the most realistic one:
  1. Fedora 15 slips until GNOME 3 is ready
  2. Fedora 15 ships GNOME 3 in fallback mode only (shell with metacity+panel)
  3. Fedora 15 ships GNOME 3 and arranges for fallback to happen for all but known good graphics hardware
Where can I find GNOME 3 marketing plans for upstream GNOME and Fedora?
http://www.gnome3.org is the new GNOME 3 website
http://live.gnome.org/GnomeMarketing/ThreePointZero has marketing plans
What testing (GNOME and Fedora) is planned for GNOME 3 ?
For GNOME development releases, see the schedule at http://live.gnome.org/action/edit/TwoPointNinetyone/. These get smoke-tested by the release-team and get some community testing as well. A considerable amount of testing comes in the form of having GNOME development versions in rawhide (currently 2.91.5). There are several Fedora test events scheduled to test various aspects of GNOME 3 (see QA/Fedora_15_test_days)

Features

What happened to the Fedora 14-vintage GNOME shell favorites sidebar allowing selection+presentation of favorite applications and folders?
it was just an experiment that did not work out; it is not part of the final GNOME 3 design
How should multi-monitor support behave with GnomeShell in Fedora 15?
Currently, gnome-shell just treats any additional monitors as extra space to put windows in but otherwise more or less ignores them. When you go into overview mode, it only takes effect on one screen, the others are just left blank. There's nothing yet done to integrate the workspace model the Shell encourages with multi-monitor setups. There's a bug for this, but again, AFAICT no particular commitment to fixing it up before the 3.0 release. (This isn't actually much of a 'regression' compared to GNOME 2, which was similarly lax about doing much with extra screens, but it's the sort of thing people might expect GNOME 3 to have fixed).
There are some ways in which multi-monitor support is better in GNOME3 than in 2.x:
* On the secondary monitor, dragging the window to the top edge maximizes
* We have working configuration for primary monitors in the control-center display panel
* We are also hoping to have working barriers in X soon, so that we can improve the situation when the 'hot corner' is at a shared edge. Barriers have been promised for F15.
What happened to applets ?
gnome-shell does not support applets. The general design of GNOME 3 puts a lot more emphasis on full applications, instead of squeezing too much into a small strip or space at the edge of your screen. There are however, people working on adding an extension mechanism (similar to firefox extensions) to the shell; the code lives in http://git.gnome.org/browse/gnome-shell-extensions . We don't expect this to be available in polished or packaged form for GNOME 3.0, though.

Workarounds

What is the procedure to manually revert to fallback mode?
Fallback mode is just that: a fallback. Therefore it is not planned to have a manual 'Choose your User Interface' application.
You can of course open the hood and rewire what gdm and gnome-session do. Gdm looks at the files in /usr/share/xsessions to find out how to run the chosen session. For GNOME, the file is /usr/share/xsessions/gnome.session and it just executes gnome-session. One way to change this is to use the --session option of gnome-session. Without a --session argument, gnome-session looks at the files /usr/share/gnome-session/sessions/gnome.session and /usr/share/gnome-session/sessions/gnome-fallback.session to find out what should be run in the session. Changing these files might void your warranty...
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