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libsoup 3: Part One

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This is a proposed Change for Fedora Linux.
This document represents a proposed Change. As part of the Changes process, proposals are publicly announced in order to receive community feedback. This proposal will only be implemented if approved by the Fedora Engineering Steering Committee.

Summary

libsoup 3 is a new API version of libsoup that provides support for HTTP/2. Unfortunately, it is incompatible with libsoup 2. To avoid misbehavior, applications will crash on startup if linked to both libsoup 2 and libsoup 3 at the same time. Because many libraries depend on libsoup, and applications have limited control over which libsoup they link to transitively, this transition will be relatively tricky.

Owner


Current status

  • Targeted release: Fedora Linux 37
  • Last updated: 2022-06-27
  • FESCo issue: <will be assigned by the Wrangler>
  • Tracker bug: <will be assigned by the Wrangler>
  • Release notes tracker: <will be assigned by the Wrangler>

Detailed Description

libsoup 3 was introduced in Fedora 36, but nothing actually uses it yet. For Fedora 37 and GNOME 43, many GNOME applications and libraries will switch from libsoup 2 to libsoup 3. libsoup 2 will remain in Fedora 37 as a compatibility library. Because libsoup is a sensitive network-facing HTTP library written in an unsafe language and where CVEs may have disastrous impact, it is not safe to leave libsoup 2 hanging around indefinitely, but we are not yet ready to remove it altogether. We will propose removing libsoup 2 (and all applications and libraries that still depend on it) for Fedora 39 in a separate change proposal.

For Fedora 37 and Fedora 38, we propose a transition period where both libsoup 2 and libsoup 3 will coexist. Applications can switch to libsoup 3 without significant impact on the rest of the distribution, but libraries switching to libsoup 3 are very disruptive. Libraries have two options:

  • Recommended: provide a new API version for libsoup 3. This gives applications that depend on your library a transition period to switch from libsoup 2 to libsoup 3. Applications will bump to your new API version at the same time they transition to libsoup 3. If the application does not directly depend on libsoup and does not depend on libsoup via any other libraries, then this can be done at any time. Example: webkit2gtk-4.0 is the libsoup 2 version of WebKitGTK's GTK 3 API, while webkit2gtk-4.1 is the libsoup 3 version. Currently only webkit2gtk-4.0 is available in Fedora (via the webkit2gtk3 package), but webkit2gtk-4.1 will be made available as part of this change (package name TBD).
  • Not recommended: provide a build option to toggle between libsoup 2 and libsoup 3, while retaining the same API version. All applications that depend on your library must port to libsoup 3 at exactly the same time. Unfortunately, many GNOME libraries have selected this approach, and building these libraries with libsoup 3 enabled will be required for GNOME 43. Known affected libraries will include geocode-glib, libgweather, librest-1.0, libosinfo, and probably also libphodav. All applications that link to these libraries will crash on startup if they link to libsoup 2.

Because many GNOME libraries have adopted the second approach, applications that depend on these libraries, whether directly or indirectly, must take action immediately or they will crash.

Feedback

Benefit to Fedora

Transitioning to libsoup 3 adds support for HTTP/2 and allows Fedora to continue packaging the latest versions of GNOME. If we do not transition to libsoup 3, then we will be unable to update certain GNOME packages to the latest version.

Scope

  • Proposal owners: The proposal owner is working upstream to ensure GNOME 43 is buildable without conflicts between packages that require libsoup 2 dependencies vs. libsoup 3 dependencies. The proposal owner will also package webkit2gtk-4.1 for Fedora 37. Because this is a large transition that will require the efforts of dozens of developers, the proposal owner cannot help with individual Fedora packages.
  • Other developers:

Check your applications and libraries for direct or indirect dependencies on libsoup using ldd. You must assess each situation individually to decide the best course of action based on whether your dependencies require libsoup 2 or libsoup 3. If you're not sure where a dependency on libsoup comes from, use the lddtree tool from the pax-utils package.

  • Policies and guidelines: No policy changes required
  • Trademark approval: N/A (not needed for this Change)
  • Alignment with Objectives: No alignment with current objectives

Upgrade/compatibility impact

If applications do not link to both libsoup 2 and libsoup 3, everything should be fine and users should not notice this transition. But applications that link to both libsoup 2 and libsoup 3 will crash on startup.

How To Test

Although it's possible that bugs will be introduced when porting an application from libsoup 2 to libsoup 3, we should focus on testing to see whether applications crash on startup. An application that does not crash immediately is probably good.

User Experience

Applications that use libsoup 3 will support HTTP/2, which multiplexes multiple HTTP requests over a single connection. Users may notice performance improvements.

Dependencies

{{{ $ dnf repoquery --whatdepends libsoup --latest-limit 1 --arch 'noarch,x86_64' Last metadata expiration check: 0:37:45 ago on Mon 27 Jun 2022 10:43:26 AM CDT. abrt-retrace-client-0:2.15.1-1.fc36.x86_64 badwolf-0:1.2.2-2.fc36.x86_64 bookworm-0:1.1.3-0.7.20200414git.c7c3643.fc36.x86_64 cawbird-0:1.4.2-3.fc36.x86_64 chatty-0:0.6.0-1.fc36.x86_64 chezdav-0:2.5-6.fc36.x86_64 claws-mail-plugins-fancy-0:4.1.0-1.fc36.x86_64 claws-mail-plugins-gdata-0:4.1.0-1.fc36.x86_64 coin-0:1.3.0-6.fc36.x86_64 cutter-0:1.2.7-6.fc36.x86_64 darktable-0:3.8.1-1.fc36.x86_64 dino-0:0.3.0-2.fc36.x86_64 dleyna-renderer-0:0.6.0-14.fc36.x86_64 dleyna-server-0:0.6.0-13.fc36.x86_64 dmapd-0:0.0.91-1.fc36.x86_64 elementary-calendar-0:6.1.1-1.fc36.x86_64 elementary-code-0:6.2.0-1.fc36.x86_64 elementary-mail-0:6.4.0-1.fc36.x86_64 elementary-photos-0:2.7.5-1.fc36.x86_64 elementary-planner-1:3.0.7-1.fc36.x86_64 elementary-tasks-0:6.2.0-1.fc36.x86_64 emacs-1:27.2-11.fc36.x86_64 ephemeral-0:7.1.0-3.fc36.x86_64 epiphany-1:42.2-1.fc36.x86_64 evolution-0:3.44.2-1.fc36.x86_64 evolution-chime-0:1.4.1-5.fc36.x86_64 evolution-data-server-0:3.44.2-1.fc36.x86_64 evolution-ews-0:3.44.2-1.fc36.x86_64 evolution-rspam-0:0.6.0-35.fc36.x86_64 evolution-rss-1:0.3.96-9.fc36.x86_64 exfalso-0:4.5.0-1.fc36.noarch flatpak-0:1.12.7-2.fc36.x86_64 flatpak-builder-0:1.2.2-2.fc36.x86_64 flatpak-libs-0:1.12.7-2.fc36.x86_64 flatpak-tests-0:1.12.7-2.fc36.x86_64 fondo-0:1.6.1-2.fc36.x86_64 frogr-0:1.6-5.fc35.x86_64 gajim-0:1.4.4-1.fc36.noarch gambas3-gb-gtk3-webview-0:3.17.2-1.fc36.x86_64 gamehub-0:0.16.3.2-4.fc36.x86_64 geany-plugins-geniuspaste-0:1.38-3.fc36.x86_64 geany-plugins-markdown-0:1.38-3.fc36.x86_64 geany-plugins-updatechecker-0:1.38-3.fc36.x86_64 geary-0:40.0-5.fc36.x86_64 geoclue2-0:2.6.0-2.fc36.x86_64 geocode-glib-0:3.26.2-5.fc36.x86_64 gfbgraph-0:0.2.4-2.fc36.x86_64 gnome-boxes-0:42.1-1.fc36.x86_64 gnome-builder-0:42.1-1.fc36.x86_64 gnome-calculator-0:42.1-1.fc36.x86_64 gnome-calendar-0:42.2-1.fc36.x86_64 gnome-games-0:40.0-3.fc36.x86_64 gnome-music-0:42.1-1.fc36.noarch gnome-online-accounts-0:3.44.0-1.fc36.x86_64 gnome-panel-0:3.44.0-1.fc36.x86_64 gnome-software-0:42.2-4.fc36.x86_64 gnome-tweaks-0:42~beta-1.fc36.noarch gnome-video-arcade-0:0.8.8-12.fc36.x86_64 goodvibes-0:0.7.2-2.fc36.x86_64 grilo-0:0.3.14-2.fc36.x86_64 grilo-plugins-0:0.3.14-3.fc36.x86_64 gsequencer-0:3.17.6-0.fc36.x86_64 gssdp-0:1.4.0.1-2.fc36.x86_64 gssdp-utils-0:1.4.0.1-2.fc36.x86_64 gthumb-1:3.12.1-1.fc36.x86_64 gtranslator-0:40.0-3.fc36.x86_64 gupnp-0:1.4.3-2.fc36.x86_64 gupnp-tools-0:0.10.3-1.fc36.x86_64 homebank-0:5.5.5-1.fc36.x86_64 libabiword-1:3.0.5-2.fc36.x86_64 libappstream-glib-0:0.7.18-4.fc36.x86_64 libchamplain-0:0.12.20-6.fc36.x86_64 libdmapsharing-0:2.9.41-6.fc36.x86_64 libdmapsharing4-0:3.9.10-5.fc36.x86_64 libepc-0:0.4.0-22.fc36.x86_64 libepc-ui-0:0.4.0-22.fc36.x86_64 libgda-tools-1:5.2.10-5.fc36.x86_64 libgda-web-1:5.2.10-5.fc36.x86_64 libgdata-0:0.18.1-4.fc36.x86_64 libgepub-0:0.6.0-9.fc36.x86_64 libgovirt-0:0.3.8-3.fc36.x86_64 libgrss-0:0.7.0-14.fc36.x86_64 libgweather-0:40.0-3.fc36.x86_64 libgweather4-0:4.0.0-1.fc36.x86_64 libmateweather-0:1.26.0-2.fc36.x86_64 libosinfo-0:1.10.0-1.fc36.x86_64 libphodav-0:2.5-6.fc36.x86_64 libsoup-devel-0:2.74.2-2.fc36.x86_64 libtimezonemap-0:0.4.5.1-11.fc36.x86_64 libtracker-sparql-0:3.3.1-1.fc36.x86_64 libtranslate-0:0.99-112.fc36.x86_64 liferea-1:1.13.7-2.fc36.x86_64 linphone-0:3.6.1-48.fc36.x86_64 logjam-1:4.6.2-27.fc36.x86_64 meteo-0:0.9.9.1-2.fc36.x86_64 midori-0:9.0-9.fc36.x86_64 mmsd-tng-0:1.8-1.fc36.x86_64 mpdscribble-0:0.22-24.fc36.x86_64 osinfo-db-tools-0:1.10.0-1.fc36.x86_64 osm-gps-map-0:1.1.0-10.fc36.x86_64 ostree-tests-0:2022.4-2.fc36.x86_64 perl-HTTP-Soup-0:0.01-26.fc36.x86_64 polari-0:42.0-1.fc36.x86_64 pragha-0:1.3.3-22.fc36.x86_64 purple-chime-0:1.4.1-5.fc36.x86_64 python3-nbxmpp-0:3.1.0-2.fc36.noarch remmina-0:1.4.27-2.fc36.x86_64 rest-0:0.8.1-12.fc36.x86_64 rhythmbox-0:3.4.6-1.fc36.x86_64 rygel-0:0.40.3-1.fc36.x86_64 seahorse-0:42.0-1.fc36.x86_64 shotwell-0:0.31.3-8.fc36.x86_64 snapd-glib-0:1.58-4.fc36.x86_64 snapd-glib-tests-0:1.58-4.fc36.x86_64 snapd-qt-tests-0:1.58-4.fc36.x86_64 soup-sharp-0:2.42.2-6.20190810git0f36d10.fc36.x86_64 spice-glib-0:0.40-1.fc36.x86_64 srain-0:1.4.0-2.fc36.x86_64 surf-0:2.0-13.fc36.x86_64 switchboard-plug-onlineaccounts-0:6.5.0-1.fc36.x86_64 syncevolution-libs-1:2.0.0-3.fc36.x86_64 syncevolution-libs-akonadi-1:2.0.0-3.fc36.x86_64 taxi-0:2.0.1-2.fc36.x86_64 telepathy-gabble-0:0.18.4-18.fc36.x86_64 telepathy-salut-0:0.8.1-27.fc36.x86_64 uhttpmock-0:0.5.0-15.fc36.x86_64 vfrnav-0:20201231-22.fc36.x86_64 webkit2gtk3-0:2.36.3-1.fc36.x86_64 webkit2gtk3-devel-0:2.36.3-1.fc36.x86_64 xfce4-screenshooter-0:1.9.8-4.fc36.x86_64 xfce4-screenshooter-plugin-0:1.9.8-4.fc36.x86_64 xfce4-weather-plugin-0:0.11.0-3.fc36.x86_64 yelp-libs-2:42.1-1.fc36.x86_64 }}}


Contingency Plan

  • Contingency mechanism: We may be required to switch particular packages back to libsoup 2. Due to interdependencies between packages, this could be quite disruptive.
  • Contingency deadline: Beta freeze
  • Blocks release? Possibly. Applications that crash on startup will fail the "basic functionality test" release criterion.


Documentation

Migrating from libsoup 2

Release Notes

Many applications and libraries now use libsoup 3, a new version of libsoup that adds support for HTTP/2.

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