Hello there,
In the last days, I have been fighting against || ( ) dependencies.
Here are the most common use cases:
— virtuals
— autotools.exlib (and similar slotted tools like vala.exlib)
— ffmpeg vs. libav
— vim vs. gvim
— cdrtools and friends
— ruby vs. rake/rubygems
— text-based browsers
There are a few other cases but I am not familiar enough with these so I
will focus on the list above before “fixing” corner cases.
From bottom to top:
The last cases (from vim to text-based browsers) can be solved with
virtuals quite easily. I will just wait for the virtuals case to be
decided to update them.
The ffmpeg vs. libav case is a bit more tricky. I will need the answer
to one question to decide here: can you *always* runtime-switch between
libav and ffmpeg? IOW, are some packages using build-time #ifs to use them?
If we *can* runtime-switch, a virtual is good here too.
If we *cannot*, here are two and a half solutions:
1. a slot-based virtual. With a := slot dependency, that would force
people to rebuild packages if they change from libav to ffmpeg
2. use [ffmpeg] and [libav] on each package, two variants here:
a. make them mutually exclusive (but this is not
DEFAULT_SRC_CONFIGURE_*-friendly, unless we add something to handle that
choose-between -two-implementations case, which is quite common)
b. make [libav] prefer libav over ffmpeg, while [ffmpeg] is always “use
that feature” (which may confuse people for packages non-libav-aware
that will lead to a blocker)
The autotools.exlib case can be solved in two ways:
1. a new annotation "|| ( ) [[ selection = first-unmasked ]]"
2. always use the best slot available (which would simplify a lot of things)
With 1., we can simplify the resolver work by always picking the best
version while the use is still able to mask newer slots to keep only one
(older) slot installed.
With 2. we just force everyone to have all the needed slots installed.
Last but not least, the virtuals. Simple: || ( ) dependencies in
virtuals need to die. The elegant solution came from Ciaran:
option-driven virtuals. You will find attached to this email an example.
The first part is such a virtual created by hand. The second part is the
same virtual using virtual.exlib to fill MYOPTIONS and DEPENDENCIES
automatically. The last part is the resulting "cave show -c".
Which solution (manual or exlib) do you prefer, or do you have another idea?
Of course, I will happily update everything we have currently to the new
decided style.
Comments and questions are welcome.
Cheers,
--
Quentin “Sardem FF7” Glidic
Manual virtual/notification-daemon.exheres-0:
# Copyright 2009 Mike Kelly
# Copyright 2013 Quentin "Sardem FF7" Glidic <[email protected]>
# Distributed under the terms of the GNU General Public License v2
SUMMARY="virtual for notification-daemon providers"
PLATFORMS="~amd64 ~x86"
MYOPTIONS="
( virtuals:
awesome [[ description = [ Use Awesome as a
notification daemon (with the naughty library) ] ]]
dunst [[ description = [ Use dunst as a notification
daemon ] ]]
eventd [[ description = [ Use eventd as a
notification daemon ] ]]
gnome-shell [[ description = [ Use GNOME-Shell as a
notification daemon ] ]]
kde-runtime [[ description = [ Use KDE as a notification
daemon (with knotify) ] ]]
notification-daemon [[ description = [ Use notification-daemon as
a notification daemon ] ]]
notification-daemon-xfce [[ description = [ Use
notification-daemon-xfce as a notification daemon ] ]]
notify-osd [[ description = [ Use Notify-OSD as a
notification daemon ] ]]
) [[ number-selected = exactly-one ]]
"
DEPENDENCIES="
virtuals:awesome? ( x11-wm/awesome[>=3.1] )
virtuals:dunst? ( x11-apps/dunst )
virtuals:eventd? ( net/eventd[dbus] )
virtuals:gnome-shell? ( gnome-desktop/gnome-shell )
virtuals:kde-runtime? ( kde/kde-runtime )
virtuals:notification-daemon? ( x11-apps/notification-daemon )
virtuals:notification-daemon-xfce? ( xfce-extra/notification-daemon-xfce )
virtuals:notify-osd? ( x11-apps/notify-osd )
"
exlib virtual/notification-daemon.exheres-0:
# Copyright 2009 Mike Kelly
# Copyright 2013 Quentin "Sardem FF7" Glidic <[email protected]>
# Distributed under the terms of the GNU General Public License v2
VIRTUAL_PACKAGES=(
'x11-wm/awesome[>=3.1] Awesome with the naughty library'
'x11-apps/dunst dunst'
'net/eventd[dbus] eventd'
'gnome-desktop/gnome-shell GNOME-Shell'
'kde/kde-runtime KDE with knotify'
'x11-apps/notification-daemon notification-daemon'
'xfce-extra/notification-daemon-xfce notification-daemon-xfce'
'x11-apps/notify-osd Notify-OSD'
)
require virtual [ usage="as a notification daemon" ]
SUMMARY="virtual for notification-daemon providers"
PLATFORMS="~amd64 ~x86"
MYOPTIONS=""
DEPENDENCIES=""
$ cave show -c notification-daemon::arbor
* virtual/notification-daemon::arbor
::arbor 0(~)* {:0}
virtual/notification-daemon-0:0::arbor
Homepage
Summary virtual for notification-daemon providers
Options
virtuals
-awesome Use Awesome as a notification daemon (with the
naughty library)
-dunst Use dunst as a notification daemon
-eventd Use eventd as a notification daemon
-gnome-shell Use GNOME-Shell as a notification daemon
-kde-runtime Use KDE as a notification daemon (with knotify)
-notification-daemon Use notification-daemon as a notification
daemon
-notification-daemon-xfce Use notification-daemon-xfce as a
notification daemon
-notify-osd Use Notify-OSD as a notification daemon
Build Options
symbols=compress How to handle debug symbols in installed files
Permitted values:
compress: Split and compress debug symbols
preserve: Preserve debug symbols
split: Split debug symbols
strip: Strip debug symbols
jobs=5 How many jobs the package's build system should
use, where supported
Should be an integer >= 1
-dwarf_compress Compress DWARF2+ debug information
recommended_tests Run tests considered by the package to be
recommended
-trace Trace actions executed by the package (very
noisy, for debugging broken builds only)
work=tidyup Whether to preserve or remove working directories
Permitted values:
leave: Do not remove, but allow
destructive merges
preserve: Preserve the working directory
remove: Always remove the working directory
tidyup: Tidy up work directory after a
successful build
Dependencies
(
virtuals:awesome? (
x11-wm/awesome[>=3.1]
)
virtuals:dunst? (
x11-apps/dunst
)
virtuals:eventd? (
net/eventd[dbus]
)
virtuals:gnome-shell? (
gnome-desktop/gnome-shell
)
virtuals:kde-runtime? (
kde/kde-runtime
)
virtuals:notification-daemon? (
x11-apps/notification-daemon
)
virtuals:notification-daemon-xfce? (
xfce-extra/notification-daemon-xfce
)
virtuals:notify-osd? (
x11-apps/notify-osd
)
) [[ defined-in = [ virtual.exlib ] ]]
Downloads
Overridden Masks
Supported platforms ~amd64 ~x86
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