[OE-core] DISTRO_FEATURES and world builds.

[Randy MacLeod]

Some world builds without the DFs: x11 or opengl fail unless
I run: bitbake -k world. Ideally packages would exclude themselves
from world builds if a required DF isn't set. Otherwise identifying
broken packages in bb world builds is not straight-forward. I can
add the DFs in to my world test builds but then I'm not really
exercising at least some of the recipes properly.

So....
What are the rules around DISTRO_FEATURES and bitbake world builds?
What testing has been done and which if any DFs are mandatory.


I copied the default DFs from
meta/conf/distro/include/default-distrovars.inc:
DISTRO_FEATURES_DEFAULT ?= \
"alsa argp bluetooth ext2 irda largefile pcmcia usbgadget \
  usbhost wifi xattr nfs zeroconf pci 3g nfc x11"

into my conf/local.conf file as:
DISTRO_FEATURES = \
"alsa argp bluetooth ext2 irda largefile pcmcia usbgadget \
usbhost wifi xattr nfs zeroconf pci 3g nfc x11"

and I if I do a bitbake world it fails with:


NOTE: Resolving any missing task queue dependencies
ERROR: Nothing PROVIDES 'virtual/libgl' (but
/home/rmacleod/src/distro/oe/oe-core.git/meta/recipes-graphics/clutter/clutter-1.0_1.14.4.bb, 
/home/rmacleod/src/distro/oe/oe-core.git/meta/recipes-graphics/mesa/mesa-demos_8.1.0.bb, 
/home/rmacleod/src/distro/oe/oe-core.git/meta/recipes-graphics/glew/glew_1.10.0.bb, 
/home/rmacleod/src/distro/oe/oe-core.git/meta/recipes-qt/qt4/qt4-x11-free_4.8.5.bb, 
/home/rmacleod/src/distro/oe/oe-core.git/meta/recipes-graphics/mesa/libglu_9.0.0.bb, 
/home/rmacleod/src/distro/oe/oe-core.git/meta/recipes-graphics/cogl/cogl-1.0_1.14.0.bb 
DEPENDS on or otherwise requires it)
ERROR: mesa PROVIDES virtual/libgl but was skipped: missing required 
distro feature ['opengl'] (not in DISTRO_FEATURES)
ERROR: mesa-gl PROVIDES virtual/libgl but was skipped: missing required 
distro feature ['opengl'] (not in DISTRO_FEATURES)
ERROR: mesa PROVIDES virtual/libgl but was skipped: missing required 
distro feature ['opengl'] (not in DISTRO_FEATURES)
ERROR: Required build target 'clutter-gtk-1.0' has no buildable providers.
Missing or unbuildable dependency chain was: ['clutter-gtk-1.0', 
'clutter-1.0', 'virtual/libgl']



If I drop x11 from the DF list things are even worse.

I tried to sprinkle these recipes with:
    REQUIRED_DISTRO_FEATURES = "opengl"
but just as I thought, that didn't work either.

-- 
# Randy MacLeod. SMTS, Linux, Wind River
Direct: 613.963.1350