[1/1] conf/bitbake.conf: add DISTRO_FEATURES_BACKFILL
Submitted by Paul Eggleton on Feb. 23, 2012, 7:26 p.m.
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Patch ID: 21849
Details
Commit Message
@@ -694,6 +694,9 @@ MACHINE_ESSENTIAL_EXTRA_RDEPENDS ?= ""
MACHINE_ESSENTIAL_EXTRA_RRECOMMENDS ?= ""
IMAGE_FEATURES += "${EXTRA_IMAGE_FEATURES}"
+DISTRO_FEATURES_BACKFILL = ""
+DISTRO_FEATURES_append = "${@oe.utils.distro_features_backfill(d)}"
+
COMBINED_FEATURES = "\
${@base_both_contain("DISTRO_FEATURES", "MACHINE_FEATURES", "alsa", d)} \
${@base_both_contain("DISTRO_FEATURES", "MACHINE_FEATURES", "bluetooth", d)} \
@@ -88,3 +88,23 @@ def param_bool(cfg, field, dflt = None):
def inherits(d, *classes):
"""Return True if the metadata inherits any of the specified classes"""
return any(bb.data.inherits_class(cls, d) for cls in classes)
+
+def distro_features_backfill(d):
+ # This construct allows the addition of new features to DISTRO_FEATURES
+ # that if not present would disable existing functionality, without
+ # disturbing distributions that have already set DISTRO_FEATURES.
+ # Distributions wanting to elide a value in DISTRO_FEATURES_BACKFILL should
+ # add the feature to DISTRO_FEATURES_BACKFILL_CONSIDERED
+
+ backfill = (d.getVar("DISTRO_FEATURES_BACKFILL", True) or "").split()
+ considered = (d.getVar("DISTRO_FEATURES_BACKFILL_CONSIDERED", True) or "").split()
+
+ addfeatures = []
+ for feature in backfill:
+ if feature not in considered:
+ addfeatures.append(feature)
+
+ if addfeatures:
+ return " %s" % (" ".join(addfeatures))
+ else:
+ return ""
Comments
When introducing new items to DISTRO_FEATURES that control functionality that is already enabled, in order to leave existing distro configuration unchanged we need a way to "backfill" these new feature items onto the existing DISTRO_FEATURES value. This introduces a DISTRO_FEATURES_BACKFILL variable whose items will be added to the end of DISTRO_FEATURES, unless they also appear in DISTRO_FEATURES_BACKFILL_CONSIDERED which distros can use in their configuration to prevent specific items from being added. Fixes [YOCTO #1946]. Signed-off-by: Paul Eggleton <paul.eggleton@linux.intel.com> --- meta/conf/bitbake.conf | 3 +++ meta/lib/oe/utils.py | 20 ++++++++++++++++++++ 2 files changed, 23 insertions(+), 0 deletions(-)