[OE-core] more pedantry -- looking to clarify layers definition, BBPATH, BBFILES, etc.

[Robert P. J. Day]

  (most of this is sort of self-evident but it's not documented as
well as it could be so i just want to make sure i have it exactly
right.)

  snippets of some layer.conf files:

oe-core:

BBPATH .= ":${LAYERDIR}"
BBFILES += "${LAYERDIR}/recipes-*/*/*.bb"

meta-hob:

BBPATH := "${BBPATH}:${LAYERDIR}"
BBFILES := "${BBFILES} ${LAYERDIR}/recipes-*/*/*.bb"

meta-yocto:

BBPATH := "${LAYERDIR}:${BBPATH}"
BBFILES := "${BBFILES} ${LAYERDIR}/recipes-*/*/*.bb \
            ${LAYERDIR}/recipes-*/*/*.bbappend"

  note how meta-hob *appends* itself to BBPATH, while meta-yocto
*prepends* itself.  is there no possibility that this will cause some
confusion based on how BBPATH is used to resolve the location of class
or conf files?  i realize you should try to avoid that sort of
conflict but it still seems possible that someone might choose the
names of some files badly and the unpredictable ordering in BBPATH
will cause grief, no?

rday

-- 

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Robert P. J. Day                                 Ottawa, Ontario, CANADA
                        http://crashcourse.ca

Twitter:                                       http://twitter.com/rpjday
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