[OE-core] more pedantry: inconsistent presentation of how to introduce layers

[Robert P. J. Day]

  i asked about this not that long ago but i'm still a bit puzzled --
what's the best practice for adding new layers in terms of how
bblayers.conf and the various layer.conf files are defined?

  the default layer.conf for oe-core contains:

BBPATH .= ":${LAYERDIR}"
...
BBFILE_PRIORITY_normal = "5"

so, clearly, the oe-core layer is being *appended* to whatever is in
BBPATH.  ok, let's go with that.

  on the other hand, that same file for the meta-yocto layer contains:

BBPATH := "${LAYERDIR}:${BBPATH}"
...
BBFILE_PRIORITY_yocto = "5"

so it's being *prepended*.  is that deliberate?  the end result is
that my BBPATH is:

/home/rpjday/yocto/git/meta-yocto:/home/rpjday/yocto/builds/bbc4:/home/rpjday/yocto/git/meta

which clearly represents:

 * the yocto layer
 * my build layer
 * the oe-core layer

with both the yocto and oe-core layer having priority 5.  is there no
chance of confusion here?

  in addition, the yocto development manual itself, in section 4.1.2
on layers, stresses the use of:

BBPATH := "${LAYERDIR}:${BBPATH}"

but every single meta-openembedded sub-layer uses the *other* form:

BBPATH .= ":${LAYERDIR}"

  anyone reading the manual and trying to match it up to the code is
bound to get confused.  thoughts?

rday

-- 

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

Twitter:                                       http://twitter.com/rpjday
LinkedIn:                               http://ca.linkedin.com/in/rpjday
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