[OE-core] curious about why bitbake.conf setting of FILES_${PN}-bin

[Robert P. J. Day]

  currently doing a writeup on file distribution among a recipe's
generated packages, and noticed the following. here's a snippet from
OE's bitbake.conf:


PACKAGE_BEFORE_PN ?= ""
PACKAGES = "${PN}-dbg ${PN}-staticdev ${PN}-dev ${PN}-doc ${PN}-locale ${PACKAGE_BEFORE_PN} ${PN}"
PACKAGES_DYNAMIC = "^${PN}-locale-.*"
FILES = ""

FILES_${PN} = "${bindir}/* ${sbindir}/* ${libexecdir}/* ${libdir}/lib*${SOLIBS} \
            ${sysconfdir} ${sharedstatedir} ${localstatedir} \
            ${base_bindir}/* ${base_sbindir}/* \
            ${base_libdir}/*${SOLIBS} \
            ${base_prefix}/lib/udev/rules.d ${prefix}/lib/udev/rules.d \
            ${datadir}/${BPN} ${libdir}/${BPN}/* \
            ${datadir}/pixmaps ${datadir}/applications \
            ${datadir}/idl ${datadir}/omf ${datadir}/sounds \
            ${libdir}/bonobo/servers"


  first, to make sure i understand the above correctly, the setting of
FILES_${PN} defines the (default) entire possible set of generated
files that will be used to populate the packages created by a single
recipe, correct?

  also, since packages are populated in order, left to right, we'll
see file definitions like:

FILES_${PN}-dbg = ...
FILES_${PN}-staticdev = ...
FILES_${PN}-dev = ...

where, once a file is placed in a package, even if that name occurs
again in a later package, it will be skipped. (anyone remember which
manual this is mentioned in?)

  however, i also see this:

FILES_${PN}-bin = "${bindir}/* ${sbindir}/*"

and i thought, that's weird, that particular package isn't mentioned
anywhere in bitbake.conf, why is it being defined if it isn't used?
ah, then i see this in lib_package.bbclass:

PACKAGE_BEFORE_PN = "${PN}-bin"

which clearly defines a library being packaged, but also allowing
binary executables to be broken out separately, which is fine, but
it's confusing why the setting of FILES_${PN}-bin is done in
bitbake.conf, when its only application is (currently) for library
packaging.

  wouldn't it make more sense to move that line so that
lib_package.bbclass contained:

FILES_${PN}-bin = "${bindir}/* ${sbindir}/*"
PACKAGE_BEFORE_PN = "${PN}-bin"

that would make lib_package.bbclass more self-contained, and stop
bitbake.conf from setting a variable that most recipes don't care
about. thoughts?

rday

p.s. this kind of goes back to the image vs core-image discussion,
where one wonders why base classes are doing things that require
inheriting classes to finish off for them. or something like that.

-- 

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

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