We would like to include license texts (generic LICENSE + LIC_FILES_CHKSUMs) in PN-lic to install them on target.

http://lists.linuxtogo.org/pipermail/openembedded-core/2012-November/032174.html

I've talked with Beth about this:
Tue Nov 27 18:50:49 2012:
18:24 <pidge> hey martin, I have some questions about what you're looking for with license.bbclass
18:26 <JaMa> hi
18:27 <pidge> hiya
18:27 <pidge> I want to understand a bit more fully what you're looking to do
18:28 <JaMa> currently there is license in package metadata and opkg shows it
18:28 <pidge> yes
18:28 <JaMa> for proprietary packages we would like to also package license text in main package
18:28 <JaMa> so that on target device you can actually read what license 'proprietary-foo' says
18:29 <pidge> ah, ok
18:29 <pidge> so, a few things
18:29 <pidge> you know about LICENSE_PATH I assume
18:29 <JaMa> so such functionality should add do_install_append which copies files referenced by LIC_FILES_CHKSUM to some unified location
18:30 <pidge> yes, that'd kind of what I was thinking.
18:31 <JaMa> I'm not sure if LICENSE_PATH is what I'm looking for
18:32 <pidge> no, only for adding the custom generic
18:32 <pidge> ok, so... one way to do it is with COPY_LIC_MANIFEST and COPY_LIC_FILES but I don't think it will do exactly what you want.
18:33 <pidge> if I understand correctly, what you want is for the license text to be added to the package so when the package is installed it's added to the image.
18:33 <pidge> that sound about right?
18:33 <JaMa> ah reading COPY_LIC_DIRS + COPY_LIC_MANIFEST once again looks close to what we want
18:34 <JaMa> yes it's close, but doesn't solve when some package is installed by opkg after image creation
18:34 <pidge> yeah. not exact, but I think what you're asking for may be more useful in certain use cases
18:34 <pidge> right
18:35 <pidge> and honestly, we should be packaging with licenses anyway
18:35 <JaMa> I think what I want can replace COPY_LIC_DIRS + COPY_LIC_MANIFEST
18:35 <pidge> so, I think the right place to do this is within package.bbclass
18:36 <JaMa> because with licenses in packages itself you don't need to create manifest and license dir on rootfs time
18:37 <pidge> some people do require the manifest. but yeah, I think that doing it via the packager is cleaner.
18:37 <pidge> hrm.......
18:37 <pidge> ok, how does this sound....
18:38 <pidge> on do_package the packager grabs the license text and also creates the spdx metadata and packages it up with everything.
18:38 <JaMa> looks good to me
18:39 <pidge> on do_install if COPY_LIC_MANIFEST is set, we do_install_append to tack on the spdx metadata to the main manifest.
18:39 <JaMa> there is also option to add PN-license with only license included and add PN-license to PN RDEPENDS
18:39 <pidge> and COPY_LIC_DIRS sets up if we package with license text
18:40 <JaMa> but in both cases there is issue with "shared" license text as 2 packages cannot install the same file
18:40 <JaMa> so you can install bigger package with all common-licenses included and then PN installs just symlink which is unique
18:40 <pidge> hrm. right. but they can install a simlink heh, exactly
18:40 <JaMa> or you have to duplicate common license text for each package
18:41 <pidge> simlinks, or else dvhart will have my head ;)
18:41 <JaMa> then there is problem how to generate that big package with all common-licenses :)
18:41 <pidge> poky-tiny will no longer be tiny without that
18:42 <JaMa> it should include all licenses (not only those used on rootfs time) to catch all those ipk files only in feed
18:42 <pidge> hrm.... yeah. can opkg do a conditional install? if the file exists, install?
18:42 <pidge> does not exist
18:42 <pidge> hrm...
18:42 <JaMa> and if it includes all then you have to bump PR or something in such package when common/licenses directory is changed in git
18:43 <pidge> yeah, I think having 168 different common licenses on an image won't fly]
18:43 <pidge> let me think of a cleaner way here.
18:43 <JaMa> or generate package for each license :)
18:44 <JaMa> then PN which wants to install just symlink to shared license will just set right RDEPENDS to install shared license text
18:45 <pidge> hrm. let me look at the package bbclasses. I think there is a way to do this conditionally, which would be the best way to do this

I'll send pull request implementing first part which is good enough for us to use it in package manager, but it doesn't handle shared generic licenses.