more user manual questions about bitbake tasks

["Robert P. J. Day" <rpjday@crashcourse.ca>]

  it's humbling to realize all the niggling little details i don't
understand completely. oh, well ... some questions about bitbake
tasks, most of which i think i know the answers to but let's play it
safe.

  first, is it true that the *only* way to define a bitbake task is
with the "addtask" directive? given that, one can at least consult
OE's base.bbclass to see the low-level tasks that will be defined for
all work, which i just noticed is a surprisingly short list:

$ grep "^addtask" meta/classes/base.bbclass
addtask fetch
addtask unpack after do_fetch
addtask configure after do_patch
addtask compile after do_configure
addtask install after do_compile
addtask build after do_populate_sysroot
addtask cleansstate after do_clean
addtask cleanall after do_cleansstate
$

  a couple observations about the above. i notice the general format
of the "addtask" directive:

  addtask X after do_Y

where the "do_" prefix is used only on the latter task name. (you'll
see why i mention this shortly.)

  also, i notice that

    addtask build after do_populate_sysroot

defines a task as being run after another task that is undefined in
base.bbclass; that's ok, i can see it being defined in
staging.bbclass:

  addtask populate_sysroot after do_install

so i assume the general rule is that you can define tasks that
"depend" on other tasks that you only have to *eventually* define,
correct?

  one more question. i'm puzzled by this snippet from staging.bbclass:

  python do_populate_sysroot_setscene () {
      sstate_setscene(d)
  }
  addtask do_populate_sysroot_setscene

why is it

  addtask do_populate_sysroot_setscene

rather than:

  addtask populate_sysroot_setscene

i thought the general form of addtask was:

  addtask X ... etc etc ...

the bitbake user manual definitely doesn't explain the syntax of

  addtask do_X ...

but there seems to be some of that scattered around:

$ grep -r "^addtask do_" *
meta/classes/kernel.bbclass:addtask do_strip before do_sizecheck after do_kernel_link_vmlinux
meta/classes/staging.bbclass:addtask do_populate_sysroot_setscene
meta/classes/package_rpm.bbclass:addtask do_package_write_rpm_setscene
meta/classes/license.bbclass:addtask do_populate_lic_setscene
meta/classes/archiver.bbclass:addtask do_ar_original after do_unpack
... snip ...

  are both forms valid?  more task questions coming shortly on another
topic.

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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