how to build last

[Luigi Semenzato]

Suppose I want to take a Chromiumos image and add stuff to it.  Suppose I wish to ensure that my stuff is installed after everything else, and I am OK with giving up some build parallelism.  Can I do this by interposing an ebuild, say "mydir/mystuff.ebuild", between "virtual/target-os" and its DEPENDs?  Would I do that by creating a new ebuild (mydir/mystuff.ebuild) in my private overlay, and also making a copy of "virtual/target-os" in my private overlay, that depends only on mydir/mystuff?  (What's a good existing dir for "mydir", or a good name?)

Thanks!

[Manoj Gupta]

You will have to make everything in target-os as a dependency of this package.

As an example of custom target-os ebuild, see

https://source.corp.google.com/chromeos_internal/src/private-overlays/overlay-viking-private/virtual/target-os/target-os-4.ebuild

It has:

RDEPEND="

virtual/viking-os

sys-kernel/apex

virtual/u-boot

"

Now lets say you want to build your package <foo> in the end.

Then in the foo ebuild:

You need to add the same dependencies as well in <foo>. 

Also add <foo> as a dependency of target-os.

In the current build script, target-os is a terminal package i.e. nothing can depend on it.

You could however simplify the dependency chain maybe by putting these in another synthetic package e.g. my-project-os.

i.e. my-project-os will have

RDEPEND="
virtual/viking-os
sys-kernel/apex
virtual/u-boot

"

And the package foo can RDEPEND on my-project-os.

Thanks,

Manoj

On Mon, Mar 6, 2023 at 8:54 PM 'Luigi Semenzato' via ChromiumOS Development <chromiu...@chromium.org> wrote:

Suppose I want to take a Chromiumos image and add stuff to it.  Suppose I wish to ensure that my stuff is installed after everything else, and I am OK with giving up some build parallelism.  Can I do this by interposing an ebuild, say "mydir/mystuff.ebuild", between "virtual/target-os" and its DEPENDs?  Would I do that by creating a new ebuild (mydir/mystuff.ebuild) in my private overlay, and also making a copy of "virtual/target-os" in my private overlay, that depends only on mydir/mystuff?  (What's a good existing dir for "mydir", or a good name?)

Thanks!

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[Luigi Semenzato]

Thank you Manoj!

Just to clarify: I want to ensure that _building_ happens in that order, so I should also use DEPEND, not just RDEPEND, correct?  I am not sure that RDEPEND enforces any build order.

[Manoj Gupta]

ime, RDEPEND usually enforces build order but you could also add(or not) to DEPEND and experiment.

[Luigi Semenzato]

Thank you.  Experimenting may not resolve the issue because of that "usually", but this works fine if I add DEPEND="${RDEPEND}" and gives me more confidence that the build order will be respected.