[LEDE-DEV] Need help with package dependencies

[Zefir Kurtisi]

Hi,

to those understanding the package dependency logic by heart, I'm trying to
achieve something I assumed to be common, but fail to get there with the help of
the available documentation.

The short version is this:
* package A has an optional feature X provided by package B
* package B is optional (feeds package)
  => feature X should be selectable only if B is installed and selected
* if feature X is activated, package A depends from package B

I did:
1) in Config.in of package A add
config WITH_FEATURE_X
	bool
	depends on PACKAGE_B
	prompt "Enable feature X"
	default n

2) in Makefile of package A add
DEPENDS += +WITH_FEATURE_X:B


With those changes, build fails due to recursive dependencies, because
- symbol PACKAGE_B is selected by WITH_FEATURE_X
- symbol WITH_FEATURE_X depends on PACKAGE_B

If I leave out the additional line in Makefile of A and in menu select
WITH_FEATURE_X, the build of A fails with missing dependency to package B.

If I leave out the 'depends on PACKAGE_B' line in Config.in, I can select
WITH_FEATURE_X without package B even being installed, which obviously fails building.


Is this doable out of the box? What am I missing?

BTW, this is about SNMP agentx support for lldpd.


Cheers,
Zefir