[yocto] Correctly setting a package-specific RDEPENDS

[Jon Szymaniak]

> On Wednesday 05 June 2013 10:53:23 Jon Szymaniak wrote:
>> I recently upgraded to the Dylan (9.0.0) release and am looking to
>> clean up some QA issues associated with my RDEPENDS variables not
>> being package-specific.
>>
>> I'm a bit confused by a couple lines in the manual [1]:
>>
>> "The names of the variables you list with RDEPENDS must be the names
>> of other packages as listed in the PACKAGES variable. You should not
>> list recipe names (PN)."
>
> I think the mention of PN here is confusing. It's trying to explain that you
> should use package names and not recipe names, but perhaps the wording needs
> to be improved.
>
>> It makes sense to me that you'd want to set the run-time deps on a
>> per-package basis to avoid creating false-dependencies. However, I'm
>> unsure as to how can simply not write RDEPENDS_${PN} in some cases.
>> Furthermore, I feel like I'm not quite understanding what the
>> consequences of using RDEPENDS_${PN} are.
>>
>> Here's an example of what I'm trying to do -- perhaps someone will
>> catch where I'm getting confused and offer some insight?
>>
>> Let's say I have a program_a.bb and a program_b.bb. Both are simple
>> recipes that compile and install ${D}/usr/bin/program_a and
>> ${D}/usr/bin/program_b.
>>
>> Because program_a forks and execs program_b, but otherwise does not
>> depend upon it to compile, I thought I should place RDEPENDS_${PN} =
>> "program_b " in program_a.bb.  However, this seems to violate the
>> aforementioned snippet from the manual.
>
> That is the expected usage; I guess the manual has confused you. All the QA
> warning is saying is you should do this:
>
> RDEPENDS_${PN} = "somepackage"
>
> and _not_ this:
>
> RDEPENDS = "somepackage"
>
> (The reason being, the latter would add a runtime dependency on "somepackage"
> to every package in the recipe's PACKAGES, which is almost never the desired
> result.)
>
> Cheers,
> Paul
>
> --
>
> Paul Eggleton
> Intel Open Source Technology Centre


Hi Paul,

That clarifies things greatly. Many thanks!

- Jon