Re: Debug Packaging

[Mark Hatle <mark.hatle@windriver.com>]

On 4/29/13 3:10 PM, Richard Purdie wrote:
> On Sat, 2013-04-27 at 17:15 -0400, Chris Larson wrote:
>
>> On Thu, Apr 25, 2013 at 7:12 AM, Phil Blundell <pb@pbcl.net> wrote:
>
>>          I'm not quite sure what the right way to fix (2) is.  I
>>          suppose in an
>>          ideal world the -dbg packages would be separated in the same
>>          way the
>>          parent binary packages are, but that doesn't look entirely
>>          straightforward to arrange.
>>
>> I had implemented something along these lines back in oe classic, when
>> I was at MontaVista.  See
>> http://git.openembedded.org/openembedded/tree/classes/package_dbg.bbclass for that implementation. I haven't touched it or tried using it in some time, however.
>
> I have to admit I've been wondering if we shouldn't overhaul the -dbg
> part of the system a bit. There are a few things I've been wondering
> about:
>
> a) Should we ditch FILES_${PN}-dbg and have it auto constructed from
> any .debug directories? This would be a rather nice automation/cleanup.
> I can't see a pressing reason not to do this.
>
> b) Consider splitting it to a -dbg package per package where there are
> debug files as per above. There are pros and cons to this and I'm torn,
> see c).
>
> c) Consider splitting the debug source into a separate package. If we
> did do b), the question is where should the sources go?

I think that the proposal for automatically generating a -dbg per regular 
package is a good one.  Then the sources can go into -dbg-source or something 
similar.. (source-dbg so it still ends in dbg).

This will give us the most flexibility to limit the amount of code that HAS to 
be installed onto a target to do basic crash dumping, if not full debug on the 
target.

> In the bigger picture we have various dependency chain issues as the
> -dbg and -dev dependency changes are horrible. The question has always
> been whether X-dbg or X-dev should be usable to pull in sensible
> dependencies.
>
> Thinking about the scenarios you might use these in:
>
> a) A binary from package X segfaults. You want to get good gdb data for
> why. You therefore install X-dbg. X links against Y. You therefore want
> the symbols/code for Y too so you can trace into the problem which may
> be in Y.

This is the one that is sketchy to me.  I think the rrecommend is a good idea 
here.  If you recommend everything that the main package (that you based on) 
needs that you should be able to do this.  By splitting the size of the -dbg 
into smaller units then the -dbg recommends should be limited as well.  I say 
recommend vs depend simply because the there are cases where I only want the 
symbols for one binary, I don't care about it's dependencies.

The question though is should the source also be a recommend or suggest?

> b) You want to compile against X, you install X-dev. You expect anything
> X needs to link with (e.g. through any .pc file) to also be present.
>
> c) You want to rebuild X and hence install X-dev to ensure the build
> dependencies are present.

I think this very much reasonable on the -dev front.  If I install a -dev 
package, I expect the system to be able to compile software without additional 
manual steps.

> d) There was once an idea that you could do something like install
> core-image-minimal-dev to get the equivalent of core-image-minimal with
> dev-pkgs. I think we've found better ways to do this kind of thing now?
>
> In a/b/c, the usability fail is if you try to gdb/compile, find a
> dependency missing, install it and repeat this cycle several times over.

Ya, the issue though is there are more use cases for debug then for the -dev 
case.  So I'm comfortable with slight differences in behavior between the two.

--Mark

> Given d) is dead, thankfully, does that let us rip some code out and
> improve the dependencies?
>
> Cheers,
>
> Richard
>
>
>
>
>
>
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