[Buildroot] [PATCH 50/50 v2] support/scripts: don't draw most of busybox' dependencies

Sun Jul 8 14:05:59 UTC 2018

On 08-07-18 14:42, Yann E. MORIN wrote:
> Arnout, All,
> 
> On 2018-07-08 13:25 +0200, Arnout Vandecappelle spake thusly:
>> On 08-07-18 11:46, Yann E. MORIN wrote:
>>> Since most dependencies of busybox' are there to guarantee that busybox
>>> does not install applets that are already provided by other packages,
>>> they are not really functional dependencies, and mostly clutter the
>>> dependency graph.
>>
>>  The thing is, they still are dependencies. I often use graph-depends to do a
>> poor man's TLPB by starting builds of individual packages in separate shells,
>> but then I first have to check that their dependency chains are non-overlapping.
>> If you're going to hide some dependencies, that's not going to work any more...
>>
>>  I also sometimes use it to understand why make decides to execute things in a
>> particular order. Again, hiding dependencies doesn't help there.
>>
>>  On the other hand, it's like the toolchain: you know everything depends on the
>> toolchain, and similarly you know that buildroot depends on everything. So maybe
>> it's not that bad.
> 
> Well, I like the depednency graph to also represent "why is the foo
> package enabled, when I don;t want it? Oh, it is a dependnecy of bar,
> I should disable bar then." In the case of busybox, that is wrong:
> busybox does not need those packages, so graphing such dependency can
> be misleading...

 That would indeed be really useful. Unfortunately, the dependency graph gives
you none of that information, because you also get the automatic optional
dependencies.

 And actually, the Kconfig help text already gives that information. If you
think it is unreadable (which it is), update to the latest linux kconfig, it has
been much improved.

> 
> But I don;t care much, so I marked it as rejected.

 Great! :-)

 Regards,
 Arnout

> 
> Regards,
> Yann E. MORIN.
> 
>>>
>>> Only the dependencies on libraries are interesting, so that is all we
>>> keep.
>>>
>>> Even though that function is only called with pkg set to 'busybox', we
>>> still pass it as an argument, for symetry with the other functions that
>>> removes the dependencies of a package.
>>>
>>> Signed-off-by: "Yann E. MORIN" <yann.morin.1998 at free.fr>
>>> Reviewed-by: Matt Weber <matthew.weber at rockwellcollins.com>
>>> Cc: Carlos Santos <casantos at datacom.com.br>
>>>
>>> ---
>>> Changes v1 -> v2:
>>>   - carry tag from Matt
>>>   - clarify linux-pam case  (Carlos)
>>> ---
>>>  support/scripts/graph-depends | 11 +++++++++++
>>>  1 file changed, 11 insertions(+)
>>>
>>> diff --git a/support/scripts/graph-depends b/support/scripts/graph-depends
>>> index 621e603278..0a3bc11be7 100755
>>> --- a/support/scripts/graph-depends
>>> +++ b/support/scripts/graph-depends
>>> @@ -181,6 +181,15 @@ def remove_mandatory_deps(pkg, deps):
>>>      return [p for p in deps[pkg] if p not in ['toolchain', 'skeleton']]
>>>  
>>>  
>>> +# This function removes all dependencies of busybox, except its
>>> +# dependencies on libraries (of which libpam, from linux-pam) and
>>> +# host-pkgconf.
>>> +def remove_busybox_deps(pkg, deps):
>>> +    busybox_dep_whitelist = ['linux-pam', 'host-pkgconf']
>>> +    return [p for p in deps[pkg]
>>> +            if p.startswith('lib') or p in busybox_dep_whitelist]
>>
>>  This feels horribly fragile to me...
>>
>>
>>  I would feel more comfortable if we would introduce _INSTALL_DEPENDENCIES, as
>> discussed in v1 of the series, and then simply exclude the _INSTALL_DEPENDENCIES
>> from the graph. Or maybe even add a graph-depends option to do that.
>>
>>
>>  Note: I have *not* marked this patch as changes requested, since it's actually
>> good to go, except that I have more fundamental concerns about it.
>>
>>  Regards,
>>  Arnout
>>
>>
>>> +
>>> +
>>>  # This function will check that there is no loop in the dependency chain
>>>  # As a side effect, it builds up the dependency cache.
>>>  def check_circular_deps(deps):
>>> @@ -211,6 +220,8 @@ def check_circular_deps(deps):
>>>  # This functions trims down the dependency list of all packages.
>>>  # It applies in sequence all the dependency-elimination methods.
>>>  def remove_extra_deps(deps, transitive):
>>> +    if 'busybox' in list(deps.keys()):
>>> +        deps['busybox'] = remove_busybox_deps('busybox', deps)
>>>      for pkg in list(deps.keys()):
>>>          if not pkg == 'all':
>>>              deps[pkg] = remove_mandatory_deps(pkg, deps)
>>>
>>
>> -- 
>> Arnout Vandecappelle                          arnout at mind be
>> Senior Embedded Software Architect            +32-16-286500
>> Essensium/Mind                                http://www.mind.be
>> G.Geenslaan 9, 3001 Leuven, Belgium           BE 872 984 063 RPR Leuven
>> LinkedIn profile: http://www.linkedin.com/in/arnoutvandecappelle
>> GPG fingerprint:  7493 020B C7E3 8618 8DEC 222C 82EB F404 F9AC 0DDF
> 

-- 
Arnout Vandecappelle                          arnout at mind be
Senior Embedded Software Architect            +32-16-286500
Essensium/Mind                                http://www.mind.be
G.Geenslaan 9, 3001 Leuven, Belgium           BE 872 984 063 RPR Leuven
LinkedIn profile: http://www.linkedin.com/in/arnoutvandecappelle
GPG fingerprint:  7493 020B C7E3 8618 8DEC 222C 82EB F404 F9AC 0DDF