[Buildroot] [PATCH 2/3] graph-depends: split off get_version/get_depends into pkgutil.py

[Yann E. MORIN <yann.morin.1998@free.fr>]

Arnout, All,

On 2018-11-07 23:26 +0100, Arnout Vandecappelle spake thusly:
> On 07/11/18 20:39, Yann E. MORIN wrote:
> > I'm changing the way the dependency tree is extracted from the Makefile
> > data, and the function now has this API (function name yet to be
> > bike-shedded about):
>  Let me take this opportunity to bikeshed on this right away :-)

If that were not you, then who else? ;-)

> >     dict_deps, dict_types = get_dependency_tree(direction)
>  I like the function name! However...

Oh come on, that *is* the most important thing! ;-)

> > where:
> > 
> >   - direction is either string 'forward' or 'back',
>  I would make this a boolean argument:
> def get_dependency_tree(backward: bool = True) -> Dict[str, Package]:

Just for my own understanding: what syntax is that? I was trying to write
the protoype of the function, but in Python there is no prototype where
you can explain the return type. Yours seems like it is what I was
looking for. Is it described somewhere?

(See how I'm trying to sidetrack you into not bikeshedding? ;-))

>  Note however that it is trivial to populate the backward dependencies once you
> have the forward ones, so I'm not sure its worth it to make the distinction.

I was also thinking about that too.

> >   - dict_deps is a dictionnary, which keys are the package names, and
> >     which values are lists of packages that are direct dependencies of
> >     the key package (basically, what get_all_depends() currently
> >     returns, but the whole dependency tree)
> > 
> >   - dict_types is a dictionnary, which keys are the package names, and
> >     the values are string representing whtehr the packages are target or
> >     host, and virtual or not, e.g.: 'target', 'target-virtual', 'host',
> >     'host-virtual'.
> 
>  I would take this opportunity to create a class Package with members:
> 
> name: str                  # Package name including hsot- prefix
> dependencies: Set[Package] # Forward dependencies
> dependencies_backwards: Set[Package] # Backward dependencies
> virtual: bool              # If true, it's a virtual package
> host: bool                 # If true, it's a host package
> version: str               # Package version

Meh, I was thinking about exactly the same thing, but it is quite an
invasive change. But let me bikeshed in turn: I would make your proposed
'host' field an enum instead, because we don't have only packages, but
also rootfs. So I would have 'kind' (or 'type' if that's not reserved?)
which could be one of 'target','host', or 'rootfs'.

>  The __init__ would set name, virtual, host, version. The dependencies are added
> dynamically, and whenever you add one you do it in both directions.

Yep.

Dang, I'm always getting side-tracked into side topics. All I wanted was
a faster graph-depends, and it's already there now! Sob... ;-)

Regards,
Yann E. MORIN.

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