Emerge: Plotting build dependencies graph, emerge -k/-j

[Ralf Habacker]

Sascha L. Teichmann schrieb:
> Hi together,
>
> some of you may heard me talking about the "emerge -j/-k" stuff at
> the KDE for Windows meeting here at Osnabrück/2010-06-05. Now its
> finally there! :-)
>
> We've have made some improvements to emerge that allow us to set
> it up in a more automated/unattended environment to build
> Kontact Enterprise 5 (KDE/PIM E5).
>   
This looks very good.
>   I - Plotting the build dependencies graph as a dot graph.
>
>     $ python bin\dependencies.py enterprise5/kdepim-e5 > kdepim-e5.dot
>     $ dot -Tsvg -okdepim-e5.svg kdepim-e5.dot
>
>     That gives you [1]. Visualizing this helped us a lot to fix
>     broken dependencies. What we've found should be in upstream already.
>     You can use the bin/dependencies.py with a --format=xml parameter
>     to get the deps as XML which may be useful to process it further
>     with other tools
>   
This is a very usefull feature for dependency checking - I played 
yesterday with this  and found immediatly two dependency issues which 
should be solved.

1. win32libs-bin/libxml depends on iconv, while other packages requiring 
iconv depends on win_iconv
2. wget is listed as dependency for many packages. For my opinion wget 
should only be the first dependency of virtual/base and nowhere else.


An issue i found while running

python bin\dependencies.py enterprise5/kdepim-e5 > kdepim-e5.dot

is that a debug line is printed at the top of the dot file  - not sure 
yet where it came from.

Another little issue i found is a naming problem - In portage.py there 
is a new  function def get_packages_categories - in emerge function are 
normally written in Camel Case with first character lowercase, so it 
should be  def getPackagesCategories

One extension I suggest is to change

def __str__(self):
140 	return "%s:%s:%s:%s" % (
141 	self.category, self.package, self.version, self.tag)


into

def __str__(self):
140 	return "%s\\n%s\\n%s\\n%s" % (
141 	self.category, self.package, self.version, self.tag)


which increases readability by printing each attribute in a new line. 
Also with this change the graph is smaller in width. If you you forced 
to use the original style, we should add a parameter to switch the 
output format.

Second I suggest to add an additional emerge command like

emerge --print-dependencies <package>

to make this features callable in the normal way.

> II - emerge -k
>   
I will take a look later
> III - emerge -j
>   
I will take a look later
> You find our emerge changes in the intevation-merge branch [4].
> It would be nice to have merged them back into trunk. :-)
>   
I will take some time for merging the stuff into trunk.

Many thanks for contributing this stuff.


Regards
 Ralf