[Zope-dev] zope.app.publication dependencies (volunteers needed!)

[Martijn Faassen]

Hi there,

zope.app.publisher is depended on by quite a bit of code that uses the 
Zope Toolkit, as it defines  brower:view and browser:resource and the like.

Unfortunately zope.app.publisher currently depends on more than 60 
packages. This is rather excessive, and we'd like to cut down on this.

Also interesting about zope.app.publisher is that while it defines a 
'browser' directory it actually doesn't contain any ZMI code; instead 
ZCML directives are defined there. Refactoring so the ZMI isn't around 
anymore is usually a good first step, but that's not needed here.

If you look at the dependency graph for zope.app.publisher the task of 
fixing this looks daunting:

http://startifact.com/depgraphs/zope.app.publisher.svg

But now please observe the following:

http://startifact.com/depgraphs/zope_app_publisher_cycles.svg

This identifies the main cycles in that dependency graph. If we break 
those in the right way, we can cut down a lot of dependencies in one go. 
Getting rid of the zope.app.form and zope.formlib dependencies looks 
like a sensible step.

 From this little graph, it looks clear we could do some of the 
following things (research is needed to see how difficult they are):

* cut the dependency of zope.app.publisher on zope.app.component

* OR cut the dependency of zope.app.component on zope.formlib

* cut the dependency of zope.app.publisher on zope.app.publication

* OR cut the dependency of zope.app.component on zope.app.security

* cut the dependency of zope.app.publisher on zope.app.publication

* OR cut the dependency of zope.app.publication on zope.app.exception

* OR cut the dependency of zope.app.exception on zope.formlib

There are probably a few more options there, but given that small graph, 
you get the picture.

Any volunteers to do this research on how hard some of these steps would 
look and report back here? Once we've discussed the options we can 
proceed fixing the problem.

Regards,

Martijn