[Product-Developers] Re: unit test on Plone 4.0b1

Ross Patterson me at rpatterson.net
Sat Mar 20 20:10:20 UTC 2010

Derek Broughton <derek at pointerstop.ca> writes:

> Wichert Akkerman wrote:
>> On 3/20/10 15:33 , Derek Broughton wrote:
>>> Thanks for this discussion - I'm loathe to even test Plone4 at the
>>> moment beccause I don't know enough about this sort of change.
>>> Surely, though, dependencies on something like CMFCore should be
>>> fulfilled by declaring the dependency on Plone.
>> They are, but you should never rely on that: Plone might be modified
>> to not use CMFCore anymore itself, and your package would suddenly
>> break.  For Plone and CMFCore that is not very likely short term, but
>> in general you should never rely on indirect dependencies. They
>> *will* hurt you at some point.
> Ah, but I rather look at it the opposite way - I _should_ rely on
> indirect dependencies for something like CMFCore, because I only use
> it as required in Plone.  If plone was to drop that dependency and use
> something else (specifically this _did_ happen with CMFCore
> Permissions - at least the module moved), I _want_ my product to break
> and require me to fix my code.  The absolutely last thing I want is
> for my code to continue to import something that will only be used by
> my own products while everybody else is doing something different.

+1  Well said, I've often thought this when I've heard the
above install_requires dogma.


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