[Zope3-dev] Re: "most specific" interface?

[Florent Guillaume]

Philipp von Weitershausen wrote:
>   >>> from zope.app.content.interfaces import IContentType
>   >>> from zope.app.file.interfaces import IFile
>   >>> from zope.interface import directlyProvides
>   >>> directlyProvides(IFile, IContentType)

Watch out! directlyProvides is evil, it *replaces* the interfaces provided 
by something. Here, if IFile implemented something else, it would be lost.

You should always use:

   directlyProvides(ob, ISomething, directlyProvidedBy(ob))

(Or use a convenience method to do that, I'm not sure if alsoProvides() was 
ever implemented.)

Florent

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Florent Guillaume, Nuxeo (Paris, France)   CTO, Director of R&D
+33 1 40 33 71 59   http://nuxeo.com   fg at nuxeo.com