SilvaLayout IMetadata interface doesn't get metadata of versions

[Andy Altepeter]

The SilvaLayout views are defined on IContent and IContainer. Documents are types of IContent (IVersionedContent, to be exact). In a public view layout for a document, the "context" (or model) is the VersionedContent object (document), not the IVersion (documentversion).

When you get the metadata adapter, e.g.
from Products.SilvaLayout.interfaces import IMetadata
md = IMetadata(context)

You get a metadata adapter for the VersionedContent. BUT, versionedcontent objects do not store the metadata, the versions do! So the metadata values you get cannot be for the document, but for the container.

IMetadata is not registered for IVersions.

Since "context" is the document, and we can use SilvaView.is_preview_view to determine which version to adapt, I propose SilvaView should have a get_metadata_adapter method which retrieves an IMetadata adapter for the the correct version (if IVersionedContent), or just for the context.

[Sylvain Viollon (thefunny)]

1. In Silva 3.0 if you ask the metadata of the IVersionedContent you can the metadata of the public (or next or last closed) version in read only, invalidating this issue.

2. The IMetadata adapter have already been fixed to handle this case, in 2.3.