Package relationships

[dread]

New domain object: PackageRelationship? (revisioned)

Attributes:

• src (Package reference)
• dest (Package reference)
• type (string)
• comment

Relationship types: is_dependent_on (is_dependency_of) is_derived_from (has_derivation) is_child_of (is_parent_of)

Relationship type is stored using an inherited mapped object, as given in the first column. The reverse relationship (bracketed) is given just for display purposes only.

WUI:

• View: show both sides of the relationship (but think carefully -- e.g. a given package may have *many* dependents ...)
• Editable as part of package or separately? (e.g. like authz)
• Do we normalize to only one type name of the pair?
• Do we allow create of relationship from both ends (e.g. only from dependency to dependent or either way?)

API:

• Appear in package listing Example: 'relationships': [{'is_dependency_of':'osm', comments:'Since version 0.2'}, {'is_parent_of':'bobs_maps'}]
• No need for write access to be provided API for the moment.

This ticket encompasses ticket:169 (Package derivations) and ticket:176 (Package dependencies).