[OASIS Issue Tracker] (TOSCA-226) Proposal (incomplete) to change Requirement Def. from Ordered List to a Map

Matthew Rutkowski  created TOSCA-226:
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             Summary: Proposal (incomplete) to change Requirement Def. from Ordered List to a Map
                 Key: TOSCA-226
                 URL: https://issues.oasis-open.org/browse/TOSCA-226
             Project: OASIS Topology and Orchestration Specification for Cloud Applications (TOSCA) TC
          Issue Type: New Feature
          Components: Profile-YAML
    Affects Versions: CSD2
            Reporter: Matthew Rutkowski 
            Assignee: Thomas Spatzier 
            Priority: Minor


Currently, the listing of requirement definitions in Node Types are in the form of an Ordered List to assure determinism by type/template authors to provide deterministic order to orchestrators when fulfilling them.  

Thomas proposes we make this a simple "map" (or hashmap), but this has acknowledged problems and cannot be done without a comprehensive proposal that addresses them including:

- Hashmaps cannot have duplicate keynames however, TOSCA allows duplication of symbolic requirement names.
- Maps are "sets" and have no order.

In any event, we have a (potential) ordering problem  when Node Types are sublcassed and the child type adds new Requirement defintions.  There is currently no way to indicate how these new requirements introduced by the child Type should be ordered relative to the parents' requirements.



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