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Type: New Feature
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Status: Closed
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Priority: Major
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Resolution: Fixed
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Affects Version/s: V4.0_CSD01
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Fix Version/s: V4.0_CSD02
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Component/s: Protocol
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Labels:None
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Environment:
[Applied]
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Proposal:
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Resolution:
Protocol spec (2013-03-12) states in section 10.3 Requesting Changes.
Services MAY support requesting changes for arbitrary queries against the entityset or MAY require that any filters be applied solely to immutable (i.e., key) fields.
Now suppose that a client is interested in change tracking for a particular entity set, using a filter.
The client must first try the query with the filter (and with odata.track-changes preference), and will get a result, but it may finally prove to have no delta link (the client has no way to know in advance if the server will provide a delta link).
Then the client (if the server doesn't provide a delta link) may need to try the query again without a filter, and then somehow apply the filter "locally" (on the client-side). Again the client may discover that the server doesn't support change tracking (even for the case without a filter).
It would be much preferred by client application and framework designers for OData services somehow to be able to "advertise" their support (or not) for change tracking (and any limits that are placed upon it, such as what kind of filters can be used), rather than the clients having to discover by a process of trial and error.