Prevent setting non-nullable reference properties to NULL

[dotnet-bot]

Issue by piotrpMSFT
Tuesday Jan 20, 2015 at 19:16 GMT
Originally opened as https://github.com/Microsoft/vipr-old/issues/50

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OData supports properties of structrural reference types [e.g. string, Complex Types]. These reference type properties can be specified to be nullable or non-nullable. When non-nullable, the generated proxy cannot express that a user is unable to set the value to null.

When a user tries setting such a property's value to null we could throw an exception from the property Setter. It is unclear if this is necessary or beneficial since the generated proxy would not provide design-time support for preventing invalid code, and a runtime exception would be propagated from the service when a request is made.

[TheRealPiotrP]

Issue #30 has a proposed design which seems analagous to this problem. A solution here would be to introduce a construct akin to Nullable called NonNullable [or similar]. NonNullable would support setting its internal Value property to any value but null. This construct would itself be wrapped in a Fetchable [or whatever we decide to call it] such that it can exist in the uninitialized state.