CustomUriFunctions should not be static or irreversible

[robward-ms]

CustomUriFunctions is a static class. Registering a function with it by calling AddCustomUriFunction is irreversible. This is a problem for unit testing and object lifecycle in the application itself.

Assemblies affected

Microsoft.OData.Core, Version=7.0.0.0

Reproduce steps

Register a custom function.

Expected result

ODataUriParser can be created with and without the custom functions regardless of global state.

Actual result

CustomUriFunctions.AddCustomUriFunction(...) is the way to register custom functions. ODataUriParser uses CustomUriFunctions to look up signatures, so it's not possible to supply it with a list independent of other instances of ODataUriParser. It's not possible to unregister a function once it's registered, either.

Additional details

In addition, CustomUriFunctions.AddCustomUriFunction(...) can only be called once with the same signature, otherwise it throws an exception with the CustomUriFunctions_AddCustomUriFunction_CustomFunctionOverloadExists error message.

Why is this necessary? Even checking the built-in functions - what is the harm of registering the same signature twice? The implementation is not part of the registration, so this error handling seems counterproductive. It forces the user to lock and check to make sure registration hasn't already happened before calling AddCustomUriFunction.

This wouldn't be an issue if registration was not at a global/class level but at an instance level.

Copied from: OData/WebApi#949

[2BitSalute]

I meant to give it a try myself, but haven't found the time so far.

[habbes]

Closing this due to inactivity. If this issue still affects the latest version of the library, kindly open a new issue.