public override void X(){ base.X(); } How can this code change program function?

Question

Why can Overriding a a virtual method, but only calling the base method and doing nothing else, cause a change in how a program functions?

For Example:

    public override void OnDeserialize(NetworkReader reader, bool initialState)
    {
        base.OnDeserialize(reader, initialState);
    }

Overriding:

    public virtual void OnDeserialize ( NetworkReader reader, bool initialState );

Causes different outcomes.

In my case a networking Library called UNET does not work.

You can see the minimised test case here, which includes the logs.

Can you describe how it causes different outcomes? Can you provide an [MCVE]? — ProgrammingLlama, Mar 10 '18 at 10:15
Just building the test case, as I believe it to surely be a bug? Having the method available causes Unity UNET networking to fail. I intended to submit it to Unity, but wanted to make sure I wasn't missing something about C# and override — Jethro, Mar 10 '18 at 10:39
Sorry if it's a bad question, I was hoping it was clear and was hoping that the simple answer is "No"? Will update with the test case one i finish minimizing — Jethro, Mar 10 '18 at 10:42
Yes... The simple answer is `No`. It doesn't change anything if you are just calling base method from the overridden method. I asked for clarification to understand if you have any different expectations from the code. — Chetan, Mar 10 '18 at 11:16
@john Sure, I updated the Q, please see the test case - sorry for delay was minimising it. You can see the logs in the repo too. I have a bug in with Unity which can be found here https://fogbugz.unity3d.com/default.asp?1012108_nj3qm5pqjd3av052 — Jethro, Mar 10 '18 at 11:41

Jethro · Accepted Answer · 2018-03-18T19:52:00.117

Function change should not happen if overrides are used as intended, however function changes are still easily possible.

Libraries could use Reflection to determine if a class is overriding a function, and change it's actions dependent on that check.

In this case it seems to be a bug with Unity. I think it checks to see if a method needs to be called, as an optimisation, are incorrectly written, and cause the change in program flow.

public override void X(){ base.X(); } How can this code change program function?

1 Answers1