C# behaving abnormally in checking for conditions

Question

rule value:

Can any one help me understand how the control is moving into the 'if' block even if rule variable is not null? I'm using EF6

Thanks!

Answer 1

This is a debugger bug. The behavior that is evident in the screenshot is impossible under the C# language spec.

This could be a CLR bug but that is highly unlikely. if does not have bugs.

Create a small, executable repro and report it on MS Connect.

You can add an assertion rule == null in the if statement body and it will not fire. That proves that the value is actually null as expected.

As a funny yet unlikely alternative theory there could be an overloaded and broken operator equals.

In my experience debugger bugs are not rare. I have found a few over the years. Nothing too serious. The debugger is a very complicated piece of machinery that inspects running programs in a very invasive way. Hard to get that 100% right.

Answer 2

The only explanation (outside of an unlikely bug in VS) is that the source version does not match the compiled version (compiled version = debug symbols). This is possible using this setting in Visual Studio.

Debug (menu) -> Options (menu item) -> Debugging (tab) -> General -> "Require source files to exactly match the original version"

If you had if(rule != null) before and all you did was change it to if(rule == null) in the code but the debug symbols did not update then this could explain the behavior on screen.