Configuration merging logic is incorrect

[maxb]

Whilst reading the code, I noticed a problem with the configuration merging logic.

Consider the case of setting something to a non-default value in the main server configuration and then wanting to override it to the value that happens to be the default for that setting in a .

Since for non-pointer types the current code does not track the difference between "explicitly set to default value" and "not set so using default value", the merging logic cannot take account of this and will incorrectly ignore the inner scope's setting.

[dhawes]

I can verify that the situation you explain exists (tested with CASAttributePrefix). That said, I have never seen any issues reported because of this.

The fix seems easy enough, but I'll have to look at it a little closer.