Gavin Williams details accidental CLR backdoors on DOTNET-CLR list
Here's the problem in a nutshell: Because class instances are always
passed by reference and are often mutable, it is very easy to
accidentally create back doors in your classes, causing:
1. Unexpected changes in internal state
2. Race conditions in methods executing asynchronously
3. Modification of properties you thought were read-only
("immutability leakage", a special case of #1)
He gives an example of problem #3 in System.Net code:
using System.Net;
class Main
{
static void Main(string[] args)
{
IPAddress ip = IPAddress.Loopback;
// Do something interesting with ip...
// Now set a new value
ip.Address = 2345235;
// Congratulations!
// You've just changed IPAddress.Loopback to
// 19.201.35.0
// and broken the IPAddress.IsLoopback method.
}
}
So far, the discussion on the list offers no solutions to what appers to be pretty serious problem.
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