Recreate stack trace with line numbers from user bug-report in .net?

Question

First, the problem: I have several free projects, and as any software they contains bugs. Some fellow users when encounter bug send me a bug-reports with stack

Answer 1

You can get the offset of the last MSIL instruction from the Exception using System.Diagnostics.StackTrace:

// Using System.Diagnostics
static void Main(string[] args)
{
    try { ThrowError(); }
    catch (Exception e)
    {
        StackTrace st = new System.Diagnostics.StackTrace(e);
        string stackTrace = "";
        foreach (StackFrame frame in st.GetFrames())
        {
            stackTrace = "at " + frame.GetMethod().Module.Name + "." + 
                frame.GetMethod().ReflectedType.Name + "." 
                + frame.GetMethod().Name 
                + "  (IL offset: 0x" + frame.GetILOffset().ToString("x") + ")\n" + stackTrace;
        }
        Console.Write(stackTrace);
        Console.WriteLine("Message: " + e.Message);
    }
    Console.ReadLine();
}

static void ThrowError()
{
    DateTime myDateTime = new DateTime();
    myDateTime = new DateTime(2000, 5555555, 1); // won't work
    Console.WriteLine(myDateTime.ToString());
}

Output:

at ConsoleApplicationN.exe.Program.Main (IL offset: 0x7)
at ConsoleApplicationN.exe.Program.ThrowError (IL offset: 0x1b)
at mscorlib.dll.DateTime..ctor (IL offset: 0x9)
at mscorlib.dll.DateTime.DateToTicks (IL offset: 0x61)
Message: Year, Month, and Day parameters describe an un-representable DateTime.

You can then use Reflector or ILSpy to interpret the offset:

.method private hidebysig static void ThrowError() cil managed
{
    .maxstack 4
    .locals init (
        [0] valuetype [mscorlib]System.DateTime myDateTime)
    L_0000: nop 
    L_0001: ldloca.s myDateTime
    L_0003: initobj [mscorlib]System.DateTime
    L_0009: ldloca.s myDateTime
    L_000b: ldc.i4 0x7d0
    L_0010: ldc.i4 0x54c563
    L_0015: ldc.i4.1 
    L_0016: call instance void [mscorlib]System.DateTime::.ctor(int32, int32, int32)
    L_001b: nop 
    L_001c: ldloca.s myDateTime
    L_001e: constrained [mscorlib]System.DateTime
    L_0024: callvirt instance string [mscorlib]System.Object::ToString()
    L_0029: call void [mscorlib]System.Console::WriteLine(string)
    L_002e: nop 
    L_002f: ret 
}

You know that the instruction before 0x1b threw the exception. It's easy to find the C# code for that:

 myDateTime = new DateTime(2000, 5555555, 1);

You could map the IL code to your C# code now, but I think the gain would be too little and the effort too big (though there might be a reflector plugin). You should be fine with the IL offset.