ALTER ASSEMBLY and Continuous Integration

Question

I have a small assembly of scalar SQL functions built in .NET that I've manually integrated to SQL Server with CREATE ASSEMBLY and then CREATE FUNCTION.  However, as part of my continuous integration and deploy process, I'd like to update the assembly
with every build using ALTER ASSEMBLY.
I've already taken care to guard against an unchanged MvID in the SQL batch I execute to do the update, but whenever a new build runs (and the MvID apparently changes), I get the following error:
ALTER ASSEMBLY failed because the required method "Xxx" in type "Yyy" was not found with the same signature in the updated assembly.
But the signature hasn't changed!  The signature is still just "DateTime? Yyy(DateTime?)".
I've found very little information about this error in particular.  Any suggestions?

Answer 1

I figured out what's the main reason in my case. In SQL Server 2008 R2, it is problem to have UDT with method that contains Nullable return or input parameters in it. For example if you have UDT and added one such method to it, then you do ALTER ASSEMBLY On
SQL Server, assembly will deploy successfully, but the real issue comes when you will try deploy next version of your assembly, even if you don't touch that UDT and that method with Nullable param, you will get. 
"ASSEMBLY failed because the required method "myfunction" in type  "myUDT" was not found
with the same signature in the updated assembly." error
for sure.
I want to mention that I tested and this is not the case on Sql 2005 and Sql 2012