Suggestions for building legacy product patches after upgrading to TFS 2012

Question

We're looking at upgrading our TFS 2010 server to TFS 2012. As I understand it, this requires upgrading the build servers to TFS 2012 too. Unfortunately it seems that installing the TFS 2012 build server causes .NET 4.5 to be installed. .NET 4.5 is an in-place upgrade of .NET 4.0 and hence all .NET 4.0 components, including the C# compiler, are replaced when it is installed. I do not wish to do this on the build server that is responsible for building patches of our established legacy products - we don't have the resources to fully test that building with the .NET 4.5 compiler/framework will not cause an issues when up until now they have always been built with .NET 4.0 components, and I've seen a number of posts online suggesting that moving from .NET 4.0 to 4.5 can cause compilations to break. At this stage I only see two options: a) Maintain a separate TFS 2010 system just for building the legacy product. b) Don't use a build server to build the patches (execute msbuild manually against the build definition from a machine with just .NET 4.0/VS 2010 - assuming that's possible?)

Any suggestions welcome!

(Edit: did a little reading and I don't see any straightforward way of executing build from a build definition/build process file from a command-line: yes there's tfsbuild but that just tells TFS build server to build it. It might be somehow possible using Windows Workflow foundation command line tools but it's hard to see how. More likely I'd have to rewrite the build script as some sort of batch file that calls msbuild to build the solution then calls other tools as needed to build/sign the installer and copy to the required location.)

Answer 1

As of TFS 2012 update 2 you can continue to use TFS 2010 build agents . So you can continue to build your .net 4.0 code without worrying about compatibility with 4.5