Use assemblies aliases when perform migration from SharePointPnPCoreOnline to PnP.Framework

Some time ago PnP team announced that SharePointPnPCoreOnline nuget package became retired and we should use PnP.Framework now. Latest available version of SharePointPnPCoreOnline is 3.28.2012 and it won't be developed further. Based on that recommendation we performed migration from SharePointPnPCoreOnline to PnP.Framework. During migration there were several interesting issues and I'm going to write series of posts about these issues.

One of the issue was that one class SharePointPnP.IdentityModel.Extensions.S2S.Protocols.OAuth2.OAuth2AccessTokenResponse was defined in 2 different assemblies in the same namespace:

• SharePointPnP.IdentityModel.Extensions.dll
• PnP.Framework
  

Compiler couldn't resolve this ambiguity and showed an error:

Since class name is the same and namespace is the same - in order to resolve this issue we need to use  quite rarely used technique called extern aliases. At first in VS on referenced assembly's properties window we need to specify assembly alias. By default all referenced assemblies have "global" alias - so we need to change it on custom one:

Then in cs file which has ambiguous class name on the top of the file we need to define our alias and then add "using" with this alias:

SharePointPnPIdentityModelExtensions;
...
using SharePointPnPIdentityModelExtensions::SharePointPnP.IdentityModel.Extensions.S2S.Tokens;

After these steps compilation error has gone and solution has been successfully built.