Fix Null Warnings (#874)

* Fixing null warnings

* Fix null warnings
Fix other compiler warnings

src/Infrastructure/Identity/AppIdentityDbContextSeed.cs

@@ -24,6 +24,9 @@ public class AppIdentityDbContextSeed
         var adminUser = new ApplicationUser { UserName = adminUserName, Email = adminUserName };
         await userManager.CreateAsync(adminUser, AuthorizationConstants.DEFAULT_PASSWORD);
         adminUser = await userManager.FindByNameAsync(adminUserName);
-        await userManager.AddToRoleAsync(adminUser, BlazorShared.Authorization.Constants.Roles.ADMINISTRATORS);
+        if (adminUser != null)
+        {
+            await userManager.AddToRoleAsync(adminUser, BlazorShared.Authorization.Constants.Roles.ADMINISTRATORS);
+        }
     }
 }

src/Infrastructure/Identity/IdentityTokenClaimService.cs

@@ -25,6 +25,7 @@ public class IdentityTokenClaimService : ITokenClaimsService
         var tokenHandler = new JwtSecurityTokenHandler();
         var key = Encoding.ASCII.GetBytes(AuthorizationConstants.JWT_SECRET_KEY);
         var user = await _userManager.FindByNameAsync(userName);
+        if (user == null) throw new UserNotFoundException(userName);
         var roles = await _userManager.GetRolesAsync(user);
         var claims = new List<Claim> { new Claim(ClaimTypes.Name, userName) };
 

src/Infrastructure/Identity/UserNotFoundException.cs

@@ -0,0 +1,10 @@
+using System;
+
+namespace Microsoft.eShopWeb.Infrastructure.Identity;
+
+public class UserNotFoundException : Exception
+{
+    public UserNotFoundException(string userName) : base($"No user found with username: {userName}")
+    {
+    }
+}