Refactor to introduce nullable types and reduce compiler warnings (#801)

* Introduce nullable types to Core, Infrastructure and PublicApi projects

* Refactor unit tests

* Fixed failing tests

* Introduce Parameter object for CatalogItem update method

* Refactor CataloItemDetails param object

* Refactor following PR comments

src/Web/Controllers/ManageController.cs

@@ -1,5 +1,6 @@
 using System.Text;
 using System.Text.Encodings.Web;
+using Ardalis.GuardClauses;
 using Microsoft.AspNetCore.Authentication;
 using Microsoft.AspNetCore.Authorization;
 using Microsoft.AspNetCore.Identity;
@@ -119,6 +120,7 @@ public class ManageController : Controller
 
         var code = await _userManager.GenerateEmailConfirmationTokenAsync(user);
         var callbackUrl = Url.EmailConfirmationLink(user.Id, code, Request.Scheme);
+        Guard.Against.Null(callbackUrl, nameof(callbackUrl));
         var email = user.Email;
         await _emailSender.SendEmailConfirmationAsync(email, callbackUrl);
 
@@ -405,7 +407,7 @@ public class ManageController : Controller
         }
 
         // Strip spaces and hypens
-        var verificationCode = model.Code.Replace(" ", string.Empty).Replace("-", string.Empty);
+        var verificationCode = model.Code?.Replace(" ", string.Empty).Replace("-", string.Empty);
 
         var is2faTokenValid = await _userManager.VerifyTwoFactorTokenAsync(
             user, _userManager.Options.Tokens.AuthenticatorTokenProvider, verificationCode);

src/Web/Controllers/OrderController.cs

@@ -1,4 +1,5 @@
-using MediatR;
+using Ardalis.GuardClauses;
+using MediatR;
 using Microsoft.AspNetCore.Authorization;
 using Microsoft.AspNetCore.Mvc;
 using Microsoft.eShopWeb.Web.Features.MyOrders;
@@ -20,7 +21,8 @@ public class OrderController : Controller
 
     [HttpGet]
     public async Task<IActionResult> MyOrders()
-    {
+    {   
+        Guard.Against.Null(User?.Identity?.Name, nameof(User.Identity.Name));
         var viewModel = await _mediator.Send(new GetMyOrders(User.Identity.Name));
 
         return View(viewModel);
@@ -29,6 +31,7 @@ public class OrderController : Controller
     [HttpGet("{orderId}")]
     public async Task<IActionResult> Detail(int orderId)
     {
+        Guard.Against.Null(User?.Identity?.Name, nameof(User.Identity.Name));
         var viewModel = await _mediator.Send(new GetOrderDetails(User.Identity.Name, orderId));
 
         if (viewModel == null)

src/Web/Controllers/UserController.cs

@@ -28,7 +28,7 @@ public class UserController : ControllerBase
 
     private async Task<UserInfo> CreateUserInfo(ClaimsPrincipal claimsPrincipal)
     {
-        if (!claimsPrincipal.Identity.IsAuthenticated)
+        if (claimsPrincipal.Identity == null || claimsPrincipal.Identity.Name == null || !claimsPrincipal.Identity.IsAuthenticated)
         {
             return UserInfo.Anonymous;
         }