Fixes #11405 - Adds AuthenticationProperties to ExternalLoginInfo (#12074)

* Fixes #11405 - Adds AuthenticationProperties to ExternalLoginInfo in SignInManager.GetExternalLoginInfoAsync().

* Public API changed; ran dotnet msbuild /t:GenerateReferenceSource in src/Identity/Core/src per docs/ReferenceAssemblies.md.

* Add unit test to verify SignInManager.GetExternalLoginInfoAsync() can return CustomValue from ExternalLoginInfo.AuthenticationProperties.Items.

src/Identity/Core/ref/Microsoft.AspNetCore.Identity.netcoreapp3.0.cs

@@ -35,6 +35,7 @@ namespace Microsoft.AspNetCore.Identity
     public partial class ExternalLoginInfo : Microsoft.AspNetCore.Identity.UserLoginInfo
     {
         public ExternalLoginInfo(System.Security.Claims.ClaimsPrincipal principal, string loginProvider, string providerKey, string displayName) : base (default(string), default(string), default(string)) { }
+        public Microsoft.AspNetCore.Authentication.AuthenticationProperties AuthenticationProperties { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } [System.Runtime.CompilerServices.CompilerGeneratedAttribute]set { } }
         public System.Collections.Generic.IEnumerable<Microsoft.AspNetCore.Authentication.AuthenticationToken> AuthenticationTokens { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } [System.Runtime.CompilerServices.CompilerGeneratedAttribute]set { } }
         public System.Security.Claims.ClaimsPrincipal Principal { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } [System.Runtime.CompilerServices.CompilerGeneratedAttribute]set { } }
     }

src/Identity/Core/src/ExternalLoginInfo.cs

@@ -35,5 +35,10 @@ namespace Microsoft.AspNetCore.Identity
         /// The <see cref="AuthenticationToken"/>s associated with this login.
         /// </summary>
         public IEnumerable<AuthenticationToken> AuthenticationTokens { get; set; }
+
+        /// <summary>
+        /// The <see cref="Authentication.AuthenticationProperties"/> associated with this login.
+        /// </summary>
+        public AuthenticationProperties AuthenticationProperties { get; set; }
     }
 }

src/Identity/Core/src/SignInManager.cs

@@ -668,7 +668,8 @@ namespace Microsoft.AspNetCore.Identity
                                       ?? provider;
             return new ExternalLoginInfo(auth.Principal, provider, providerKey, providerDisplayName)
             {
-                AuthenticationTokens = auth.Properties.GetTokens()
+                AuthenticationTokens = auth.Properties.GetTokens(),
+                AuthenticationProperties = auth.Properties
             };
         }
 

src/Identity/test/Identity.Test/SignInManagerTest.cs

@@ -979,5 +979,40 @@ namespace Microsoft.AspNetCore.Identity.Test
             // Assert
             Assert.Equal("Blah blah", externalLoginInfo.ProviderDisplayName);
         }
+
+        [Fact]
+        public async Task ExternalLoginInfoAsyncReturnsAuthenticationPropertiesWithCustomValue()
+        {
+            // Arrange
+            var user = new PocoUser { Id = "foo", UserName = "Foo" };
+            var userManager = SetupUserManager(user);
+            var context = new DefaultHttpContext();
+            var identity = new ClaimsIdentity();
+            identity.AddClaim(new Claim(ClaimTypes.NameIdentifier, "bar"));
+            var principal = new ClaimsPrincipal(identity);
+            var properties = new AuthenticationProperties();
+            properties.Items["LoginProvider"] = "blah";
+            properties.Items["CustomValue"] = "fizzbuzz";
+            var authResult = AuthenticateResult.Success(new AuthenticationTicket(principal, properties, "blah"));
+            var auth = MockAuth(context);
+            auth.Setup(s => s.AuthenticateAsync(context, IdentityConstants.ExternalScheme)).ReturnsAsync(authResult);
+            var schemeProvider = new Mock<IAuthenticationSchemeProvider>();
+            var handler = new Mock<IAuthenticationHandler>();
+            schemeProvider.Setup(s => s.GetAllSchemesAsync())
+                .ReturnsAsync(new[]
+                    {
+                        new AuthenticationScheme("blah", "Blah blah", handler.Object.GetType())
+                    });
+            var signInManager = SetupSignInManager(userManager.Object, context, schemeProvider: schemeProvider.Object);
+            var externalLoginInfo = await signInManager.GetExternalLoginInfoAsync();
+
+            // Act
+            var externalProperties = externalLoginInfo.AuthenticationProperties;
+            var customValue = externalProperties?.Items["CustomValue"];
+
+            // Assert
+            Assert.NotNull(externalProperties);
+            Assert.Equal("fizzbuzz", customValue);
+        }
     }
 }