fix(auth): queue the reset email only after its code is stored

Api.SeaHavenIndustries.Tests/AuthenticationServiceTests.cs

@@ -151,7 +151,7 @@ public class AuthenticationServiceTests
     }
 
     [Fact]
-    public async Task ForgetPassword_EmailThatCannotBeQueued_DropsTheCodeAndDoesNotCountTheRequest()
+    public async Task ForgetPassword_EmailThatCannotBeQueued_DoesNotCountTheRequest()
     {
         var user = IdentityTestHelpers.User();
         var userData = new Mock<IUserDataService>();
@@ -175,19 +175,38 @@ public class AuthenticationServiceTests
         for (var request = 0; request < 4; request++)
             await service.ForgetPasswordAsync("alice@example.com", CancellationToken.None);
 
-        // The three undelivered requests did not use up the hourly limit of three.
+        // The three undelivered requests did not use up the hourly limit of three, and every
+        // email carries the code stored just before it was queued.
         email.Verify(e => e.TryEnqueue(user.Email!, It.IsAny<string>(), It.IsAny<string>()), Times.Exactly(4));
         stored.Should().HaveCount(4);
-        for (var request = 0; request < 3; request++)
+        for (var request = 0; request < 4; request++)
         {
             var code = System.Text.RegularExpressions.Regex.Match(bodies[request], @"Your Password Reset Code is: (\d{6})").Groups[1].Value;
-            PasswordResetCodeSecrets.Matches(ResetKey, stored[request].Salt, code, stored[request].Hash).Should().BeFalse();
+            PasswordResetCodeSecrets.Matches(ResetKey, stored[request].Salt, code, stored[request].Hash).Should().BeTrue();
         }
-        var delivered = System.Text.RegularExpressions.Regex.Match(bodies[3], @"Your Password Reset Code is: (\d{6})").Groups[1].Value;
-        PasswordResetCodeSecrets.Matches(ResetKey, stored[3].Salt, delivered, stored[3].Hash).Should().BeTrue();
         forget.Verify(f => f.RemoveByEmailAsync(It.IsAny<string>(), It.IsAny<CancellationToken>()), Times.Never);
     }
 
+    [Theory]
+    [InlineData(false)]
+    [InlineData(true)]
+    public async Task ForgetPassword_WriteThatFailsOrIsCancelled_QueuesNoEmail(bool cancelled)
+    {
+        var user = IdentityTestHelpers.User();
+        var userData = new Mock<IUserDataService>();
+        userData.Setup(u => u.GetByEmailNormalizedAsync(It.IsAny<string>(), It.IsAny<CancellationToken>())).ReturnsAsync(user);
+        var forget = new Mock<IForgetPasswordDataService>();
+        forget.Setup(f => f.ReplaceCodeAsync(It.IsAny<string>(), It.IsAny<string>(), It.IsAny<string>(), It.IsAny<string>(), It.IsAny<DateTime>(), It.IsAny<DateTime>(), It.IsAny<CancellationToken>()))
+            .Returns(Task.FromException(cancelled ? new OperationCanceledException() : new InvalidOperationException("database unavailable")));
+        var email = new Mock<IPasswordResetEmailQueue>();
+        email.Setup(e => e.TryEnqueue(It.IsAny<string>(), It.IsAny<string>(), It.IsAny<string>())).Returns(true);
+
+        var act = () => NewService(userData, forget, email, out _, out _).ForgetPasswordAsync("alice@example.com", CancellationToken.None);
+
+        await act.Should().ThrowAsync<Exception>();
+        email.Verify(e => e.TryEnqueue(It.IsAny<string>(), It.IsAny<string>(), It.IsAny<string>()), Times.Never);
+    }
+
     [Fact]
     public async Task ForgetPassword_EmailThatCannotBeQueued_MakesTheSameDataCallsAsAnUnknownEmail()
     {

SeaHaven.Services/Implementation/AuthenticationService.cs

@@ -170,12 +170,22 @@ namespace SeaHaven.Services.Implementation
             var hash = PasswordResetCodeSecrets.Hash(ResetCodeKey, salt, code);
             var active = user != null && user.IsDeleted != true && !string.IsNullOrWhiteSpace(user.Email);
 
-            // The request stays counted only once its row is stored. A code that cannot be
+            // The email is queued only after its code is stored, so a failed or cancelled
-            // emailed is stored unmatchable and not counted, and a failed or cancelled
+            // write never sends a code that cannot be used. The request stays counted only
-            // write is not counted either.
+            // when the row is stored and, for an account, its email was queued; when the
+            // queue is full the stored code is left unsent and the user can ask again.
             var counted = false;
             try
             {
+                await _forgetPasswordDataService.ReplaceCodeAsync(
+                    active ? user!.Email! : requested,
+                    active ? user!.Id : string.Empty,
+                    active ? hash : PasswordResetCodeSecrets.NewUnmatchableHash(),
+                    salt,
+                    nowUtc.Add(ResetCodeLifetime),
+                    nowUtc,
+                    cancellationToken);
+
                 var queued = false;
                 if (active)
                 {
@@ -183,14 +193,6 @@ namespace SeaHaven.Services.Implementation
                     queued = _resetEmails.TryEnqueue(user!.Email!, "Forget Password Request.", body);
                 }
 
-                await _forgetPasswordDataService.ReplaceCodeAsync(
-                    active ? user!.Email! : requested,
-                    active ? user!.Id : string.Empty,
-                    queued ? hash : PasswordResetCodeSecrets.NewUnmatchableHash(),
-                    salt,
-                    nowUtc.Add(ResetCodeLifetime),
-                    nowUtc,
-                    cancellationToken);
                 counted = queued || !active;
             }
             finally