fix: complete already removed temporary bans

Jobs/TemporaryBansJob.cs

@@ -1,4 +1,6 @@
+using System.Net;
 using Discord;
+using Discord.Net;
 using Discord.WebSocket;
 using Microsoft.EntityFrameworkCore;
 using Morpheus.Database;
@@ -36,9 +38,12 @@ public async Task Execute(IJobExecutionContext context)
                     continue;
                 }
 
-                await guild.RemoveBanAsync(ban.UserId);
-                ban.UnbannedAt = DateTime.UtcNow;
-                Log($"Unbanned user {ban.UserId} from guild {ban.GuildId} (temp ban {ban.Id}).");
+                bool wasAlreadyUnbanned = await CompleteUnbanAsync(
+                    ban,
+                    () => guild.RemoveBanAsync(ban.UserId));
+                Log(wasAlreadyUnbanned
+                    ? $"User {ban.UserId} was already unbanned from guild {ban.GuildId} (temp ban {ban.Id})."
+                    : $"Unbanned user {ban.UserId} from guild {ban.GuildId} (temp ban {ban.Id}).");
             }
             catch (Exception ex)
             {
@@ -49,6 +54,28 @@ public async Task Execute(IJobExecutionContext context)
 
         await db.SaveChangesAsync();
     }
+
+    internal static async Task<bool> CompleteUnbanAsync(
+        TemporaryBan ban,
+        Func<Task> removeBanAsync)
+    {
+        bool wasAlreadyUnbanned = false;
+        try
+        {
+            await removeBanAsync();
+        }
+        catch (HttpException ex) when (
+            ex.HttpCode == HttpStatusCode.NotFound &&
+            ex.DiscordCode == DiscordErrorCode.UnknownBan)
+        {
+            // A moderator may have removed the ban before this job ran. Discord's
+            // Unknown Ban response means the desired state is already reached.
+            wasAlreadyUnbanned = true;
+        }
+
+        ban.UnbannedAt = DateTime.UtcNow;
+        return wasAlreadyUnbanned;
+    }
 }
 
 

Morpheus.Tests/TemporaryBansJobTests.cs

@@ -1,3 +1,6 @@
+using System.Net;
+using Discord;
+using Discord.Net;
 using Discord.WebSocket;
 using Microsoft.Data.Sqlite;
 using Microsoft.EntityFrameworkCore;
@@ -10,6 +13,45 @@ namespace Morpheus.Tests;
 
 public class TemporaryBansJobTests
 {
+    [Fact]
+    public async Task CompleteUnbanAsync_WhenBanIsAlreadyMissing_MarksBanCompleted()
+    {
+        TemporaryBan ban = new();
+        HttpException notFound = new(
+            HttpStatusCode.NotFound,
+            null!,
+            DiscordErrorCode.UnknownBan,
+            "Unknown Ban",
+            []);
+
+        bool wasAlreadyUnbanned = await TemporaryBansJob.CompleteUnbanAsync(
+            ban,
+            () => Task.FromException(notFound));
+
+        Assert.True(wasAlreadyUnbanned);
+        Assert.NotNull(ban.UnbannedAt);
+    }
+
+    [Fact]
+    public async Task CompleteUnbanAsync_WhenDifferentDiscordResourceIsMissing_LeavesBanPending()
+    {
+        TemporaryBan ban = new();
+        HttpException unknownGuild = new(
+            HttpStatusCode.NotFound,
+            null!,
+            DiscordErrorCode.UnknownGuild,
+            "Unknown Guild",
+            []);
+
+        HttpException thrown = await Assert.ThrowsAsync<HttpException>(() =>
+            TemporaryBansJob.CompleteUnbanAsync(
+                ban,
+                () => Task.FromException(unknownGuild)));
+
+        Assert.Same(unknownGuild, thrown);
+        Assert.Null(ban.UnbannedAt);
+    }
+
     [Fact]
     public async Task Execute_WhenGuildIsUnavailable_LeavesBanPendingForRetry()
     {