prevent building bot at design time & fix event handler injection error

Author: conaticus

Boolean/EventHandlers.cs

@@ -5,11 +5,11 @@
 using Discord.Interactions;
 using Discord.WebSocket;
 using Microsoft.EntityFrameworkCore;
+using Microsoft.Extensions.DependencyInjection;
 
 namespace Boolean;
 
 public class EventHandlers(
-    DataContext db,
     IServiceProvider serviceProvider,
     Config config,
     DiscordSocketClient client,
@@ -84,6 +84,9 @@ public async Task UserJoined(IGuildUser user)
        if (user.IsBot)
            return;
 
+       // We can't pass in data context to the class because EventHandlers is a singleton and data context is scoped
+       var db = serviceProvider.GetRequiredService<DataContext>();
+       
        var guild = await db.Guilds.FirstOrDefaultAsync(g => g.Snowflake == user.Guild.Id);
        if (guild?.JoinRoleSnowflake != null) 
            await user.AddRoleAsync(guild.JoinRoleSnowflake ?? 0);

Boolean/Modules/UserInfo.cs

@@ -1,7 +1,6 @@
 using Boolean.Util;
 using Discord;
 using Discord.Interactions;
-using Discord.WebSocket;
 using Microsoft.EntityFrameworkCore;
 
 namespace Boolean;

Boolean/Program.cs

@@ -16,36 +16,44 @@ class Program
 
     public static async Task Main()
     {
-        // Dependency injection & application setup
-        _client = new DiscordSocketClient(new DiscordSocketConfig()
+        HostApplicationBuilder builder = Host.CreateApplicationBuilder();
+        Config config = builder.Configuration.Get<Config>()
+                         ?? throw new Exception("Failed to load valid config from appsettings.json, please refer to the README.md for instructions.");
+        
+        builder.Services
+            .AddDbContext<DataContext>(options => options.UseNpgsql(config.GetConnectionString()));
+        
+        // Only start the bot outside of design time (avoids app running during dotnet ef commands)
+        if (EF.IsDesignTime) {
+            _serviceProvider = builder.Services.BuildServiceProvider();
+            goto buildApp;
+        }
+        
+        _client = new DiscordSocketClient(new DiscordSocketConfig
         {
             GatewayIntents = GatewayIntents.All,
             UseInteractionSnowflakeDate = false // Prevents a funny from happening when your OS clock is out of sync
         });
 
         var interactionService = new InteractionService(_client.Rest);
 
-        HostApplicationBuilder builder = Host.CreateApplicationBuilder();
-        Config config = builder.Configuration.Get<Config>()
-                         ?? throw new Exception("Failed to load valid config from appsettings.json, please refer to the README.md for instructions.");
-        
-        _serviceProvider = builder.Services
-            .AddDbContext<DataContext>(options => options.UseNpgsql(config.GetConnectionString()))
+        builder.Services
             .AddSingleton(interactionService)
             .AddSingleton(_client)
             .AddSingleton(config)
-            .AddSingleton<EventHandlers>()
-            .BuildServiceProvider();
+            .AddSingleton<EventHandlers>();
+        
+        _serviceProvider = builder.Services.BuildServiceProvider();
 
-        // Start the bot
         await _client.LoginAsync(TokenType.Bot, config.DiscordToken);
         await _client.StartAsync();
 
         await interactionService.AddModulesAsync(Assembly.GetEntryAssembly(), _serviceProvider);
         AttachEventHandlers();
 
-        IHost app = builder.Build();
-        await app.RunAsync();
+        buildApp:
+            IHost app = builder.Build();
+            await app.RunAsync();
     }
 
     private static void AttachEventHandlers()