fix: don't try to re-send stickers and activity invites

PluralKit.Bot/Proxy/ProxyService.cs

@@ -115,6 +115,12 @@ public class ProxyService
         if (isMessageBlank && msg.Attachments.Length == 0)
             throw new ProxyChecksFailedException("Message cannot be blank.");
 
+        if (msg.Activity != null)
+            throw new ProxyChecksFailedException("Message contains an invite to an activity, which cannot be re-sent by PluralKit.");
+
+        if (msg.StickerItems != null) // && msg.StickerItems.Any(s => s.Type == Sticker.StickerType.GUILD && s.GuildId != msg.GuildId))
+            throw new ProxyChecksFailedException("Message contains stickers, which cannot be re-sent by PluralKit.");
+
         // All good!
         return true;
     }
@@ -158,6 +164,7 @@ public class ProxyService
             Attachments = trigger.Attachments,
             FileSizeLimit = guild.FileSizeLimit(),
             Embeds = embeds.ToArray(),
+            Stickers = trigger.StickerItems,
             AllowEveryone = allowEveryone
         });
         await HandleProxyExecutedActions(ctx, trigger, proxyMessage, match);

PluralKit.Bot/Services/WebhookExecutorService.cs

@@ -37,6 +37,7 @@ public record ProxyRequest
     public Message.Attachment[] Attachments { get; init; }
     public int FileSizeLimit { get; init; }
     public Embed[] Embeds { get; init; }
+    public Sticker[] Stickers { get; init; }
     public bool AllowEveryone { get; init; }
 }
 
@@ -115,7 +116,8 @@ public class WebhookExecutorService
             Content = content,
             AllowedMentions = allowedMentions,
             AvatarUrl = !string.IsNullOrWhiteSpace(req.AvatarUrl) ? req.AvatarUrl : null,
-            Embeds = req.Embeds
+            Embeds = req.Embeds,
+            Stickers = req.Stickers,
         };
 
         MultipartFile[] files = null;