From 138e18cb7a2511701c8c2b5a47bba729eebc5b0f Mon Sep 17 00:00:00 2001
From: Mihail Gribkov <61027276+Misha-133@users.noreply.github.com>
Date: Thu, 11 Jan 2024 22:29:07 +0300
Subject: [PATCH] [Fix] `GetEventCoverImageUrl` throwing NRE in case event
 cover image is null (#2818)

* return null instead of throwing NRE

* fix xmldoc
---
 src/Discord.Net.Core/CDN.cs                                 | 6 ++++--
 src/Discord.Net.Rest/Entities/Guilds/RestGuildEvent.cs      | 2 +-
 .../Entities/Guilds/SocketGuildEvent.cs                     | 2 +-
 3 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/src/Discord.Net.Core/CDN.cs b/src/Discord.Net.Core/CDN.cs
index ecce668f..a41eda35 100644
--- a/src/Discord.Net.Core/CDN.cs
+++ b/src/Discord.Net.Core/CDN.cs
@@ -223,7 +223,7 @@ namespace Discord
             => $"{DiscordConfig.CDNUrl}stickers/{stickerId}.{FormatToExtension(format)}";
 
         /// <summary>
-        ///     Returns an events cover image url.
+        ///     Returns an events cover image url. <see langword="null"/> if the assetId <see langword="null"/>.
         /// </summary>
         /// <param name="guildId">The guild id that the event is in.</param>
         /// <param name="eventId">The id of the event.</param>
@@ -232,7 +232,9 @@ namespace Discord
         /// <param name="size">The size of the image.</param>
         /// <returns></returns>
         public static string GetEventCoverImageUrl(ulong guildId, ulong eventId, string assetId, ImageFormat format = ImageFormat.Auto, ushort size = 1024)
-            => $"{DiscordConfig.CDNUrl}guild-events/{eventId}/{assetId}.{FormatToExtension(format, assetId)}?size={size}";
+            => string.IsNullOrEmpty(assetId)
+                ? null
+                : $"{DiscordConfig.CDNUrl}guild-events/{eventId}/{assetId}.{FormatToExtension(format, assetId)}?size={size}";
 
         private static string FormatToExtension(StickerFormatType format)
         {
diff --git a/src/Discord.Net.Rest/Entities/Guilds/RestGuildEvent.cs b/src/Discord.Net.Rest/Entities/Guilds/RestGuildEvent.cs
index ee1b14d7..59791984 100644
--- a/src/Discord.Net.Rest/Entities/Guilds/RestGuildEvent.cs
+++ b/src/Discord.Net.Rest/Entities/Guilds/RestGuildEvent.cs
@@ -110,7 +110,7 @@ namespace Discord.Rest
 
         /// <inheritdoc/>
         public string GetCoverImageUrl(ImageFormat format = ImageFormat.Auto, ushort size = 1024)
-            => CDN.GetEventCoverImageUrl(Guild.Id, Id, CoverImageId, format, size);
+            => CDN.GetEventCoverImageUrl(GuildId, Id, CoverImageId, format, size);
 
         /// <inheritdoc/>
         public Task StartAsync(RequestOptions options = null)
diff --git a/src/Discord.Net.WebSocket/Entities/Guilds/SocketGuildEvent.cs b/src/Discord.Net.WebSocket/Entities/Guilds/SocketGuildEvent.cs
index cb0ef05d..07ec839c 100644
--- a/src/Discord.Net.WebSocket/Entities/Guilds/SocketGuildEvent.cs
+++ b/src/Discord.Net.WebSocket/Entities/Guilds/SocketGuildEvent.cs
@@ -121,7 +121,7 @@ namespace Discord.WebSocket
 
         /// <inheritdoc/>
         public string GetCoverImageUrl(ImageFormat format = ImageFormat.Auto, ushort size = 1024)
-            => CDN.GetEventCoverImageUrl(Guild.Id, Id, CoverImageId, format, size);
+            => CDN.GetEventCoverImageUrl(GuildId, Id, CoverImageId, format, size);
 
         /// <inheritdoc/>
         public Task DeleteAsync(RequestOptions options = null)