From b6ddd4ce413663aef6f4ea637f2551f5e19bdf6e Mon Sep 17 00:00:00 2001
From: Sugden <28943913+NotSugden@users.noreply.github.com>
Date: Wed, 12 Aug 2020 20:25:38 +0100
Subject: [PATCH] fix(APIMessage): add reply user to allowedMentions (#4591)

---
 src/structures/APIMessage.js | 17 ++++++++++++++++-
 1 file changed, 16 insertions(+), 1 deletion(-)

diff --git a/src/structures/APIMessage.js b/src/structures/APIMessage.js
index a3c44a4e7..673db0390 100644
--- a/src/structures/APIMessage.js
+++ b/src/structures/APIMessage.js
@@ -178,10 +178,25 @@ class APIMessage {
       flags = this.options.flags != null ? new MessageFlags(this.options.flags).bitfield : this.target.flags.bitfield;
     }
 
-    const allowedMentions =
+    let allowedMentions =
       typeof this.options.allowedMentions === 'undefined'
         ? this.target.client.options.allowedMentions
         : this.options.allowedMentions;
+    if (this.options.reply) {
+      const id = this.target.client.users.resolveID(this.options.reply);
+      if (allowedMentions) {
+        // Clone the object as to alter the ClientOptions object
+        allowedMentions = Util.cloneObject(allowedMentions);
+        const parsed = allowedMentions.parse && allowedMentions.parse.includes('users');
+        // Check if the mention won't be parsed, and isn't supplied in `users`
+        if (!parsed && !(allowedMentions.users && allowedMentions.users.includes(id))) {
+          if (!allowedMentions.users) allowedMentions.users = [];
+          allowedMentions.users.push(id);
+        }
+      } else {
+        allowedMentions = { users: [id] };
+      }
+    }
 
     this.data = {
       content,