feat: allow partial DMChannel without client user (#11462)

* feat(DMChannel): allow partial DMChannel without client user

* chore: apply code review comments

* chore: apply code review suggestion

packages/discord.js/src/client/actions/Action.js

@@ -33,10 +33,16 @@ class GenericAction {
     const payloadData = {};
     const id = data.channel_id ?? data.id;
 
-    if (!('recipients' in data)) {
-      // Try to resolve the recipient, but do not add the client user.
+    if ('recipients' in data) {
+      // Try to resolve the recipient, but do not add if already existing in recipients.
       const recipient = data.author ?? data.user ?? { id: data.user_id };
-      if (recipient.id !== this.client.user.id) payloadData.recipients = [recipient];
+      if (!data.recipients.some(existingRecipient => recipient.id === existingRecipient.id)) {
+        payloadData.recipients = [...data.recipients, recipient];
+      }
+    } else {
+      // Try to resolve the recipient.
+      const recipient = data.author ?? data.user ?? { id: data.user_id };
+      payloadData.recipients = [recipient];
     }
 
     if (id !== undefined) payloadData.id = id;

packages/discord.js/src/client/actions/InteractionCreate.js

@@ -21,7 +21,9 @@ class InteractionCreateAction extends Action {
     const client = this.client;
 
     // Resolve and cache partial channels for Interaction#channel getter
-    const channel = data.channel && this.getChannel(data.channel);
+    const channel =
+      data.channel &&
+      this.getChannel({ ...data.channel, ...('recipients' in data.channel ? { user: data.user } : undefined) });
 
     // Do not emit this for interactions that cache messages that are non-text-based.
     let InteractionClass;

packages/discord.js/src/managers/UserManager.js

@@ -41,9 +41,12 @@ class UserManager extends CachedManager {
    * @private
    */
   dmChannel(userId) {
+    const expectedRecipientIds = [userId, this.client.user.id];
     return (
-      this.client.channels.cache.find(channel => channel.type === ChannelType.DM && channel.recipientId === userId) ??
-      null
+      this.client.channels.cache.find(
+        channel =>
+          channel.type === ChannelType.DM && channel.recipientIds.every(id => expectedRecipientIds.includes(id)),
+      ) ?? null
     );
   }
 

packages/discord.js/src/structures/DMChannel.js

@@ -30,16 +30,18 @@ class DMChannel extends BaseChannel {
     super._patch(data);
 
     if (data.recipients) {
-      const recipient = data.recipients[0];
-
       /**
-       * The recipient's id
-       * @type {Snowflake}
+       * The recipients' ids
+       * @type {Snowflake[]}
        */
-      this.recipientId = recipient.id;
+      this.recipientIds = [
+        ...new Set([...(this.recipientIds ?? []), ...data.recipients.map(recipient => recipient.id)]),
+      ];
 
-      if ('username' in recipient || this.client.options.partials.includes(Partials.User)) {
-        this.client.users._add(recipient);
+      for (const recipient of data.recipients) {
+        if ('username' in recipient || this.client.options.partials.includes(Partials.User)) {
+          this.client.users._add(recipient);
+        }
       }
     }
 
@@ -71,6 +73,18 @@ class DMChannel extends BaseChannel {
     return this.lastMessageId === undefined;
   }
 
+  /**
+   * The recipient's id.
+   * <info>For DMChannel the client user is not a part of this might return a wrong id.
+   * This will return `null` in the next major version.</info>
+   * @type {Snowflake}
+   * @readonly
+   */
+  get recipientId() {
+    // To not be a breaking change this returns the arbitrary first id if this is not a DMChannel with the client user
+    return this.recipientIds.find(recipientId => recipientId !== this.client.user.id) ?? this.recipientIds[0];
+  }
+
   /**
    * The recipient on the other end of the DM
    * @type {?User}

packages/discord.js/typings/index.d.ts

@@ -1514,7 +1514,8 @@ export interface DMChannel extends Omit<
 export class DMChannel extends BaseChannel {
   private constructor(client: Client<true>, data?: RawDMChannelData);
   public flags: Readonly<ChannelFlagsBitField>;
-  public recipientId: Snowflake;
+  public get recipientId(): Snowflake;
+  public recipientIds: Snowflake[];
   public get recipient(): User | null;
   public type: ChannelType.DM;
   public fetch(force?: boolean): Promise<this>;