close_on_leave config, resolves #2757

bot.py

@@ -1059,10 +1059,13 @@ async def on_member_remove(self, member):
             return
         thread = await self.threads.find(recipient=member)
         if thread:
-            embed = discord.Embed(
-                description="The recipient has left the server.", color=self.error_color
-            )
-            await thread.channel.send(embed=embed)
+            if self.config["close_on_leave"]:
+                await thread.close(closer=member.guild.me, message="The recipient has left the server.", silent=True)
+            else:
+                embed = discord.Embed(
+                    description="The recipient has left the server.", color=self.error_color
+                )
+                await thread.channel.send(embed=embed)
 
     async def on_member_join(self, member):
         if member.guild != self.guild:

core/config.py

@@ -69,6 +69,7 @@ class ConfigManager:
         "disabled_current_thread_response": "We are not accepting any messages.",
         "disabled_current_thread_footer": "Please try again later...",
         "transfer_reactions": True,
+        "close_on_leave": False,
         # moderation
         "recipient_color": str(discord.Color.gold()),
         "mod_color": str(discord.Color.green()),
@@ -142,6 +143,7 @@ class ConfigManager:
         "thread_move_notify",
         "thread_move_notify_mods",
         "transfer_reactions",
+        "close_on_leave",
         "enable_plugins",
         "enable_eval",
     }

core/config_help.json

@@ -572,6 +572,14 @@
     ],
     "notes": []
   },
+  "close_on_leave": {
+    "default": "No",
+    "description": "Closes a modmail thread upon user leave automatically",
+    "examples":[
+      "`{prefix}config set close_on_leave yes"
+    ],
+    "notes": []
+  },
   "modmail_guild_id": {
     "default": "Fallback on `GUILD_ID`",
     "description": "The ID of the discord server where the threads channels should be created (receiving server).",