Pre-fetch app owners and fail early on no owners (#4926)

* Pre-fetch app owners and fail early on no owners

* Improve command mention in error message

* Further change the order of startup actions

redbot/__main__.py

@@ -28,7 +28,7 @@ from redbot import _early_init, __version__
 _early_init()
 
 import redbot.logging
-from redbot.core.bot import Red, ExitCodes
+from redbot.core.bot import Red, ExitCodes, _NoOwnerSet
 from redbot.core.cli import interactive_config, confirm, parse_cli_flags
 from redbot.setup import get_data_dir, get_name, save_config
 from redbot.core import data_manager, drivers
@@ -384,7 +384,7 @@ async def run_bot(red: Red, cli_flags: Namespace) -> None:
         await red.http.close()
         sys.exit(0)
     try:
-        await red.start(token, bot=True, cli_flags=cli_flags)
+        await red.start(token, bot=True)
     except discord.LoginFailure:
         log.critical("This token doesn't seem to be valid.")
         db_token = await red._config.token()
@@ -403,6 +403,24 @@ async def run_bot(red: Red, cli_flags: Namespace) -> None:
             style="red",
         )
         sys.exit(1)
+    except _NoOwnerSet:
+        print(
+            "Bot doesn't have any owner set!\n"
+            "This can happen when your bot's application is owned by team"
+            " as team members are NOT owners by default.\n\n"
+            "Remember:\n"
+            "ONLY the person who is hosting Red should be owner."
+            " This has SERIOUS security implications."
+            " The owner can access any data that is present on the host system.\n"
+            "With that out of the way, depending on who you want to be considered as owner,"
+            " you can:\n"
+            "a) pass --team-members-are-owners when launching Red"
+            " - in this case Red will treat all members of the bot application's team as owners\n"
+            f"b) set owner manually with `redbot --edit {cli_flags.instance_name}`\n"
+            "c) pass owner ID(s) when launching Red with --owner"
+            " (and --co-owner if you need more than one) flag\n"
+        )
+        sys.exit(1)
 
     return None