From dfc1e742f88310f5ea6d3af4e08622d29e1216d7 Mon Sep 17 00:00:00 2001
From: Jakub Kuczys <me@jacken.men>
Date: Thu, 6 Feb 2025 01:42:42 +0100
Subject: [PATCH] Handle invalid locale configuration graciously during startup
 (#6517)

---
 redbot/core/_i18n.py |  3 ++-
 redbot/core/bot.py   | 25 ++++++++++++++++++++++---
 2 files changed, 24 insertions(+), 4 deletions(-)

diff --git a/redbot/core/_i18n.py b/redbot/core/_i18n.py
index f2b5e7ec9..f1f445045 100644
--- a/redbot/core/_i18n.py
+++ b/redbot/core/_i18n.py
@@ -22,8 +22,9 @@ __all__ = (
 )
 
 
+FRESH_INSTALL_LOCALE = "en-US"
 current_locale = ContextVar("current_locale")
-current_locale_default = "en-US"
+current_locale_default = FRESH_INSTALL_LOCALE
 current_regional_format = ContextVar("current_regional_format")
 current_regional_format_default = None
 
diff --git a/redbot/core/bot.py b/redbot/core/bot.py
index a1d1048a2..f322595bd 100644
--- a/redbot/core/bot.py
+++ b/redbot/core/bot.py
@@ -115,7 +115,7 @@ class Red(
             owner=None,
             whitelist=[],
             blacklist=[],
-            locale="en-US",
+            locale=_i18n.FRESH_INSTALL_LOCALE,
             regional_format=None,
             embeds=True,
             color=15158332,
@@ -1145,9 +1145,28 @@ class Red(
             self.owner_ids.add(self._owner_id_overwrite)
 
         i18n_locale = await self._config.locale()
-        _i18n.set_global_locale(i18n_locale)
+        try:
+            _i18n.set_global_locale(i18n_locale)
+        except ValueError:
+            log.warning(
+                "The bot's global locale was set to an invalid value (%r)"
+                " and will be reset to default (%s).",
+                i18n_locale,
+                _i18n.FRESH_INSTALL_LOCALE,
+            )
+            i18n_locale = _i18n.FRESH_INSTALL_LOCALE
+            await self._config.locale.clear()
         i18n_regional_format = await self._config.regional_format()
-        _i18n.set_global_regional_format(i18n_regional_format)
+        try:
+            _i18n.set_global_regional_format(i18n_regional_format)
+        except ValueError:
+            log.warning(
+                "The bot's global regional format was set to an invalid value (%r)"
+                " and will be reset to default (which is to inherit global locale, i.e. %s).",
+                i18n_regional_format,
+                i18n_locale,
+            )
+            await self._config.regional_format.clear()
 
     async def _pre_connect(self) -> None:
         """