From a58f25bc3b34400f494f6ad722585fd400719fb6 Mon Sep 17 00:00:00 2001
From: kikuyan <kikuyan@users.noreply.github.com>
Date: Sat, 17 Jul 2021 18:10:46 +0900
Subject: [PATCH] [utils] improve to verify date format

---
 youtube_dl/utils.py | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/youtube_dl/utils.py b/youtube_dl/utils.py
index e722eed58..f75a44e61 100644
--- a/youtube_dl/utils.py
+++ b/youtube_dl/utils.py
@@ -3081,7 +3081,15 @@ def date_from_str(date_str):
         unit += 's'
         delta = datetime.timedelta(**{unit: time})
         return today + delta
-    return datetime.datetime.strptime(date_str, '%Y%m%d').date()
+
+    if re.match(r'^\d{8}$', date_str):
+        try:
+            return datetime.datetime.strptime(date_str, '%Y%m%d').date()
+        except ValueError as err:
+            errmsg = 'Invalid date: %s (%s)' % (date_str, err)
+    else:
+        errmsg = 'Invalid date format: %s (must be 8 digit number)' % date_str
+    raise ValueError(errmsg)
 
 
 def hyphenate_date(date_str):