From 1f14ef7747c2eade2eae3ef2f0486036037b08bf Mon Sep 17 00:00:00 2001
From: cuom1999 <lephuocdinh99@gmail.com>
Date: Wed, 5 Jan 2022 16:18:59 +0700
Subject: [PATCH] Fix infinite loop when handling utf-8

---
 judge/utils/problem_data.py | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/judge/utils/problem_data.py b/judge/utils/problem_data.py
index e22aa4f..b0a187b 100644
--- a/judge/utils/problem_data.py
+++ b/judge/utils/problem_data.py
@@ -286,7 +286,11 @@ def get_problem_case(problem, files):
                     s.decode('utf-8')
                     break
                 except UnicodeDecodeError:
-                    s += f.read(1)
+                    next_char = f.read(1)
+                    if next_char:
+                        s += next_char
+                    else:
+                        raise Exception('File %s is not able to decode in utf-8' % file)
             qs = get_visible_content(s)
         cache.set(cache_key, qs, 86400)
         result[file] = qs