Remove unnecessary decoding from getframeinfo()

linecache uses tokenize.open() to detect and use the encoding of the
file since Python 3.4.

Author: living180

debug_toolbar/utils.py

@@ -1,6 +1,5 @@
 import inspect
 import os.path
-import re
 import sys
 from importlib import import_module
 from pprint import pformat
@@ -200,27 +199,14 @@ def getframeinfo(frame, context=1):
         try:
             lines, lnum = inspect.findsource(frame)
         except Exception:  # findsource raises platform-dependant exceptions
-            first_lines = lines = index = None
+            lines = index = None
         else:
             start = max(start, 1)
             start = max(0, min(start, len(lines) - context))
-            first_lines = lines[:2]
             lines = lines[start : (start + context)]
             index = lineno - 1 - start
     else:
-        first_lines = lines = index = None
-
-    # Code taken from Django's ExceptionReporter._get_lines_from_file
-    if first_lines and isinstance(first_lines[0], bytes):
-        encoding = "ascii"
-        for line in first_lines[:2]:
-            # File coding may be specified. Match pattern from PEP-263
-            # (https://www.python.org/dev/peps/pep-0263/)
-            match = re.search(rb"coding[:=]\s*([-\w.]+)", line)
-            if match:
-                encoding = match.group(1).decode("ascii")
-                break
-        lines = [line.decode(encoding, "replace") for line in lines]
+        lines = index = None
 
     return inspect.Traceback(filename, lineno, frame.f_code.co_name, lines, index)